Air conditioner

Abstract

Disclosed herein is an air conditioner having a single oil separator mounted on a confluent discharging channel, to which are connected discharging channels provided at a plurality of compressors, and an electronic expansion valve, of which the opening level is controllable, mounted on an oil collection pipe connected to the oil separator. As a result, the number of the oil separators is decreased. Consequently, the present invention has the effect of simplifying the structure of the air conditioner and reducing the manufacturing costs of the air conditioner. Furthermore, refrigerant is bypassed by controlling the opening level of the electronic expansion valve to control the flow rate of the refrigerant. Consequently, the present invention has the effect of eliminating an additional bypassing device, and therefore, simplifying the structure of the air conditioner and the controlling method of the air conditioner.

1 . An air conditioner comprising: a plurality of compressors for compressing refrigerant; a condenser for condensing the refrigerant discharged from the compressors; an expansion mechanism for expanding the refrigerant discharged from the condenser; and an evaporator for evaporating the refrigerant passing through the expansion mechanism, wherein the air conditioner further comprises: 
 an oil separator mounted on a confluent discharging channel, which is connected to discharging channels provided at the respective compressors for guiding the refrigerant discharged through the discharging channels to the condenser, for separating oil from the refrigerant; and    an oil collection pipe for guiding the oil separated by the oil separator to the inlets of the respective compressors.    
   
   
       2 . The air conditioner as set forth in  claim 1 , further comprising: 
 a valve device mounted on the oil collection pipe for opening/closing the oil collection pipe.    
   
   
       3 . The air conditioner as set forth in  claim 2 , wherein the valve device is an electronic expansion valve.  
   
   
       4 . The air conditioner as set forth in  claim 3 , further comprising: 
 check valves mounted on the respective discharging channels for preventing back-flow of the compressed refrigerant.    
   
   
       5 . The air conditioner as set forth in  claim 3 , further comprising: 
 a common accumulator connected to introducing channels provided at the respective compressors.    
   
   
       6 . The air conditioner as set forth in  claim 5 , wherein the oil collection pipe is connected to the inlet of the common accumulator.  
   
   
       7 . The air conditioner as set forth in  claim 3 , further comprising: 
 a controller for controlling the opening level of the electronic expansion valve.    
   
   
       8 . The air conditioner as set forth in  claim 7 , wherein the controller controls the opening level of the electronic expansion valve according to load of the compressors.  
   
   
       9 . The air conditioner as set forth in  claim 8 , wherein the controller decreases the opening level of the electronic expansion valve to below a predetermined value when the load of the compressors is adequate, and increases the opening level of the electronic expansion valve to above the predetermined value when the load of the compressors is small.  
   
   
       10 . The air conditioner as set forth in  claim 4 , further comprising: 
 a four-way valve mounted on the confluent discharging channel for guiding flow of the refrigerant according to heating operation mode or cooling operation mode.    
   
   
       11 . An air conditioner comprising: a plurality of compressors for compressing refrigerant; a condenser for condensing the refrigerant discharged from the compressors; an expansion mechanism for expanding the refrigerant discharged from the condenser; an evaporator for evaporating the refrigerant passing through the expansion mechanism; and a four-way valve for guiding flow of the refrigerant according to heating operation mode or cooling operation mode, wherein the air conditioner further comprises: 
 an oil separator mounted on a confluent discharging channel, which is connected to discharging channels provided at the respective compressors for guiding the refrigerant discharged through the discharging channels to the condenser, for separating oil from the refrigerant; and    an oil collection pipe for guiding the oil separated by the oil separator to the inlets of the respective compressors.    
   
   
       12 . The air conditioner as set forth in  claim 11 , further comprising: 
 a valve device mounted on the oil collection pipe for opening/closing the oil collection pipe.    
   
   
       13 . The air conditioner as set forth in  claim 12 , wherein the valve device is an electronic expansion valve.  
   
   
       14 . The air conditioner as set forth in  claim 13 , further comprising: 
 check valves mounted on the respective discharging channels for preventing back-flow of the compressed refrigerant.    
   
   
       15 . The air conditioner as set forth in  claim 13 , further comprising: 
 a common accumulator connected to introducing channels provided at the respective compressors.    
   
   
       16 . The air conditioner as set forth in  claim 15 , wherein the oil collection pipe is connected to the inlet of the common accumulator.  
   
   
       17 . The air conditioner as set forth in  claim 13 , further comprising: 
 a controller for controlling the opening level of the electronic expansion valve.    
   
   
       18 . The air conditioner as set forth in  claim 17 , wherein the controller controls the opening level of the electronic expansion valve according to load of the compressors.  
   
   
       19 . The air conditioner as set forth in  claim 18 , wherein the controller decreases the opening level of the electronic expansion valve to below a predetermined value when the load of the compressors is adequate, and increases the opening level of the electronic expansion valve to above the predetermined value when the load of the compressors is small.  
   
   
       20 . An air conditioner comprising: a plurality of compressors for compressing refrigerant; a condenser for condensing the refrigerant discharged from the compressors; an expansion mechanism for expanding the refrigerant discharged from the condenser; an evaporator for evaporating the refrigerant passing through the expansion mechanism; and a four-way valve for guiding flow of the refrigerant according to heating operation mode or cooling operation mode, wherein the air conditioner further comprises: 
 an oil separator mounted on a confluent discharging channel, which is connected to discharging channels provided at the respective compressors for guiding the refrigerant discharged through the discharging channels to the condenser, for separating oil from the refrigerant;    an oil collection pipe for guiding the oil separated by the oil separator to the inlets of the respective compressors;    an electronic expansion valve mounted on the oil collection pipe for opening/closing the oil collection pipe;    a controller for controlling the opening level of the electronic expansion valve; and    check valves mounted on the respective discharging channels for preventing back-flow of the compressed refrigerant.