Abstract:
Embodiments of the present invention provide a refrigerator, comprising a main body having a food storage compartment therein, a door installed on the main body and having an ice compartment therein and for opening and closing the food storage compartment, a compressor, a condenser, and an expansion valve that are installed in the door, an ice maker installed in the ice compartment, the ice maker comprising a tray configured to receive and contain water therein, and a refrigerant pipe line coupling the compressor, the condenser, and the expansion valve to each other and configured to cool the tray by conduction, and wherein the ice maker further comprises a heater disposed on a perimeter of the tray and a drain duct disposed below the tray and configured to collect defrost water, and wherein a portion of the heater extends into the drain duct.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and claims priority from Korean Patent Application No. 10-2015-0086082, filed on Jun. 17, 2015, the disclosure of which is incorporated herein in its entirety by reference. 
       FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention generally relate to a refrigerator including an ice maker and a method for collecting defrost water in the refrigerator. 
       BACKGROUND OF THE INVENTION 
       [0003]    Refrigerators store food at a temperature below the ambient temperature of the compartment. Refrigerators provide freezing storage or cold storage of food according to the type of food. 
         [0004]    The internal space a refrigerator is cooled by continuously supplied cold air. Cold air is continuously generated by heat exchange of refrigerant through a cooling cycle including compression, condensation, expansion, and evaporation. Cold air is uniformly supplied into the internal space of the refrigerator by convection, whereby food in the refrigerator can be stored at a desired temperature. 
         [0005]    Generally, a main body of the refrigerator has a rectangular parallelepiped structure that is open on a front surface thereof. A refrigerating compartment and a freezing compartment are within the main body. A refrigerating compartment door and a freezing compartment door are disposed on the front surface of the main body and allow selective opening or closing the front opening of the refrigerator. A plurality of drawers, shelves, and storage boxes may be disposed in the internal space formed in the refrigerator so that different kinds of food can be stored under optimal conditions. 
         [0006]    Traditionally, top mount refrigerators, in which the freezing compartment is above the refrigerating compartment, have been commonly used. Recently, bottom-freezer refrigerators, in which a freezing compartment is below a refrigerating compartment, were introduced to improve user convenience. The bottom-freezer refrigerators are advantageous in that users can more conveniently use the refrigerating compartment because the refrigerating compartment, which is comparatively frequently used, is in an upper portion of the refrigerator, while the freezing compartment, which is used comparatively less than the refrigerating compartment, is below the refrigerating compartment. However, the bottom-freezer refrigerators require a user to bend over when removing ice from the freezing compartment because the freezing compartment is in a lower portion of the refrigerator, and thus are inconvenient for the user. 
         [0007]    In an effort to overcome the above problem, a bottom-freezer refrigerator in which an ice dispenser is disposed in a door of a refrigerating compartment disposed in an upper portion of the refrigerator has been released. In this case, an ice maker for producing ice may be provided in the refrigerating compartment door or the refrigerating compartment. 
         [0008]    The ice maker may include an ice-making assembly which generates ice and includes an ice tray, an ice bucket for storing ice therein, and a transfer assembly for transferring ice stored in the ice bucket to the dispenser. 
         [0009]    Furthermore, an ice-making duct is installed to couple the freezing compartment with the ice maker. The ice-making duct is installed in a left or right sidewall of the refrigerating compartment such that an ice compartment is coupled with the freezing compartment through the ice-making duct when a door is closed. 
         [0010]    Therefore, when the door opens, the ice-making duct is separated from the ice compartment. When the door is closed, the ice-making duct couples with the ice compartment so that cold air (for generating ice) can be supplied from the freezing compartment to the ice compartment through the ice-making duct. 
         [0011]    However, the conventional refrigerator has the following problems. 
         [0012]    First, the ice-making duct is installed in the left or right sidewall of the refrigerating compartment, and thus a separate structure for insulating the duct is required. Therefore, since the duct requires space, the internal capacity of the refrigerator is reduced, and a piping structure of the refrigerator is complex. 
         [0013]    Second, only when the door is closed can cold air be transferred from the freezing compartment to the refrigerating compartment. When the door opens, cold air that passes through the ice-making duct is discharged out of the refrigerator. Therefore, the energy efficiency of the refrigerator is reduced. 
         [0014]    Third, ice is produced by indirect cooling using cold air that is supplied from the ice-making duct. Since ice is not directly cooled, the amount of time it takes to produce ice is increased. 
         [0015]    Fourth, because the ice maker is maintained at a low temperature, frost easily forms on the ice maker. However, with conventional refrigerator designs, such frost cannot be effectively removed, and the ice maker frequently malfunctions. 
       SUMMARY OF THE INVENTION 
       [0016]    In view of the above, embodiments of the present invention provide a refrigerator which does not need a separate duct for transferring cold air for producing ice while the ice maker is installed in a refrigerating compartment door, whereby the structure of the refrigerator is reduced, and the internal capacity of the refrigerator can be maximized. Furthermore, embodiments of the present invention provide a method for collecting defrost water of the refrigerator. 
         [0017]    Further, embodiments of the present invention provide a refrigerator with an ice compartment that can be cooled regardless of whether the door is open or closed, with increased energy efficiency. The embodiments of the present invention provide a method for collecting defrost water of the refrigerator. 
         [0018]    In addition, embodiments of the present invention provide a refrigerator in which ice is generated by direct cooling in an ice compartment installed in the door, and a method for collecting defrost water of the refrigerator. 
         [0019]    Furthermore, embodiments of the present invention provide a refrigerator which can effectively remove frost formed on an ice maker, and a method for collecting defrost water of the refrigerator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The objects and features of the present invention will become apparent from the following description of embodiments given in conjunction with the accompanying drawings, in which: 
           [0021]      FIG. 1  is a perspective view showing a refrigerator with an open door in accordance with an embodiment of the present invention; 
           [0022]      FIG. 2  is a front view illustrating an ice maker of  FIG. 1 ; 
           [0023]      FIG. 3  is a perspective view showing a tray and a refrigerant pipe line of the ice maker of  FIG. 1 ; 
           [0024]      FIG. 4  is a bottom view showing the tray and the refrigerant pipe line of the ice maker of  FIG. 1 ; and 
           [0025]      FIG. 5  is a sectional view showing a portion of the internal structure of the ice maker of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0026]    Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings which form a part hereof. 
         [0027]    In describing the embodiment of the present invention, a detailed description of known functions or constructions related to the present invention will be omitted to make description of the subject matter of present invention clear. 
         [0028]      FIG. 1  is a perspective view a refrigerator with an open door in accordance with an embodiment of the present invention. 
         [0029]    Referring to  FIG. 1 , a refrigerator  1 , in accordance with the embodiment of the present invention, includes a main body  10 , a barrier  12 , and a door  20 . The main body  10  forms the structure and/or appearance of the refrigerator  1  and is configured for food storage or the like therein. The barrier  12  partitions a food storage space defined in the main body  10  into an upper refrigerating compartment R and a lower freezing compartment F. The door  20  is disposed on a front surface of the main body  10  and is configured to be rotatable so that the main body  10  can be selectively opened or closed by the door  20 . 
         [0030]    The door  20  includes an ice compartment  22 , a machinery compartment  24 , and an insulator  26 . An ice maker  100  which generates ice is installed in the ice compartment  22 . The machinery compartment  24  includes a compressor  242  and a condenser  244 . The insulator  26  is disposed between the ice compartment  22  and the machinery compartment  24  and partitions the ice compartment  22  from the machinery compartment  24 . 
         [0031]    In the present embodiment, although the ice compartment  22  is shown formed on the door  20  for selective access to the refrigerating compartment R of the main body  10 , this does not preclude the case where the ice compartment is formed in a door configured to selectively open or close the freezing compartment F. 
         [0032]    Furthermore, in the present embodiment, although the structure in which the ice compartment  22  is formed in an upper portion of the door  20  and the machinery compartment  24  is formed in a lower portion of the door  20  are described for illustrative purposes, the spirit of the present invention is not limited to this structure. For example, the ice compartment  22  may be formed in the lower portion of the door  20 , and the machinery compartment  24  may be formed in the upper portion of the door  20 . 
         [0033]    The insulator  26  may be made of a foam material, e.g., urethane foam, and configured to prevent heat exchange between the ice compartment  22  at a low temperature and the machinery compartment at a comparative high temperature. 
         [0034]    The door  20  includes a cover which closes a portion of the door  20  that faces the main body  10  so that even when the door  20  is open, the ice compartment  22  and machinery compartment  24  are sealed from the outside or external environment. The cover functions to insulate an internal space of the door  20  from an internal space of the main body  10  when the door  20  is closed. As such, the cover may include a foam member having an area corresponding to the entire area of the door  20 . However, for the sake of explanation, illustration of the cover is omitted from  FIG. 1 . 
         [0035]    Furthermore, an insulation member is disposed on a perimeter of the door  20  to insulate the internal space of the door  20  from the outside. 
         [0036]    The compressor  242  and the condenser  244  are disposed in the machinery compartment  24  of the door  20 . Furthermore, an expansion valve (not shown) of a cooling cycle may also be disposed in the machinery compartment  24 . Alternatively, the expansion valve may be disposed in the insulator  26 . 
         [0037]    The compressor  242  may be a small or reduced size compressor which is smaller than a typical compressor disposed in the main body of the refrigerator so that the compressor  242  can be installed in a small space in the door  20 . A representative example of the small-sized compressor was proposed in Korean Patent Unexamined Publication No. 10-2013-0048817, which is incorporated herein by reference. 
         [0038]    The condenser  244  is coupled to a rear end of the compressor  242  by a refrigerant pipe line  248 . Gas-phased refrigerant compressed by the compressor  242  to high-temperature and high-pressure can be changed by the condenser  244  to a middle-temperature and high-pressure liquid-phased state. Further, the condenser  244  may also be a compact or reduced size condenser so that it can be installed in the internal space of the door  20 . 
         [0039]    The compressor  242  and the condenser  244  are connected to a power supply (not shown) disposed in the main body  10  so that power can be supplied to the compressor  242  and the condenser  244 . Here, cables which couple the compressor  242  and the condenser  244  to the power supply of the main body  10  are disposed in a hinge pipe that forms a rotating shaft of the door  20 . 
         [0040]    A through hole  246 , through which the machinery compartment  24  couples with the outside when the door  20  opens, is formed in a surface of the door  20  that forms the machinery compartment  24 . When the door  20  opens, the outside air drawn into the machinery compartment  24  through the through hole  246  cools the condenser  244  such that the refrigerant in the condenser  244  can be condensed. For this, a hole (not shown) is formed in the surface of the condenser  244  to allow the outside air to be supplied into the condenser  244 . A structure for heat exchange between the refrigerant and the outside air supplied through the hole is disposed in the condenser  244 . 
         [0041]    The refrigerant pipe line  248  connects the compressor  242  to the condenser  244  and extends from a rear end of the condenser  244  to the ice compartment  22 , disposed in the upper portion of the door  20 , through the insulator  26 . The refrigerant pipe line  248  is also connected to the ice maker  100  provided in the ice compartment  22 . 
         [0042]    The construction of the ice maker  100  installed in the ice compartment  22  will be described in detail with reference to  FIGS. 2 to 4 . 
         [0043]      FIG. 2  is a front view illustrating the ice maker of  FIG. 1 .  FIG. 3  is a perspective view showing a tray and the refrigerant pipe line of the ice maker of  FIG. 1 .  FIG. 4  is a bottom view showing the tray and the refrigerant pipe line of the ice maker of  FIG. 1 .  FIG. 5  is a sectional view showing a portion of the internal structure of the ice maker of  FIG. 1 . 
         [0044]    Referring to  FIGS. 2 to 5 , the ice maker  100  may include a casing  110 , an ice-making assembly  120 , an ice bucket  130 , a transfer assembly  140 , and an outlet port  150 . 
         [0045]    A cooling space, in which ice can be produced, is defined in the casing  110 . The ice-making assembly  120  is disposed in an upper position in the cooling space. The ice bucket  130  is disposed below the ice-making assembly  120 . 
         [0046]    The ice-making assembly  120  includes the tray  122  which includes a mold or frame that receives water and forms ice therein, a heater  126  which is disposed on the perimeter of the tray  122 , and a drive unit  124  which rotates the tray  122  to drop ice from the tray  122  in a downward direction. Furthermore, the drive unit  124  operates the heater  126  and heats the surface of the tray  122  for a short time to slightly melt a surface of ice that adheres to the surface of the tray  122 , thus making it easy to remove the ice from the tray  122 . 
         [0047]    Moreover, the ice-making assembly  120  includes a drain duct  128  which collects defrost water W generated when defrosting using the heater  126 . 
         [0048]    The tray  122  provides space which receives water from a water supply pipe (not shown) or the like and in which the water is cooled to form ice. The tray  122  includes in an upper surface thereof a plurality of forming spaces configured for storing water therein. The forming spaces can have a variety of shapes depending on shapes of ice to be produced. The number of forming spaces can also vary. 
         [0049]    The tray  122  is preferably made of metal, e.g., aluminum, having high thermal conductivity. As the thermal conductivity of the tray  122  is increased, a heat exchange rate between the tray  122  and the refrigerant flowing through the refrigerant pipe line is increased. 
         [0050]    The lower surface of the tray  122  is in contact with the refrigerant pipe line  248  extending from the machinery compartment  24 . A portion of the refrigerant pipe line  248  that comes into contact with the tray  122  is referred to as contact part  2482 . As shown in  FIG. 3 , the contact part  2482  may have a “U” shape. The contact part  2482  extends from a first end of the tray  122 , curves roughly 180° around a second end of the tray  122 , and then is extends toward the first end of the tray  122  and connects to the machinery compartment  24 . 
         [0051]    However, this is only an example. For example, the contact part  2482  may have a plurality of curved portions so that refrigerant can flow back and forth several times under the lower surface of the tray  122 . 
         [0052]    Here, the contact part  2482  may simply come into surface contact with the lower surface of the tray  122 . Alternatively, to enhance heat transfer efficiency, the contact part  2482  may be firmly attached to the lower surface of the tray  122 , e.g., by an adhesive, a fastener or the like. 
         [0053]    Therefore, refrigerant that is compressed and condensed in the machinery compartment  24  is expanded by the expansion valve and thus cooled. The cooled refrigerant is transferred to the contact part  2482  of the refrigerant pipe line  248 . The refrigerant transferred to the contact part  2482  cools water in the tray  122 . The cooled water is phase-changed into ice. 
         [0054]    In other words, the contact part  2482  of the refrigerant pipe line  248  and the tray  122  function as a small-sized evaporator in a cooling cycle. 
         [0055]    In a conventional refrigerator with the ice maker installed in the door, cold air is generated by heat exchanged between the refrigerant and air, and the generated cold air is supplied to the tray through a cold air duct by a blower or the like. As such, with the conventional technique, an indirect cooling method using heat exchange between a gas and a solid is used to produce ice. Because the efficiency of the heat exchange between a gas and a solid is comparatively low, it takes a long time to produce ice. 
         [0056]    However, in the present embodiment, ice is produced by a direct cooling method using heat exchange between solids, that is, between the refrigerant pipe line  248  and the tray  122 . Therefore, the efficiency of heat exchange is enhanced, and the time it takes to produce ice is markedly reduced. 
         [0057]    The produced ice can be dropped, by the drive unit  124 , into the ice bucket  130  disposed below the ice tray  122 . The drive unit  124  heats the heater  126  for a predetermined time so that the surface of ice that adheres to the surface of the tray  122  can slightly melt. As the surface of the ice slightly melts, the ice that had adhered to the surface of the tray  122  detaches from the surface of the tray  122 . 
         [0058]    If the time the heater  126  is heated is excessively long, the ice formed in the tray  122  may be completely melted. Therefore, it is preferable that time and rate of heat generation are set such that only the surface of ice slightly melts. The ice-making assembly  120  may include a control unit (not shown) which controls the operation of the drive unit  124 . 
         [0059]    After the operation of heating the tray  122  has been completed, a rotating shaft (not shown) of the rotating unit  124  is rotated. Then, the tray  122  is turned upside down such that the upper surface of the tray  122  faces the ice bucket  130 . When the tray  122  is rotated to a predetermined angle or more, the tray  122  is twisted by an interference member (not shown). Then, pieces of ice that have been in the tray  122  fall into the ice bucket  130  by twisting action of the tray  122 . 
         [0060]    Furthermore, a plurality of ejectors (not shown) may be disposed on the rotating shaft and arranged along the length of the rotating shaft so that ice can be removed from the tray  122  by rotating only the ejectors without rotating the entire tray  122 . 
         [0061]    The heater  126  is disposed on the perimeter of the tray  122  and functions to heat the tray  122 . The heater  126  may comprise a heating rod, a portion of which is curved downward to have a “U” shape. First and second ends of the heating rod are coupled to the drive unit  124 . Thus, the heating rod can selectively generate heat by a control mechanism of the drive unit  124 , thus heating the tray  122 . 
         [0062]    Furthermore, the U-shaped curved portion of the heater  126  extends downward to form a protrusion part  1262 . The protrusion part  1262  may extend from the heating rod to the drain duct  128 . 
         [0063]    In addition, the heater  126  may be configured such that a lowermost end of the protrusion part  1262  is disposed in the drain duct  128 . The protrusion part  1262  is disposed adjacent to an end of the tray  122  that is opposite to a side at which the heater  126  is connected to the drive unit  124 . 
         [0064]    The heater  126  having the above-mentioned construction functions not only to slightly melt the surface of ice in the tray  122  and make removal of the ice from the tray  122  easy, but also to heat the interior of the ice maker  100  when ice production is interrupted and thus defrost the interior of the ice maker  100 . This will be described in more detail later herein. 
         [0065]    The drain duct  128  functions to collect defrost water W, which is generated by phase change of frost from a solid to a liquid while the heater  126  defrosts the ice maker  100 , and then drains the defrost water W to the outside. The drain duct  128  is installed below the tray  122  and configured such that an end of the drain duct  128  is connected to an exhaust port housing  129  which has a through hole that is coupled with the outside or exterior environment. 
         [0066]    Furthermore, the drain duct  128  is configured such that the bottom thereof declines downward toward the exhaust port housing  129  so that defrost water W colleted in the drain duct  128  flows to the exhaust port housing  129  and discharged to the exterior environment. 
         [0067]    Defrost water W collected in the drain duct  128  flows into the exhaust port housing  129 , changes into vapor at a position adjacent to the exhaust port housing  129  by heat generated from the protrusion part  1262 , and then is discharged to the exterior environment. 
         [0068]    The transfer assembly  140  functions to transfer ice toward the outlet port  150  and includes an auger  142 , a motor housing  144 , and an auger motor  146 . 
         [0069]    The auger  142  is a rotatable member which has a screw or a spiral blade. The auger motor  146  rotates the auger  142 . The auger  142  is disposed in the ice bucket  130 . Pieces of ice that are in the ice bucket  130  are disposed between portions of the blades of the auger  142  and thus can be transferred to the outlet port  150  by the rotation of the auger  142 . The auger motor  146  is housed in the motor housing  144 . 
         [0070]    The outlet port  150  may be coupled to a dispenser (not shown) disposed in the door  20 . Depending on the selection of the user, pieces of ice can be transferred by the transfer assembly  140  and supplied to the user via the dispenser. Although it is not shown in the drawings, a cutting unit which can cut ice into a predetermined size may be disposed in the outlet port  150 . 
         [0071]    The operation and effect of the refrigerator  1  in accordance with the present embodiment having the above-mentioned construction will be described below. 
         [0072]    In the refrigerator  1  in accordance with the present embodiment, refrigerant flowing along the refrigerant pipe line  248  can be cooled while passing through the compressor, the condenser, and the expansion valve that are installed in the door  20  configured for openably closing the main body  10 . The cooled refrigerant is supplied to the contact part  2482  of the refrigerant pipe line  248  that makes contact with the tray  122 . Thus, the tray  122  is directly cooled by the refrigerant. 
         [0073]    Water can be supplied to the tray  122  by a water supply means (not shown). Water supplied to the tray  122  is cooled by refrigerant provided to the contact part  2482  and thus changes phase to produce ice. 
         [0074]    Here, refrigerant flows to the contact part  2482  by compressive force provided by the compressor  242 . 
         [0075]    The ice produced in the tray  122  falls downward by the operation of the drive unit  124  and becomes stored in the ice bucket  130  disposed below the tray  122 . 
         [0076]    Furthermore, refrigerant that has been transferred to the contact part  2482  via the expansion valve and has received heat from the tray  122  is transferred again to the machinery compartment  24  through the refrigerant pipe line  248 . The refrigerant transferred to the machinery compartment  24  is supplied to the compressor  242  so that it can be re-cooled through a cooling cycle. 
         [0077]    The interior of the ice maker  100  is usually maintained below zero degrees to produce ice. Therefore, when outside air enters the ice maker  100 , vapor in the outside air is condensed and solidified, thus forming frost. Such frost forms on the surfaces of different kinds of devices in the ice maker  100 , thereby potentially causing malfunction or failure of the devices of the ice maker  100 . 
         [0078]    To defrost the ice maker  100 , the heater  126  generates heat to change solid-phased frost into a liquid phase and then discharges it to the exterior environment. Here, although frost may be partially removed when the heater  126  generates heat to melt the surface of ice produced in the tray  122 , operating the heater  126  for a short time may not be enough to remove the frost if a large amount of frost has formed over a long period of time. 
         [0079]    Given this, the ice maker  100  may be operated in two modes, that is, an ice-making mode and a maintenance mode. In the ice-making mode, ice is produced. In the maintenance mode, while the cooling cycle in the door  20  is interrupted, the drive unit  124  operates the heater  126  to generate heat. Frost that has formed on the devices, including the tray  122  provided in the ice maker  100 , is changed into liquid by heat generated from the heater  126  and thus is removed from the devices. 
         [0080]    Defrost water W, which is generated by phase change of frost, is collected in the drain duct  128 . Further, defrost water W collected in the drain duct  128  is changed into vapor by heat emitted from the protrusion part  1262  of the heater  126  that extends into the drain duct  128 . The vapor moves to the exhaust port housing  129  and then is discharged out of the exhaust port housing  129 . 
         [0081]    Under normal conditions, the ice maker  100  is operated in the ice-making mode to produce ice. The maintenance mode of the ice maker  100  is periodically operated for a preset time. However, this is only one example of a method of controlling the maintenance mode. In other words, the method of controlling the maintenance mode of the ice maker  100  can be changed in various forms without departing from the scope of the invention. 
         [0082]    As described above, in accordance with the present invention, the piping structure of the refrigerator is reduced. The internal capacity of the refrigerator is increased, whereby space efficiency is increased. Furthermore, energy efficiency for cooling is improved, so that the time it takes to produce ice is reduced. In addition, the present invention can effectively defrost the ice maker. 
         [0083]    While a refrigerator in accordance with the invention have been shown and described with respect to the exemplary embodiment, embodiments of the present invention is not limited thereto. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims. 
         [0084]    Accordingly, the scope of the present invention should be interpreted based on the following appended claims, and all technical spirits within an equivalent range thereof should be construed as being included in the scope of the present invention.