Defrost apparatus of refrigerator

Abstract

The present invention discloses a defrost apparatus of a refrigerator which can defrost an evaporator by a defrost heater, when moisture of the ambient air of the evaporator is frozen on the surface of the evaporator. The defrost apparatus of the refrigerator includes a pair of evaporators and a pair of defrost heaters to selectively defrost the pair of evaporators. A path varying means for guiding air flow is installed near the pair of evaporators. The air is not supplied to the defrosted evaporator, for performing the defrosting operation. The air is supplied to the non-defrosted evaporator, for performing the cooling operation. As a result, the defrosting operation is efficiently performed, and the temperature does not sharply increase in freezing and refrigerating chambers, so that the food can be maintained fresh for an extended period of time.

1 . A defrost apparatus of a refrigerator, comprising: 
 a refrigerator main body in which a freezing chamber and a refrigerating chamber are formed, cool air circulation holes being formed on a partition wall for separating the freezing chamber from the refrigerating chamber;    a freezing cycle including first and second evaporators installed on a cool air circulation path on the inner wall of the freezing chamber, for cooling the air by the heat exchange operation with refrigerants, and a compressor, a condenser and expansion means built in one side of the refrigerator main body to be connected to the first and second evaporators, for circulating the refrigerants;    a ventilation device installed at one side of the first and second evaporators, for sending the cool air from the first and second evaporators to the freezing chamber;    temperature sensors installed in the first and second evaporators, for sensing temperature variations of the first and second evaporators, respectively;    first and second defrost heaters installed in the first and second evaporators and controlled according to the sensing values of the temperature sensors, for defrosting the first and second evaporators, respectively;    a refrigerant distributing means for wholly or selectively distributing the refrigerants to the first and second evaporators;    a path varying means installed between the first and second evaporators, for controlling inflow of the cool air to the first and second evaporators; and    a control unit for controlling the operations of the ventilation device, the first and second defrost heaters, the refrigerant distributing means and the path varying means according to the sensing values of the temperature sensors.    
   
   
       2 . The defrost apparatus of  claim 1 , wherein the expansion means are first and second capillary tubes connected to the first and second evaporators, respectively, for decompressing the refrigerants, and the refrigerant distributing means is a 3-way valve installed between the condenser and the first and second capillary tubes.  
   
   
       3 . The defrost apparatus of  claim 2 , wherein the path varying means comprises a partition wall installed on the cool air circulation path, for partitioning off the first and second evaporators, and first and second dampers rotatably installed on the front and rear ends of the partition wall, for selectively controlling inflow of the cool air to the first and second evaporators.  
   
   
       4 . The defrost apparatus of  claim 3 , wherein the control unit operates one of the first and second defrost heaters or stops the first and second defrost heaters according to the sensing values of the temperature sensors, and continuously operates the ventilation device.  
   
   
       5 . The defrost apparatus of  claim 4 , wherein, when the first defrost heater is operated, the control unit controls the 3-way valve to supply the refrigerants to the second capillary tube and the second evaporator, and also controls the first and second dampers to supply the cool air to the second evaporator.  
   
   
       6 . The defrost apparatus of  claim 4 , wherein, when the second defrost heater is operated, the control unit controls the 3-way valve to supply the refrigerants to the first capillary tube and the first evaporator, and also controls the first and second dampers to supply the cool air to the first evaporator.  
   
   
       7 . The defrost apparatus of  claim 4 , wherein, when the first and second defrost heaters are not operated, the control unit controls the 3-way valve to supply the refrigerants to the first and second capillary tubes and the first and second evaporators, and also controls the first and second dampers to supply the cool air to the first and second evaporators.  
   
   
       8 . The defrost apparatus of  claim 5 , wherein, when the second defrost heater is operated, the control unit controls the 3-way valve to supply the refrigerants to the first capillary tube and the first evaporator, and also controls the first and second dampers to supply the cool air to the first evaporator.  
   
   
       9 . The defrost apparatus of  claim 5 , wherein, when the first and second defrost heaters are not operated, the control unit controls the 3-way valve to supply the refrigerants to the first and second capillary tubes and the first and second evaporators, and also controls the first and second dampers to supply the cool air to the first and second evaporators.  
   
   
       10 . The defrost apparatus of  claim 6 , wherein, when the first and second defrost heaters are not operated, the control unit controls the 3-way valve to supply the refrigerants to the first and second capillary tubes and the first and second evaporators, and also controls the first and second dampers to supply the cool air to the first and second evaporators.