Refrigeration apparatus

Abstract

A refrigeration apparatus implements a control method capable of suppressing occurrence of a situation in which a refrigerating machine oil from an oil separator is unsatisfactorily returned to a compressor and a discharge gas refrigerant is mostly returned to the compressor. An oil return valve is disposed on an oil return pipe connecting an oil separator disposed on a discharge side of a compressor to an injection pipe for supplying a refrigerant to the compressor. A controller controls the oil return valve to reduce a flow rate when a temperature of the refrigerant discharged from the compressor or a pressure of the refrigerant flowing through the injection pipe satisfies a predetermined condition.

1 . A refrigeration apparatus comprising:
 a compressor;   an oil separator disposed on a discharge side of the compressor;   a refrigerant supply pipe through which a refrigerant is supplied to the compressor;   an oil return pipe connecting the oil separator to the refrigerant supply pipe;   a flow rate adjusting mechanism disposed on the oil return pipe; and   a control unit controller configured to control the flow rate adjusting mechanism to reduce a flow rate when a temperature of the refrigerant discharged from the compressor or a pressure of the refrigerant flowing through the refrigerant supply pipe satisfies a predetermined condition.   
     
     
         2 . The refrigeration apparatus according to  claim 1 , wherein
 the controller performs normal control to control the flow rate adjusting mechanism, based on an amount of oil loss in the compressor, the amount of oil loss being obtained by multiplying a circulation amount of the refrigerant by a rate of oil loss in the compressor, and   when the predetermined condition is satisfied in the normal control, the controller controls the flow rate adjusting mechanism to further reduce the flow rate from a state of the flow rate adjusting mechanism in the normal control.   
     
     
         3 . The refrigeration apparatus according to  claim 1 , further comprising:
 a heat source-side heat exchanger configured to condense the refrigerant discharged from the compressor,   wherein   the refrigerant supply pipe is an injection pipe through which a part of the refrigerant condensed by the heat source-side heat exchanger is guided to a middle of a compression process in the compressor,   the refrigeration apparatus further comprising:   an intermediate expansion valve disposed at a middle of the injection pipe.   
     
     
         4 . The refrigeration apparatus according to  claim 1 , wherein
 the controller controls the flow rate adjusting mechanism to a state that blocks passage of the refrigerant through the flow rate adjusting mechanism upon activation of the compressor.   
     
     
         5 . The refrigeration apparatus according to  claim 1 , wherein
 the controller controls the flow rate adjusting mechanism to a state that permits passage of the refrigerant through the flow rate adjusting mechanism before activation of the compressor.   
     
     
         6 . The refrigeration apparatus according to  claim 2 , further comprising:
 a heat source-side heat exchanger configured to condense the refrigerant discharged from the compressor,   wherein   the refrigerant supply pipe is an injection pipe through which a part of the refrigerant condensed by the heat source-side heat exchanger is guided to a middle of a compression process in the compressor,   the refrigeration apparatus further comprising:   an intermediate expansion valve disposed at a middle of the injection pipe.   
     
     
         7 . The refrigeration apparatus according to  claim 2 , wherein
 the controller controls the flow rate adjusting mechanism to a state that blocks passage of the refrigerant through the flow rate adjusting mechanism upon activation of the compressor.   
     
     
         8 . The refrigeration apparatus according to  claim 3 , wherein
 the controller controls the flow rate adjusting mechanism to a state that blocks passage of the refrigerant through the flow rate adjusting mechanism upon activation of the compressor.   
     
     
         9 . The refrigeration apparatus according to  claim 2 , wherein
 the controller controls the flow rate adjusting mechanism to a state that permits passage of the refrigerant through the flow rate adjusting mechanism before activation of the compressor.   
     
     
         10 . The refrigeration apparatus according to  claim 3 , wherein
 the controller controls the flow rate adjusting mechanism to a state that permits passage of the refrigerant through the flow rate adjusting mechanism before activation of the compressor.   
     
     
         11 . The refrigeration apparatus according to  claim 4 , wherein
 the controller controls the flow rate adjusting mechanism to a state that permits passage of the refrigerant through the flow rate adjusting mechanism before activation of the compressor.