Patent Publication Number: US-2007107452-A1

Title: Refrigerator having independent sterilization duct

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit of Korean Patent Application Nos. 2005-110217 and 2005-110218, both filed on Nov. 17, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a refrigerator, and more particularly, to a refrigerator in which a sterilization duct is arranged independently from a chilled air duct for distributing chilled air into compartments to sterilize and deodorize so that the compartments can be maintained clean.  
      2. Description of the Related Art  
      Generally, a refrigerator is structured to maintain compartments such as a freezer compartment and a refrigerator compartment at suitable temperatures for accommodating foods so that the foods accommodated in the compartments can be kept fresh for a long time. In this refrigerator, vegetables, meat, fish, and various raw and cooked foods are accommodated.  
      Thus, unless the compartments are cleaned periodically, the compartments become impregnated with odors emitted from various foods and mold, bacteria, and viruses propagate in the compartments so that the compartments can be considered unhealthy and unpleasant for a user.  
      In order to remove bacteria, viruses, and odors, there is proposed a refrigerator in which a sterilizer and a deodorizer are installed in the compartments, for example, Japanese Laid-Open Patent Publication No. 6-82151.  
      The sterilizer and the deodorizer of the conventional refrigerator includes a cover having an inlet for suctioning air from the compartments and a discharge port for discharging the suctioned air to the compartments again, a high voltage generator and an ozone generating electrode, which are installed in the cover, an ion generating electrode, and a blower fan such that air introduced into the cover is sterilized and deodorized in the cover by ozone gas and is emitted into the compartments again so that the air circulating within the compartments becomes clean.  
      However, since the sterilizer and the deodorizer of the conventional refrigerator are disposed between shelves and the sterilized and deodorized air is discharged into their vicinity, the sterilized and deodorized air does not propagate into the space of the compartments uniformly so that the sterilizing and deodorizing effect is deteriorated.  
      Moreover, since the sterilizer and the deodorizer of the conventional refrigerator sterilizes and deodorizes air only therein, the sterilizer and the deodorizer of the conventional refrigerator cannot effectively sterilize and deodorize air in the compartments.  
     SUMMARY OF THE INVENTION  
      The present invention has been made in view of the above-mentioned problems, and an aspect of the invention is to provide a refrigerator in which a sterilizer duct is disposed in the vertical direction independent from a chilled air duct to discharge air containing active hydrogen and negative ions uniformly into compartments through a sterilizer duct.  
      It is another aspect of the present invention to provide a refrigerator in which an ion generator for generating active hydrogen and sterilizing ions is installed near an end of a sterilizer duct to improve the sterilizing and deodorizing effect.  
      It is a still another aspect of the present invention to provide a refrigerator in which a sterilizer duct is installed to rotate such that air passing through the sterilizer duct can be discharged into compartments in multiple directions.  
      It is a still another aspect of the present invention to provide a refrigerator capable of conveniently adjusting quantity and rate of air passing through a sterilizer duct.  
      In accordance with one aspect, the present invention provides a refrigerator including at least one compartment, a chilled air duct for supplying chilled air to the compartment, a sterilizer duct installed in the compartment independent from the chilled air duct, and an ion generator for supplying sterilizing air through the sterilizer duct to the compartment.  
      The refrigerator further includes a cooling fan for blowing the chilled air to the chilled air duct, and a blower fan for blowing air in the compartment to the sterilizer duct, wherein a plurality of chilled air discharge ports and sterilized air discharge ports are respectively formed in the chilled air duct and the sterilizer duct at regular intervals.  
      The chilled air duct may be disposed at the central region of the rear side of the compartment, and the sterilizer duct may be disposed at a corner of the rear side of the compartment.  
      The ion generator may be made of a micro plasma ion generator (MPI) for generating negative ions and active hydrogen, and may be disposed in the sterilizer duct.  
      The refrigerator further includes a blower duct, coupled with the sterilizer duct, in which the blower fan is installed, a rotation duct coupled with the blower duct, and a driving motor for rotating the rotation duct, wherein the sterilizer duct is installed to rotate together with the blower duct.  
      The driving motor is installed in a housing fixed to a rear wall of the compartment, and a rotation shaft of the driving motor is coupled with a hub provided in the center of the rotation duct to rotate the rotation duct.  
      The blower fan is coupled with a fan motor fixed in a hub provided at the center of the blower duct to rotate.  
      The sterilizer duct, the blower duct, and the rotation duct may have a cylindrical shape and rotate.  
      An insertion protrusion and an insertion recess may be formed in the end rims of the blower duct, and insertion protrusions and insertion recesses may be formed in respective ends of the blower duct and the rotation duct such that the insertion protrusion of the sterilizer duct is inserted into the insertion recess of the blower duct and the insertion protrusion of the blower duct is inserted into the insertion recess of the rotation duct for the convenient separation from and coupling with each other.  
      The inner surface of the sterilizer duct is coated with anti-electrification material, such as polyethylene.  
      The refrigerator further includes a distribution duct installed between the sterilizer duct and the chilled air duct to communicate and block the chilled air duct to and from the sterilizer duct, wherein the ion generator is installed in the sterilizer duct or the distribution duct.  
      The distribution duct may have first and second exits, and a cooling fan disposed in an entrance of the distribution duct. The sterilizer duct and the chilled air duct are respectively connected to the first and second exits of the distribution duct such that chilled air blown by the cooling fan flows the sterilizer duct and the chilled air duct through the distribution duct.  
      The refrigerator further includes a damper installed between the first and second exits within the distribution duct to open and close the first and second exits. The damper is driven by a driving motor to adjust an opening degree of the first and second exits.  
      The ion generator may be disposed at the side of the first exit connected to the sterilizer duct within the distribution duct.  
      The refrigerator further includes a chilled air supply duct connected to the entrance of the distribution duct, wherein a plurality of introducing holes for introducing air in the compartment is formed in the front side of the chilled air supply duct, and an evaporator is installed in the chilled air supply duct together with the cooling fan.  
      Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:  
       FIG. 1  is a front view illustrating a refrigerator, in which a sterilizer duct for sterilizing and deodorizing air in compartments is disposed in a refrigerator compartment parallel to a chilled air duct according to a first embodiment of the present invention;  
       FIG. 2  is an exploded perspective view illustrating a structure of the sterilizer duct according to the first embodiment of the present invention for enabling the sterilizer duct to rotate;  
       FIG. 3  is a vertical sectional view of the structure of the sterilizer duct in  FIG. 2 ;  
      FIGS.  4  to  6  are views illustrating directional change of a discharge port of the sterilizer duct according to the first embodiment of the present invention, in which  FIG. 4  shows the direction of the discharge port is changed such that air containing sterilizing ions is emitted toward a wall of a compartment,  FIG. 5  shows the direction of the discharge port is changed such that air containing sterilizing ions is discharged toward the central region of the compartment, and  FIG. 6  shows the direction of the discharge port is changed such that air containing sterilizing ions is discharged toward a rear wall of the compartment; and  
       FIG. 7  is a sectional view taken along the line A-A in  FIG. 1  and shows the air discharged from the sterilizer duct according to the first embodiment of the present invention distributed into the compartments;  
       FIG. 8  is a front view illustrating a refrigerator, in which a sterilizer duct for sterilizing and deodorizing air in compartments is disposed in a refrigerator compartment parallel to a chilled air duct according to a second embodiment of the present invention;  
       FIG. 9  is an enlarged perspective view of a part of the sterilizer duct in  FIG. 8  and shows that chilled air is distributed into the sterilizer duct and the chilled air duct through a distribution duct in which a damper and an ion generator are installed;  
      FIGS.  10  to  12  are views illustrating operation of the damper installed in the distribution duct according to the second embodiment of the present invention, in which  FIG. 10  shows that the damper installed in the distribution duct closes the chilled air duct completely and opens the sterilizer duct fully such that all the chilled air discharged from a cooling fan is supplied into the sterilizer duct,  FIG. 11  shows that the damper opens the chilled air duct fully and closes the sterilizer duct completely such that all the chilled air is supplied into the chilled air duct, and  FIG. 12  shows that the damper opens the chilled air duct fully and partially opens the sterilizer duct such that some of the chilled air is supplied into the sterilizer duct; and  
       FIG. 13  is a sectional view taken along the line B-B in  FIG. 8  and shows the chilled air containing active hydrogen and sterilizing ions, generated by the ion generator, is uniformly distributed into the compartments through the sterilizer duct. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.  
       FIG. 1  is a front view illustrating a refrigerator, in which a sterilizer duct for sterilizing and deodorizing air in compartments is disposed in a refrigerator compartment parallel to a chilled air duct according to a first embodiment of the present invention. As shown in  FIG. 1 , the refrigerator according to the first embodiment of the present invention has an open-front box-shaped cabinet  1  having a space for accommodating foods, a partition  2  for partitioning the cabinet  1  into two compartments  3  and  4 , and two doors  5  and  6  hinged to the front side of the cabinet  1  to open and close the compartments  3  and  4 .  
      Generally, the two compartments  3  and  4  serve as a freezer compartment  3  for accommodating foods under 0 (zero) degrees centigrade (preferably, 16 degrees centigrade below zero to 21 degrees centigrade below zero) and as a refrigerator compartment  4  for accommodating foods above zero degrees centigrade (preferably, 3 degrees centigrade to 5 degrees centigrade), thus, hereinafter the compartment  3  is referred to as the freezer compartment  3  and the compartment  4  is referred to as the refrigerator compartment  4 .  
      In order to arrange various foods accommodated in the freezer compartment  3  and the refrigerator compartment  4  effectively, the freezer compartment  3  and the refrigerator compartment  4  have shelves  7  and accommodating boxes  8  (See  FIG. 7 ).  
      In the rear side of the refrigerator compartment  4 , a chilled air duct  10  is disposed in the vertical direction to distribute the chilled air into the oval space of the refrigerator compartment  4  uniformly, and a sterilizer duct  60  is disposed in the vertical direction independently from the chilled air duct  10  to discharge the sterilized and deodorized air and a great deal of active hydrogen and negative ions into the refrigerator.  
      In the rear side of the refrigerator compartment  4 , a blower fan  17  and an evaporator  18  communicate with the chilled air duct  10  to supply the chilled air into the chilled air duct  10  (See  FIG. 7 ), and in the chilled air duct  10  and the sterilizer duct  60 , a plurality of chilled air discharge ports  11  and sterilized air discharge ports  61  are arranged at regular intervals.  
      The chilled air duct  10  is disposed at the central region of the refrigerator compartment  4 , and the sterilizer duct  60  installed independently from the chilled air duct  10  is disposed at a corner of the refrigerator compartment  4 , thereby supplying the chilled air and the sterilized and deodorized air into the refrigerator compartment  4 , respectively.  
      Alternatively, the chilled air duct  10  and the sterilizer duct  60  may be disposed at each corner of the rear side of the refrigerator compartment  4 , or the chilled air duct  10  may be disposed at a corner and the sterilizer duct  60  may be disposed at the central region.  
      The sterilizer duct  60  is installed to rotate in the refrigerator compartment  4  to sterilize and deodorize air in the refrigerator compartment  4  rapidly and effectively. Hereinafter, a structure in which the sterilizer duct  60  is installed to rotate in the refrigerator compartment  4  is described with reference to FIGS.  2  to  6 .  
       FIG. 2  is an exploded perspective view illustrating a structure of the sterilizer duct according to the first embodiment of the present invention for enabling the sterilizer duct to rotate, and  FIG. 3  is a vertical sectional view of the structure of the sterilizer duct in  FIG. 2 .  
      As shown in  FIGS. 2 and 3 , the refrigerator according to the first preferred embodiment of the present invention includes a blower duct  70  for circulating air in the refrigerator compartment  4 , a rotation duct  80  for rotating the sterilizer duct  60  forward and backward such that the air passed through the sterilizer duct  60  is distributed into the refrigerator compartment  4  uniformly, and a housing  90  for rotatably supporting the rotation duct  80 .  
      The sterilizer duct  60 , in which a plurality of sterilized air discharge ports  61  is formed, has a cylindrical shape having an opened lower side and a closed upper side, and includes an ion generator  40  installed in the vicinity of the opened lower side to discharge a great deal of active hydrogen and negative ions into the refrigerator compartment  4  through the sterilizer duct  60 .  
      Generally, the sterilizer duct  60  is made of expanded polystyrene having a surface resistivity higher than 10 12  Ω/sq and causes an electrification phenomenon with the ions emitted from the ion generator  40 , thereby annihilating the ions and decreasing the quantity of emitted ions. In order to remove the electrification of the ions, the inner surfaces of the sterilizer duct  60  are coated with polyethylene, an anti-electrification material.  
      The ion generator  40  is a micro plasma ion (MPI) generator designed to generate only hydrogen ions (H + ) by a plasma discharge under atmospheric pressure. The MPI generator generates electrons around the MPI generator to generate active hydrogen (hydrogen atoms) and the active hydrogen reacts with ambient active oxygen to neutralize harmful active oxygen, to annihilate source bacteria by being absorbed in cells of source bacteria such as viruses and mold, and to be able to sterilize without discharging unhealthy positive ions in the air.  
      The ion generator  40  implemented by the MPI generator includes a ceramic plate  41  serving as a positive ion generator and a needle-shaped electrode  42  serving as a negative ion generator. When a positive high voltage is applied to the ceramic plate  41 , water (H 2 O) in the air is ionized due to the plasma discharge so that hydrogen ions (H + ) are generated, and when a negative high voltage is applied to the needle-shaped electrode  42 , positive ions are accumulated around the needle-shaped electrode  42  due to the plasma discharge and a great deal of electrons are emitted from the needle-shaped electrode  42  to the air.  
      Since a great deal of the electrons emitted to air are very unstable, the electrons are captured by oxygen molecules (O 2 ) to generate super-oxide anions (O 2− ) so that the needle-shaped electrode  42  generates electrons and the super-oxide anions.  
      When the needle-shaped electrode  42  discharges the electrons, the electrons are generated from the ceramic plate  41  and are combined with hydrogen ions passing near the needle-shaped electrode  42  to generate hydrogen atoms (or active hydrogen). As such, the hydrogen ions generated from the ceramic plate  41  are combined with the electrons emitted from the needle-shaped electrode  42  to form hydrogen atoms, thus emitted elements finally become hydrogen atoms and super-oxide anions.  
      The hydrogen atoms and the super-oxide anions are mixed with air passing through the sterilizer duct  60  and finally discharged into the refrigerator compartment  4  so that bacteria and viruses are sterilized and source bacteria of mold are removed and the air is thereby deodorized.  
      The blower duct  70  has a cylindrical shape having the same diameter as that of the sterilizer duct  60  and opened ends to circulate air in the refrigerator compartment  4  through the sterilizer duct  60  and is coupled with the sterilizer duct  60 , and includes a blower fan  75  installed therein.  
      In order to install the blower fan  75  in the blower duct  70 , at the center of the blower duct  70 , a hub  73  connected to a plurality of ribs  74  extended from the inner circumference of the blower duct  70  is provided, and a fan motor  76  is installed in the hub  73  so that the blower fan  75  is coupled with the fan motor  76 .  
      Thus, the fan motor  76  is coupled with the hub  73  of the blower duct  70 , a rotation shaft  77  of the fan motor  76  is inserted into a shaft hole  75   a  formed at the center of the blower fan  75  so that the blower fan  70  is installed in the blower duct  70 , whereby air in the refrigerator compartment  4  can be supplied into the sterilizer duct  60  through the blower duct  70 .  
      The rotation duct  80  is provided with a hub  83  connected to a plurality of ribs  84  extended from the inner circumference of the blower duct  80  at the center thereof, and the hub  83  is formed with a shaft hole  83 a such that the rotation duct  80  is allowed to be connected to a driving motor  91  described later.  
      Like the blower duct  70 , the rotation duct  80  has a cylindrical shape having the same diameter as that of the blower duct  70  and is coupled with the blower duct  70  coupled with the sterilizer duct  60 . To this end, in the lower rims of the sterilizer duct  60  and the blower duct  70 , insertion protrusions  62  and  72  are formed respectively, and in the upper rims thereof, insertion recesses  71  and  81  are formed respectively.  
      The housing  90  fixed to the rear wall of the refrigerator compartment  4  includes the driving motor  91  for rotating the rotation duct  80 . The driving motor  91  includes a rotation shaft  92  upwardly protruded and inserted into the shaft hole  83   a  formed in the hub  83  of the rotation duct  80 . The housing  90  may be coupled with the rear wall of the refrigerator compartment  4  by screws or other ways.  
      Thus, as shown in  FIG. 3 , the rotation shaft  92  of the driving motor  91  is inserted into the shaft hole  83   a  of the rotation duct  80  such that the rotation duct  80  is installed to rotate in the housing  90 , the insertion protrusion  72  of the blower duct  70  is inserted into the insertion recess  81  of the rotation duct  80 , the insertion protrusion  62  of the sterilizer duct  60  is inserted into the insertion recess  71  of the blower duct  70  such that the sterilizer duct  60  is coupled with the blower duct  70 , so that the sterilizer duct  60 , the blower duct  80 , and the rotation duct  80  are rotatably supported by the housing  90 .  
      The sterilizer duct  60 , the blower duct  70 , and the rotation duct  80  are separated from each other easily and quickly.  
      FIGS.  4  to  6  are views illustrating directional change of a discharge port of the sterilizer duct according to the first embodiment of the present invention, and  FIG. 7  shows the air discharged from the sterilizer duct according to the first embodiment of the present invention is distributed into an oval space in the compartments.  
      As shown in  FIG. 4 , when an ion detector installed in the refrigerator compartment  4  and a contaminant detector (not shown) determine that a great deal of active hydrogen and ion is required for sterilization and deodorization of the refrigerator compartment  4 , the ion generator  40  is driven simultaneously with driving the fan motor  76  to rotate the blower fan  75  such that air in the refrigerator compartment  4  is introduced into the blower duct  70  through the lower side of the rotation duct  80  by the blower fan  75  so that the introduced air flows through the sterilizer duct  60  and is mixed with a great deal of the active hydrogen and negative ions emitted from the ion generator  40 .  
      The sterilized and deodorized air by being mixed with the active hydrogen and negative ions flows upward in the sterilizer duct  60 , and is distributed uniformly toward a side wall of the refrigerator compartment  4  in the vertical direction through the respective sterilized air discharge ports  61 , so that as shown in  FIG. 7 , the sterilized and deodorized air sterilizes and deodorizes the whole refrigerator compartment  4  rapidly.  
      In order to concentrate the active hydrogen and the negative ions to the central region of the refrigerator compartment  4 , the driving motor  91  is driven to rotate the rotation shaft  92  at a predetermined angle counterclockwise, then, as shown in  FIG. 5 , the rotation duct  80  coupled with the driving motor  91  and the blower duct  70  and the sterilizer duct  60  coupled with the rotation duct  80  rotate together so that the sterilized air discharge ports  61  of the sterilizer duct  60  are disposed toward the central region of the refrigerator compartment  4 .  
      Moreover, in order to concentrate the active hydrogen and the negative ions to the rear wall of the refrigerator compartment  4 , the driving motor  91  is further driven to rotate the rotation shaft  92  at a predetermined angle counterclockwise, then, as shown in  FIG. 6 , the rotation duct  80 , the blower duct  70 , and the sterilizer duct  60  rotate together so that the sterilized air discharge ports  61  of the sterilizer duct  60  are disposed toward the rear wall of the refrigerator compartment  4 .  
      When the driving motor  91  is driven to continuously rotate the rotation shaft  92  of the driving motor  91  clockwise and counterclockwise within a predetermined angular range, air containing a great deal of the active hydrogen and the negative ions can be distributed into the whole space of the refrigerator compartment  4  through the sterilizer duct  60  more rapidly.  
      When the ion detector and the contaminant detector determine that air in the refrigerator compartment  4  is sterilized and deodorized to some degree, the rotation speed of the blower fan  75  is reduced so that the quantity and rate of airflow passing through the sterilizer duct  60  can be reduced.  
      After a predetermined time has lapsed, when it is determined that the sterilization and the deodorization of air in the refrigerator compartment  4  is completed, the ion generator  40 , the fan motor  76 , and the driving motor  71  are stopped to prevent further sterilization and deodorization by the sterilizer duct  60 .  
      Although in the first embodiment of the present invention the sterilizer duct, the blower duct, and the rotation duct have circular cross-sections, but the shapes are not limited to this, and may have a polygonal shape.  
      Next, a refrigerator according to a second embodiment of the present invention will be described in detail with reference to FIGS.  8  to  13 . Hereinafter, in the refrigerator according to this embodiment, identical numerals are assigned to the similar components of the refrigerator according to the first embodiment of the present invention, and thus the detailed description will be omitted.  
       FIG. 8  is a front view illustrating a refrigerator, in which a sterilizer duct for sterilizing the refrigerator compartment and deodorizing air in compartments is disposed in the refrigerator compartment parallel to a chilled air duct according to the second embodiment of the present invention. As shown in  FIG. 8 , in the rear side of the refrigerator compartment  4  of the refrigerator according to the second preferred embodiment of the present invention, are disposed, a chilled air duct  10  installed in the vertical direction such that the chilled air is uniformly distributed into the refrigerator compartment  4 , and a sterilizer duct  20  installed parallel to the chilled air duct  10  in the vertical direction to discharge sterilized and deodorized air and to emit a great deal of active hydrogen and negative ion to the whole space of the refrigerator compartment  4 .  
      Moreover, in the rear side of the refrigerator compartment  4  are disposed a distribution duct  30  connected to the sides (depicted as the lower sides in  FIG. 8 ) of the chilled air duct  10  and the sterilizer duct  20 , and a chilled air supply duct  15  connected to the distribution duct  30  and provided with a cooling fan  17  and an evaporator  18  installed therein.  
      In the front sides of the chilled air duct  10  and the sterilizer duct  10  is formed, a plurality of chilled air discharge ports  11  and sterilized air discharge ports  21  arranged at regular intervals, and in the front side of the chilled air supply duct  15  is formed, a plurality of air introducing holes  16  for introducing air in the refrigerator compartment  4  into the chilled air supply duct  15  (See  FIG. 13 ).  
      Inside the distribution duct  30  are installed a damper  50  for adjusting the chilled air blown by the cooling fan  17  passing through the chilled air duct  10  and the sterilizer duct  20 , and an ion generator  40  for emitting a great deal of active hydrogen and negative ions into the refrigerator compartment  4  through the sterilizer duct  20 .  
      Like the sterilizer duct  60  according to the first embodiment of the present invention, the sterilizer duct  20  according to the second embodiment of the present invention is made of expanded polystyrene having surface resistivity higher than 10 12  Ω/sq and the inner surfaces of the sterilizer duct  20  are coated with polyethylene, an anti-electrification material.  
      Thus, when the cooling fan  17  is driven, air introduced into the chilled air duct  15  is chilled through the evaporator  18 , flows to the chilled air duct  10  and/or the sterilizer duct  20  through the distribution duct  30 , is discharged from the chilled air discharge ports  11  and the sterilized air discharge ports  21 , and then is distributed into the refrigerator compartment  4 .  
       FIG. 9  is an enlarged perspective view of a part of the sterilizer duct in  FIG. 8  and shows that chilled air is distributed into the sterilizer duct and the chilled air duct through the distribution duct in which the damper and an ion generator are installed. As shown in  FIG. 9 , the distribution duct  30  has an approximately Y-shaped structure coupled with a cover plate  30   a  and having an entrance  31  and first and second exits  32  and  33 , respectively formed in ends thereof.  
      The chilled air duct  15  is inserted into and coupled with the entrance  31 , the sterilizer duct  20  is inserted into and coupled with the first exit  32 , and the chilled air duct  10  is inserted into and coupled with the second exit  33 . Thus, the chilled air blown from the chilled air supply duct  15  to the distribution duct  30  is distributed into the chilled air duct  10  and the sterilizer duct  20 .  
      Between the first and second exits  32  and  33  in the distribution duct  30 , the damper  50  is installed to selectively open the first and second exits  32  and  33 . The damper  50  is made of a plate of the same size as cross-sections of the first and second exits  32  and  33 , has an end connected to a driving motor  51  and an opposite end hinged to the cover plate  30   a  of the distribution duct  30  to be rotated by the driving motor  51  so as to control the opening degree of the first and second exits  32  and  33 .  
      The ion generator  40  is disposed at a side of the first exit connected to the sterilizer duct  20  within the distribution duct  30  such that the sterilized and deodorized air and a great deal of active hydrogen and negative ions are distributed to the sterilizer duct  20 . Naturally, the ion generator  40  may be installed in the entrance of the sterilizer duct  20 .  
      As described in the first embodiment, the ion generator  40  implemented by the MPI generator includes a ceramic plate  41  serving as a positive ion generator and a needle-shaped electrode  42  serving as a negative ion generator. Hydrogen atoms and super-oxide anions generated by the interaction between the ceramic plate  41  and the needle-shaped electrode  42  flow from the first exit  32  to the sterilizer duct  20  to sterilize bacteria and viruses contained in air and to remove source bacteria of mold.  
      The damper  50  controls the quantity and flow rate of the chilled air sent to the sterilizer duct  20  to adjust opening degree of the first exit  32  of the distribution duct  30  such that the quantity of the active hydrogen and ions generated by the ion generator  40 , more precisely the quantity of super-oxide anions is optimized, and it will be described hereafter with reference to FIGS.  10  to  12 .  
      As shown in  FIG. 10 , when the ion detector installed in the refrigerator compartment  4  and the contaminant detector (not shown) determine that there is a great deal of active hydrogen and ions required for the purpose of sterilization and deodorization of the refrigerator  4 , the damper  50  activates the driving motor  51  to close the second exit  33  connected to the chilled air duct  10  completely and to fully open the first exit  32  connected to the sterilizer duct  20 .  
      In this status, the cooling fan  17  and the ion generator  50  are activated, all the chilled air sent from the chilled air supply duct  15  to the distribution duct  30  flows through the sterilizer duct  20  so that a great deal of active hydrogen and ions are emitted to the chilled air in a short time, resulting in sterilizing and deodorizing the chilled air. Further, as shown in  FIG. 13 , the chilled air containing a great deal of active hydrogen and ions goes out of the sterilized air discharge port  21  of the sterilizer duct  20  and is uniformly distributed into an entire space of the refrigerator  4 , resulting in rapidly sterilizing and deodorizing the refrigerator  4 .  
      As shown in  FIG. 11 , the ion detector and the contaminant detector determine that the sterilization and deodorization of air in the refrigerator  4  is completed, the damper  50  drives the driving motor  51  to fully open the second exit  33  connected to the chilled air duct  10  and to close the first exit  32  connected to the sterilizer duct  20  completely, and stops the ion generator  40  to send chilled air without negative ions and active hydrogen to the chilled air duct  10 .  
      Meanwhile, as shown in  FIG. 12 , when the damper  50  opens the chilled air duct  10  fully and the sterilizer duct  20  partially to control the opening degree of the second exit  32 , the flow rate of the chilled air flowing through the sterilizer duct  20  is very fast so that the chilled air containing the active hydrogen and negative ions rapidly flows out of the sterilizer duct  20 , thus to more effectively prevent the electrification phenomenon of the negative ions in the sterilizer duct  20  and to send the chilled air containing the active hydrogen and negative ions far away from the refrigerator  4 .  
      As described above, the refrigerator of the present invention includes the sterilizer duct disposed in the vertical direction in the refrigerator compartment independent from the chilled air duct to emit active hydrogen and negative ions into the entire space of the refrigerator compartment uniformly through the sterilizer duct so that the entire space of the refrigerator compartment can be effectively sterilized and deodorized.  
      Moreover, in the refrigerator according to the present invention, since the sterilizer duct is installed to rotate such that the flow direction and flow rate of air passing through the sterilizer duct are conveniently controlled, the emission amount, the emission rate, and the emission direction of the active hydrogen and negative ions can be optimized.  
      Further, since the damper is installed in the distribution duct connected to the sterilizer duct to conveniently control the quantity and flow rate of air passing through the sterilizer duct, the emission amount and the emission rate of the active hydrogen and negative ions, and the operation time of the ion generator can be optimized, thus the power consumption is also reduced.  
      Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents, and that various may be made with reference to the embodiments of the present invention.