Abstract:
Ice making assembly for a refrigerator and a method for controlling the ice making assembly. The ice making assembly and method capable of more effectively providing transparent ice. The ice making assembly and method also capable of preventing water overflow.

Description:
[0001]    The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2008-0017604 (filed on Feb. 27, 2008), which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    The present disclosure relates to an ice making assembly for a refrigerator and a method for controlling the ice making assembly. 
         [0003]    Refrigerators are domestic appliances used for storing foods by refrigerating or freezing the foods. Recently, various kinds of refrigerators have been introduced into the market. Examples of recent refrigerators include: a side by side type refrigerator in which a refrigerator compartment and a freezer compartment are disposed on the left and right sides; a bottom freezer type refrigerator in which a refrigerator compartment is disposed above a freezer compartment; and a top mount type refrigerator in which a refrigerator compartment is disposed under a freezer compartment. 
         [0004]    Furthermore, many of the recently introduced refrigerators have a home bar structure. These permit users to access foods or drinks disposed inside a refrigerator compartment through the home bar (i.e., a relatively small access portal) without having to open the larger refrigerator door. 
         [0005]    Refrigerators typically employ a number of refrigeration-cycle components. These include a compressor, a condenser, and an expansion member disposed inside the refrigerator. An evaporator is typically disposed on the backside of the refrigerator main body. 
         [0006]    In addition, an ice making assembly may be provided. The ice making assembly may be mounted in the freezer compartment, the refrigerator compartment, on the freezer compartment door, or on the refrigerator compartment door. 
         [0007]    To satisfy consumers&#39; increasing demands for transparent ice, ice making assemblies are now being designed to produce ice that is very clear and not cloudy. Accordingly much research has been conducted on ice making assemblies that can provide transparent ice. 
         [0008]    Known related art ice making assemblies generally employ an additional water tank disposed at a predetermined side of the refrigerator. It is connected to the ice making tray through a tube which supplies water to the ice making tray. Alternatively, the ice making tray may be directly connected to a tap (i.e., external water source) through a tube. 
       SUMMARY 
       [0009]    The exemplary embodiments of the present invention provide for an ice making assembly for a refrigerator that can more easily produce transparent ice and maintain the amount of water supplied for making ice at a constant level for each ice making cycle. Said embodiments also provide for a method for doing the same. 
         [0010]    The exemplary embodiments also provide for an ice making assembly for a refrigerator having a water supply that is automatically interrupted to prevent overflow when the water supplied to an ice making tray reaches a set level. Said embodiments also provide for a method for doing the same. 
         [0011]    The exemplary embodiments further provide for an ice making assembly for a refrigerator that can maintain the water supply at a constant level regardless of water pressure variations, and a method for doing the same. 
         [0012]    The exemplary embodiments still further provide for an ice making assembly for a refrigerator that can reduce unnecessary power consumption by rapidly detecting a water supply error which may result when water is not supplied to the ice making tray due to, for example, a malfunction of a water supply valve. These embodiments also provide a method for doing the same. 
         [0013]    In one exemplary embodiment, an ice making assembly includes a tray, accommodated in the refrigerator, which in turn include a plurality of ice recesses for receiving water; a plurality of fins above the tray; and a plurality of rods disposed through the fins to absorb heat from the water in the ice recesses, wherein the rods and the tray are used as electrodes and are electrically connected to each other when water in the ice recesses reaches a set level. 
         [0014]    In another exemplary embodiment, there is provided a method for controlling an ice making assembly of a refrigerator, the method includes disposing a rod vertically at an upper side of a tray, in which an ice recess is formed; moving the rod downward into the ice recess to a predefined height conducive for making ice supplying water to the ice recess; and controlling the amount of water such that the water reaches a pre set level that achieves an electrical connection between the rod and the tray. 
         [0015]    It will become apparent from the following disclosure that the ice making assembly and the method of controlling an ice making assembly according to the present disclosure, more easily produces transparent ice. It will also be apparent from the disclosure that water can be supplied at a constant level for each ice making cycle regardless of water pressure variations at the installed location of the refrigerator. Therefore, overflowing of supplied water, freezing of overflowed water in the refrigerator, and outflow of overflowed water from the refrigerator can be prevented. 
         [0016]    Further, in accordance with the present invention, while different amounts of water may remain in the ice recesses of the tray, water can be supplied to the ice recesses such that the final water level is the same. 
         [0017]    Still further, when water is not supplied to the tray due to a malfunction of the water supply valve, the exemplary embodiments of the present invention are capable of rapidly detecting this situation and reducing unnecessary power consumption. 
         [0018]    In addition, the ice making assembly can detect the level of water using existing components without using any additional devices so that the manufacturing costs of the ice making assembly can be reduced. 
         [0019]    The exemplary embodiments are fully described in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIGS. 1 and 2  are perspective views illustrating an ice making assembly structure for a refrigerator according to an exemplary embodiment of the present invention. 
           [0021]      FIG. 3  is a perspective view illustrating in more detail an ice making assembly according to the exemplary embodiments. 
           [0022]      FIG. 4  is a perspective view illustrating the ice making assembly just before ice is transferred to a container. 
           [0023]      FIGS. 5 and 6  illustrate the method of detecting the water level for the ice making tray according to exemplary embodiments. 
           [0024]      FIG. 7  is a circuit diagram illustrating a water level detecting circuit provided in the ice making assembly according to exemplary embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0025]    Hereinafter, an ice making assembly for a refrigerator will be described in detail according to exemplary embodiments of the present disclosure with reference to the accompanying drawings. In the following description, an ice making assembly is mounted at a freezer compartment door. However, the ice making assembly can alternatively be mounted at other places such as the freezer compartment, the refrigerator compartment, and on the refrigerator compartment door. 
         [0026]      FIGS. 1 and 2  are perspective views illustrating an ice making assembly structure for a refrigerator according to exemplary embodiments of the present invention. As shown, an ice making assembly  20  is mounted on the backside of a door  10 , and the backside of the door  10  is recessed to form an ice making assembly space  11  for accommodating the ice making assembly  20 . A cooling air supply hole  111  is formed at a side of the ice making assembly space  11  for allowing the inflow of cooling air from an evaporator (not shown), and a cooling air discharge hole  112 , formed in the side of the ice making assembly space  11 , for allowing the cooling air to be discharged from the ice making assembly space  11  to the evaporator. 
         [0027]    The ice making assembly  20  is mounted at an upper portion of the ice making assembly space  11 , and a container  30  is mounted under the ice making assembly  20  to store ice made by the ice making assembly  20 . The ice making assembly  20  is protected by an ice making cover  31 . In addition, owing to the ice making cover  31 , ice, when separating from the ice making assembly  20 , does not spill outward. It instead falls cleanly into the container  30 . 
         [0028]      FIG. 3  is a perspective view illustrating the ice making assembly  20  according to exemplary embodiments of the present invention, and  FIG. 4  is a perspective view illustrating the ice making assembly  20  just before ice is transferred to the container  30 . As shown, the ice making assembly  20  includes a tray  21  having a plurality of ice recesses  211  for making ice in a predetermined shape; a plurality of fins  24  rotatably and movably stacked above the tray  21 ; a plurality of rods  23  configured to be inserted into the ice recesses  211  through the fins  24 ; an ice ejecting heater  25  provided at the lowermost fin  24 ; a supporting plate  27  configured to support the ice ejecting heater  25 , the fins  24 , and the rods  23  as one unit; a water supply part  26  disposed at an end of the tray  21 ; and a control box  28  disposed at the opposite end of the tray  21 . 
         [0029]    A heater (not shown) is mounted at the bottom of the tray  21  to maintain the tray  21  at a temperature higher than freezing. A supporting lever  271  extends from the front of supporting plate  27 , and a hinge  272  is formed at one end of the supporting plate  27 . During an ice making operation, as shown in  FIG. 4 , ice (I) having a shape corresponding to the shape of the ice recesses  211  are formed around the rods  23 . 
         [0030]    Referring again to  FIG. 3 , a cam  29  and a driving motor for actuating the cam  29  are disposed inside the control box  28 . The hinge  272  is connected to the cam  29  so that the hinge  272  can be lifted and rotated by the movement of cam  29 . The ice ejecting heater  25  may be form in the shape of a plate and it contacts the rods  23 . Alternatively, the ice ejecting heater  25  may be contained inside the rods  23 . The supporting plate  27  also serves as a top for tray  21  such that water supplied to the tray  21  is indirectly cooled by the cooling air supplied to the ice making assembly space  11 . 
         [0031]    Hereinafter, the ice making and ice ejecting operation of the ice making assembly  20  will be described. First, the aforementioned heater attached to tray  21  maintains the tray  21  at a temperature higher than 0° C. This facilitates the process of making transparent ice in the ice making assembly  20  as described in greater detail below. 
         [0032]    More particularly, because water is rapidly frozen by cooling air supplied by an evaporator in accordance with known ice making assemblies, air dissolved in the water is trapped in and cannot be discharged from the water during freezing. Consequently, the water freezes with gas dissolved in the water, and this results in cloudy (i.e., non-transparent) ice. 
         [0033]    Accordingly, the tray  21  in accordance with exemplary embodiment of the present invention is maintained at a temperature higher than freezing, thus the water freezes slowly so that air dissolved in the water has time to escape the water before the water is frozen. The resulting ice is transparent, not cloudy. 
         [0034]    Towards the beginning of the ice making process, the rods  23  are inserted in the ice recesses  211  of the tray  21 . Water is then supplied to the tray  21 , and the freezing operation begins after the supply of water is completed. The freezing operation begins when cooling air is supplied to the ice making assembly space  11 . The temperature of the fins  24  is then reduced to a temperature below freezing by the supplied cooling air. The temperature of the rods  23  is also reduced to a temperature below freezing through conduction with the fins  24 . A Portions of each rod  23  is submerged in the water; therefore, the water is gradually frozen beginning with the water located closest to the rods  23 . Eventually, water located further from the rods  23  also freeze. 
         [0035]    After the water freezing operation is completed, cam  29  is rotated to move the rods  23  out of the ice recesses  211 . That is, the cam  29  is rotated to lift the rods  23 , and after the ice (I) is removed from the ice recesses  211 , the cam  29  is further rotated causing the rods  23  to tilt at a predetermined angle. More specifically, the rotation of the cam  29  causes the hinge  272  to rotate. The rotation of the hinge  272 , in turn, causes the rods  23  to tilt at a predetermined angle. When the rods  23  are tilted at a predetermined angle, as shown in  FIG. 4 , the ice ejecting heater  25  begins operating. 
         [0036]    The ice ejecting heater  25  causes the temperature of the rods  23  to increase. This causes the ice (I) to separate from the rods  23 . The ice (I) then falls into the container  30 . 
         [0037]      FIGS. 5 and 6  illustrate an exemplary method of detecting the level of the water supplied to tray  21  according to a exemplary embodiments of the present invention. As shown, the ice making assembly  20  detects water level using the rod  23  and the tray  21  without the need for any additional water level detecting sensor. 
         [0038]    More specifically, rod  23  and tray  21  are configured to function as electrodes, thus, when tray  21  is filled with water, the resistance of the water between the rod  23  and the tray  21  is measured to determine water level. 
         [0039]    As shown in  FIG. 5 , rod  23  is moved downward into the ice recess  211  of tray  21  until rod  23  reaches a set position. Water is then supplied to the ice recess  211 . As shown in  FIG. 6 , when the ice recess  211  is filled with water to the set level, the lower end of the rod  23  makes contact with the water in the ice recess  211 . Next, the level of the water in the ice recess  211  can be detected by measuring the resistance of the water between the tray  21  and the rod  23 . As such, water can be precisely supplied to the set level. In addition, if there is no current between the tray  21  and the rod  23  after water is supplied for a predetermined time, it can be determined that there is a water supply error, and thus a malfunction associated with the ice making assembly  20  can also be detected. 
         [0040]      FIG. 7  is a circuit diagram illustrating a water level detecting circuit for the ice making assembly according to exemplary embodiments of the present invention. As shown, a rod electrode and a tray electrode are provided at one side of the water level detecting circuit, where the tray electrode is grounded. A control unit MICOM is provided as shown, and a reference voltage Vcc is provided by a power supply. A resistor R 1  is disposed between a reference voltage terminal and the control unit. Before water is supplied to the ice recess  211 , the reference voltage Vcc is detected by the control unit. When water is supplied to the ice recess  211  to a set level, the rod electrode and the tray electrode are electrically connected, and a resistor R 2  forms, by virtue of the water between the rod and tray electrodes. Then, the control unit detects the voltage, different from the reference voltage VCC, across R 2 . The voltage across R 2  is proportional to the amount of water present. Thus, the control unit can determine when the ice recess  211  is filled with water to the set level. 
         [0041]    When the rod and tray electrodes are electrically connected, the voltage detected by the control unit can be expressed by the following equation. 
         [0000]        V=Vcc×R 2/( R 1 +R 2) 
         [0000]    Referring to the above equation, when the ice recess  211  is not filled with water, air fills the space between the rod and tray electrodes, and since the resistance of air is practically infinite, V=Vcc. However, when water is supplied to the ice recess  211  and the rod  23  makes contact with the water, the water acts like a resistor R 2  between the rod and tray electrodes. Because the resistance of water is smaller than that of air, the control unit detects a voltage V across R 2  that is smaller than the reference voltage Vcc (V&lt;Vcc), and thus the level of water can be determined from the voltage drop at the control unit. 
         [0042]    After it is determined that water is supplied to a set level, the supply of water is interrupted, and the rod  23  is further moved downward into the ice recess  211 . Then, the water supplied to the ice recess  211  is frozen by rod  23  which is cooled by the cooling air. The freezing of the water proceeds from the outer surface of the rod  23  to the inner surface of the ice recess  211 . 
         [0043]    Further in accordance with the exemplary embodiments of the present invention, the position of the rods relative to the ice recesses may be user adjustable. For example, the user may have an option to select the size of the ice that is produced by the ice making assembly, through the use of a selection button and a corresponding control circuit. The position of the rods relative to the ice recesses is then adjusted as a function of the user&#39;s selection. If the user wants the ice making assembly to produce small sized ice, it will be understood, from the preceding disclosure that the position of the rods will be automatically set relative far down in the ice recesses. Accordingly, when water is supplied to the tray, a relatively small amount of water will be required to achieve an electrical connection between the rods and the tray. When the connection is achieved, the control circuit, such as the control circuit illustrated in  FIG. 7 , stops the water supply and smaller sized ice is ultimately produced as less water was used to fill the tray. If the user instead chooses medium or large sized ice, the rods will not be positioned as far down in the ice recesses as was the case with smaller sized ice, thus allowing a greater amount of water to be supplied to the tray, resulting in larger sized ice. 
         [0044]    Although exemplary embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.