JP2018040548A - Freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezer capable of reducing the flow resistance and the deviation of refrigeration oil to the utmost when returning to a compressor through low-pressure pipes including a first low pressure pipe for communicating a first compressor with the first usage side heat exchanger; a second low pressure pipe for communicating a second compressor with the second usage side heat exchanger or the heat source side heat exchanger; and a connecting low pressure pipe having a control valve whose opening degree can be adjusted.SOLUTION: A freezer further comprises: a second suction pipe 32 connected to the second compressor; and a second branch pipe 36. The second branch pipe 36 is a branch pipe having influent side opening part 36a that opens in the prescribed direction; and two branch side opening parts 36b and 36c that open in a direction substantially opposite to the influent side opening part 36a. The second low pressure pipe 32 is connected to the influent side opening part 36a, and the connecting low pressure pipe 33 and the second suction pipe 22d are connected to the two branch side opening parts 36b and 36c.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a refrigeration apparatus, in particular, first and second compressors, a heat source side heat exchanger, first and second usage side heat exchangers, and a first compressor as a first usage side heat exchanger. A first low-pressure pipe for communicating, a second low-pressure pipe for communicating the second compressor with the second use side heat exchanger or the heat source side heat exchanger, and a control valve capable of adjusting the opening. The present invention relates to a refrigeration apparatus including a connecting low-pressure pipe for communicating a first low-pressure pipe and a second low-pressure pipe.

  Conventionally, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2014-70822), there is a refrigeration apparatus having a plurality of types of usage-side heat exchangers. In this refrigeration system, as a plurality of types of use side heat exchangers, a refrigeration heat exchanger (first use side heat exchanger) for cooling the interior of a showcase or the like, and indoor cooling or heating (air conditioning) And an indoor heat exchanger (second utilization side heat exchanger) for performing. This refrigeration apparatus has a plurality of compressors and a heat source side heat exchanger. As a plurality of compressors, a first compressor that sucks and compresses the refrigerant evaporated in the first usage side heat exchanger, and a refrigerant that evaporates in the second usage side heat exchanger or the heat source side heat exchanger And a second compressor for compression. A first low-pressure pipe for connecting the first compressor to the first use side heat exchanger is connected to the first compressor. The second compressor is connected to a second low pressure pipe for communicating the second compressor with the second use side heat exchanger or the heat source side heat exchanger. The first low-pressure pipe and the second low-pressure pipe communicate with each other via a connection low-pressure pipe having a control valve capable of adjusting the opening degree.

  In the refrigeration apparatus of Patent Document 1, since the first low-pressure pipe can be communicated with the second low-pressure pipe by opening the control valve of the connection low-pressure pipe, the refrigerant flowing through the second low-pressure pipe is subjected to the second compression. The first compressor can be inhaled as well as the machine. For this reason, for example, when the air conditioning load in the second usage side heat exchanger (that is, the flow rate of the refrigerant corresponding to the air conditioning load) cannot be processed only by the second compressor, the air conditioning load in the second usage side heat exchanger. (That is, the refrigerant flow rate corresponding to a part of the air-conditioning load) can also be processed by the first compressor. At this time, the flow rate of the refrigerant sucked into the first compressor can be finely controlled by adjusting the opening of the control valve or the like.

  However, when performing the operation with the control valve of the connection low-pressure pipe opened, it is desirable to minimize the flow resistance when the refrigerant returns to the compressor through these low-pressure pipes. In addition, since the refrigeration apparatus is filled with refrigeration oil together with refrigerant for lubrication of the compressor, when operating with such a connection low-pressure pipe control valve opened, these low-pressure pipes are used. It is desirable to minimize the bias of the refrigerating machine oil when the refrigerant returns to the compressor through.

  An object of the present invention is to communicate a first low-pressure pipe for communicating a first compressor with a first use side heat exchanger, and a second compressor with a second use side heat exchanger or a heat source side heat exchanger. In the refrigerating apparatus in which the second low-pressure pipe communicates with the connecting low-pressure pipe having a control valve capable of adjusting the opening degree, the flow resistance and refrigerant oil flow when the refrigerant returns to the compressor through these low-pressure pipes The purpose is to make the bias as small as possible.

  A refrigeration apparatus according to a first aspect includes a first compressor and a second compressor, a heat source side heat exchanger, a first usage side heat exchanger and a second usage side heat exchanger, a first low pressure pipe, And a second low-pressure pipe and a connecting low-pressure pipe. The first low-pressure pipe communicates the first compressor with the first usage-side heat exchanger. The second low-pressure pipe causes the second compressor to communicate with the second use side heat exchanger or the heat source side heat exchanger. The connection low-pressure pipe has an adjustment valve capable of adjusting the opening degree, and connects the first low-pressure pipe and the second low-pressure pipe. And here, it has further the 2nd suction pipe connected to the 2nd compressor, and the 2nd branch pipe. Here, the second branch pipe is a branch pipe having a merging side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merging side opening, The second low pressure pipe is connected to the merge side opening, and the connection low pressure pipe and the second suction pipe are connected to the two branch side openings.

  Here, in the connection configuration between the second low-pressure pipe, the second compressor (second suction pipe), and the connection low-pressure pipe, as described above, the merging-side opening that opens in a predetermined direction, and the merging-side opening, Includes a second branch pipe having two branch side openings that open in substantially opposite directions, a second low pressure pipe connected to the merge side opening, a low pressure pipe connected to the two branch side openings, and It is characterized in that the second suction pipe is connected. Here, as described above, since the branch side opening is opened in the direction substantially opposite to the merge side opening as described above, the second branch pipe allows the fluid flowing in from the merge side opening side to branch side opening. Can flow smoothly to the side. In such a connection configuration between the second low-pressure pipe, the second compressor (second suction pipe), and the connection low-pressure pipe using the second branch pipe, the operation is performed with the control valve of the connection low-pressure pipe open. In addition, the refrigerant flowing through the second low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant are smoothly supplied to the second suction pipe (second compressor side) and the connecting low-pressure pipe (first compressor side) via the second branch pipe. Can be shunted.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the second low-pressure pipe and the connecting low-pressure pipe can be minimized.

  In the refrigeration apparatus according to the second aspect, in the refrigeration apparatus according to the first aspect, the second branch pipe splits the refrigerant flowing in from the merging side opening in the horizontal direction and flows out from the two branch side openings. Are arranged as follows.

  Here, with the horizontal arrangement of the second branch pipe as described above, it is possible to improve the flow of refrigerant and refrigerating machine oil in the second branch pipe.

  The refrigeration apparatus according to the third aspect is the refrigeration apparatus according to the first or second aspect, further comprising a first suction pipe connected to the first compressor, and a first branch pipe. Here, the first branch pipe is a branch pipe having a merge side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merge side opening, The first low pressure pipe is connected to the merge side opening, and the connection low pressure pipe and the first suction pipe are connected to the two branch side openings.

  Here, in the connection configuration between the first low-pressure pipe, the first compressor (first suction pipe), and the connection low-pressure pipe, as described above, the merging-side opening that opens in a predetermined direction, and the merging-side opening Includes a first branch pipe having two branch side openings that open in substantially opposite directions, a first low pressure pipe connected to the merge side opening, a low pressure pipe connected to the two branch side openings, and It is characterized in that the first suction pipe is connected. Here, as described above, since the branch side opening is opened in the direction substantially opposite to the merge side opening as described above, the first branch pipe allows the fluid flowing in from the merge side opening side to branch side opening. Can flow smoothly to the side. In such a connection configuration between the first low-pressure pipe, the first compressor (first suction pipe), and the connection low-pressure pipe using the first branch pipe, the refrigerant flowing through the first low-pressure pipe is sucked into the first compressor. At this time, the refrigerant flowing through the first low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant can flow smoothly to the first suction pipe via the first branch pipe.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the first low-pressure pipe can be minimized.

  In the refrigeration apparatus according to the fourth aspect, in the refrigeration apparatus according to the third aspect, the first branch pipe splits the refrigerant flowing in from the merge side opening in the horizontal direction and flows out from the two branch side openings. Are arranged as follows.

  A refrigeration apparatus according to a fifth aspect is the refrigeration apparatus according to the third or fourth aspect, further comprising a third compressor and a third suction pipe connected to the third compressor. Here, the third suction pipe is connected to a portion of the connection low-pressure pipe closer to the first branch pipe than the control valve.

  Here, the third compressor is further provided, and the third suction pipe of the third compressor is connected to a portion of the connecting low pressure pipe closer to the first branch pipe than the control valve. Yes. In the configuration in which the third compressor is further connected to the first branch pipe side of the connecting low-pressure pipe in such a connection low-pressure pipe, the refrigerant flowing through the first low-pressure pipe is sucked into the third compressor together with the first compressor. In this case, the refrigerant flowing through the first low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant are connected to the first suction pipe (first compressor side) and the connecting low-pressure pipe (third) via the first branch pipe. Can be smoothly diverted to the compressor side. In addition, by arranging the first branch pipe horizontally, it is possible to improve the flow of refrigerant and refrigerating machine oil in the first branch pipe. In such a configuration, the refrigerant flowing through the second low-pressure pipe can be sucked into the third compressor together with the second compressor by opening the adjustment valve of the connection low-pressure pipe. 2 Refrigerant flowing through the low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant are smoothly divided into the second suction pipe (second compressor side) and the connecting low-pressure pipe (third compressor side) via the second branch pipe. be able to.

  Thereby, here, the refrigerant flowing through the first low-pressure pipe is sucked into the third compressor together with the first compressor, or the refrigerant flowing through the second low-pressure pipe is sucked into the third compressor together with the second compressor. In addition, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the first low pressure pipe, the second low pressure pipe, and the connection low pressure pipe can be minimized.

  The refrigeration apparatus according to a sixth aspect further includes a third branch pipe in the refrigeration apparatus according to the fifth aspect. Here, the third branch pipe is a branch pipe having a merge side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merge side opening, A third suction pipe is connected to the merging side opening. The connecting low-pressure pipe includes a first connecting low-pressure pipe connecting the branch side opening of the first branch pipe and one of the two branch side openings of the third branch pipe, and a branch side opening of the second branch pipe. And a second connection low-pressure pipe connecting the control valve and a third connection low-pressure pipe connecting the other of the two branch side openings of the control valve and the third branch pipe.

  Here, in the connection configuration between the third compressor (third suction pipe) and the connection low-pressure pipe (first and third connection low-pressure pipes), as described above, a merging side opening that opens in a predetermined direction; A third branch pipe having two branch side openings that open in a direction substantially opposite to the merge side opening is interposed, the third suction pipe is connected to the merge side opening, and two branch side openings The first connecting low-pressure pipe and the third connecting low-pressure pipe are connected to each other. Here, as described above, the third branch pipe has the branch side opening portion opened in a direction substantially opposite to the merge side opening portion, so that any fluid flowing from any branch side opening portion side can also be joined. Smooth flow to the opening side. In such a connection configuration between the third suction pipe using the third branch pipe and the first and third connection low-pressure pipes, when the third compressor sucks the refrigerant flowing through the first low-pressure pipe, Regardless of when the refrigerant flowing through the low-pressure pipe is sucked into the third compressor, the refrigerant flowing through the first and second low-pressure pipes or the refrigerating machine oil flowing together with the refrigerant is passed through the third branch pipe to the third suction. Can flow smoothly into the tube.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the connection low-pressure pipe can be minimized.

  A refrigeration apparatus according to a seventh aspect is the refrigeration apparatus according to the first or second aspect, wherein the first low-pressure pipe connected to the first low-pressure pipe and the connecting low-pressure pipe and the first compressor connected to the first compressor. It further has a suction pipe, a third compressor, a third suction pipe connected to the third compressor, and a fourth branch pipe. The fourth branch pipe is a branch pipe having a merging side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merging side opening. Are connected to the merge side opening, and the first suction pipe and the third suction pipe are connected to the two branch side openings.

  Here, a point where a third compressor is further provided, and a first suction pipe of the first compressor and a third suction pipe of the third compressor are connected to the combined low pressure pipe connected to the first low pressure pipe and the connecting low pressure pipe. It is characterized by connecting In the configuration in which the first and third compressors are connected to such a combined low-pressure pipe, the refrigerant flowing through the first low-pressure pipe can be sucked into the third compressor together with the first compressor through the combined low-pressure pipe. Further, in such a configuration, the control valve of the connection low-pressure pipe is opened, so that the refrigerant flowing through the second low-pressure pipe is sucked into the second compressor, and the third compression is performed through the connection low-pressure pipe and the merged low-pressure pipe. The refrigerant flowing through the second low-pressure pipe and the refrigeration oil flowing together with the refrigerant can be connected to the second suction pipe (second compressor side) and the low-pressure pipe via the second branch pipe. And can be smoothly diverted to the combined low-pressure pipe (the third compressor side). In addition, here, in the connection configuration between the merging low pressure pipe, the first compressor (first suction pipe), and the third compressor (third suction pipe), the merging side opening that opens in a predetermined direction as described above. And a fourth branch pipe having two branch side openings that open in a direction substantially opposite to the merging side opening, and a merging low pressure pipe is connected to the merging side opening. A feature is that the first suction pipe and the third suction pipe are connected to the opening. Here, as described above, the fourth branch pipe has a branch-side opening that opens in a direction substantially opposite to the merging-side opening, so that a fluid (refrigerant or refrigeration oil) flows from the merging-side opening. ) Can flow smoothly to the branch side opening side. In the connection configuration between the merged low pressure pipe, the first suction pipe, and the third suction pipe using the fourth branch pipe, the refrigerant flowing through the first low pressure pipe and the second low pressure pipe and the refrigerating machine oil flowing together with the refrigerant are joined. Through the low-pressure pipe and the fourth branch pipe, the flow can be smoothly divided into the first suction pipe (first compressor side) and the third suction pipe (third compressor side).

  Thereby, here, the refrigerant flowing through the first low-pressure pipe is sucked into the third compressor together with the first compressor, or the refrigerant flowing through the second low-pressure pipe is sucked into the third compressor together with the second compressor. In addition, it is possible to minimize the flow resistance and the bias of the refrigeration oil when the refrigerant returns to the compressor through the first low pressure pipe, the second low pressure pipe, the connection low pressure pipe, the joining low pressure pipe, and the fourth branch pipe. .

  In the refrigeration apparatus according to the eighth aspect, in the refrigeration apparatus according to the seventh aspect, the fourth branch pipe causes the refrigerant flowing from the merge side opening to be diverted in the horizontal direction and flows out from the two branch side openings. Are arranged as follows.

  Here, with the horizontal arrangement of the fourth branch pipe as described above, it is possible to improve the flow of refrigerant and refrigerating machine oil in the fourth branch pipe.

  The refrigeration apparatus according to the ninth aspect further includes a fifth branch pipe in the refrigeration apparatus according to the seventh or eighth aspect. Here, the fifth branch pipe is a branch pipe having a merging side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merging side opening, The merged low pressure pipe is connected to the merged side opening, and the first low pressure pipe and the connection low pressure pipe are connected to the two branch side openings.

  Here, in the connection configuration between the first low-pressure pipe, the first and third compressors (merging low-pressure pipe), and the connecting low-pressure pipe, as described above, the merging-side opening that opens in a predetermined direction, and the merging-side opening A fifth branch pipe having two branch side openings that open in a direction substantially opposite to the first section is interposed, a junction low pressure pipe is connected to the merge side opening, and a first low pressure is provided to the two branch side openings. It is characterized in that the pipe and the connecting low-pressure pipe are connected. Here, as described above, the first branch pipe has the branch side opening portion opened in a direction substantially opposite to the merge side opening portion, so that any fluid flowing from any branch side opening portion side can be joined. Smooth flow to the opening side. In such a connection configuration among the first low-pressure pipe, the merged low-pressure pipe and the connecting low-pressure pipe using the fifth branch pipe, when the refrigerant flowing through the first low-pressure pipe is sucked into the third compressor, and the connecting low-pressure pipe In any of the cases where the refrigerant flowing through the third compressor is sucked into the refrigerant, the refrigerant flowing through the first low-pressure pipe and the connecting low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant are passed through the fifth branch pipe to the combined low-pressure pipe. It can flow smoothly.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the merged low-pressure pipe can be minimized.

  As described in the above description, according to the present invention, it is possible to minimize the flow resistance and the refrigerating machine oil bias when the refrigerant returns to the compressor through the low-pressure pipe.

It is a schematic block diagram of the freezing apparatus concerning 1st Embodiment of this invention. It is a figure which shows the flow of the refrigerant | coolant in cooling / cooling operation. It is a figure which shows the flow of the refrigerant | coolant in cooling and heating operation. It is a figure which shows the connection structure of a low pressure pipe and a suction pipe. It is sectional drawing of a branch pipe. It is a schematic block diagram of the freezing apparatus concerning 2nd Embodiment of this invention. It is a figure which shows the flow of the refrigerant | coolant in cooling / cooling operation. It is a figure which shows the flow of the refrigerant | coolant in cooling and heating operation. It is a figure which shows the connection structure of a low pressure pipe and a suction pipe. It is a figure which shows the connection structure of the low pressure pipe and the suction pipe in the modification of 2nd Embodiment.

  Hereinafter, an embodiment of a refrigeration apparatus according to the present invention will be described based on the drawings. In addition, the specific structure of embodiment of the freezing apparatus concerning this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) First Embodiment <Configuration of Refrigeration Apparatus>
FIG. 1 is a schematic configuration diagram of a refrigeration apparatus 1 according to the first embodiment of the present invention. The refrigeration apparatus 1 is an apparatus configured to simultaneously perform cooling in a store such as a showcase and cooling or heating (air conditioning) in a store or the like in a store such as a convenience store by a vapor compression refrigeration cycle. It is. The refrigeration apparatus 1 mainly includes a heat source unit 2, a first usage unit 6 for cooling the inside of the cabinet, a second usage unit 7 for indoor air conditioning, the heat source unit 2 and the first usage unit 6. First liquid refrigerant communication pipe 8 and first gas refrigerant communication pipe 9 to be connected, second liquid refrigerant communication pipe 10 and second gas refrigerant communication pipe 11 to connect the heat source unit 2 and the second usage unit 7, And a control unit 12 that controls the components of the device 1. The vapor compression refrigerant circuit 13 of the refrigeration apparatus 1 is configured by connecting the heat source unit 2 and the utilization units 6 and 7 via the refrigerant communication tubes 8 to 11 and enclosed in the refrigerant circuit 13. The cooled refrigerant is circulated.

-First use unit-
As described above, the first usage unit 6 is connected to the heat source unit 2 via the first liquid refrigerant communication pipe 8 and the first gas refrigerant communication pipe 9 and constitutes a part of the refrigerant circuit 13. .

  Next, the configuration of the first usage unit 6 will be described.

  The first usage unit 6 mainly includes a first usage-side expansion valve 61, a first usage-side heat exchanger 62, and a first usage-side on-off valve 63.

  The first usage-side expansion valve 61 is a temperature-sensitive expansion valve capable of opening control for reducing the pressure of the high-pressure refrigerant in the refrigeration cycle. One end of the first usage side expansion valve 61 is connected to the first usage side on-off valve 63, and the other end of the first usage side expansion valve 61 is connected to the liquid side end of the first usage side heat exchanger 62. Has been.

  The 1st utilization side heat exchanger 62 is a heat exchanger which functions as an evaporator of the refrigerant | coolant of the low voltage | pressure (1st low voltage | pressure suitable for cooling in a warehouse) in a refrigerating cycle, and cools the air in a warehouse. The liquid side end of the first usage side heat exchanger 62 is connected to the first usage side expansion valve 61, and the gas side end of the first usage side heat exchanger 62 is connected to the first gas refrigerant communication tube 9. Has been. Here, the first usage unit 6 sucks the in-compartment air into the first usage unit 6 and exchanges heat with the refrigerant in the first usage-side heat exchanger 62, and then supplies the first usage unit 6 to the interior. One use side fan 64 is provided. The first usage-side fan 64 is driven by a first usage-side fan motor 65.

  The first use side on-off valve 63 is an electromagnetic valve capable of opening / closing control. One end of the first usage side on / off valve 63 is connected to the first liquid refrigerant communication pipe 8, and the other end of the first usage side on / off valve 63 is connected to the first usage side expansion valve 61.

-Second usage unit-
As described above, the second usage unit 7 is connected to the heat source unit 2 via the second liquid refrigerant communication pipe 10 and the second gas refrigerant communication pipe 11 and constitutes a part of the refrigerant circuit 13. .

  Next, the configuration of the second usage unit 7 will be described.

  The second usage unit 7 mainly includes a second usage-side expansion valve 71 and a second usage-side heat exchanger 72.

  The second usage side expansion valve 71 is an electric expansion valve capable of opening control for reducing the pressure of the high-pressure refrigerant in the refrigeration cycle. One end of the second usage side expansion valve 71 is connected to the second liquid refrigerant communication pipe 10, and the other end of the second usage side expansion valve 71 is connected to the liquid side end of the second usage side heat exchanger 72. Has been.

  The second usage-side heat exchanger 72 functions as an evaporator of a low-pressure refrigerant (a second low-pressure that is higher than the first low-pressure and suitable for indoor cooling) in the refrigeration cycle, and cools indoor air. Or it is a heat exchanger which functions as a radiator of the high-pressure refrigerant in the refrigeration cycle and heats indoor air. The liquid side end of the second usage side heat exchanger 72 is connected to the second usage side expansion valve 71, and the gas side end of the second usage side heat exchanger 72 is connected to the second gas refrigerant communication pipe 11. Has been. Here, the second usage unit 7 sucks room air into the second usage unit 7, exchanges heat with the refrigerant in the second usage side heat exchanger 72, and then supplies the second usage unit 7 to the room. A side fan 73 is provided. The second usage-side fan 73 is driven by a second usage-side fan motor 74.

-Heat source unit-
As described above, the heat source unit 2 is connected to the utilization units 6 and 7 via the refrigerant communication tubes 8 to 11 and constitutes a part of the refrigerant circuit 13.

  Next, the configuration of the heat source unit 2 will be described.

  The heat source unit 2 mainly includes a first compressor 21, a second compressor 22, a heat source side heat exchanger 24, a first switching mechanism 25, a second switching mechanism 26, a receiver 27, supercooling heat. An exchanger 28 and an injection tube 29 are provided.

  The first compressor 21 and the second compressor 22 are compressors that compress the refrigerant until it reaches a high pressure in the refrigeration cycle. Here, as the first compressor 21 and the second compressor 22, a compression structure having a hermetic structure in which a displacement type compression element (not shown) such as a rotary type or a scroll type is driven by compressor motors 21a and 22a. The machine is being used. In addition, the compression elements of the first compressor 21 and the second compressor 22 are provided with intermediate ports 21b and 22b that open to the position of the intermediate pressure in the refrigeration cycle. The compressor motors 21a and 22a can control the rotation speed (operation frequency) by an inverter, and thereby capacity control of the first compressor 21 and the second compressor 22 is possible.

  A first discharge pipe 21 c is connected to the discharge side of the first compressor 21. The first discharge pipe 21 c is connected to the first port 25 a of the first switching mechanism 25. A first suction pipe 21 d is connected to the suction side of the first compressor 21. The first suction pipe 21d communicates with the first low-pressure pipe 31 for communicating the first compressor 21 with the first usage-side heat exchanger 62 via the first gas refrigerant communication pipe 9 and the like. A first low-pressure refrigerant in the refrigeration cycle flows through the first low-pressure pipe 31, and the first gas refrigerant communication pipe 9 is connected via a first gas-side closing valve 41. The first gas side shut-off valve 41 is a manual valve provided at a connection portion between the heat source unit 2 and the first gas refrigerant communication pipe 9.

  A second discharge pipe 22 c is connected to the discharge side of the second compressor 22. The second discharge pipe 22 c is connected to the first port 25 a of the first switching mechanism 25. A second suction pipe 22 d is connected to the suction side of the second compressor 22. The second suction pipe 22d connects the second compressor 22 to the second use side heat exchanger 72 or the heat source side heat exchanger via the first switching mechanism 25, the second switching mechanism 26, the second gas refrigerant communication pipe 11, and the like. The second low-pressure pipe 32 communicates with the second low-pressure pipe 32. The second low-pressure pipe 32 is configured to flow a second low-pressure refrigerant in the refrigeration cycle, and is connected to the second port 26b of the second switching mechanism 26.

  The first low-pressure pipe 31 and the second low-pressure pipe 32 can communicate with each other via a connection low-pressure pipe 33. The connection low-pressure pipe 33 is provided with an adjustment valve 34 capable of adjusting the opening degree.

  The heat source side heat exchanger 24 is a heat exchanger that functions as a radiator of a high-pressure refrigerant in the refrigeration cycle or functions as an evaporator of a second low-pressure refrigerant in the refrigeration cycle. The gas side end of the heat source side heat exchanger 24 is connected to the third port 25 c of the first switching mechanism 25, and the liquid side end of the heat source side heat exchanger 24 is a receiver via the first liquid refrigerant pipe 45. 25. Here, the heat source unit 2 has a heat source side fan 46 for sucking outdoor air into the heat source unit 2, exchanging heat with the refrigerant in the heat source side heat exchanger 24, and then discharging the heat to the outside. . The heat source side fan 46 is driven by a heat source side fan motor 47.

  The first switching mechanism 25 and the second switching mechanism 26 are four-way switching valves. The first switching mechanism 25 includes a first port 25a connected to the first and second discharge pipes 21c and 22c, a second port 25b connected to the fourth port 26d of the second switching mechanism 26, and heat source side heat. Connected to the third port 25c connected to the gas side end of the exchanger 24 and the second gas side closing valve 43 which is a manual valve provided at the connection portion between the heat source unit 2 and the second gas refrigerant communication pipe 11. And a fourth port 25d. The second switching mechanism 26 includes a first port 26a connected to the first and second discharge pipes 21c and 22c, a second port 26b connected to the second low-pressure pipe 32, and a sealed third port 26c. And a fourth port 26d connected to the second port 25b of the first switching mechanism 25.

  The first switching mechanism 25 and the second switching mechanism 26 are in a first state (indicated by a solid line in FIG. 1) in which the first port and the third port communicate with each other and the second port and the fourth port communicate with each other. State) and a second state (state indicated by a broken line in FIG. 1) in which the first port and the fourth port communicate with each other and the second port and the third port communicate with each other. Has been. As a result, the first switching mechanism 25 and the second switching mechanism 26 are configured so that the second low-pressure pipe 32 communicates with the second usage-side heat exchanger 72 and the second low-pressure pipe 32 communicates with the heat source-side heat exchanger 24. A switching mechanism for switching between states is configured.

  The receiver 27 is a container that stores excess refrigerant therein. A first liquid refrigerant pipe 45 and a second liquid refrigerant pipe 46 are connected to the receiver 27. One end of the first liquid refrigerant tube 45 is connected to the liquid side end of the heat source side heat exchanger 24, and the other end of the first liquid refrigerant tube 45 is connected to the upper part of the receiver 27. The first liquid refrigerant pipe 45 includes a first check valve 45a that allows a refrigerant flow in the direction of the receiver 27 and prohibits a refrigerant flow in the opposite direction, and an electromagnetic valve that can be opened and closed. A first on-off valve 45b is provided. One end of the second liquid refrigerant pipe 46 is connected to the lower part of the receiver 27, and the other end of the second liquid refrigerant pipe 46 is connected to the supercooling heat exchanger 28. One end of a third liquid refrigerant pipe 47 is connected to the middle part of the second liquid refrigerant pipe 46. The other end of the third liquid refrigerant pipe 47 is connected to the second liquid refrigerant communication pipe 10 via the second liquid side closing valve 44. The second liquid side closing valve 44 is a manual valve provided at a connection portion between the heat source unit 2 and the second liquid refrigerant communication pipe 10. The third liquid refrigerant pipe 47 is provided with a third check valve 47a that allows the refrigerant to flow in the direction of the second liquid side closing valve 44 and prohibits the refrigerant from flowing in the opposite direction. . One end of the fourth liquid refrigerant pipe 48 is connected to the downstream portion of the third check valve 47 a of the third liquid refrigerant pipe 47. The other end of the fourth liquid refrigerant pipe 48 is connected to a downstream portion of the first on-off valve 45 b of the first liquid refrigerant pipe 45. The fourth liquid refrigerant pipe 48 is provided with a fourth check valve 48a that permits the refrigerant flow in the direction of the first liquid refrigerant pipe 45 and prohibits the refrigerant flow in the opposite direction.

  The subcooling heat exchanger 28 is a heat exchanger that cools the refrigerant supplied to the first usage unit 6, and is an intermediate that performs heat exchange with the refrigerant flowing through the high-pressure side heat AC path 28a and the high-pressure side heat AC path 26a. And a compression side heat exchange path 28b. One end of the high-pressure side thermal AC path 28 a is connected to the second liquid refrigerant pipe 46, and the other end of the high-pressure side thermal AC path 28 a is connected to the fifth liquid refrigerant pipe 49. Both ends of the intermediate pressure side heat exchange path 28 b are connected to an inflow side injection pipe 29 a and an outflow side injection pipe 29 b that constitute the injection pipe 29.

  The injection pipe 29 branches the high-pressure refrigerant in the refrigeration cycle from the fifth liquid refrigerant pipe 49 and depressurizes it to an intermediate pressure, and then injects into the intermediate ports 21 b and 22 b of the first compressor 21 and the second compressor 22. It is. The injection pipe 29 has an inflow side injection pipe 29a and an outflow side injection pipe 29b. One end of the inflow side injection pipe 29a is connected to the fifth liquid refrigerant pipe 49, and the other end of the inflow side injection pipe 29a is connected to one end of the intermediate pressure side heat AC path 28b. The inflow side injection pipe 29a is provided with an inflow side injection expansion valve 29c for reducing the high-pressure refrigerant in the refrigeration cycle to an intermediate pressure. The inflow side injection expansion valve 29c is an electric expansion valve capable of opening degree control. One end of the outflow side injection pipe 29b is connected to the other end of the intermediate pressure side heat exchange path 28b, and the other end of the outflow side injection pipe 29b is branched into two. It is connected to the intermediate ports 21b and 22b of the compressor 22. The outflow side injection pipe 29b is provided with outflow side injection expansion valves 30a and 30b for adjusting the flow rate of the refrigerant injected into the intermediate ports 21b and 22b. Outflow side injection expansion valves 30a and 30b are electric expansion valves capable of opening control. The other end of the fifth liquid refrigerant pipe 49 is connected to the first liquid refrigerant communication pipe 8 via the first liquid side closing valve 42. The first liquid side closing valve 42 is a manual valve provided at a connection portion between the heat source unit 2 and the first liquid refrigerant communication pipe 8. One end of a sixth liquid refrigerant pipe 50 is connected to the middle part of the fourth liquid refrigerant pipe 49. The other end of the sixth liquid refrigerant pipe 50 is connected to the first liquid refrigerant pipe 45. The sixth liquid refrigerant pipe 50 has a sixth check valve 50a that allows the refrigerant flow in the direction of the first liquid refrigerant pipe 45 and prohibits the refrigerant flow in the opposite direction, and has an opening degree control. And a heat source side expansion valve 50b composed of a possible electric expansion valve. One end of the seventh liquid refrigerant pipe 51 is connected to a portion of the sixth liquid refrigerant pipe 50 between the sixth check valve 50a and the heat source side expansion valve 50b. The other end of the seventh liquid refrigerant pipe 51 is connected to a downstream portion of the first on-off valve 45 b of the first liquid refrigerant pipe 45. The seventh liquid refrigerant pipe 51 is provided with a seventh check valve 51a that allows the refrigerant to flow in the direction of the first liquid refrigerant pipe 45 and prohibits the refrigerant from flowing in the opposite direction.

<Operation of refrigeration equipment>
Next, operation | movement of the freezing apparatus 1 is demonstrated using FIG.2 and FIG.3.

  In the refrigeration apparatus 1, an operation combining a cooling operation and an air conditioning operation (cooling operation or heating operation) can be performed. Here, among such operations, the cooling / cooling operation and the cooling / heating operation will be described. These operations are performed by the control unit 12 that controls the components of the refrigeration apparatus 1.

−Cooling / cooling operation−
The cooling / cooling operation is an operation in which the interior of the refrigerator is cooled by the first usage unit 6 and the room is cooled by the second usage unit 7. Therefore, in the cooling / cooling operation, the heat source side heat exchanger 24 functions as a refrigerant radiator, the first usage side heat exchanger 62 functions as a refrigerant evaporator, and the second usage side heat exchanger 72 It functions as a refrigerant evaporator.

  First, in the cooling / cooling operation, the first switching mechanism 25 and the second switching mechanism 26 are set to the first state (the state shown by the solid line in FIG. 2), and the first opening / closing valve 45b and the first usage-side opening / closing valve 63 are set. Is set to the open state, the heat source side expansion valve 50b is set to the fully closed state, the regulating valve 34, the inflow side injection expansion valve 29c, the outflow side injection expansion valves 30a and 30b, the first use side expansion valve 61 and the second. The use side expansion valve 71 is adjusted to a predetermined opening. In the cooling / cooling operation, the first compressor 21, the second compressor 22, the heat source side fan 46, the first usage side fan 64, and the second usage side fan 73 are driven.

  Then, as shown in FIG. 2, the high-pressure gas refrigerant in the refrigeration cycle compressed by the first compressor 21 and the second compressor 22 is sent to the heat source side heat exchanger 24 through the first switching mechanism 25. In the heat source side heat exchanger 24, the high-pressure gas refrigerant exchanges heat with the outdoor air and dissipates heat (condenses). The high-pressure liquid refrigerant radiated by the heat source side heat exchanger 24 flows in the order of the first liquid refrigerant pipe 45, the receiver 27, and the second liquid refrigerant pipe 46. A part of the high-pressure liquid refrigerant flowing through the second liquid refrigerant pipe 46 flows through the high-pressure side heat AC path 28 a of the supercooling heat exchanger 28, and the rest passes through the third liquid refrigerant pipe 47 to the second liquid refrigerant communication pipe 10. Sent. In the supercooling heat exchanger 28, the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a is cooled by exchanging heat with the intermediate-pressure refrigerant in the refrigeration cycle flowing through the intermediate-pressure side heat AC path 28b. The high-pressure liquid refrigerant cooled by the high-pressure side heat exchange path 28 a flows through the fifth liquid refrigerant pipe 49. A part of the high-pressure liquid refrigerant flowing through the fifth liquid refrigerant pipe 49 is branched to the inflow-side injection pipe 29 a of the injection pipe 29, and the rest is sent to the first liquid refrigerant communication pipe 8. The high-pressure liquid refrigerant branched to the inflow side injection pipe 29a is reduced to the intermediate pressure by the inflow side injection expansion valve 29c, and then flows through the intermediate pressure side heat AC path 28b of the supercooling heat exchanger 28. The intermediate-pressure refrigerant flowing through the intermediate-pressure side heat AC path 28b evaporates by exchanging heat with the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a. The intermediate pressure refrigerant evaporated in the intermediate pressure side heat exchange path 28 b flows through the outflow side injection pipe 29 b of the injection pipe 29. The intermediate pressure refrigerant flowing through the outflow side injection pipe 29b is branched into two and injected into the intermediate ports 21b and 22b of the first compressor 21 and the second compressor 22 through the outflow side injection expansion valves 30a and 30b. The

  The high-pressure liquid refrigerant sent to the first liquid refrigerant communication tube 8 is reduced to the first low-pressure in the refrigeration cycle by the first usage-side expansion valve 61 and then sent to the first usage-side heat exchanger 62. In the first usage side heat exchanger 62, the first low-pressure refrigerant evaporates by exchanging heat with the internal air. The first low-pressure gas refrigerant evaporated in the first usage-side heat exchanger 62 is sent to the first low-pressure pipe 31 through the first gas refrigerant communication pipe 9. The first low-pressure gas refrigerant flowing through the first low-pressure pipe 31 is sucked into the first compressor 21 through the first suction pipe 21d and is compressed again.

  The high-pressure liquid refrigerant sent to the second liquid refrigerant communication tube 10 is reduced to the second low-pressure in the refrigeration cycle by the second usage-side expansion valve 71 and then sent to the second usage-side heat exchanger 72. In the second usage-side heat exchanger 72, the second low-pressure refrigerant evaporates by exchanging heat with room air. The second low-pressure gas refrigerant evaporated in the second usage-side heat exchanger 72 is sent to the second low-pressure pipe 32 through the second gas refrigerant communication pipe 11 and the first and second switching mechanisms 25 and 26. The second low-pressure gas refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22 through the second suction pipe 22d and is compressed again.

  Here, when the cooling load (that is, the flow rate of the second low-pressure refrigerant corresponding to the cooling load) in the second usage unit 7 (second usage-side heat exchanger 72) can be processed only by the second compressor 22. By setting the control valve 34 of the connection low-pressure pipe 33 to a fully closed state, the first low-pressure refrigerant flowing through the first low-pressure pipe 31 is processed by the first compressor 21 as described above, and the second low-pressure pipe The second low-pressure refrigerant flowing through the second compressor 22 is processed by the second compressor 22.

  However, when the cooling load in the second usage unit 7 (second usage-side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to this cooling load) cannot be processed by the second compressor 22 alone, By setting the control valve 34 to the open state, the first low-pressure pipe 31 is communicated with the second low-pressure pipe 32 and the second low-pressure refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22. The first compressor 21 is also inhaled (see the broken arrow indicating the refrigerant flow shown in the vicinity of the low pressure pipe 33 in FIG. 2). That is, a part of the cooling load in the second usage unit 7 (second usage-side heat exchanger 72) is also processed by the first compressor 21. At this time, the regulating valve 34 reduces a part of the second low-pressure refrigerant flowing through the second low-pressure pipe 32 (the flow rate of the second low-pressure refrigerant that cannot be processed by the second compressor 22) from the second low pressure to the first low pressure. The opening degree is adjusted to

-Cooling / heating operation-
The cooling / heating operation is an operation in which the interior is cooled by the first usage unit 6 and the room is heated by the second usage unit 7. Therefore, in the cooling / heating operation, the heat source side heat exchanger 24 functions as a refrigerant evaporator, the first usage side heat exchanger 62 functions as a refrigerant evaporator, and the second usage side heat exchanger 72 Functions as a refrigerant radiator.

  First, in the cooling / heating operation, the first switching mechanism 25 is set to the second state (the state indicated by the broken line in FIG. 3), and the second switching mechanism 26 is set to the first state (the state indicated by the solid line in FIG. 3). The first use side on-off valve 63 is set to the open state, the heat source side expansion valve 50b is set to the fully open state, the first on-off valve 45b is set to the closed state, the control valve 34, the inflow side injection expansion The valve 29c, the outflow side injection expansion valves 30a and 30b, the first usage side expansion valve 61 and the second usage side expansion valve 71 are adjusted to a predetermined opening degree. In the cooling / heating operation, the first compressor 21, the second compressor 22, the heat source side fan 46, the first usage side fan 64, and the second usage side fan 73 are driven.

  Then, as shown in FIG. 3, the high-pressure refrigerant in the refrigeration cycle compressed by the first compressor 21 and the second compressor 22 is sent to the second gas refrigerant communication pipe 11 through the first switching mechanism 25.

  The high-pressure gas refrigerant sent to the second gas refrigerant communication tube 11 is sent to the second usage side heat exchanger 72. In the second usage-side heat exchanger 72, the high-pressure gas refrigerant exchanges heat with room air and dissipates heat (condenses). The high-pressure liquid refrigerant radiated by the second usage side heat exchanger 72 is sent to the second liquid refrigerant communication tube 10 through the second usage side expansion valve 71.

  The high-pressure liquid refrigerant sent to the second liquid refrigerant communication tube 10 flows in the order of the third liquid refrigerant tube 47, the fourth liquid refrigerant tube 48, the first liquid refrigerant tube 45, the receiver 27, and the second liquid refrigerant tube 46. . The high-pressure liquid refrigerant flowing through the second liquid refrigerant pipe 46 flows through the high-pressure side heat AC path 28 a of the supercooling heat exchanger 28. In the supercooling heat exchanger 28, the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a is cooled by exchanging heat with the intermediate-pressure refrigerant in the refrigeration cycle flowing through the intermediate-pressure side heat AC path 28b. The high-pressure liquid refrigerant cooled by the high-pressure side heat exchange path 28 a flows through the fifth liquid refrigerant pipe 49. A part of the high-pressure liquid refrigerant flowing through the fifth liquid refrigerant pipe 49 is branched into the inflow-side injection pipe 29 a and the sixth liquid refrigerant pipe 50 of the injection pipe 29, and the rest is sent to the first liquid refrigerant communication pipe 8. The high-pressure liquid refrigerant branched to the inflow side injection pipe 29a is reduced to the intermediate pressure by the inflow side injection expansion valve 29c, and then flows through the intermediate pressure side heat AC path 28b of the supercooling heat exchanger 28. The intermediate-pressure refrigerant flowing through the intermediate-pressure side heat AC path 28b evaporates by exchanging heat with the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a. The intermediate pressure refrigerant evaporated in the intermediate pressure side heat exchange path 28 b flows through the outflow side injection pipe 29 b of the injection pipe 29. The intermediate pressure refrigerant flowing through the outflow side injection pipe 29b is branched into two and injected into the intermediate ports 21b and 22b of the first compressor 21 and the second compressor 22 through the outflow side injection expansion valves 30a and 30b. The The high-pressure liquid refrigerant branched to the sixth liquid refrigerant pipe 50 is sent to the heat source side heat exchanger 24 after being reduced to the second low pressure in the refrigeration cycle by the heat source side expansion valve 50b. In the heat source side heat exchanger 24, the second low-pressure refrigerant evaporates by exchanging heat with outdoor air. The second low-pressure gas refrigerant evaporated in the heat source side heat exchanger 24 is sent to the second low-pressure pipe 32 through the first and second switching mechanisms 25 and 26. The second low-pressure gas refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22 through the second suction pipe 22d and is compressed again.

  The high-pressure liquid refrigerant sent to the first liquid refrigerant communication tube 8 is reduced to the first low-pressure in the refrigeration cycle by the first usage-side expansion valve 61 and then sent to the first usage-side heat exchanger 62. In the first usage side heat exchanger 62, the first low-pressure refrigerant evaporates by exchanging heat with the internal air. The first low-pressure gas refrigerant evaporated in the first usage-side heat exchanger 62 is sent to the first low-pressure pipe 31 through the first gas refrigerant communication pipe 9. The first low-pressure gas refrigerant flowing through the first low-pressure pipe 31 is sucked into the first compressor 21 through the first suction pipe 21d and is compressed again.

  Here, when the heating load in the second usage unit 7 (second usage-side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to the heating load) can be processed only by the second compressor 22. By setting the control valve 34 of the connection low-pressure pipe 33 to a fully closed state, the first low-pressure refrigerant flowing through the first low-pressure pipe 31 is processed by the first compressor 21 as described above, and the second low-pressure pipe The second low-pressure refrigerant flowing through the second compressor 22 is processed by the second compressor 22.

  However, when the heating load in the second usage unit 7 (second usage-side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to the heating load) cannot be processed only by the second compressor 22, By setting the control valve 34 to the open state, the first low-pressure pipe 31 is communicated with the second low-pressure pipe 32 and the second low-pressure refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22. The first compressor 21 is also inhaled (see the broken arrow indicating the refrigerant flow shown in the vicinity of the low pressure pipe 33 in FIG. 3). That is, a part of the heating load in the second usage unit 7 (second usage-side heat exchanger 72) is also processed by the first compressor 21. At this time, the regulating valve 34 reduces a part of the second low-pressure refrigerant flowing through the second low-pressure pipe 32 (the flow rate of the second low-pressure refrigerant that cannot be processed by the second compressor 22) from the second low pressure to the first low pressure. The opening degree is adjusted to

<Connection configuration of low pressure pipe and suction pipe>
In the above-described cooling / cooling operation or cooling / heating operation (see FIGS. 2 and 3), when the operation is performed with the control valve 34 of the connection low-pressure pipe 33 opened, the refrigerant passes through the low-pressure pipes 31-33. It is desirable to minimize the flow resistance when returning to the compressor 21 and the second compressor 22. Further, since the refrigerating machine 1 is filled with the refrigerating machine oil together with the refrigerant for lubricating the first compressor 21 and the second compressor 22, the control valve 34 of the connecting low-pressure pipe 33 is opened. When performing the operation, it is desirable to minimize the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21 and the second compressor 22 through the low pressure pipes 31 to 33.

  Therefore, here, as shown in FIG. 4, in the connection configuration among the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d), and the connection low-pressure pipe 33, a second branch pipe 36 is interposed. It is characterized by that. Here, as shown in FIG. 5, the second branch pipe 36 has a merging side opening 36 a that opens in a predetermined direction (left direction in FIG. 5), and a direction that is substantially opposite to the merging side opening 36 a. The branch pipe has two branch side openings 36b and 36c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the second branch pipe 36, since the branch side openings 36b and 36c are opened in the direction substantially opposite to the merge side opening 36a, fluid (refrigerant or refrigerating machine oil) flows from the merge side opening 36a side. Can flow smoothly to the branch side openings 36b and 36c. Here, the second low pressure pipe 32 is connected to the merge side opening 36a of the second branch pipe 36, and the connection low pressure pipe 33 and the second suction pipe 22d are connected to the two branch side openings 36b and 36c. It is characterized by that.

  In such a connection configuration between the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33 using the second branch pipe 36, the control valve 34 of the connection low-pressure pipe 33 is opened. When performing the operation in the state, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) via the second branch pipe 36. The flow can be smoothly diverted to the pipe 33 (the first compressor 21 side).

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21 and the second compressor 22 through the second low-pressure pipe 32 and the connecting low-pressure pipe 33 can be minimized.

  In addition, here, as shown in FIG. 4, the second branch pipe 36 is arranged so that the refrigerant flowing in from the merge side opening 36a is divided in the horizontal direction and flows out from the two branch side openings 36b, 36c. Has been. That is, the merge side opening 36a of the second branch pipe 36 faces in the lateral direction, the branch side openings 36b and 36c face in the lateral direction substantially opposite to the merge side opening 36a, and the branch side opening 36b, 36c is arranged so as to open at the same height position (hereinafter, this arrangement is referred to as "horizontal arrangement").

  Here, with such a horizontal arrangement of the second branch pipe 36, it is possible to improve the flow of refrigerant and refrigerating machine oil in the second branch pipe 36.

  Further, as shown in FIG. 4, the first branch pipe 35 is interposed in the connection configuration among the first low-pressure pipe 31, the first compressor 21 (first suction pipe 21 d), and the connection low-pressure pipe 33. It is a feature. Here, as shown in FIG. 5, the first branch pipe 35 has a merging side opening 35a that opens in a predetermined direction (the left side in FIG. 5), and a direction that is substantially opposite to the merging side opening 35a. The branch pipe has two branch side openings 35b and 35c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the first branch pipe 35, the branch side openings 35b and 35c are opened in the direction substantially opposite to the merge side opening 35a, so that the fluid (refrigerant or refrigerating machine oil) flows in from the merge side opening 35a side. Can flow smoothly toward the branch side openings 35b and 35c. In this example, the first low-pressure pipe 31 is connected to the merging-side opening 35a of the first branch pipe 35, and the connection low-pressure pipe 33 and the first suction pipe 21d are connected to the two branch-side openings 35b and 35c. It is characterized by that. Further, the first branch pipe 35 is also arranged horizontally, like the second branch pipe 36. That is, the merge side opening 35a of the first branch pipe 35 faces in the lateral direction, the branch side openings 35b, 35c face in the lateral direction substantially opposite to the merge side opening 56a, and the branch side opening 35b, 35c is arrange | positioned so that it may open to the same height position.

  In such a connection configuration between the first low-pressure pipe 31, the first compressor 21 (first suction pipe 21 d), and the connection low-pressure pipe 33 using the first branch pipe 35, the refrigerant flowing through the first low-pressure pipe 31 is the first. When the first compressor 21 is inhaled, the refrigerant flowing through the first low-pressure pipe 31 and the refrigerating machine oil flowing together with the refrigerant can flow smoothly to the first intake pipe 21d via the first branch pipe 35.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21 through the first low-pressure pipe 21d can be minimized.

(2) Second embodiment <Configuration of refrigeration apparatus>
In 1st Embodiment (refer FIGS. 1-3), while having the 1st compressor 21 which compresses a 1st low pressure refrigerant | coolant, and the 2nd compressor 22 which compresses a 2nd low pressure refrigerant | coolant, 1st A configuration is adopted in which a first low-pressure pipe 31 through which a low-pressure refrigerant flows and a second low-pressure pipe 32 through which a second low-pressure refrigerant flows communicate with each other via a connection low-pressure pipe 33 having an adjustment valve 34 capable of adjusting the opening degree. Has been. And when the air-conditioning load in the 2nd utilization side heat exchanger 72 cannot be processed only by the 2nd compressor 22, the 1st low pressure pipe 31 is made into the 2nd low pressure pipe 32 by setting the control valve 34 to an open state. The second low-pressure refrigerant flowing through the second low-pressure pipe 32 is caused to communicate with the second compressor 22 and also with the first compressor 21.

  However, such a configuration is not limited to the two compressors, ie, the first and second compressors 21 and 22, and may further include a third compressor 23.

  FIG. 6 is a schematic configuration diagram of the refrigeration apparatus 1 according to the second embodiment of the present invention. Here, in the structure of 1st Embodiment, the 3rd suction pipe 23d connected to the 3rd compressor 23 and the 3rd compressor 23 is further provided.

  The third compressor 23 is a compressor that compresses the refrigerant until it reaches a high pressure in the refrigeration cycle. Here, like the first compressor 21 and the second compressor 22, a positive displacement type compression element (not shown) such as a rotary type or a scroll type is driven by a compressor motor 23a as the third compressor 23. A closed type compressor is used. Further, like the first compressor 21 and the second compressor 22, the compression element of the third compressor 23 is provided with an intermediate port 23b that opens to the position of the intermediate pressure in the refrigeration cycle. Further, unlike the first compressor 21 and the second compressor 22, a compressor motor 23a having a constant rotational speed is used. A third discharge pipe 23 c is connected to the discharge side of the third compressor 23. The third discharge pipe 23 c is connected to the first port 25 a of the first switching mechanism 25, similarly to the first compressor 21 and the second compressor 22. The third suction pipe 23 d communicates with the first low-pressure pipe 31 through the first branch pipe 35 and the connection low-pressure pipe 33. Similarly to the first compressor 21 and the second compressor 22, a branch portion of the outflow side injection pipe 29 b constituting the injection pipe 29 is connected to the intermediate port 23 b. That is, the other end of the outflow side injection pipe 29b is branched into three and connected to the intermediate ports 21b, 22b, and 23d of the first compressor 21, the second compressor 22, and the third compressor 23. . The outflow side injection pipe 29b is also provided with an outflow side injection expansion valve 30c for adjusting the flow rate of the refrigerant injected into the intermediate port 23b, in addition to the outflow side injection expansion valves 30a and 30b. The outflow side injection expansion valve 30c is an electric expansion valve capable of opening degree control, like the outflow side injection expansion valves 30a and 30b.

  The configuration of the refrigeration apparatus 1 of the present embodiment is the same as that of the first embodiment except for the third compressor 23 and its peripheral configuration (including a connection configuration of a low-pressure pipe and a suction pipe described later). The description is omitted here.

<Operation of refrigeration equipment>
Next, operation | movement of the freezing apparatus 1 of this embodiment is demonstrated using FIG.7 and FIG.8.

  As in the first embodiment, the refrigeration apparatus 1 can perform a cooling / cooling operation and a cooling / heating operation in which a cooling operation and an air-conditioning operation (cooling operation or heating operation) are combined. Here, with respect to the cooling / cooling operation and the cooling / heating operation, the differences from the first embodiment will be mainly described. Note that these operations are performed by the control unit 12 that controls the components of the refrigeration apparatus 1 as in the first embodiment.

  In the cooling / cooling operation and cooling / heating operation of the present embodiment, the same operation and setting of the equipment as in the cooling / cooling operation and cooling / heating operation of the first embodiment are performed, and the outflow side injection expansion valve 30c is set to a predetermined value. The third compressor 23 is driven by adjusting the opening.

  In the cooling / cooling operation and the cooling / heating operation of the present embodiment, the refrigerant flows as shown in FIGS. 7 and 8 are obtained. The refrigerant flow shown in FIGS. 7 and 8 is injected into the intermediate port 23b of the third compressor 23 through the injection pipe 29, and the third compressor 23 sucks and compresses the low-pressure refrigerant in the refrigeration cycle. Except for this point, it is the same as the cooling / cooling operation of the first embodiment, and thus the description thereof is omitted here.

  Here, when the air conditioning load (that is, the flow rate of the second low-pressure refrigerant corresponding to the air conditioning load) in the second usage unit 7 (second usage side heat exchanger 72) can be processed only by the second compressor 22. By setting the control valve 34 of the connection low-pressure pipe 33 to a fully closed state, the first low-pressure refrigerant flowing through the first low-pressure pipe 31 is processed by the first compressor 21 and the third compressor 23 as described above. The second low-pressure refrigerant flowing through the second low-pressure pipe 32 is processed by the second compressor 22.

  However, when the air conditioning load in the second usage unit 7 (second usage side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to the air conditioning load) cannot be processed only by the second compressor 22, By setting the control valve 34 to the open state, the first low-pressure pipe 31 is communicated with the second low-pressure pipe 32 and the second low-pressure refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22. The third compressor 23 is also sucked (see the broken arrow indicating the refrigerant flow shown in the vicinity of the low pressure pipe 33 in FIGS. 7 and 8). That is, part of the air conditioning load in the second usage unit 7 (second usage-side heat exchanger 72) is also processed by the third compressor 23. At this time, the regulating valve 34 reduces a part of the second low-pressure refrigerant flowing through the second low-pressure pipe 32 (the flow rate of the second low-pressure refrigerant that cannot be processed by the second compressor 22) from the second low pressure to the first low pressure. The opening degree is adjusted to

<Connection configuration of low pressure pipe and suction pipe>
Also in the above cooling / cooling operation or cooling / heating operation (see FIGS. 7 and 8), when the operation is performed with the control valve 34 of the connection low-pressure pipe 33 opened, the refrigerant flows through the low-pressure pipes 31-33. It is desirable to minimize the flow resistance when returning to the first compressor 21, the second compressor 22, and the third compressor 23. Moreover, since the refrigerating machine oil is enclosed with the refrigerant in order to lubricate the first compressor 21, the second compressor 22, and the third compressor 23 in the refrigeration apparatus 1, such adjustment of the connection low-pressure pipe 33 is performed. When performing the operation with the valve 34 opened, the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21, the second compressor 22, and the third compressor 23 through the low pressure pipes 31 to 33 is minimized. It is desirable to do.

  Therefore, here, as shown in FIG. 9, in the connection configuration among the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d), and the connection low-pressure pipe 33, as in the first embodiment, The second branch pipe 36 is interposed, the second low pressure pipe 32 is connected to the merge side opening 36a of the second branch pipe 36, and the connection low pressure pipe 33 and the second suction pipe 22d are connected to the two branch side openings 36b, 36c. It is characterized by being connected.

  In such a connection configuration between the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33 using the second branch pipe 36, the control valve 34 of the connection low-pressure pipe 33 is opened. When performing the operation in the state, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) via the second branch pipe 36. The flow can be smoothly divided into the pipe 33 (the third compressor 23 side).

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the second compressor 22 and the third compressor 23 through the second low-pressure pipe 32 and the connection low-pressure pipe 33 can be minimized. Here, similarly to the first embodiment, the horizontal arrangement of the second branch pipe 36 can improve the flow of refrigerant and refrigerating machine oil in the second branch pipe 36.

  Further, here, as shown in FIG. 9, in the connection configuration among the first low-pressure pipe 31, the first compressor 21 (first suction pipe 21d) and the connection low-pressure pipe 33, as in the first embodiment, The first branch pipe 35 is interposed, the first low-pressure pipe 31 is connected to the merge side opening 35a of the first branch pipe 35, and the connection low-pressure pipe 33 and the first suction pipe 21d are connected to the two branch side openings 35b and 35c. It is characterized by being connected. Further, the first branch pipe 35 is also arranged horizontally as in the first embodiment. Here, the third low pressure pipe 33 is characterized in that the third suction pipe 23d of the third compressor 23 is connected to a portion of the connection low pressure pipe 33 closer to the first branch pipe 35 than the control valve 34.

  In the configuration in which the third compressor 23 is further connected to a portion of the connection low pressure pipe 33 closer to the first branch pipe 35 than the control valve 34, the refrigerant flowing through the first low pressure pipe 31 is combined with the first compressor 21. At this time, the refrigerant flowing through the first low-pressure pipe 31 and the refrigerating machine oil flowing together with the refrigerant can be sucked into the first suction pipe 21d (first compression pipe 21d) via the first branch pipe 35. Machine 21 side) and the connecting low-pressure pipe 33 (third compressor 23 side) can be smoothly diverted. In addition, by arranging the first branch pipe 35 horizontally, the flow of refrigerant and refrigerating machine oil in the first branch pipe 35 can be improved. In such a configuration, the refrigerant flowing through the second low-pressure pipe 32 can be sucked into the third compressor 23 together with the second compressor 22 by opening the adjustment valve 34 of the connection low-pressure pipe 33. At this time, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) and the connection low-pressure pipe 33 (third) via the second branch pipe 36. Can be smoothly diverted to the compressor 23 side).

  Thereby, here, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23 together with the first compressor 21, or the refrigerant flowing through the second low-pressure pipe 32 is drawn together with the second compressor 22 into the third compressor. When the refrigerant returns to the first compressor 21, the second compressor 22, and the third compressor 23 through the first low pressure pipe 31, the second low pressure pipe 32, and the connection low pressure pipe 33. The flow resistance and refrigerating machine oil bias can be minimized.

  Here, as shown in FIG. 9, in the connection configuration between the third compressor 23 (third suction pipe 23d) and the connection low-pressure pipe 33 (first and third connection low-pressure pipes 33a and 33c), It is characterized in that a branch pipe 37 is interposed. Here, as shown in FIG. 5, the third branch pipe 37 has a merging side opening 37 a that opens in a predetermined direction (left direction in FIG. 5) and a direction substantially opposite to the merging side opening 37 a. The branch pipe has two branch side openings 37b and 37c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the third branch pipe 37, the branch side openings 37b and 37c are opened in a direction substantially opposite to the merge side opening 37a, so that the fluid (refrigerant) flowing in from any branch side opening 37b or 37c side. And refrigerating machine oil) can also flow smoothly to the merging side opening 37a side. Here, the third suction pipe 23d is connected to the merge side opening 37a of the third branch pipe 37, and the first connection low pressure pipe 33a and the third connection low pressure pipe 33c are connected to the two branch side openings 37b and 37c. It is characterized by being connected. Here, the first connection low-pressure pipe 33 a is one of the branch-side opening 35 b of the first branch pipe 35 and the two branch-side openings 37 a and 37 b of the third branch pipe 37 (here, This is the part that connects the branch side opening 37b). The second connection low-pressure pipe 33 b is a part of the connection low-pressure pipe 33 that connects the branch side opening 36 b of the second branch pipe 36 and the control valve 34. The third connection low-pressure pipe 33c is a part that connects the control valve 34 and the other of the two branch side openings 37b and 37c of the third branch pipe 37 (here, the branch side opening 37c). Further, the third branch pipe 37 is also arranged horizontally as in the first and second branch pipes 35 and 36.

  In such a connection configuration between the third suction pipe 23d using the third branch pipe 37 and the first and third connection low-pressure pipes 33a and 33c, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23. Refrigeration oil flowing together with the refrigerant flowing through the first and second low-pressure pipes 31 and 32 and the refrigerant oil flowing through the second low-pressure pipe 32 together with the refrigerant flowing through the first and second low-pressure pipes 31 and 32. Through the third branch pipe 37, it is possible to smoothly flow to the third suction pipe 23d.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the third compressor 23 through the connection low-pressure pipe 33 can be minimized.

<Modification>
The connection configuration of the low pressure pipe and the suction pipe applied to the configuration having the first compressor 21, the second compressor 22, and the third compressor 23 (see FIGS. 6 to 8) is limited to the configuration shown in FIG. Instead of this, a configuration as shown in FIG. 10 may be used.

  First, as shown in FIG. 10, in the connection configuration among the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33, as in the configuration of FIG. The second branch pipe 36 is interposed, the second low pressure pipe 32 is connected to the merge side opening 36a of the second branch pipe 36, and the connection low pressure pipe 33 and the second suction pipe 22d are connected to the two branch side openings 36b, 36c. It is characterized by being connected.

  In such a connection configuration between the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33 using the second branch pipe 36, the control valve 34 of the connection low-pressure pipe 33 is opened. When performing the operation in the state, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) via the second branch pipe 36. The flow can be smoothly divided into the pipe 33 (the third compressor 23 side).

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the second compressor 22 and the third compressor 23 through the second low-pressure pipe 32 and the connection low-pressure pipe 33 can be minimized. Here, similarly to the configuration of FIG. 9, the horizontal distribution of the second branch pipe 36 can improve the flow of refrigerant and refrigerating machine oil in the second branch pipe 36.

  Further, here, as shown in FIG. 10, the first low pressure pipe 31, the first compressor 21 (first suction pipe 21 d), the third compressor 21 (third suction pipe 23 d), and the connection low pressure pipe 33 are connected. In the connection configuration, the merging low-pressure pipe 40 is connected to the first low-pressure pipe 31 and the connecting low-pressure pipe 33, and the merging low-pressure pipe 40 connected to the first low-pressure pipe 31 and the connecting low-pressure pipe 33 is connected to the first compressor 21. It is characterized in that the first suction pipe 21d and the third suction pipe 23d of the third compressor 23 are connected.

  In the configuration in which the first and third compressors 21, 23 are connected to the merging low pressure pipe 40, the refrigerant flowing through the first low pressure pipe 31 is passed through the merging low pressure pipe 40 together with the first compressor 21 and the third compressor. 23 can be inhaled. In such a configuration, the control valve 34 of the connection low-pressure pipe 33 is opened so that the refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22 and the connection low-pressure pipe 33 and the combined low-pressure pipe 33 The third compressor 23 can be sucked through the pipe 40, and at this time, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are passed through the second branch pipe 36 to the second suction pipe 22 d ( The second compressor 22 side) and the connecting low pressure pipe 33 and the merged low pressure pipe 40 (third compressor 23 side) can be smoothly diverted.

  In addition, as shown in FIG. 10, in the connection configuration among the merging low pressure pipe 40, the first compressor 21 (first suction pipe 21d), and the third compressor 23 (third suction pipe 23d), It is characterized in that a branch pipe 38 is interposed. Here, as shown in FIG. 5, the fourth branch pipe 38 has a merging side opening 38 a that opens in a predetermined direction (left direction in FIG. 5), and a direction that is substantially opposite to the merging side opening 38 a. The branch pipe has two branch side openings 38b and 38c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the fourth branch pipe 38, the branch side openings 38b and 38c are opened in a direction substantially opposite to the merge side opening 38a, so that the fluid (refrigerant or refrigerating machine oil) flows from the merge side opening 38a side. Can flow smoothly toward the branch side openings 38b and 38c. Here, the merged low pressure pipe 40 is connected to the merge side opening 38a of the fourth branch pipe 38, and the first suction pipe 21d and the third suction pipe 23d are connected to the two branch side openings 38b, 38c. It is characterized by that.

  In such a connection configuration between the merging low pressure pipe 40, the first suction pipe 21d, and the third suction pipe 23d using the fourth branch pipe 38, together with the refrigerant and the refrigerant flowing through the first low pressure pipe 31 and the second low pressure pipe 32, The flowing refrigeration oil flows smoothly into the first suction pipe 21d (first compressor 21 side) and the third suction pipe 23d (third compressor 23 side) via the merged low-pressure pipe 40 and the fourth branch pipe 38. Can be diverted.

  Thereby, here, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23 together with the first compressor 21, or the refrigerant flowing through the second low-pressure pipe 32 is drawn together with the second compressor 22 into the third compressor. 23, and the refrigerant passes through the first low-pressure pipe 31, the second low-pressure pipe 32, the connecting low-pressure pipe 33, the combined low-pressure pipe 40, and the fourth branch pipe 38. The flow resistance when returning to the machine 22 and the third compressor 23 and the deviation of the refrigerating machine oil can be minimized.

  In addition, here, as shown in FIG. 10, the fourth branch pipe 38 is horizontally arranged, so that the refrigerant and refrigerating machine oil in the fourth branch pipe 38 can be excellently divided.

  Further, here, as shown in FIG. 10, in the connection configuration between the first low-pressure pipe 31, the first and third compressors 21 and 23 (merging low-pressure pipe 40), and the connection low-pressure pipe 33, the fifth branch pipe 39. It is characterized by interposing. Here, as shown in FIG. 5, the fifth branch pipe 39 has a merging side opening 39a that opens in a predetermined direction (the left side in FIG. 5), and a direction that is substantially opposite to the merging side opening 39a. The branch pipe has two branch side openings 39b and 39c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the fourth branch pipe 39, the branch side openings 39b and 39c open in a direction substantially opposite to the merge side opening 39a, and therefore fluid (refrigerant) flowing in from any branch side opening 39b or 39c side. And refrigerating machine oil) can also flow smoothly to the merging side opening 39a. And here, the confluence low-pressure pipe 40 is connected to the confluence-side opening 39a of the fifth branch pipe 39, and the first low-pressure pipe 31 and the connection low-pressure pipe 33 are connected to the two branch-side openings 39b and 39c. Characterized by dots. Similarly to the second branch pipe 36 and the fourth branch pipe 38, the fifth branch pipe 39 is also arranged horizontally.

  In such a connection configuration between the first low-pressure pipe 31, the joining low-pressure pipe 40 and the connecting low-pressure pipe 33 using the fifth branch pipe 39, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23. In any of the cases where the refrigerant flowing through the connection low-pressure pipe 33 is sucked into the third compressor 23, the refrigerant flowing through the first low-pressure pipe 31 and the connection low-pressure pipe 33 and the refrigerant oil flowing together with the refrigerant are It is possible to smoothly flow through the branch pipe 39 to the merged low pressure pipe 40.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 31 and the third compressor 23 through the merged low-pressure pipe 40 can be minimized.

  The present invention provides a first and second compressor, a heat source side heat exchanger, a first and second usage side heat exchanger, and a first for communicating the first compressor with the first usage side heat exchanger. The first low pressure pipe has a first low pressure pipe, a second low pressure pipe for communicating the second compressor with the second use side heat exchanger or the heat source side heat exchanger, and a control valve capable of adjusting the opening degree. The present invention is widely applicable to a refrigeration apparatus including a connection low-pressure pipe for communicating the pipe and the second low-pressure pipe.

DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 21 1st compressor 21d 1st suction pipe 22 2nd compressor 22d 2nd suction pipe 23 3rd compressor 23d 3rd suction pipe 24 Heat source side heat exchanger 31 1st low pressure pipe 32 2nd low pressure pipe 33 Connection low pressure pipes 33a to 33c First to third connection low pressure pipes 34 Control valve 35 to 39 First to fifth branch pipes 35a to 39a Merge side opening 35b to 39b Branch side opening 35c to 39c Branch side opening 40 Merge Low pressure pipe 62 First use side heat exchanger 72 Second use side heat exchanger

JP 2014-70822 A

  The present invention relates to a refrigeration apparatus, in particular, first and second compressors, a heat source side heat exchanger, first and second usage side heat exchangers, and a first compressor as a first usage side heat exchanger. A first low-pressure pipe for communicating, a second low-pressure pipe for communicating the second compressor with the second use side heat exchanger or the heat source side heat exchanger, and a control valve capable of adjusting the opening. The present invention relates to a refrigeration apparatus including a connecting low-pressure pipe for communicating a first low-pressure pipe and a second low-pressure pipe.

  Conventionally, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2014-70822), there is a refrigeration apparatus having a plurality of types of usage-side heat exchangers. In this refrigeration system, as a plurality of types of use side heat exchangers, a refrigeration heat exchanger (first use side heat exchanger) for cooling the interior of a showcase or the like, and indoor cooling or heating (air conditioning) And an indoor heat exchanger (second utilization side heat exchanger) for performing. This refrigeration apparatus has a plurality of compressors and a heat source side heat exchanger. As a plurality of compressors, a first compressor that sucks and compresses the refrigerant evaporated in the first usage side heat exchanger, and a refrigerant that evaporates in the second usage side heat exchanger or the heat source side heat exchanger And a second compressor for compression. A first low-pressure pipe for connecting the first compressor to the first use side heat exchanger is connected to the first compressor. The second compressor is connected to a second low pressure pipe for communicating the second compressor with the second use side heat exchanger or the heat source side heat exchanger. The first low-pressure pipe and the second low-pressure pipe communicate with each other via a connection low-pressure pipe having a control valve capable of adjusting the opening degree.

  In the refrigeration apparatus of Patent Document 1, since the first low-pressure pipe can be communicated with the second low-pressure pipe by opening the control valve of the connection low-pressure pipe, the refrigerant flowing through the second low-pressure pipe is subjected to the second compression. The first compressor can be inhaled as well as the machine. For this reason, for example, when the air conditioning load in the second usage side heat exchanger (that is, the flow rate of the refrigerant corresponding to the air conditioning load) cannot be processed only by the second compressor, the air conditioning load in the second usage side heat exchanger. (That is, the refrigerant flow rate corresponding to a part of the air-conditioning load) can also be processed by the first compressor. At this time, the flow rate of the refrigerant sucked into the first compressor can be finely controlled by adjusting the opening of the control valve or the like.

  However, when performing the operation with the control valve of the connection low-pressure pipe opened, it is desirable to minimize the flow resistance when the refrigerant returns to the compressor through these low-pressure pipes. In addition, since the refrigeration apparatus is filled with refrigeration oil together with refrigerant for lubrication of the compressor, when operating with such a connection low-pressure pipe control valve opened, these low-pressure pipes are used. It is desirable to minimize the bias of the refrigerating machine oil when the refrigerant returns to the compressor through.

  An object of the present invention is to communicate a first low-pressure pipe for communicating a first compressor with a first use side heat exchanger, and a second compressor with a second use side heat exchanger or a heat source side heat exchanger. In the refrigerating apparatus in which the second low-pressure pipe communicates with the connecting low-pressure pipe having a control valve capable of adjusting the opening degree, the flow resistance and refrigerant oil flow when the refrigerant returns to the compressor through these low-pressure pipes The purpose is to make the bias as small as possible.

  A refrigeration apparatus according to a first aspect includes a first compressor and a second compressor, a heat source side heat exchanger, a first usage side heat exchanger and a second usage side heat exchanger, a first low pressure pipe, And a second low-pressure pipe and a connecting low-pressure pipe. The first low-pressure pipe communicates the first compressor with the first usage-side heat exchanger. The second low-pressure pipe causes the second compressor to communicate with the second use side heat exchanger or the heat source side heat exchanger. The connection low-pressure pipe has an adjustment valve capable of adjusting the opening degree, and connects the first low-pressure pipe and the second low-pressure pipe. And here, it has further the 2nd suction pipe connected to the 2nd compressor, and the 2nd branch pipe. Here, the second branch pipe is a branch pipe having a merging side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merging side opening, The second low pressure pipe is connected to the merge side opening, and the connection low pressure pipe and the second suction pipe are connected to the two branch side openings.

  Here, in the connection configuration between the second low-pressure pipe, the second compressor (second suction pipe), and the connection low-pressure pipe, as described above, the merging-side opening that opens in a predetermined direction, and the merging-side opening, Includes a second branch pipe having two branch side openings that open in substantially opposite directions, a second low pressure pipe connected to the merge side opening, a low pressure pipe connected to the two branch side openings, and It is characterized in that the second suction pipe is connected. Here, as described above, since the branch side opening is opened in the direction substantially opposite to the merge side opening as described above, the second branch pipe allows the fluid flowing in from the merge side opening side to branch side opening. Can flow smoothly to the side. In such a connection configuration between the second low-pressure pipe, the second compressor (second suction pipe), and the connection low-pressure pipe using the second branch pipe, the operation is performed with the control valve of the connection low-pressure pipe open. In addition, the refrigerant flowing through the second low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant are smoothly supplied to the second suction pipe (second compressor side) and the connecting low-pressure pipe (first compressor side) via the second branch pipe. Can be shunted.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the second low-pressure pipe and the connecting low-pressure pipe can be minimized.

In addition, here, it further includes a first suction pipe connected to the first compressor and a first branch pipe. Here, the first branch pipe is a branch pipe having a merge side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merge side opening, The first low pressure pipe is connected to the merge side opening, and the connection low pressure pipe and the first suction pipe are connected to the two branch side openings.

Here, in the connection configuration between the first low-pressure pipe, the first compressor (first suction pipe), and the connection low-pressure pipe, as described above, the merging-side opening that opens in a predetermined direction, and the merging-side opening Includes a first branch pipe having two branch side openings that open in substantially opposite directions, a first low pressure pipe connected to the merge side opening, a low pressure pipe connected to the two branch side openings, and It is characterized in that the first suction pipe is connected. Here, as described above, since the branch side opening is opened in the direction substantially opposite to the merge side opening as described above, the first branch pipe allows the fluid flowing in from the merge side opening side to branch side opening. Can flow smoothly to the side. In such a connection configuration between the first low-pressure pipe, the first compressor (first suction pipe), and the connection low-pressure pipe using the first branch pipe, the refrigerant flowing through the first low-pressure pipe is sucked into the first compressor. At this time, the refrigerant flowing through the first low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant can flow smoothly to the first suction pipe via the first branch pipe.

Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the first low-pressure pipe can be minimized.

Furthermore, here, it further has a third compressor and a third suction pipe connected to the third compressor. Here, the third suction pipe is connected to a portion of the connection low-pressure pipe closer to the first branch pipe than the control valve.

Here, the third compressor is further provided, and the third suction pipe of the third compressor is connected to a portion of the connecting low pressure pipe closer to the first branch pipe than the control valve. Yes. In the configuration in which the third compressor is further connected to the first branch pipe side of the connecting low-pressure pipe in such a connection low-pressure pipe, the refrigerant flowing through the first low-pressure pipe is sucked into the third compressor together with the first compressor. In this case, the refrigerant flowing through the first low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant are connected to the first suction pipe (first compressor side) and the connecting low-pressure pipe (third) via the first branch pipe. Can be smoothly diverted to the compressor side. In addition, by arranging the first branch pipe horizontally, it is possible to improve the flow of refrigerant and refrigerating machine oil in the first branch pipe. In such a configuration, the refrigerant flowing through the second low-pressure pipe can be sucked into the third compressor together with the second compressor by opening the adjustment valve of the connection low-pressure pipe. 2 Refrigerant flowing through the low-pressure pipe and the refrigerating machine oil flowing together with the refrigerant are smoothly divided into the second suction pipe (second compressor side) and the connecting low-pressure pipe (third compressor side) via the second branch pipe. be able to.

Thereby, here, the refrigerant flowing through the first low-pressure pipe is sucked into the third compressor together with the first compressor, or the refrigerant flowing through the second low-pressure pipe is sucked into the third compressor together with the second compressor. In addition, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the first low pressure pipe, the second low pressure pipe, and the connection low pressure pipe can be minimized.

  In the refrigeration apparatus according to the second aspect, in the refrigeration apparatus according to the first aspect, the second branch pipe splits the refrigerant flowing in from the merging side opening in the horizontal direction and flows out from the two branch side openings. Are arranged as follows.

  Here, with the horizontal arrangement of the second branch pipe as described above, it is possible to improve the flow of refrigerant and refrigerating machine oil in the second branch pipe.

In the refrigeration apparatus according to the third aspect , in the refrigeration apparatus according to the first or second aspect , the first branch pipe is divided into two branch side openings by horizontally dividing the refrigerant flowing in from the merge side opening. It is arranged to flow out from.

Fourth according to the aspect refrigeration system, the refrigeration apparatus according to any one of the first to third aspects, further includes a third branch pipe. Here, the third branch pipe is a branch pipe having a merge side opening that opens in a predetermined direction and two branch side openings that open in a direction substantially opposite to the merge side opening, A third suction pipe is connected to the merging side opening. The connecting low-pressure pipe includes a first connecting low-pressure pipe connecting the branch side opening of the first branch pipe and one of the two branch side openings of the third branch pipe, and a branch side opening of the second branch pipe. And a second connection low-pressure pipe connecting the control valve and a third connection low-pressure pipe connecting the other of the two branch side openings of the control valve and the third branch pipe.

  Here, in the connection configuration between the third compressor (third suction pipe) and the connection low-pressure pipe (first and third connection low-pressure pipes), as described above, a merging side opening that opens in a predetermined direction; A third branch pipe having two branch side openings that open in a direction substantially opposite to the merge side opening is interposed, the third suction pipe is connected to the merge side opening, and two branch side openings The first connecting low-pressure pipe and the third connecting low-pressure pipe are connected to each other. Here, as described above, the third branch pipe has the branch side opening portion opened in a direction substantially opposite to the merge side opening portion, so that any fluid flowing from any branch side opening portion side can also be joined. Smooth flow to the opening side. In such a connection configuration between the third suction pipe using the third branch pipe and the first and third connection low-pressure pipes, when the third compressor sucks the refrigerant flowing through the first low-pressure pipe, Regardless of when the refrigerant flowing through the low-pressure pipe is sucked into the third compressor, the refrigerant flowing through the first and second low-pressure pipes or the refrigerating machine oil flowing together with the refrigerant is passed through the third branch pipe to the third suction. Can flow smoothly into the tube.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the compressor through the connection low-pressure pipe can be minimized.

  As described in the above description, according to the present invention, it is possible to minimize the flow resistance and the refrigerating machine oil bias when the refrigerant returns to the compressor through the low-pressure pipe.

It is a schematic block diagram of the freezing apparatus concerning 1st Embodiment of this invention. It is a figure which shows the flow of the refrigerant | coolant in cooling / cooling operation. It is a figure which shows the flow of the refrigerant | coolant in cooling and heating operation. It is a figure which shows the connection structure of a low pressure pipe and a suction pipe. It is sectional drawing of a branch pipe. It is a schematic block diagram of the freezing apparatus concerning 2nd Embodiment of this invention. It is a figure which shows the flow of the refrigerant | coolant in cooling / cooling operation. It is a figure which shows the flow of the refrigerant | coolant in cooling and heating operation. It is a figure which shows the connection structure of a low pressure pipe and a suction pipe. It is a figure which shows the connection structure of the low pressure pipe and the suction pipe in the modification of 2nd Embodiment.

  Hereinafter, an embodiment of a refrigeration apparatus according to the present invention will be described based on the drawings. In addition, the specific structure of embodiment of the freezing apparatus concerning this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) First Embodiment <Configuration of Refrigeration Apparatus>
FIG. 1 is a schematic configuration diagram of a refrigeration apparatus 1 according to the first embodiment of the present invention. The refrigeration apparatus 1 is an apparatus configured to simultaneously perform cooling in a store such as a showcase and cooling or heating (air conditioning) in a store or the like in a store such as a convenience store by a vapor compression refrigeration cycle. It is. The refrigeration apparatus 1 mainly includes a heat source unit 2, a first usage unit 6 for cooling the inside of the cabinet, a second usage unit 7 for indoor air conditioning, the heat source unit 2 and the first usage unit 6. First liquid refrigerant communication pipe 8 and first gas refrigerant communication pipe 9 to be connected, second liquid refrigerant communication pipe 10 and second gas refrigerant communication pipe 11 to connect the heat source unit 2 and the second usage unit 7, And a control unit 12 that controls the components of the device 1. The vapor compression refrigerant circuit 13 of the refrigeration apparatus 1 is configured by connecting the heat source unit 2 and the utilization units 6 and 7 via the refrigerant communication tubes 8 to 11 and enclosed in the refrigerant circuit 13. The cooled refrigerant is circulated.

-First use unit-
As described above, the first usage unit 6 is connected to the heat source unit 2 via the first liquid refrigerant communication pipe 8 and the first gas refrigerant communication pipe 9 and constitutes a part of the refrigerant circuit 13. .

  Next, the configuration of the first usage unit 6 will be described.

  The first usage unit 6 mainly includes a first usage-side expansion valve 61, a first usage-side heat exchanger 62, and a first usage-side on-off valve 63.

  The first usage-side expansion valve 61 is a temperature-sensitive expansion valve capable of opening control for reducing the pressure of the high-pressure refrigerant in the refrigeration cycle. One end of the first usage side expansion valve 61 is connected to the first usage side on-off valve 63, and the other end of the first usage side expansion valve 61 is connected to the liquid side end of the first usage side heat exchanger 62. Has been.

  The 1st utilization side heat exchanger 62 is a heat exchanger which functions as an evaporator of the refrigerant | coolant of the low voltage | pressure (1st low voltage | pressure suitable for cooling in a warehouse) in a refrigerating cycle, and cools the air in a warehouse. The liquid side end of the first usage side heat exchanger 62 is connected to the first usage side expansion valve 61, and the gas side end of the first usage side heat exchanger 62 is connected to the first gas refrigerant communication tube 9. Has been. Here, the first usage unit 6 sucks the in-compartment air into the first usage unit 6 and exchanges heat with the refrigerant in the first usage-side heat exchanger 62, and then supplies the first usage unit 6 to the interior. One use side fan 64 is provided. The first usage-side fan 64 is driven by a first usage-side fan motor 65.

  The first use side on-off valve 63 is an electromagnetic valve capable of opening / closing control. One end of the first usage side on / off valve 63 is connected to the first liquid refrigerant communication pipe 8, and the other end of the first usage side on / off valve 63 is connected to the first usage side expansion valve 61.

-Second usage unit-
As described above, the second usage unit 7 is connected to the heat source unit 2 via the second liquid refrigerant communication pipe 10 and the second gas refrigerant communication pipe 11 and constitutes a part of the refrigerant circuit 13. .

  Next, the configuration of the second usage unit 7 will be described.

  The second usage unit 7 mainly includes a second usage-side expansion valve 71 and a second usage-side heat exchanger 72.

  The second usage side expansion valve 71 is an electric expansion valve capable of opening control for reducing the pressure of the high-pressure refrigerant in the refrigeration cycle. One end of the second usage side expansion valve 71 is connected to the second liquid refrigerant communication pipe 10, and the other end of the second usage side expansion valve 71 is connected to the liquid side end of the second usage side heat exchanger 72. Has been.

  The second usage-side heat exchanger 72 functions as an evaporator of a low-pressure refrigerant (a second low-pressure that is higher than the first low-pressure and suitable for indoor cooling) in the refrigeration cycle, and cools indoor air. Or it is a heat exchanger which functions as a radiator of the high-pressure refrigerant in the refrigeration cycle and heats indoor air. The liquid side end of the second usage side heat exchanger 72 is connected to the second usage side expansion valve 71, and the gas side end of the second usage side heat exchanger 72 is connected to the second gas refrigerant communication pipe 11. Has been. Here, the second usage unit 7 sucks room air into the second usage unit 7, exchanges heat with the refrigerant in the second usage side heat exchanger 72, and then supplies the second usage unit 7 to the room. A side fan 73 is provided. The second usage-side fan 73 is driven by a second usage-side fan motor 74.

-Heat source unit-
As described above, the heat source unit 2 is connected to the utilization units 6 and 7 via the refrigerant communication tubes 8 to 11 and constitutes a part of the refrigerant circuit 13.

  Next, the configuration of the heat source unit 2 will be described.

  The heat source unit 2 mainly includes a first compressor 21, a second compressor 22, a heat source side heat exchanger 24, a first switching mechanism 25, a second switching mechanism 26, a receiver 27, supercooling heat. An exchanger 28 and an injection tube 29 are provided.

  The first compressor 21 and the second compressor 22 are compressors that compress the refrigerant until it reaches a high pressure in the refrigeration cycle. Here, as the first compressor 21 and the second compressor 22, a compression structure having a hermetic structure in which a displacement type compression element (not shown) such as a rotary type or a scroll type is driven by compressor motors 21a and 22a. The machine is being used. In addition, the compression elements of the first compressor 21 and the second compressor 22 are provided with intermediate ports 21b and 22b that open to the position of the intermediate pressure in the refrigeration cycle. The compressor motors 21a and 22a can control the rotation speed (operation frequency) by an inverter, and thereby capacity control of the first compressor 21 and the second compressor 22 is possible.

  A first discharge pipe 21 c is connected to the discharge side of the first compressor 21. The first discharge pipe 21 c is connected to the first port 25 a of the first switching mechanism 25. A first suction pipe 21 d is connected to the suction side of the first compressor 21. The first suction pipe 21d communicates with the first low-pressure pipe 31 for communicating the first compressor 21 with the first usage-side heat exchanger 62 via the first gas refrigerant communication pipe 9 and the like. A first low-pressure refrigerant in the refrigeration cycle flows through the first low-pressure pipe 31, and the first gas refrigerant communication pipe 9 is connected via a first gas-side closing valve 41. The first gas side shut-off valve 41 is a manual valve provided at a connection portion between the heat source unit 2 and the first gas refrigerant communication pipe 9.

  A second discharge pipe 22 c is connected to the discharge side of the second compressor 22. The second discharge pipe 22 c is connected to the first port 25 a of the first switching mechanism 25. A second suction pipe 22 d is connected to the suction side of the second compressor 22. The second suction pipe 22d connects the second compressor 22 to the second use side heat exchanger 72 or the heat source side heat exchanger via the first switching mechanism 25, the second switching mechanism 26, the second gas refrigerant communication pipe 11, and the like. The second low-pressure pipe 32 communicates with the second low-pressure pipe 32. The second low-pressure pipe 32 is configured to flow a second low-pressure refrigerant in the refrigeration cycle, and is connected to the second port 26b of the second switching mechanism 26.

  The first low-pressure pipe 31 and the second low-pressure pipe 32 can communicate with each other via a connection low-pressure pipe 33. The connection low-pressure pipe 33 is provided with an adjustment valve 34 capable of adjusting the opening degree.

  The heat source side heat exchanger 24 is a heat exchanger that functions as a radiator of a high-pressure refrigerant in the refrigeration cycle or functions as an evaporator of a second low-pressure refrigerant in the refrigeration cycle. The gas side end of the heat source side heat exchanger 24 is connected to the third port 25 c of the first switching mechanism 25, and the liquid side end of the heat source side heat exchanger 24 is a receiver via the first liquid refrigerant pipe 45. 25. Here, the heat source unit 2 has a heat source side fan 46 for sucking outdoor air into the heat source unit 2, exchanging heat with the refrigerant in the heat source side heat exchanger 24, and then discharging the heat to the outside. . The heat source side fan 46 is driven by a heat source side fan motor 47.

  The first switching mechanism 25 and the second switching mechanism 26 are four-way switching valves. The first switching mechanism 25 includes a first port 25a connected to the first and second discharge pipes 21c and 22c, a second port 25b connected to the fourth port 26d of the second switching mechanism 26, and heat source side heat. Connected to the third port 25c connected to the gas side end of the exchanger 24 and the second gas side closing valve 43 which is a manual valve provided at the connection portion between the heat source unit 2 and the second gas refrigerant communication pipe 11. And a fourth port 25d. The second switching mechanism 26 includes a first port 26a connected to the first and second discharge pipes 21c and 22c, a second port 26b connected to the second low-pressure pipe 32, and a sealed third port 26c. And a fourth port 26d connected to the second port 25b of the first switching mechanism 25.

  The first switching mechanism 25 and the second switching mechanism 26 are in a first state (indicated by a solid line in FIG. 1) in which the first port and the third port communicate with each other and the second port and the fourth port communicate with each other. State) and a second state (state indicated by a broken line in FIG. 1) in which the first port and the fourth port communicate with each other and the second port and the third port communicate with each other. Has been. As a result, the first switching mechanism 25 and the second switching mechanism 26 are configured so that the second low-pressure pipe 32 communicates with the second usage-side heat exchanger 72 and the second low-pressure pipe 32 communicates with the heat source-side heat exchanger 24. A switching mechanism for switching between states is configured.

  The receiver 27 is a container that stores excess refrigerant therein. A first liquid refrigerant pipe 45 and a second liquid refrigerant pipe 46 are connected to the receiver 27. One end of the first liquid refrigerant tube 45 is connected to the liquid side end of the heat source side heat exchanger 24, and the other end of the first liquid refrigerant tube 45 is connected to the upper part of the receiver 27. The first liquid refrigerant pipe 45 includes a first check valve 45a that allows a refrigerant flow in the direction of the receiver 27 and prohibits a refrigerant flow in the opposite direction, and an electromagnetic valve that can be opened and closed. A first on-off valve 45b is provided. One end of the second liquid refrigerant pipe 46 is connected to the lower part of the receiver 27, and the other end of the second liquid refrigerant pipe 46 is connected to the supercooling heat exchanger 28. One end of a third liquid refrigerant pipe 47 is connected to the middle part of the second liquid refrigerant pipe 46. The other end of the third liquid refrigerant pipe 47 is connected to the second liquid refrigerant communication pipe 10 via the second liquid side closing valve 44. The second liquid side closing valve 44 is a manual valve provided at a connection portion between the heat source unit 2 and the second liquid refrigerant communication pipe 10. The third liquid refrigerant pipe 47 is provided with a third check valve 47a that allows the refrigerant to flow in the direction of the second liquid side closing valve 44 and prohibits the refrigerant from flowing in the opposite direction. . One end of the fourth liquid refrigerant pipe 48 is connected to the downstream portion of the third check valve 47 a of the third liquid refrigerant pipe 47. The other end of the fourth liquid refrigerant pipe 48 is connected to a downstream portion of the first on-off valve 45 b of the first liquid refrigerant pipe 45. The fourth liquid refrigerant pipe 48 is provided with a fourth check valve 48a that permits the refrigerant flow in the direction of the first liquid refrigerant pipe 45 and prohibits the refrigerant flow in the opposite direction.

  The subcooling heat exchanger 28 is a heat exchanger that cools the refrigerant supplied to the first usage unit 6, and is an intermediate that performs heat exchange with the refrigerant flowing through the high-pressure side heat AC path 28a and the high-pressure side heat AC path 26a. And a compression side heat exchange path 28b. One end of the high-pressure side thermal AC path 28 a is connected to the second liquid refrigerant pipe 46, and the other end of the high-pressure side thermal AC path 28 a is connected to the fifth liquid refrigerant pipe 49. Both ends of the intermediate pressure side heat exchange path 28 b are connected to an inflow side injection pipe 29 a and an outflow side injection pipe 29 b that constitute the injection pipe 29.

  The injection pipe 29 branches the high-pressure refrigerant in the refrigeration cycle from the fifth liquid refrigerant pipe 49 and depressurizes it to an intermediate pressure, and then injects into the intermediate ports 21 b and 22 b of the first compressor 21 and the second compressor 22. It is. The injection pipe 29 has an inflow side injection pipe 29a and an outflow side injection pipe 29b. One end of the inflow side injection pipe 29a is connected to the fifth liquid refrigerant pipe 49, and the other end of the inflow side injection pipe 29a is connected to one end of the intermediate pressure side heat AC path 28b. The inflow side injection pipe 29a is provided with an inflow side injection expansion valve 29c for reducing the high-pressure refrigerant in the refrigeration cycle to an intermediate pressure. The inflow side injection expansion valve 29c is an electric expansion valve capable of opening degree control. One end of the outflow side injection pipe 29b is connected to the other end of the intermediate pressure side heat exchange path 28b, and the other end of the outflow side injection pipe 29b is branched into two. It is connected to the intermediate ports 21b and 22b of the compressor 22. The outflow side injection pipe 29b is provided with outflow side injection expansion valves 30a and 30b for adjusting the flow rate of the refrigerant injected into the intermediate ports 21b and 22b. Outflow side injection expansion valves 30a and 30b are electric expansion valves capable of opening control. The other end of the fifth liquid refrigerant pipe 49 is connected to the first liquid refrigerant communication pipe 8 via the first liquid side closing valve 42. The first liquid side closing valve 42 is a manual valve provided at a connection portion between the heat source unit 2 and the first liquid refrigerant communication pipe 8. One end of a sixth liquid refrigerant pipe 50 is connected to the middle part of the fourth liquid refrigerant pipe 49. The other end of the sixth liquid refrigerant pipe 50 is connected to the first liquid refrigerant pipe 45. The sixth liquid refrigerant pipe 50 has a sixth check valve 50a that allows the refrigerant flow in the direction of the first liquid refrigerant pipe 45 and prohibits the refrigerant flow in the opposite direction, and has an opening degree control. And a heat source side expansion valve 50b composed of a possible electric expansion valve. One end of the seventh liquid refrigerant pipe 51 is connected to a portion of the sixth liquid refrigerant pipe 50 between the sixth check valve 50a and the heat source side expansion valve 50b. The other end of the seventh liquid refrigerant pipe 51 is connected to a downstream portion of the first on-off valve 45 b of the first liquid refrigerant pipe 45. The seventh liquid refrigerant pipe 51 is provided with a seventh check valve 51a that allows the refrigerant to flow in the direction of the first liquid refrigerant pipe 45 and prohibits the refrigerant from flowing in the opposite direction.

<Operation of refrigeration equipment>
Next, operation | movement of the freezing apparatus 1 is demonstrated using FIG.2 and FIG.3.

  In the refrigeration apparatus 1, an operation combining a cooling operation and an air conditioning operation (cooling operation or heating operation) can be performed. Here, among such operations, the cooling / cooling operation and the cooling / heating operation will be described. These operations are performed by the control unit 12 that controls the components of the refrigeration apparatus 1.

−Cooling / cooling operation−
The cooling / cooling operation is an operation in which the interior of the refrigerator is cooled by the first usage unit 6 and the room is cooled by the second usage unit 7. Therefore, in the cooling / cooling operation, the heat source side heat exchanger 24 functions as a refrigerant radiator, the first usage side heat exchanger 62 functions as a refrigerant evaporator, and the second usage side heat exchanger 72 It functions as a refrigerant evaporator.

  First, in the cooling / cooling operation, the first switching mechanism 25 and the second switching mechanism 26 are set to the first state (the state shown by the solid line in FIG. 2), and the first opening / closing valve 45b and the first usage-side opening / closing valve 63 are set. Is set to the open state, the heat source side expansion valve 50b is set to the fully closed state, the regulating valve 34, the inflow side injection expansion valve 29c, the outflow side injection expansion valves 30a and 30b, the first use side expansion valve 61 and the second. The use side expansion valve 71 is adjusted to a predetermined opening. In the cooling / cooling operation, the first compressor 21, the second compressor 22, the heat source side fan 46, the first usage side fan 64, and the second usage side fan 73 are driven.

  Then, as shown in FIG. 2, the high-pressure gas refrigerant in the refrigeration cycle compressed by the first compressor 21 and the second compressor 22 is sent to the heat source side heat exchanger 24 through the first switching mechanism 25. In the heat source side heat exchanger 24, the high-pressure gas refrigerant exchanges heat with the outdoor air and dissipates heat (condenses). The high-pressure liquid refrigerant radiated by the heat source side heat exchanger 24 flows in the order of the first liquid refrigerant pipe 45, the receiver 27, and the second liquid refrigerant pipe 46. A part of the high-pressure liquid refrigerant flowing through the second liquid refrigerant pipe 46 flows through the high-pressure side heat AC path 28 a of the supercooling heat exchanger 28, and the rest passes through the third liquid refrigerant pipe 47 to the second liquid refrigerant communication pipe 10. Sent. In the supercooling heat exchanger 28, the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a is cooled by exchanging heat with the intermediate-pressure refrigerant in the refrigeration cycle flowing through the intermediate-pressure side heat AC path 28b. The high-pressure liquid refrigerant cooled by the high-pressure side heat exchange path 28 a flows through the fifth liquid refrigerant pipe 49. A part of the high-pressure liquid refrigerant flowing through the fifth liquid refrigerant pipe 49 is branched to the inflow-side injection pipe 29 a of the injection pipe 29, and the rest is sent to the first liquid refrigerant communication pipe 8. The high-pressure liquid refrigerant branched to the inflow side injection pipe 29a is reduced to the intermediate pressure by the inflow side injection expansion valve 29c, and then flows through the intermediate pressure side heat AC path 28b of the supercooling heat exchanger 28. The intermediate-pressure refrigerant flowing through the intermediate-pressure side heat AC path 28b evaporates by exchanging heat with the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a. The intermediate pressure refrigerant evaporated in the intermediate pressure side heat exchange path 28 b flows through the outflow side injection pipe 29 b of the injection pipe 29. The intermediate pressure refrigerant flowing through the outflow side injection pipe 29b is branched into two and injected into the intermediate ports 21b and 22b of the first compressor 21 and the second compressor 22 through the outflow side injection expansion valves 30a and 30b. The

  The high-pressure liquid refrigerant sent to the first liquid refrigerant communication tube 8 is reduced to the first low-pressure in the refrigeration cycle by the first usage-side expansion valve 61 and then sent to the first usage-side heat exchanger 62. In the first usage side heat exchanger 62, the first low-pressure refrigerant evaporates by exchanging heat with the internal air. The first low-pressure gas refrigerant evaporated in the first usage-side heat exchanger 62 is sent to the first low-pressure pipe 31 through the first gas refrigerant communication pipe 9. The first low-pressure gas refrigerant flowing through the first low-pressure pipe 31 is sucked into the first compressor 21 through the first suction pipe 21d and is compressed again.

  The high-pressure liquid refrigerant sent to the second liquid refrigerant communication tube 10 is reduced to the second low-pressure in the refrigeration cycle by the second usage-side expansion valve 71 and then sent to the second usage-side heat exchanger 72. In the second usage-side heat exchanger 72, the second low-pressure refrigerant evaporates by exchanging heat with room air. The second low-pressure gas refrigerant evaporated in the second usage-side heat exchanger 72 is sent to the second low-pressure pipe 32 through the second gas refrigerant communication pipe 11 and the first and second switching mechanisms 25 and 26. The second low-pressure gas refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22 through the second suction pipe 22d and is compressed again.

  Here, when the cooling load (that is, the flow rate of the second low-pressure refrigerant corresponding to the cooling load) in the second usage unit 7 (second usage-side heat exchanger 72) can be processed only by the second compressor 22. By setting the control valve 34 of the connection low-pressure pipe 33 to a fully closed state, the first low-pressure refrigerant flowing through the first low-pressure pipe 31 is processed by the first compressor 21 as described above, and the second low-pressure pipe The second low-pressure refrigerant flowing through the second compressor 22 is processed by the second compressor 22.

  However, when the cooling load in the second usage unit 7 (second usage-side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to this cooling load) cannot be processed by the second compressor 22 alone, By setting the control valve 34 to the open state, the first low-pressure pipe 31 is communicated with the second low-pressure pipe 32 and the second low-pressure refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22. The first compressor 21 is also inhaled (see the broken arrow indicating the refrigerant flow shown in the vicinity of the low pressure pipe 33 in FIG. 2). That is, a part of the cooling load in the second usage unit 7 (second usage-side heat exchanger 72) is also processed by the first compressor 21. At this time, the regulating valve 34 reduces a part of the second low-pressure refrigerant flowing through the second low-pressure pipe 32 (the flow rate of the second low-pressure refrigerant that cannot be processed by the second compressor 22) from the second low pressure to the first low pressure. The opening degree is adjusted to

-Cooling / heating operation-
The cooling / heating operation is an operation in which the interior is cooled by the first usage unit 6 and the room is heated by the second usage unit 7. Therefore, in the cooling / heating operation, the heat source side heat exchanger 24 functions as a refrigerant evaporator, the first usage side heat exchanger 62 functions as a refrigerant evaporator, and the second usage side heat exchanger 72 Functions as a refrigerant radiator.

  First, in the cooling / heating operation, the first switching mechanism 25 is set to the second state (the state indicated by the broken line in FIG. 3), and the second switching mechanism 26 is set to the first state (the state indicated by the solid line in FIG. 3). The first use side on-off valve 63 is set to the open state, the heat source side expansion valve 50b is set to the fully open state, the first on-off valve 45b is set to the closed state, the control valve 34, the inflow side injection expansion The valve 29c, the outflow side injection expansion valves 30a and 30b, the first usage side expansion valve 61 and the second usage side expansion valve 71 are adjusted to a predetermined opening degree. In the cooling / heating operation, the first compressor 21, the second compressor 22, the heat source side fan 46, the first usage side fan 64, and the second usage side fan 73 are driven.

  Then, as shown in FIG. 3, the high-pressure refrigerant in the refrigeration cycle compressed by the first compressor 21 and the second compressor 22 is sent to the second gas refrigerant communication pipe 11 through the first switching mechanism 25.

  The high-pressure gas refrigerant sent to the second gas refrigerant communication tube 11 is sent to the second usage side heat exchanger 72. In the second usage-side heat exchanger 72, the high-pressure gas refrigerant exchanges heat with room air and dissipates heat (condenses). The high-pressure liquid refrigerant radiated by the second usage side heat exchanger 72 is sent to the second liquid refrigerant communication tube 10 through the second usage side expansion valve 71.

  The high-pressure liquid refrigerant sent to the second liquid refrigerant communication tube 10 flows in the order of the third liquid refrigerant tube 47, the fourth liquid refrigerant tube 48, the first liquid refrigerant tube 45, the receiver 27, and the second liquid refrigerant tube 46. . The high-pressure liquid refrigerant flowing through the second liquid refrigerant pipe 46 flows through the high-pressure side heat AC path 28 a of the supercooling heat exchanger 28. In the supercooling heat exchanger 28, the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a is cooled by exchanging heat with the intermediate-pressure refrigerant in the refrigeration cycle flowing through the intermediate-pressure side heat AC path 28b. The high-pressure liquid refrigerant cooled by the high-pressure side heat exchange path 28 a flows through the fifth liquid refrigerant pipe 49. A part of the high-pressure liquid refrigerant flowing through the fifth liquid refrigerant pipe 49 is branched into the inflow-side injection pipe 29 a and the sixth liquid refrigerant pipe 50 of the injection pipe 29, and the rest is sent to the first liquid refrigerant communication pipe 8. The high-pressure liquid refrigerant branched to the inflow side injection pipe 29a is reduced to the intermediate pressure by the inflow side injection expansion valve 29c, and then flows through the intermediate pressure side heat AC path 28b of the supercooling heat exchanger 28. The intermediate-pressure refrigerant flowing through the intermediate-pressure side heat AC path 28b evaporates by exchanging heat with the high-pressure liquid refrigerant flowing through the high-pressure side heat AC path 28a. The intermediate pressure refrigerant evaporated in the intermediate pressure side heat exchange path 28 b flows through the outflow side injection pipe 29 b of the injection pipe 29. The intermediate pressure refrigerant flowing through the outflow side injection pipe 29b is branched into two and injected into the intermediate ports 21b and 22b of the first compressor 21 and the second compressor 22 through the outflow side injection expansion valves 30a and 30b. The The high-pressure liquid refrigerant branched to the sixth liquid refrigerant pipe 50 is sent to the heat source side heat exchanger 24 after being reduced to the second low pressure in the refrigeration cycle by the heat source side expansion valve 50b. In the heat source side heat exchanger 24, the second low-pressure refrigerant evaporates by exchanging heat with outdoor air. The second low-pressure gas refrigerant evaporated in the heat source side heat exchanger 24 is sent to the second low-pressure pipe 32 through the first and second switching mechanisms 25 and 26. The second low-pressure gas refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22 through the second suction pipe 22d and is compressed again.

  The high-pressure liquid refrigerant sent to the first liquid refrigerant communication tube 8 is reduced to the first low-pressure in the refrigeration cycle by the first usage-side expansion valve 61 and then sent to the first usage-side heat exchanger 62. In the first usage side heat exchanger 62, the first low-pressure refrigerant evaporates by exchanging heat with the internal air. The first low-pressure gas refrigerant evaporated in the first usage-side heat exchanger 62 is sent to the first low-pressure pipe 31 through the first gas refrigerant communication pipe 9. The first low-pressure gas refrigerant flowing through the first low-pressure pipe 31 is sucked into the first compressor 21 through the first suction pipe 21d and is compressed again.

  Here, when the heating load in the second usage unit 7 (second usage-side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to the heating load) can be processed only by the second compressor 22. By setting the control valve 34 of the connection low-pressure pipe 33 to a fully closed state, the first low-pressure refrigerant flowing through the first low-pressure pipe 31 is processed by the first compressor 21 as described above, and the second low-pressure pipe The second low-pressure refrigerant flowing through the second compressor 22 is processed by the second compressor 22.

  However, when the heating load in the second usage unit 7 (second usage-side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to the heating load) cannot be processed only by the second compressor 22, By setting the control valve 34 to the open state, the first low-pressure pipe 31 is communicated with the second low-pressure pipe 32 and the second low-pressure refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22. The first compressor 21 is also inhaled (see the broken arrow indicating the refrigerant flow shown in the vicinity of the low pressure pipe 33 in FIG. 3). That is, a part of the heating load in the second usage unit 7 (second usage-side heat exchanger 72) is also processed by the first compressor 21. At this time, the regulating valve 34 reduces a part of the second low-pressure refrigerant flowing through the second low-pressure pipe 32 (the flow rate of the second low-pressure refrigerant that cannot be processed by the second compressor 22) from the second low pressure to the first low pressure. The opening degree is adjusted to

<Connection configuration of low pressure pipe and suction pipe>
In the above-described cooling / cooling operation or cooling / heating operation (see FIGS. 2 and 3), when the operation is performed with the control valve 34 of the connection low-pressure pipe 33 opened, the refrigerant passes through the low-pressure pipes 31-33. It is desirable to minimize the flow resistance when returning to the compressor 21 and the second compressor 22. Further, since the refrigerating machine 1 is filled with the refrigerating machine oil together with the refrigerant for lubricating the first compressor 21 and the second compressor 22, the control valve 34 of the connecting low-pressure pipe 33 is opened. When performing the operation, it is desirable to minimize the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21 and the second compressor 22 through the low pressure pipes 31 to 33.

  Therefore, here, as shown in FIG. 4, in the connection configuration among the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d), and the connection low-pressure pipe 33, a second branch pipe 36 is interposed. It is characterized by that. Here, as shown in FIG. 5, the second branch pipe 36 has a merging side opening 36 a that opens in a predetermined direction (left direction in FIG. 5), and a direction that is substantially opposite to the merging side opening 36 a. The branch pipe has two branch side openings 36b and 36c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the second branch pipe 36, since the branch side openings 36b and 36c are opened in the direction substantially opposite to the merge side opening 36a, fluid (refrigerant or refrigerating machine oil) flows from the merge side opening 36a side. Can flow smoothly to the branch side openings 36b and 36c. Here, the second low pressure pipe 32 is connected to the merge side opening 36a of the second branch pipe 36, and the connection low pressure pipe 33 and the second suction pipe 22d are connected to the two branch side openings 36b and 36c. It is characterized by that.

  In such a connection configuration between the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33 using the second branch pipe 36, the control valve 34 of the connection low-pressure pipe 33 is opened. When performing the operation in the state, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) via the second branch pipe 36. The flow can be smoothly diverted to the pipe 33 (the first compressor 21 side).

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21 and the second compressor 22 through the second low-pressure pipe 32 and the connecting low-pressure pipe 33 can be minimized.

  In addition, here, as shown in FIG. 4, the second branch pipe 36 is arranged so that the refrigerant flowing in from the merge side opening 36a is divided in the horizontal direction and flows out from the two branch side openings 36b, 36c. Has been. That is, the merge side opening 36a of the second branch pipe 36 faces in the lateral direction, the branch side openings 36b and 36c face in the lateral direction substantially opposite to the merge side opening 36a, and the branch side opening 36b, 36c is arranged so as to open at the same height position (hereinafter, this arrangement is referred to as "horizontal arrangement").

  Here, with such a horizontal arrangement of the second branch pipe 36, it is possible to improve the flow of refrigerant and refrigerating machine oil in the second branch pipe 36.

  Further, as shown in FIG. 4, the first branch pipe 35 is interposed in the connection configuration among the first low-pressure pipe 31, the first compressor 21 (first suction pipe 21 d), and the connection low-pressure pipe 33. It is a feature. Here, as shown in FIG. 5, the first branch pipe 35 has a merging side opening 35a that opens in a predetermined direction (the left side in FIG. 5), and a direction that is substantially opposite to the merging side opening 35a. The branch pipe has two branch side openings 35b and 35c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the first branch pipe 35, the branch side openings 35b and 35c are opened in the direction substantially opposite to the merge side opening 35a, so that the fluid (refrigerant or refrigerating machine oil) flows in from the merge side opening 35a side. Can flow smoothly toward the branch side openings 35b and 35c. In this example, the first low-pressure pipe 31 is connected to the merging-side opening 35a of the first branch pipe 35, and the connection low-pressure pipe 33 and the first suction pipe 21d are connected to the two branch-side openings 35b and 35c. It is characterized by that. Further, the first branch pipe 35 is also arranged horizontally, like the second branch pipe 36. That is, the merge side opening 35a of the first branch pipe 35 faces in the lateral direction, the branch side openings 35b, 35c face in the lateral direction substantially opposite to the merge side opening 56a, and the branch side opening 35b, 35c is arrange | positioned so that it may open to the same height position.

  In such a connection configuration between the first low-pressure pipe 31, the first compressor 21 (first suction pipe 21 d), and the connection low-pressure pipe 33 using the first branch pipe 35, the refrigerant flowing through the first low-pressure pipe 31 is the first. When the first compressor 21 is inhaled, the refrigerant flowing through the first low-pressure pipe 31 and the refrigerating machine oil flowing together with the refrigerant can flow smoothly to the first intake pipe 21d via the first branch pipe 35.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21 through the first low-pressure pipe 21d can be minimized.

(2) Second embodiment <Configuration of refrigeration apparatus>
In 1st Embodiment (refer FIGS. 1-3), while having the 1st compressor 21 which compresses a 1st low pressure refrigerant | coolant, and the 2nd compressor 22 which compresses a 2nd low pressure refrigerant | coolant, 1st A configuration is adopted in which a first low-pressure pipe 31 through which a low-pressure refrigerant flows and a second low-pressure pipe 32 through which a second low-pressure refrigerant flows communicate with each other via a connection low-pressure pipe 33 having an adjustment valve 34 capable of adjusting the opening degree. Has been. And when the air-conditioning load in the 2nd utilization side heat exchanger 72 cannot be processed only by the 2nd compressor 22, the 1st low pressure pipe 31 is made into the 2nd low pressure pipe 32 by setting the control valve 34 to an open state. The second low-pressure refrigerant flowing through the second low-pressure pipe 32 is caused to communicate with the second compressor 22 and also with the first compressor 21.

  However, such a configuration is not limited to the two compressors, ie, the first and second compressors 21 and 22, and may further include a third compressor 23.

  FIG. 6 is a schematic configuration diagram of the refrigeration apparatus 1 according to the second embodiment of the present invention. Here, in the structure of 1st Embodiment, the 3rd suction pipe 23d connected to the 3rd compressor 23 and the 3rd compressor 23 is further provided.

  The third compressor 23 is a compressor that compresses the refrigerant until it reaches a high pressure in the refrigeration cycle. Here, like the first compressor 21 and the second compressor 22, a positive displacement type compression element (not shown) such as a rotary type or a scroll type is driven by a compressor motor 23a as the third compressor 23. A closed type compressor is used. Further, like the first compressor 21 and the second compressor 22, the compression element of the third compressor 23 is provided with an intermediate port 23b that opens to the position of the intermediate pressure in the refrigeration cycle. Further, unlike the first compressor 21 and the second compressor 22, a compressor motor 23a having a constant rotational speed is used. A third discharge pipe 23 c is connected to the discharge side of the third compressor 23. The third discharge pipe 23 c is connected to the first port 25 a of the first switching mechanism 25, similarly to the first compressor 21 and the second compressor 22. The third suction pipe 23 d communicates with the first low-pressure pipe 31 through the first branch pipe 35 and the connection low-pressure pipe 33. Similarly to the first compressor 21 and the second compressor 22, a branch portion of the outflow side injection pipe 29 b constituting the injection pipe 29 is connected to the intermediate port 23 b. That is, the other end of the outflow side injection pipe 29b is branched into three and connected to the intermediate ports 21b, 22b, and 23d of the first compressor 21, the second compressor 22, and the third compressor 23. . The outflow side injection pipe 29b is also provided with an outflow side injection expansion valve 30c for adjusting the flow rate of the refrigerant injected into the intermediate port 23b, in addition to the outflow side injection expansion valves 30a and 30b. The outflow side injection expansion valve 30c is an electric expansion valve capable of opening degree control, like the outflow side injection expansion valves 30a and 30b.

  The configuration of the refrigeration apparatus 1 of the present embodiment is the same as that of the first embodiment except for the third compressor 23 and its peripheral configuration (including a connection configuration of a low-pressure pipe and a suction pipe described later). The description is omitted here.

<Operation of refrigeration equipment>
Next, operation | movement of the freezing apparatus 1 of this embodiment is demonstrated using FIG.7 and FIG.8.

  As in the first embodiment, the refrigeration apparatus 1 can perform a cooling / cooling operation and a cooling / heating operation in which a cooling operation and an air-conditioning operation (cooling operation or heating operation) are combined. Here, with respect to the cooling / cooling operation and the cooling / heating operation, the differences from the first embodiment will be mainly described. Note that these operations are performed by the control unit 12 that controls the components of the refrigeration apparatus 1 as in the first embodiment.

  In the cooling / cooling operation and cooling / heating operation of the present embodiment, the same operation and setting of the equipment as in the cooling / cooling operation and cooling / heating operation of the first embodiment are performed, and the outflow side injection expansion valve 30c is set to a predetermined value. The third compressor 23 is driven by adjusting the opening.

  In the cooling / cooling operation and the cooling / heating operation of the present embodiment, the refrigerant flows as shown in FIGS. 7 and 8 are obtained. The refrigerant flow shown in FIGS. 7 and 8 is injected into the intermediate port 23b of the third compressor 23 through the injection pipe 29, and the third compressor 23 sucks and compresses the low-pressure refrigerant in the refrigeration cycle. Except for this point, it is the same as the cooling / cooling operation of the first embodiment, and thus the description thereof is omitted here.

  Here, when the air conditioning load (that is, the flow rate of the second low-pressure refrigerant corresponding to the air conditioning load) in the second usage unit 7 (second usage side heat exchanger 72) can be processed only by the second compressor 22. By setting the control valve 34 of the connection low-pressure pipe 33 to a fully closed state, the first low-pressure refrigerant flowing through the first low-pressure pipe 31 is processed by the first compressor 21 and the third compressor 23 as described above. The second low-pressure refrigerant flowing through the second low-pressure pipe 32 is processed by the second compressor 22.

  However, when the air conditioning load in the second usage unit 7 (second usage side heat exchanger 72) (that is, the flow rate of the second low-pressure refrigerant corresponding to the air conditioning load) cannot be processed only by the second compressor 22, By setting the control valve 34 to the open state, the first low-pressure pipe 31 is communicated with the second low-pressure pipe 32 and the second low-pressure refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22. The third compressor 23 is also sucked (see the broken arrow indicating the refrigerant flow shown in the vicinity of the low pressure pipe 33 in FIGS. 7 and 8). That is, part of the air conditioning load in the second usage unit 7 (second usage-side heat exchanger 72) is also processed by the third compressor 23. At this time, the regulating valve 34 reduces a part of the second low-pressure refrigerant flowing through the second low-pressure pipe 32 (the flow rate of the second low-pressure refrigerant that cannot be processed by the second compressor 22) from the second low pressure to the first low pressure. The opening degree is adjusted to

<Connection configuration of low pressure pipe and suction pipe>
Also in the above cooling / cooling operation or cooling / heating operation (see FIGS. 7 and 8), when the operation is performed with the control valve 34 of the connection low-pressure pipe 33 opened, the refrigerant flows through the low-pressure pipes 31-33. It is desirable to minimize the flow resistance when returning to the first compressor 21, the second compressor 22, and the third compressor 23. Moreover, since the refrigerating machine oil is enclosed with the refrigerant in order to lubricate the first compressor 21, the second compressor 22, and the third compressor 23 in the refrigeration apparatus 1, such adjustment of the connection low-pressure pipe 33 is performed. When performing the operation with the valve 34 opened, the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 21, the second compressor 22, and the third compressor 23 through the low pressure pipes 31 to 33 is minimized. It is desirable to do.

  Therefore, here, as shown in FIG. 9, in the connection configuration among the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d), and the connection low-pressure pipe 33, as in the first embodiment, The second branch pipe 36 is interposed, the second low pressure pipe 32 is connected to the merge side opening 36a of the second branch pipe 36, and the connection low pressure pipe 33 and the second suction pipe 22d are connected to the two branch side openings 36b, 36c. It is characterized by being connected.

  In such a connection configuration between the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33 using the second branch pipe 36, the control valve 34 of the connection low-pressure pipe 33 is opened. When performing the operation in the state, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) via the second branch pipe 36. The flow can be smoothly divided into the pipe 33 (the third compressor 23 side).

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the second compressor 22 and the third compressor 23 through the second low-pressure pipe 32 and the connection low-pressure pipe 33 can be minimized. Here, similarly to the first embodiment, the horizontal arrangement of the second branch pipe 36 can improve the flow of refrigerant and refrigerating machine oil in the second branch pipe 36.

  Further, here, as shown in FIG. 9, in the connection configuration among the first low-pressure pipe 31, the first compressor 21 (first suction pipe 21d) and the connection low-pressure pipe 33, as in the first embodiment, The first branch pipe 35 is interposed, the first low-pressure pipe 31 is connected to the merge side opening 35a of the first branch pipe 35, and the connection low-pressure pipe 33 and the first suction pipe 21d are connected to the two branch side openings 35b and 35c. It is characterized by being connected. Further, the first branch pipe 35 is also arranged horizontally as in the first embodiment. Here, the third low pressure pipe 33 is characterized in that the third suction pipe 23d of the third compressor 23 is connected to a portion of the connection low pressure pipe 33 closer to the first branch pipe 35 than the control valve 34.

  In the configuration in which the third compressor 23 is further connected to a portion of the connection low pressure pipe 33 closer to the first branch pipe 35 than the control valve 34, the refrigerant flowing through the first low pressure pipe 31 is combined with the first compressor 21. At this time, the refrigerant flowing through the first low-pressure pipe 31 and the refrigerating machine oil flowing together with the refrigerant can be sucked into the first suction pipe 21d (first compression pipe 21d) via the first branch pipe 35. Machine 21 side) and the connecting low-pressure pipe 33 (third compressor 23 side) can be smoothly diverted. In addition, by arranging the first branch pipe 35 horizontally, the flow of refrigerant and refrigerating machine oil in the first branch pipe 35 can be improved. In such a configuration, the refrigerant flowing through the second low-pressure pipe 32 can be sucked into the third compressor 23 together with the second compressor 22 by opening the adjustment valve 34 of the connection low-pressure pipe 33. At this time, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) and the connection low-pressure pipe 33 (third) via the second branch pipe 36. Can be smoothly diverted to the compressor 23 side).

  Thereby, here, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23 together with the first compressor 21, or the refrigerant flowing through the second low-pressure pipe 32 is drawn together with the second compressor 22 into the third compressor. When the refrigerant returns to the first compressor 21, the second compressor 22, and the third compressor 23 through the first low pressure pipe 31, the second low pressure pipe 32, and the connection low pressure pipe 33. The flow resistance and refrigerating machine oil bias can be minimized.

  Here, as shown in FIG. 9, in the connection configuration between the third compressor 23 (third suction pipe 23d) and the connection low-pressure pipe 33 (first and third connection low-pressure pipes 33a and 33c), It is characterized in that a branch pipe 37 is interposed. Here, as shown in FIG. 5, the third branch pipe 37 has a merging side opening 37 a that opens in a predetermined direction (left direction in FIG. 5) and a direction substantially opposite to the merging side opening 37 a. The branch pipe has two branch side openings 37b and 37c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the third branch pipe 37, the branch side openings 37b and 37c are opened in a direction substantially opposite to the merge side opening 37a, so that the fluid (refrigerant) flowing in from any branch side opening 37b or 37c side. And refrigerating machine oil) can also flow smoothly to the merging side opening 37a side. Here, the third suction pipe 23d is connected to the merge side opening 37a of the third branch pipe 37, and the first connection low pressure pipe 33a and the third connection low pressure pipe 33c are connected to the two branch side openings 37b and 37c. It is characterized by being connected. Here, the first connection low-pressure pipe 33 a is one of the branch-side opening 35 b of the first branch pipe 35 and the two branch-side openings 37 a and 37 b of the third branch pipe 37 (here, This is the part that connects the branch side opening 37b). The second connection low-pressure pipe 33 b is a part of the connection low-pressure pipe 33 that connects the branch side opening 36 b of the second branch pipe 36 and the control valve 34. The third connection low-pressure pipe 33c is a part that connects the control valve 34 and the other of the two branch side openings 37b and 37c of the third branch pipe 37 (here, the branch side opening 37c). Further, the third branch pipe 37 is also arranged horizontally as in the first and second branch pipes 35 and 36.

  In such a connection configuration between the third suction pipe 23d using the third branch pipe 37 and the first and third connection low-pressure pipes 33a and 33c, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23. Refrigeration oil flowing together with the refrigerant flowing through the first and second low-pressure pipes 31 and 32 and the refrigerant oil flowing through the second low-pressure pipe 32 together with the refrigerant flowing through the first and second low-pressure pipes 31 and 32. Through the third branch pipe 37, it is possible to smoothly flow to the third suction pipe 23d.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the third compressor 23 through the connection low-pressure pipe 33 can be minimized.

<Modification>
The connection configuration of the low pressure pipe and the suction pipe applied to the configuration having the first compressor 21, the second compressor 22, and the third compressor 23 (see FIGS. 6 to 8) is limited to the configuration shown in FIG. Instead of this, a configuration as shown in FIG. 10 may be used.

  First, as shown in FIG. 10, in the connection configuration among the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33, as in the configuration of FIG. The second branch pipe 36 is interposed, the second low pressure pipe 32 is connected to the merge side opening 36a of the second branch pipe 36, and the connection low pressure pipe 33 and the second suction pipe 22d are connected to the two branch side openings 36b, 36c. It is characterized by being connected.

  In such a connection configuration between the second low-pressure pipe 32, the second compressor 22 (second suction pipe 22d) and the connection low-pressure pipe 33 using the second branch pipe 36, the control valve 34 of the connection low-pressure pipe 33 is opened. When performing the operation in the state, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are connected to the second suction pipe 22d (second compressor 22 side) via the second branch pipe 36. The flow can be smoothly divided into the pipe 33 (the third compressor 23 side).

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the second compressor 22 and the third compressor 23 through the second low-pressure pipe 32 and the connection low-pressure pipe 33 can be minimized. Here, similarly to the configuration of FIG. 9, the horizontal distribution of the second branch pipe 36 can improve the flow of refrigerant and refrigerating machine oil in the second branch pipe 36.

  Further, here, as shown in FIG. 10, the first low pressure pipe 31, the first compressor 21 (first suction pipe 21 d), the third compressor 21 (third suction pipe 23 d), and the connection low pressure pipe 33 are connected. In the connection configuration, the merging low-pressure pipe 40 is connected to the first low-pressure pipe 31 and the connecting low-pressure pipe 33, and the merging low-pressure pipe 40 connected to the first low-pressure pipe 31 and the connecting low-pressure pipe 33 is connected to the first compressor 21. It is characterized in that the first suction pipe 21d and the third suction pipe 23d of the third compressor 23 are connected.

  In the configuration in which the first and third compressors 21, 23 are connected to the merging low pressure pipe 40, the refrigerant flowing through the first low pressure pipe 31 is passed through the merging low pressure pipe 40 together with the first compressor 21 and the third compressor. 23 can be inhaled. In such a configuration, the control valve 34 of the connection low-pressure pipe 33 is opened so that the refrigerant flowing through the second low-pressure pipe 32 is sucked into the second compressor 22 and the connection low-pressure pipe 33 and the combined low-pressure pipe 33 The third compressor 23 can be sucked through the pipe 40, and at this time, the refrigerant flowing through the second low-pressure pipe 32 and the refrigerating machine oil flowing together with the refrigerant are passed through the second branch pipe 36 to the second suction pipe 22 d ( The second compressor 22 side) and the connecting low pressure pipe 33 and the merged low pressure pipe 40 (third compressor 23 side) can be smoothly diverted.

  In addition, as shown in FIG. 10, in the connection configuration among the merging low pressure pipe 40, the first compressor 21 (first suction pipe 21d), and the third compressor 23 (third suction pipe 23d), It is characterized in that a branch pipe 38 is interposed. Here, as shown in FIG. 5, the fourth branch pipe 38 has a merging side opening 38 a that opens in a predetermined direction (left direction in FIG. 5), and a direction that is substantially opposite to the merging side opening 38 a. The branch pipe has two branch side openings 38b and 38c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the fourth branch pipe 38, the branch side openings 38b and 38c are opened in a direction substantially opposite to the merge side opening 38a, so that the fluid (refrigerant or refrigerating machine oil) flows from the merge side opening 38a side. Can flow smoothly toward the branch side openings 38b and 38c. Here, the merged low pressure pipe 40 is connected to the merge side opening 38a of the fourth branch pipe 38, and the first suction pipe 21d and the third suction pipe 23d are connected to the two branch side openings 38b, 38c. It is characterized by that.

  In such a connection configuration between the merging low pressure pipe 40, the first suction pipe 21d, and the third suction pipe 23d using the fourth branch pipe 38, together with the refrigerant and the refrigerant flowing through the first low pressure pipe 31 and the second low pressure pipe 32, The flowing refrigeration oil flows smoothly into the first suction pipe 21d (first compressor 21 side) and the third suction pipe 23d (third compressor 23 side) via the merged low-pressure pipe 40 and the fourth branch pipe 38. Can be diverted.

  Thereby, here, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23 together with the first compressor 21, or the refrigerant flowing through the second low-pressure pipe 32 is drawn together with the second compressor 22 into the third compressor. 23, and the refrigerant passes through the first low-pressure pipe 31, the second low-pressure pipe 32, the connecting low-pressure pipe 33, the combined low-pressure pipe 40, and the fourth branch pipe 38. The flow resistance when returning to the machine 22 and the third compressor 23 and the deviation of the refrigerating machine oil can be minimized.

  In addition, here, as shown in FIG. 10, the fourth branch pipe 38 is horizontally arranged, so that the refrigerant and refrigerating machine oil in the fourth branch pipe 38 can be excellently divided.

  Further, here, as shown in FIG. 10, in the connection configuration between the first low-pressure pipe 31, the first and third compressors 21 and 23 (merging low-pressure pipe 40), and the connection low-pressure pipe 33, the fifth branch pipe 39. It is characterized by interposing. Here, as shown in FIG. 5, the fifth branch pipe 39 has a merging side opening 39a that opens in a predetermined direction (the left side in FIG. 5), and a direction that is substantially opposite to the merging side opening 39a. The branch pipe has two branch side openings 39b and 39c that open in the right direction in FIG. 5 and has a substantially Y shape as a whole. In the fourth branch pipe 39, the branch side openings 39b and 39c open in a direction substantially opposite to the merge side opening 39a, and therefore fluid (refrigerant) flowing in from any branch side opening 39b or 39c side. And refrigerating machine oil) can also flow smoothly to the merging side opening 39a. And here, the confluence low-pressure pipe 40 is connected to the confluence-side opening 39a of the fifth branch pipe 39, and the first low-pressure pipe 31 and the connection low-pressure pipe 33 are connected to the two branch-side openings 39b and 39c. Characterized by dots. Similarly to the second branch pipe 36 and the fourth branch pipe 38, the fifth branch pipe 39 is also arranged horizontally.

  In such a connection configuration between the first low-pressure pipe 31, the joining low-pressure pipe 40 and the connecting low-pressure pipe 33 using the fifth branch pipe 39, the refrigerant flowing through the first low-pressure pipe 31 is sucked into the third compressor 23. In any of the cases where the refrigerant flowing through the connection low-pressure pipe 33 is sucked into the third compressor 23, the refrigerant flowing through the first low-pressure pipe 31 and the connection low-pressure pipe 33 and the refrigerant oil flowing together with the refrigerant are It is possible to smoothly flow through the branch pipe 39 to the merged low pressure pipe 40.

  Thereby, here, the flow resistance and the bias of the refrigerating machine oil when the refrigerant returns to the first compressor 31 and the third compressor 23 through the merged low-pressure pipe 40 can be minimized.

  The present invention provides a first and second compressor, a heat source side heat exchanger, a first and second usage side heat exchanger, and a first for communicating the first compressor with the first usage side heat exchanger. The first low pressure pipe has a first low pressure pipe, a second low pressure pipe for communicating the second compressor with the second use side heat exchanger or the heat source side heat exchanger, and a control valve capable of adjusting the opening degree. The present invention is widely applicable to a refrigeration apparatus including a connection low-pressure pipe for communicating the pipe and the second low-pressure pipe.

DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 21 1st compressor 21d 1st suction pipe 22 2nd compressor 22d 2nd suction pipe 23 3rd compressor 23d 3rd suction pipe 24 Heat source side heat exchanger 31 1st low pressure pipe 32 2nd low pressure pipe 33 Connection low pressure pipes 33a to 33c First to third connection low pressure pipes 34 Control valve 35 to 39 First to fifth branch pipes 35a to 39a Merge side opening 35b to 39b Branch side opening 35c to 39c Branch side opening 40 Merge Low pressure pipe 62 First use side heat exchanger 72 Second use side heat exchanger

JP 2014-70822 A

Claims (9)

A first compressor (21) and a second compressor (22);
A heat source side heat exchanger (24);
A first usage side heat exchanger (62) and a second usage side heat exchanger (72);
A first low-pressure pipe (31) for communicating the first compressor with the first user-side heat exchanger;
A second low pressure pipe (32) for communicating the second compressor with the second use side heat exchanger or the heat source side heat exchanger;
A control valve (34) capable of adjusting the opening, and a connecting low-pressure pipe (33) for communicating the first low-pressure pipe and the second low-pressure pipe;
In a refrigeration apparatus comprising:
A second suction pipe (22d) connected to the second compressor;
A branch pipe having a merge side opening (36a) that opens in a predetermined direction and two branch side openings (36b, 36c) that open in a direction substantially opposite to the merge side opening; A second branch pipe (36) in which the second low pressure pipe is connected to the merge side opening, and the connection low pressure pipe and the second suction pipe are connected to the two branch side openings;
Further equipped with,
Refrigeration equipment (1). The second branch pipe is arranged such that the refrigerant flowing in from the merging side opening is divided in the horizontal direction and flows out from the two branch side openings.
The refrigeration apparatus according to claim 1. A first suction pipe (21d) connected to the first compressor;
A branch pipe having a merging side opening (35a) that opens in a predetermined direction and two branch side openings (35b, 35c) that open in a direction substantially opposite to the merging side opening; A first branch pipe (35) in which the first low-pressure pipe is connected to the merging-side opening, and the connection low-pressure pipe and the first suction pipe are connected to the two branch-side openings;
Further equipped with,
The refrigeration apparatus according to claim 1 or 2. The first branch pipe is arranged so that the refrigerant flowing in from the merging side opening is divided in the horizontal direction and flows out of the two branch side openings.
The refrigeration apparatus according to claim 3. A third compressor (23);
A third suction pipe (23d) connected to the third compressor;
Further comprising
The third suction pipe is connected to a portion of the connection low-pressure pipe closer to the first branch pipe than the control valve.
The refrigeration apparatus according to claim 3 or 4. A branch pipe having a merging side opening (37a) that opens in a predetermined direction and two branch side openings (37b, 37c) that open in a direction substantially opposite to the merging side opening; A third branch pipe (37) in which the third suction pipe is connected to the merge side opening;
Further comprising
The connection low-pressure pipe includes a first connection low-pressure pipe (33a) that connects the branch side opening of the first branch pipe and one of the two branch side openings of the third branch pipe, and the second A second connection low-pressure pipe (33b) that connects the branch side opening of the branch pipe and the control valve, and a second connection that connects the control valve and the other of the two branch side openings of the third branch pipe. 3 connection low-pressure pipe (33c),
The refrigeration apparatus according to claim 5. A confluence low pressure pipe (40) connected to the first low pressure pipe and the connecting low pressure pipe;
A first suction pipe (21d) connected to the first compressor;
A third compressor (23);
A third suction pipe (23d) connected to the third compressor;
A branch pipe having a merging side opening (38a) that opens in a predetermined direction and two branch side openings (38b, 38c) that open in a direction substantially opposite to the merging side opening; A fourth branch pipe (38) in which the merging low-pressure pipe is connected to the merging-side opening, and the first suction pipe and the third suction pipe are connected to the two branch-side openings;
Further equipped with,
The refrigeration apparatus according to claim 1 or 2. The fourth branch pipe is arranged such that the refrigerant flowing in from the merging side opening is divided in the horizontal direction and flows out from the two branch side openings.
The refrigeration apparatus according to claim 7. A branch pipe having a merging side opening (39a) that opens in a predetermined direction and two branch side openings (39b, 39c) that open in a direction substantially opposite to the merging side opening; A fifth branch pipe (39) in which the merging low-pressure pipe is connected to the merging-side opening, and the first low-pressure pipe and the connecting low-pressure pipe are connected to the two branch-side openings; Yes,
The refrigeration apparatus according to claim 7 or 8.

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