Refrigerating Apparatus

Abstract

A refrigerant return mechanism ( 5 ) is provided for returning liquid refrigerant in a receiver ( 17 ) to a circulation path. Whereby, the liquid refrigerant in the receiver ( 17 ) is forcedly returned to the circulation path in an operation state where the circulation path is formed in which the refrigerant sent out from compression mechanism ( 11 D, 11 E) flows from a second user side unit ( 20 ) to first user side units ( 30, 40 ) and is then returned to the compression mechanisms ( 11 D, 11 E).

1 . A refrigerating apparatus comprising:
 a heat source side unit ( 10 ) including a compression mechanism ( 11 D,  11 E), a heat source side heat exchanger ( 15 ), and a receiver ( 17 );   a first user side unit ( 30 ,  40 ) including a first user side heat exchanger ( 31 ,  41 );   a second user side unit ( 20 ) including a second user side heat exchanger ( 21 ); and   gas side communication pipes ( 51 ,  52 ) and liquid side communication pipes ( 53 ,  54 ,  55 ) which connect each unit ( 10 ,  20 ,  30 ,  40 ) to form a refrigerant circuit ( 50 ), the gas side communication pipes ( 51 ,  52 ) including a first gas side communication pipe ( 51 ) connected to the heat source side unit ( 10 ) and the first user side unit ( 30 ,  40 ) and a second gas side communication pipe ( 53 ) connected to the heat source side unit ( 10 ) and the second user side unit ( 20 ), and the liquid side communication pipes ( 53 ,  54 ,  55 ) including a collection liquid pipe ( 53 ) connected to the heat source side unit ( 10 ), a first branch liquid pipe ( 54 ) branching from the collection liquid pipe ( 53 ) and connected to the first user side unit ( 30 ,  40 ), and a second branch liquid pipe ( 55 ) branching from the collection liquid pipe ( 53 ) and connected to the second user side unit ( 20 ),   wherein the refrigerant circuit ( 50 ) is capable of forming a refrigerant circulation path in which refrigerant sent out from the compression mechanisms ( 11 D,  11 E) flows from the second user side unit ( 20 ) to the first user side unit ( 30 ,  40 ) and is then returned to the compression mechanism ( 11 D,  11 E), and   a refrigerant return mechanism ( 5 ) is provided for returning liquid refrigerant in the receiver ( 17 ) to the circulation path.   
   
   
       2 . The refrigerating apparatus of  claim 1 ,
 wherein the refrigerant return mechanism ( 5 ) includes an introduction pipe ( 71 ) for introducing high-pressure refrigerant discharged from the compression mechanism ( 11 D,  11 E) into the receiver ( 17 ), and   the liquid refrigerant in the receiver ( 17 ) is returned to the circulation path through the collection liquid pipe ( 53 ) in such a manner that the high-pressure refrigerant from the introduction pipe ( 71 ) is introduced into the receiver ( 17 ) to increase an inner pressure of the receiver ( 17 ).   
   
   
       3 . The refrigerating apparatus of  claim 1 ,
 wherein the refrigerant return mechanism ( 5 ) includes a communication pipe ( 67 ) for allowing the receiver ( 17 ) to communicate with a suction side of the compression mechanism ( 11 D,  11 E), and   the liquid refrigerant in the receiver ( 17 ) is returned to the circulation path in such a manner that the compression mechanism ( 11 D,  11 E) sucks the liquid refrigerant through the communication pipe ( 67 ).   
   
   
       4 . The refrigerating apparatus of  claim 1 ,
 wherein the refrigerant return mechanism ( 5 ) includes a communication mechanism ( 13 ) for allowing the receiver ( 17 ) to communicate with a discharge side of the compression mechanism ( 11 D,  11 E) through the heat source side heat exchanger ( 15 ), and   the liquid refrigerant in the receiver ( 17 ) is returned to the circulation path through the collection liquid pipe ( 53 ) in such a manner that the communication mechanism ( 13 ) allows the receiver ( 17 ) to communicate with the discharge side of the compression mechanism ( 11 D,  11 E) to cause high-pressure refrigerant discharged from the compression mechanism ( 11 D,  11 E) to flow into the receiver ( 17 ).   
   
   
       5 . The refrigerating apparatus of any one of  claims 1  to  4 , further comprising:
 suction side superheat detection means ( 79 ,  81 ) for detecting a degree of superheat of refrigerant flowing from the first user side heat exchanger ( 31 ,  41 ) toward a suction side of the compression mechanism ( 11 D,  11 E); and   control means ( 95 ) for controlling the refrigerant return mechanism ( 5 ) so that the refrigerant in the receiver ( 17 ) is returned to the circulation path when a detection value of the suction side superheat detection means ( 79 ,  81 ) is equal to or larger than a predetermined value.   
   
   
       6 . The refrigerating apparatus of any one of  claims 1  to  4 , further comprising:
 discharge side superheat detection means ( 75 ,  76 ) for detecting a degree of superheat of refrigerant discharged from the compression mechanism ( 11 D,  11 E); and   control means ( 95 ) for controlling the refrigerant return mechanism ( 5 ) so that the refrigerant in the receiver ( 17 ) is returned to the circulation path when a detection value of the discharge side superheat detection means ( 75 ,  76 ) is equal to or larger than a predetermined value.   
   
   
       7 . The refrigerating apparatus of any one of  claims 1  to  4 , further comprising:
 discharge side refrigerant temperature detection means ( 76 ) for detecting a temperature of refrigerant discharged from the compression mechanism ( 11 D,  11 E); and   control means ( 95 ) for controlling the refrigerant return mechanism ( 5 ) so that the refrigerant in the receiver ( 17 ) is returned to the circulation path when a detection value of the discharge side refrigerant temperature detection means ( 76 ) is equal to or larger than a predetermined value.   
   
   
       8 . A refrigerating apparatus comprising:
 a heat source side unit ( 10 ) including a compression mechanism ( 11 D,  11 E), a heat source side heat exchanger ( 15 ), and a receiver ( 17 );   a first user side unit ( 30 ,  40 ) including a first user side heat exchanger ( 31 ,  41 );   a second user side unit ( 20 ) including a second user side heat exchanger ( 21 ); and   gas side communication pipes ( 51 ,  52 ) and liquid side communication pipes ( 53 ,  54 ,  55 ) which connect each unit ( 10 ,  20 ,  30 ,  40 ) to form a refrigerant circuit ( 50 ), the gas side communication pipes ( 51 ,  52 ) including a first gas side communication pipe ( 51 ) connected to the heat source side unit ( 10 ) and the first user side unit ( 30 ,  40 ) and a second gas side communication pipe ( 53 ) connected to the heat source side unit ( 10 ) and the second user side unit ( 20 ), and the liquid side communication pipes ( 53 ,  54 ,  55 ) including a collection liquid pipe ( 53 ) connected to the heat source side unit ( 10 ), a first branch liquid pipe ( 54 ) branching from the collection liquid pipe ( 53 ) and connected to the first user side unit ( 30 ,  40 ), and a second branch liquid pipe ( 55 ) branching from the collection liquid pipe ( 53 ) and connected to the second user side unit ( 20 ),   wherein the refrigerant circuit ( 50 ) includes a switching mechanism ( 12 ) which switches between a first operation mode and a second operation mode, the first operation mode being a mode in which refrigerant sent out from the compression mechanism ( 11 D,  11 E) flows from the second user side unit ( 20 ) to the first user side unit ( 30 ,  40 ) and is then returned to the compression mechanism ( 11 D,  11 E), and the second operation mode being a mode in which the refrigerant sent out from the compression mechanism ( 11 D,  11 E) flows from the heat source side heat exchanger ( 15 ) into the receive ( 17 ) and into the first user side unit ( 30 ,  40 ) and is then returned to the compression mechanism ( 11 D,  11 E), and   the liquid refrigerant retained in the receiver ( 17 ) in the first operation mode is returned to the first user side unit ( 30 ,  40 ) through the collection liquid pipe ( 53 ) by switching the switching mechanism ( 12 ) from the first operation mode to the second operation mode.