Abstract:
A refrigeration system for a refrigerator having a freezer compartment, a fresh food compartment, an icemaker in the fresh food compartment includes distinct freezer, fresh food and icemaker evaporators and associated valving operating in conjunction with a common compressor and condenser in order to effectively regulate temperatures in specified zones of the refrigerator throughout various operational modes including at least a freezer cooling mode, a fresh food cooling mode and an ice harvesting mode. The icemaker can be serially linked with the fresh food evaporator during cooling of the fresh food compartment, while being also being selectively isolated for the ice harvesting mode.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention pertains to the art of refrigerators and, more particularly, to the operational control of a refrigerator employing multiple evaporators. 
         [0003]    2. Description of the Related Art 
         [0004]    In general, a refrigerator includes a freezer compartment for maintaining foods at or below freezing temperatures, and a fresh food compartment for maintaining foods in a temperature zone between ambient and freezing temperatures. A typical refrigerator includes a refrigeration system having a compressor, a condenser, a condenser fan, an evaporator and an evaporator fan. In operation, temperature sensors are used to measure temperatures within the fresh food and freezer compartments. When the temperature of one of the compartments deviates from a predetermined temperature, the refrigeration system is activated to return the temperature to at or below the predetermined temperature. As part of the overall refrigeration system, a damper is typically provided between the freezer and fresh food compartments, wherein operation of the damper controls the flow of cooling air from the freezer compartment to the fresh food compartment. Therefore, a common refrigeration system with a single evaporator is typically employed, along with various air flow fans, to create a flow of cold air used to cool each of the fresh food and freezer compartments, and even possibly onto an icemaker provided in the refrigerator. 
         [0005]    Certainly, it is possible to establish distinct refrigeration systems for each of the fresh food and freezer compartments. Although presenting some advantages in enabling the isolated control of the compartments, such an arrangement would be considerably more expensive. Still, there is seen to be a need in the art for a refrigeration system which can establish separated air zones and operate in various control modes in order establish a highly efficient and effective temperature supply and demand scheme. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is directed to a refrigerator incorporating a freezer compartment, a fresh food compartment, an icemaker and a refrigeration system including multiple evaporators and associated valving which operate in conjunction with a common compressor and condenser in order to effectively regulate temperatures in specified zones of the refrigerator throughout various operational modes. More particularly, the refrigerator can be operated in at least a freezer cooling mode, a fresh food cooling mode and an ice harvesting mode. The icemaker is located in the fresh food compartment and can be selectively linked to the cooling of the fresh food compartment, while being also being selectively isolated for at least the ice harvesting mode. 
         [0007]    More specifically, each of the freezer, fresh food and icemaker is provided with a dedicated evaporator such that, during the freezer cooling mode, refrigerant flows from the compressor, to the condenser, through the freezer evaporator and back to the compressor. During fresh food compartment cooling, the refrigerant bypasses the freezer evaporator and instead flows from the condenser to the fresh food evaporator, preferably through the icemaker evaporator, prior to being directed back to the compressor. During an ice harvest event, a gaseous flow from the compressor is routed directly to the evaporator of the icemaker to melt ice at an ice/icemaker evaporator interface in aiding in the release of the ice from an ice mold. The arrangement of the components and the strategic locating of the valving establishes the distinct, isolated flow patterns for the various modes of operation. 
         [0008]    Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a refrigerator according to the present invention; 
           [0010]      FIG. 2  is a schematic illustration of a refrigeration system for the refrigerator of  FIG. 1 ; 
           [0011]      FIG. 3  is a schematic illustration of the refrigeration system of  FIG. 2  in a freezer cooling mode; 
           [0012]      FIG. 4  is schematic illustration of the refrigeration system of  FIG. 2  in a fresh food cooling mode; and 
           [0013]      FIG. 5  is a schematic illustration of the refrigeration system of  FIG. 2  in an ice harvesting mode. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0014]    With initial reference to  FIG. 1 , a refrigerator  2  includes an outer shell or cabinet  4  within which is positioned a liner  6  that defines a fresh food compartment  8 . In a manner known in the art, fresh food compartment  8  can be accessed by the selective opening of a fresh food door  10 . In a similar manner, a freezer door  12  can be opened to access a freezer compartment  13 . In the embodiment shown, freezer door  12  includes a dispenser  14  that enables a consumer to retrieve ice and/or fresh water without accessing fresh food or freezer compartments  8  and  13 . For the sake of completeness, door  10  of refrigerator  2  is shown to include a dairy compartment  15  and various vertically adjustable shelving units, one of which is indicated at  16 . 
         [0015]    In a manner known in the art, fresh food compartment  8  is provided with a plurality of vertically, height adjustable shelves  20 - 22  supported by a pair of shelf support rails, one of which is indicated at  25 . At a lowermost portion of fresh food compartment  8  is illustrated various vertically spaced bins  28 - 30 . At this point, it should be recognized that the above described refrigerator structure is known in the art and presented only for the sake of completeness. The present invention is not limited for use with a side-by-side style refrigerator shown, but may be utilized with other known refrigerator styles including top-mount, bottom-mount, or French door style refrigerators. In any case, as also shown in  FIG. 1 , refrigerator  2  also includes an icemaker, generally indicated at  50 . In the preferred embodiment shown, icemaker  50  is located within fresh food compartment  8 . With this in mind, the invention is particularly directed to the refrigeration system employed in connection with fresh food compartment  8 , freezer compartment  13  and icemaker  50 , and particularly the manner in which the refrigeration system is structured and controlled through a controller  55  to operate in various distinct modes as will be detailed fully below. 
         [0016]    Details of a refrigeration system  60  constructed in accordance with a preferred embodiment of the invention will now be set forth with reference to  FIG. 2 . As shown, refrigeration system  60  includes a compressor  65  having an associated mount  67 . Although not represented in this figure, compressor  65  is preferably mounted in a lower machine compartment of cabinet  4 , such as below freezer compartment  13 . Compressor  65  is connected at an inlet (not labeled) to an intake or suction line  70  and has a main outlet line  72 . Interposed within main outlet line  72  is a first, two-way switching valve  74 . Downstream of two-way switching valve  74 , main outlet line  72  leads to a condenser  75  having an associated fan  77 . Leading from condenser  75  is a liquid refrigerant line  85  which represents an input into a three-way switching valve  90 . Stemming from three-way switching valve  90  is a first supply line  93  that leads, through a capillary tube or other expansion device (not labeled), to a freezer evaporator  96  having an associated fan  100 . From freezer evaporator  96  extends a first return line  103  which is connected to suction line  70 . Prior to reaching suction line  70 , first return line  103  is provided with a one-way check valve  105 . As illustrated, one-way check valve  105  only allows fluid to flow in one direction within first return line  103  from freezer evaporator  96  to suction line  70  and back to compressor  65 . 
         [0017]    Also stemming from three-way switching valve  90  is a second supply line  110  which leads, through another expansion device (not labeled), to an icemaker evaporator  115 . Subsequent to icemaker evaporator  115  is a second two-way switching valve  118 . A first outlet associated with two-way switching valve  118  defines a third supply line  124  which leads to a fresh food evaporator  130  having an associated fan  134 . Leading from fresh food evaporator  130  is a second return line  140  which is fluid communication with suction line  70  and leads back to compressor  65 . A second outlet associated with two-way switching valve  118  is defined by a third return line  145  which is also in fluid communication with suction line  70  and leads back to compressor  65 . Finally, first two-way switching valve  74  is also connected to a bypass line  150  which merges with second supply line  110  so as to be in fluid communication with icemaker evaporator  115 . 
         [0018]    With the above arrangement, refrigeration system  60  can effectively and efficiently operate in numerous modes. More specifically,  FIG. 3  illustrates the flow path of refrigerant when refrigeration system  60  is in a freezer cooling mode. In this mode, compressor  65  feeds refrigerant flow through two-way switching valve  74 , condenser  75  and three-way switching valve  90  to freezer evaporator  96 . With the operation of fan  100 , freezer compartment  13  is effectively cooled, with the refrigerant exiting freezer evaporator  96  being directed back to suction line  70  and compressor  65  through first return line  103  and check valve  105 . 
         [0019]    When cooling of fresh food compartment  8  is indicated, based on the signal from at least one temperature sensor (not shown) and a user-selected cooling level for fresh food compartment  8 , refrigeration system  60  is operated in a fresh food cooling mode as represented in  FIG. 4 . As depicted, compressor  65  feeds refrigerant flow through main outlet line  72 , two-way switching valve  74  and condenser  75  to three-way switching valve  90  in a manner directly corresponding to freezer cooling mode discussed above. However, based on the repositioning of three-way switching valve  90 , the refrigerant is redirected into second supply line  110  so as to flow into icemaker evaporator  115  prior to reaching two-way switching valve  118 . As icemaker evaporator  115  also receives coolant, the fresh food cooling mode of this preferred embodiment could actually be referred to as a fresh food cooling/icemaking mode. However, for the sake of simplicity and to disclose the invention in a more generic fashion, continued reference to a fresh food cooling mode will be made. In any case, given the desire to further cool fresh food compartment  8 , two-way switching valve  118  is positioned such that the refrigerant flows from icemaker evaporator  118  into third supply line  124  and fresh food evaporator  130 . At the same time, fan  134  is operated in order to direct a flow of air across fresh food evaporator  130  and into fresh food compartment  8 . Thereafter, the refrigerant continues to flow into second return line  140  which leads back to suction line  70  and compressor  65  in a recirculating fashion. Due the presence of check valve  105 , refrigerant flowing through suction line  70  is prevented from back-flowing into first return line  103  toward freezer evaporator  96  which, at this point, would be at a low pressure. 
         [0020]    As clearly illustrated in these figures, it is preferred in accordance with the present invention to include icemaker  50  in fresh food compartment  8  and, correspondingly, icemaker evaporator  115  within fresh food compartment  8 . This arrangement represents a preferred embodiment which produces clear ice in refrigerator  2  such that it is desired to maintain a supply of water in icemaker  50  except at an ice making mold or member(s) (not shown). Since the particular manner in which the ice is formed does not form part of the present invention, it will not be discussed in detail here. Instead, any ice making arrangement known in the art can be utilized in accordance with the overall invention, although clear ice making is preferred. However, it is an aspect of the present invention to establish an ice harvesting mode for icemaker  50 . To this end,  FIG. 5  illustrates an arrangement wherein refrigeration system  60  is operated such that refrigerant leading from compressor  65  does not reach condenser  75  but instead hot gases are diverted at two-way switching valve  74  into a bypass line  150 , which leads directly into icemaker evaporator  115 . In this mode, three-way switching valve  90  is closed and two-way switching valve  118  is positioned by controller  55  to redirect the flow from icemaker evaporator  115  into third return line  145 . As indicated above, third return line  145  is in direct communication with suction line  70  so as to return refrigerant to compressor  65 . In a manner directly corresponding to that discussed above with respect to the fresh food cooling mode of  FIG. 3 , check valve  105  also operates in the ice harvesting mode to prevent back-flow into first return line  103  and freezer evaporator  96 . In a similar manner, two-way switching valve  118  also blocks flow to fresh food evaporator  130 . With this arrangement, hot gases from compressor  65  are delivered into icemaker evaporator  115  to melt ice at an ice/icemaker evaporator interface in connection with releasing the ice from an ice mold (not shown) of icemaker  50 . 
         [0021]    Based on the above, it should be readily apparent that refrigerator system  60  includes a common compressor  65  and common condenser  75  and, through the use of strategically placed valving, can selectively regulate flow to one or more of freezer evaporator  96 , icemaker evaporator  115  and fresh food evaporator  130  in order to selectively establish at least freezer cooling, fresh food cooling and ice harvesting modes of operation. By providing control algorithms to establish the different modes of operation, the refrigeration system  60  effectively handles any surplus of cooling capacity and at least compressor  65  can be operated with a lower temperature differential, thereby enhancing the overall efficiency of refrigerator  2 , while rapidly making ample amounts of ice in an energy efficient manner. In addition, the multi-evaporator arrangement establishes more effective temperature control for fresh food and freezer compartments  8  and  13  through the use of separated air zones, while also enhancing odor and humidity control, minimizing temperature swings and reducing defrosting based on a lower humidity load in freezer compartment  13 . 
         [0022]    Although described with reference to preferred embodiments of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, although the most preferred form of the fresh food cooling mode has refrigerant flowing serially through the icemaker evaporator and then the fresh food evaporator, additional valving could be employed to selectively direct refrigerant from the three-way switching valve into the fresh food evaporator for fresh food cooling, while also enabling a flow to the icemaker evaporator when the icemaker further demands cooling to produce ice. In another variation, the icemaker evaporator could follow the fresh food evaporator, instead of vise-versa. In general, the invention is only intended to be limited by the scope of the following claims.