JP2011202861A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize a circulating refrigerant amount by storing a refrigerant having become excessive due to a usage condition in a tank.SOLUTION: The refrigerating device 1 comprised by carrying out parallel piping connection to a user side apparatus of a plurality of refrigerator units 10, ..., respectively having a compressor includes a receiver tank 40 for storing the refrigerant with a refrigerant inlet 41 connected to a high pressure side via a check valve 43 and a refrigerant outlet 42 connected to a low pressure side via a capillary tube 46, tank valve devices 17, 47 controlling flowing-in and flowing-out of the refrigerant with respect to the tank, and a controller C controlling the tank valve devices on the basis of an operating condition and controlling the circulating refrigerant amount to a proper value by controlling a refrigerant amount to be stored in the tank.

Description

  The present invention relates to a refrigeration apparatus in which a plurality of refrigeration unit units each having a compressor mounted therein are connected in parallel to a use side device.

  2. Description of the Related Art Conventionally, a cooling device for cooling an interior of a showcase or the like has a refrigerant circuit in which a compressor, a condenser, a receiver tank, a pressure reducing device, an evaporator, and the like are sequentially connected in an annular manner by piping. A predetermined amount of refrigerant is sealed in the refrigerant circuit. When the compressor is operated, the refrigerant is compressed into a high-temperature and high-pressure gas state and flows into the condenser. In this condenser, the refrigerant dissipates heat and is condensed and liquefied, and then temporarily stored in the receiver tank, and then decompressed by the decompression device, and then supplied to the evaporator. In the evaporator, the refrigerant evaporates, and at that time, the refrigerant absorbs heat from the surroundings to exert a cooling action.

  On the other hand, in large stores such as supermarkets, generally, a refrigeration apparatus that cools a user side device such as a plurality of showcases with one high-output refrigerator (see, for example, Patent Document 1) is known. In this case, a plurality of compressors are arranged in parallel, the discharge pipes are joined in the middle, and after passing through an oil separator, distributed and connected to a plurality of heat exchangers. After flowing into the receiver tank, the refrigerant pipe exiting the receiver tank is drawn out of the refrigerator as a high-pressure liquid pipe and distributedly connected to a plurality of usage-side devices.

  The amount of refrigerant sealed in the refrigeration apparatus is determined in accordance with the required heat load calculated from the number and capacity of showcases serving as user-side devices. However, depending on the state of use, the heat load in each showcase varies, so the appropriate amount of refrigerant also changes. If the amount of refrigerant is too large, liquid back into the compressor occurs, and if the amount of refrigerant is too small, poor cooling is caused. Therefore, in the receiver tank as described above, the refrigerant amount is optimized by accumulating the refrigerant.

JP-A-11-83216

  On the other hand, in large stores such as supermarkets, in addition to the above, a refrigeration system consisting of multiple refrigerator units each with a relatively small output and equipped with a compressor connected in parallel to the equipment on the user side is used. Has been. In this case, it is possible to realize the optimum refrigerating capacity with respect to the heat load by adjusting the combination of the refrigerator units to be connected.

  However, if a greater refrigeration capacity can be realized, the amount of refrigerant required will increase, but each refrigeration unit is equipped with only a small receiver tank, The surplus refrigerant cannot be stored in the receiver tank of each refrigerator unit.

  In a conventional refrigeration system equipped with a large receiver tank, when a malfunction occurs in a showcase or the like, the refrigerant in the refrigeration system is temporarily stored in the receiver tank, preventing the inconvenience that the refrigerant is released into the atmosphere. Although repair etc. were possible, when a refrigeration apparatus is constituted by a plurality of refrigerator units, such work becomes difficult.

  The present invention has been made to solve the conventional technical problems, and in a refrigeration apparatus in which a plurality of refrigeration unit units are connected in parallel to a use side device, there is a surplus depending on the use situation. The refrigerant can be stored in a tank and the amount of circulating refrigerant can be optimized.

  In order to solve the above-described problems, a refrigeration apparatus according to the present invention comprises a plurality of refrigerator units each having a compressor mounted in a pipe connection in parallel to a user side device, and is reverse to the high pressure side. A tank for storing a refrigerant with a refrigerant inlet connected via a stop valve and a refrigerant outlet connected to a low-pressure side via a capillary tube, and a tank for controlling the inflow and outflow of the refrigerant to the tank It is characterized by comprising a valve device and a control device that controls the tank valve device based on the operating state and controls the amount of refrigerant stored in the tank to control the amount of circulating refrigerant to an appropriate value. .

  The invention of claim 2 comprises a valve device for a liquid pipe connected to a high-pressure side pipe between the refrigerator unit and the use side device in the above, and the tank valve is closed in a state where the liquid pipe valve device is closed. The apparatus is characterized in that a refrigerant recovery operation for allowing a refrigerant to flow into a tank and recovering the refrigerant into the tank can be executed.

  The invention of claim 3 is characterized in that, in each of the above inventions, a liquid return pipe is provided which communicates the inlet side of the check valve and the refrigerant outlet of the tank.

  According to a fourth aspect of the present invention, in the second aspect of the present invention, the liquid return pipe that communicates the refrigerant outlet of the tank and the high-pressure side pipe on the outlet side of the liquid pipe valve device, and the liquid return pipe are provided. And a liquid return valve device.

  According to the present invention, in a refrigeration apparatus comprising a plurality of refrigerator units each equipped with a compressor connected in parallel to a use side device, a refrigerant inlet is connected to the high pressure side via a check valve. And a tank for storing the refrigerant with a refrigerant outlet connected to the low-pressure side via a capillary tube, a tank valve device for controlling the inflow and outflow of the refrigerant to the tank, and the operation based on the operation state. By controlling the tank valve device and controlling the amount of refrigerant stored in the tank, the control device for controlling the amount of circulating refrigerant to an appropriate value, and by controlling the tank electromagnetic valve by the control device, The refrigerant can flow into the tank from the high pressure side of each refrigerator unit through the check valve, and the refrigerant in the tank can be supplied to the low pressure side of each refrigerator unit through the capillary tube. It can be issued.

  Thereby, it becomes possible to store the refrigerant in a tank commonly connected to each refrigerator unit, and it is possible to realize the optimization of the circulating refrigerant amount according to the use situation.

  According to the invention of claim 2, in addition to the above, the liquid pipe valve device connected to the high pressure side pipe between the refrigerator unit and the use side equipment is provided, and the liquid pipe valve device is closed. The refrigerant recovery operation for allowing the refrigerant to flow into the tank by the tank valve device and recovering the refrigerant into the tank can be executed, so that, for example, during maintenance, the refrigerant is recovered and held in the tank. Therefore, the maintenance work can be smoothly performed while preventing the disadvantage that the refrigerant is released into the atmosphere.

  According to the invention of claim 3, in addition to each of the above-mentioned inventions, a liquid return pipe that communicates the inlet side of the check valve and the refrigerant outlet of the tank is provided, so that the refrigerant is supplied to the pipe that has been evacuated. When performing the returning operation, the refrigerant in the tank can be quickly returned from the high-pressure side pipe to the user side device via the liquid return pipe.

  Thereby, compared with the case where the refrigerant flowing out from the refrigerant outlet of the tank returns the refrigerant via the capillary tube, the low-pressure side piping, etc., the refrigerant can be returned to the use side device quickly and smoothly.

  According to the invention of claim 4, in addition to the invention of claim 2, a liquid return pipe communicating the refrigerant outlet of the tank and the high pressure side pipe on the outlet side of the liquid pipe valve device, and the liquid return pipe By providing an intervening liquid return valve device, the liquid return valve device is opened to return the refrigerant in the tank to the liquid return state when the refrigerant is returned to the pipe that has been evacuated. It is possible to quickly return to the user side device from the outlet side of the liquid return valve device via the pipe.

  Thereby, compared with the case where the refrigerant flowing out from the refrigerant outlet of the tank returns the refrigerant via the capillary tube, the low-pressure side piping, etc., the refrigerant can be returned to the use side device quickly and smoothly.

1 is a refrigerant circuit diagram of a refrigeration apparatus showing an embodiment of the present invention. It is an electrical block diagram of a control apparatus. It is a refrigerant circuit figure of the freezing apparatus as another Example.

  Hereinafter, embodiments of the present invention will be described by taking Example 1 and Example 2 as examples.

  First, the refrigeration apparatus 1 of Example 1 will be described with reference to FIG. FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus 1 showing an embodiment of the present invention. The refrigeration apparatus 1 according to the embodiment realizes cooling of a plurality of showcases (use side devices, such as a refrigerator case and a refrigerator case) as a cooling storage facility installed in a store such as a supermarket. It is.

  The refrigerating apparatus 1 includes a plurality of refrigerating machine units, in this embodiment, as an example, refrigerating machine units 10, 20, 30 and refrigerant pipes 3 that pipe-connect each showcase 60. Thus, the refrigerant circuit 2 is configured. The refrigerator units 10, 20, and 30 are each configured by connecting a pipe in parallel to each showcase (use side device).

  Compressor 11, 21, 31 is mounted on each refrigerator unit 10, 20, 30, respectively. On the discharge side of the compressor 11 constituting the refrigerator unit 10, a heat exchanger (for example, a condenser) 12 (in the case of the refrigerator unit 20, the heat exchanger 22 and the refrigerator unit 30) through an oil separator (not shown). , A heat exchanger 32) is connected.

  The liquid outlet 12A of this heat exchanger 12 (liquid outlet 22A in the case of the refrigerator unit 20, liquid outlet 32A in the case of the refrigerator unit 30) is connected to the valve device 13 (in the case of the refrigerator unit 20, the valve device 23, In the case of the refrigerator unit 30, the high pressure side pipe 14 (the high pressure side pipe 24 in the case of the refrigerator unit 20, and the high pressure side pipe 34 in the case of the refrigerator unit 30) through which the valve device 33) is interposed is connected. The high-pressure side pipes 14, 24, 34 of the respective refrigerator units 10, 20, 30 are joined by a high-pressure side pipe 3 </ b> A connected outside the respective refrigerator units. The high-pressure side pipe 3A is connected to each showcase 60 corresponding to the use side device.

  In addition, a liquid pipe valve device 64 is interposed in each high-pressure side pipe 3A between each refrigerator unit 10, 20, 30 and each showcase 60 as a use side device. The evaporators 61... For cooling the interior of the 60 cabinets are connected in parallel. A liquid electromagnetic valve 62 and an expansion valve 63 as a pressure reducing device are sequentially connected to the refrigerant inflow side of each evaporator 61. And after the refrigerant | coolant outflow side of each evaporator 61 joins in the downstream, the low voltage | pressure side piping 3B connected to each refrigerator unit 10,20,30 is connected.

  The low-pressure side pipe 3B is divided to correspond to each of the refrigerator units 10, 20, and 30, and the valve devices 15 (the valve device 25 in the case of the refrigerator unit 20 and the valve device 35 in the case of the refrigerator unit 30) are respectively provided. Gas inlets 11A, 21A, 31A of the compressors 11, 21, 31 via the low-pressure side pipe 16 (low-pressure side pipe 26 in the case of the refrigerator unit 20, low-pressure side pipe 36 in the case of the refrigerator unit 30). Connected to.

  One receiver tank is provided for all the refrigerator units 10, 20, 30, or a plurality of receiver tanks 40, 50 are provided in parallel to all the refrigerator units 10, 20, 30 in FIG. 1. .

  Each receiver tank is a tank for storing refrigerant, and the total capacity of the receiver tanks 40, 50 is at least in the refrigerant pipes of all the refrigerator units 10, 20, 30 and the refrigerant pipes of all the showcases 60. It is set as the capacity | capacitance which can collect | recover the inside refrigerant | coolants. In the present embodiment, each of the receiver tanks 40 and 50 is detachably connected to the refrigerant recovery pipe and the refrigerant return pipe according to the purpose of use.

  The high pressure side pipes 14, 24, 34 (high pressure side) of the respective refrigerator units 10, 20, 30 are tank valves located between the liquid outlets 12 A, 22 A, 32 A and the valve devices 13, 23, 33. Refrigerant recovery pipes 18, 28, and 38 through which the devices 17, 27, and 37 are respectively connected are connected. The tank valve devices 17, 27, and 37 control the inflow of refrigerant from the refrigerator units 10, 20, and 30 to the receiver tanks 40 and 50. The refrigerant recovery pipes 18, 28, 38 are merged, and then are divided into refrigerant recovery pipes 44, 54 provided corresponding to the receiver tanks 40, 50, and connected to the respective refrigerant inlets 41, 51. .

  In the refrigerant recovery pipes 44 and 54 connected to the refrigerant inlets 41 and 51, a check is made in which the direction from the liquid outlets 12A, 22A and 32A toward the refrigerant inlets 41 and 51 of the receiver tanks 40 and 50 is the forward direction. Valves 43 and 53 are interposed.

  Refrigerant return pipes 45 and 55 are connected to the refrigerant outlets 42 and 52 of the receiver tanks 40 and 50. The refrigerant return pipes 45 and 55 are joined together, and then each refrigerator unit 10, 20, 30 is connected. Are divided into refrigerant return pipes 19, 29, and 39, respectively, and are connected to the respective low pressure side pipes 16, 26, and 36 (low pressure side).

  Each refrigerant return pipe 19, 29, 39 is located and connected between the valve device 15, 25, 35 and the gas inlet 11A, 22A, 32A. The refrigerant return pipes 19, 29, 39 are respectively provided with capillary tubes 46, 56, 66 as decompression means, and the corresponding refrigerator units 10, 20 from the receiver tanks 40, 50. , 30 are respectively provided with tank valve devices 47, 57 and 67 for controlling the outflow of the refrigerant.

  Further, in this embodiment, a liquid return pipe 69 is provided that communicates the refrigerant inlets 41 and 51 of the receiver tanks 40 and 50 with the refrigerant outlets 42 and 52 of the receiver tanks 40 and 50.

  Next, the control device C of the refrigeration apparatus 1 in the present embodiment will be described with reference to the electric block diagram of FIG. The control device C is constituted by a general-purpose microcomputer, and various sensors 70, a control panel 71 and the like are connected to the input side thereof. Further, on the output side, compressors 11, 21, 31 of each refrigerator unit, valve devices 13, 15, 23, 25, 33, 35, tank valve devices 17, 27, 37, 47, 57, 67, The liquid electromagnetic valves 62 of the showcases 60 are connected to the expansion valves 63, etc.

(1) Normal operation Hereinafter, normal operation will be described. When the compressor 11, 21, 31 of each refrigerator unit 10, 20, 30 is operated by the control device C, the high-temperature and high-pressure gas refrigerant discharged from the discharge side of each compressor 11, 21, 31 is oil separator. The heat flows into the heat exchangers 12, 22, and 32 through the heat and dissipates heat there.

  In this case, since the control device C opens the valve devices 13, 23, and 33, the condensed and liquefied refrigerant flows into the high-pressure side piping 3A via the high-pressure side piping 14, 24, and 34. Then, it merges with the refrigerant that has flowed out of the other refrigerator unit.

  Here, the liquid pipe valve device 64 provided in advance in the high pressure side pipe 3A is manually opened. As a result, the liquid refrigerant that has flowed into the high-pressure side pipe 3A reaches the corresponding expansion valve 63 via each liquid electromagnetic valve 62 on each showcase 60 side, and is depressurized there. The refrigerant decompressed by the expansion valve 63 flows into each evaporator 61 installed in the duct of the showcase 60 and evaporates, taking heat from the surroundings and exerting a cooling action.

  And the inside of the store | warehouse | chamber of the showcase 60 is cooled to predetermined | prescribed temperature by circulating the cold air heat-exchanged with the evaporator 61 in the store | warehouse | chamber by the air blower which is not shown in figure. Since the valve devices 15, 25, and 35 are opened by the control device C, the refrigerant discharged from the evaporator 61 is supplied to each refrigerator unit via the low-pressure side pipe 3 </ b> B and the low-pressure side pipes 16, 26, and 36. Return to the compressors 11, 21, and 31 of the 10, 20, and 30 compressors.

  Each liquid electromagnetic valve 62 is controlled to be opened and closed by the control device C based on the internal temperature of the showcase 60 to control the supply of refrigerant to each evaporator 61. Thereby, when all the liquid electromagnetic valves 62 of the plurality of showcases 60 connected to the refrigeration apparatus 1 are closed, the operation of the compressors 11, 21, and 31 of the respective refrigerator units 10, 20, and 30 is stopped. When the liquid solenoid valve is opened, control is started.

  And the control apparatus C always monitors the temperature and / or pressure of the high pressure side of each refrigerator unit 10,20,30, the temperature and / or pressure of a low voltage | pressure side, and each refrigerator unit 10, It is determined whether or not the amount of refrigerant circulating in 20, 30 is an appropriate value.

  When the value is larger than the appropriate value, the control device C controls the opening and closing of the tank valve devices 17, 27, 37 of the corresponding refrigerator unit with the tank valve devices 47, 57, 67 closed. Excess refrigerant is stored in the receiver tanks 40 and 50 via the refrigerant recovery pipes 18, 28, 38, 44 and 54.

  When it is less than the appropriate value, the control device C controls the opening and closing of the tank valve devices 47, 57, and 67 of the corresponding refrigerator unit with the tank valve devices 17, 27, and 37 closed. The insufficient refrigerant is returned from each receiver tank 40, 50 to each refrigerator unit via the refrigerant return pipes 45, 55, 19, 29, 39. As a result, the refrigerant can be stored in the receiver tanks 40 and 50 that are commonly connected to the refrigerator units 10, 20, and 30, and the amount of circulating refrigerant can be optimized according to the use situation. can do.

  For this reason, as in this embodiment, a plurality of refrigerator units 10, 20, 30 each having a relatively small output and mounted with a compressor are connected in parallel to each showcase 60 (use side equipment). In the apparatus 1, each refrigerator unit can be mounted with only a receiver tank having a small capacity. Thus, the receiver tanks 40, 50 connected in common to the respective refrigerator units 10, 20, 30 are provided. Thus, the surplus refrigerant can be collected smoothly and the amount of circulating refrigerant can be reliably optimized.

(2) Refrigerant recovery operation When a failure or the like occurs in the showcase 60 or when the layout is changed, the refrigerant in the refrigeration apparatus 1 is temporarily recovered (collected) in the receiver tanks 40 and 50. I do. In addition, when the normal operation is performed, if the monitoring information such as the high-pressure side temperature and / or pressure, the low-pressure side temperature and / or pressure, etc. deviates significantly from the appropriate value, such refrigerant The collection work is done.

  In this case, first, the operator closes the liquid pipe valve device 64 interposed in the high-pressure side pipe 3A between each refrigerator unit 10, 20, 30 and each showcase 60 (use side equipment). The refrigerant recovery operation is started by operating the control panel 71. Thereby, the control device C opens the tank valve devices 17, 27, 37 provided on the high pressure side (liquid outlets 12A, 22A, 32A side) of the respective refrigerator units 10, 20, 30 and opens the low pressure side ( The tank valve devices 47, 57, 67 provided on the gas inlets 11A, 21A, 31A side) are closed.

  In this state, the control device C was discharged from each heat exchanger 12, 22, 32 by operating the compressors 11, 21, 31 of the refrigerator units 10, 20, 30 and performing pump down. The liquid refrigerant is recovered into the receiver tanks 40 and 50 from the refrigerant inlets 41 and 51 of the receiver tanks 40 and 50 via the refrigerant recovery pipes 18, 28, 38 and 44, 54. After the recovery of the refrigerant into the receiver tanks 40, 50 is completed, the control device C closes the tank valve devices 17, 27, 37.

  The liquid refrigerant collected in the receiver tanks 40, 50 does not flow back to the refrigerator unit side because the check valves 43, 53 are provided, and the tank valve devices 47, 57, 67 Since it is closed, it is contained in the tanks 40 and 50.

  This makes it possible to collect and hold the refrigerant in the receiver tanks 40 and 50 that are commonly connected to the respective refrigerator units 10, 20, and 30. Therefore, it is possible to smoothly perform maintenance work for the showcase 60 and the like while preventing inconvenience that the refrigerant is released into the atmosphere.

  When the operation is resumed after the maintenance work is completed, the tank valve devices 47, 57, and 67 provided on the low pressure side are opened while the tank valve devices 17, 27, and 37 are closed. As a result, the refrigerant stored in each receiver tank 40, 50 is returned to each refrigerator unit 10, 20, 30 via the refrigerant recovery pipes 44, 54 and the refrigerant return pipes 19, 29, 39. The

  At this time, the liquid refrigerant flowing out from the receiver tanks 40 and 50 is decompressed by the capillary tubes 46, 56 and 66 provided in the refrigerant return pipes 19, 29 and 39, and then each compressor 11 as a gas refrigerant. , 21, 31 are sucked from the suction side.

  In the normal operation as described above, since the refrigerant stored in the receiver tank is only the refrigerant adjusted by the change in the installation environment, it is smaller than the storage amount in the refrigerant recovery operation. Therefore, only the receiver tank 40 may be installed during normal operation, and the receiver tank 50 may be additionally installed during maintenance work for performing the refrigerant recovery operation. Thereby, the capacity | capacitance of a receiver tank can be changed as needed, and the improvement of the convenience can be aimed at.

(3) Vacuuming After completing the repair work of the showcase 60 and the like, vacuuming is performed to return the refrigerant collected in the receiver tanks 40 and 50 to the showcase 60 (use side device) and the like.

  In this case, first, the operator connects a vacuum line 73 having an air pump or the like to the high-pressure side pipe 3 </ b> A between the refrigerator unit and each showcase 60. At this time, the liquid pipe valve device 64 is manually closed during the refrigerant recovery operation. Vacuuming is started by operating the control panel 71. When the evacuation is completed, the air pump is disconnected from the vacuum line 73, and the operator opens the liquid pipe valve device 64. The control device C opens the high pressure side tank valve devices 17, 27, and 37 and the low pressure side tank valve devices 47, 57, and 67 in a state where the compressors 11, 21, and 31 are stopped.

  Thereby, the refrigerant | coolant which flowed out from liquid outlet 12A, 22A, 32A of each refrigerator unit 10,20,30 is returned to the showcase 60 via the high voltage | pressure side piping 14, 24, 34, 3A.

  In the present embodiment, the inlet side of the check valves 43 and 53 of the refrigerant recovery pipes 44 and 54 of the receiver tanks 40 and 50 and the refrigerant return pipes 45 and 55 on the refrigerant outlet side of the receiver tanks 40 and 50 are as follows. The liquid return pipe 69 communicates with each other.

  Therefore, the refrigerant in each receiver tank 40, 50 flows into the liquid return pipe 69 from the refrigerant outlets 42, 52 via the refrigerant return pipes 45, 55, and the refrigerant flowing into the liquid return pipe 69 is used for the tank. The high pressure side pipes 14, 24, 34 are reached via the refrigerant recovery pipes 18, 28, 38 in which the valve devices 17, 27, 37 are opened, and are drawn from the high pressure side pipe 3 </ b> A to the vacuum line 73.

  Thereby, compared with the case where the refrigerant flowing out from the refrigerant outlets 42, 52 of the receiver tanks 40, 50 returns the refrigerant via the capillary tubes 46, 56, 66, the low-pressure side pipes 16, 26, 36, etc., and Thus, it becomes possible to smoothly return the refrigerant to the showcase 60.

  Next, the refrigeration apparatus 100 of Example 2 will be described with reference to FIG. FIG. 3 is a refrigerant circuit diagram of the refrigeration apparatus 100 showing an embodiment of the present invention. The refrigeration apparatus 100 according to the embodiment has substantially the same configuration as the refrigeration apparatus 1 as described above, but is not provided with the liquid return pipe 69 as described above. Therefore, since the configuration is the same except for the configuration of the liquid return pipe 69, the description of the components denoted by the same reference numerals is omitted.

  In addition to the first embodiment, the refrigeration apparatus 100 according to the second embodiment includes the refrigerant outlets 42 and 52 of the receiver tanks 40 and 50, the refrigerator units 10, 20 and 30, and the showcases as user-side devices. A liquid return pipe 75 is provided to communicate with the outlet side of the liquid pipe valve device 64 interposed in the high pressure side pipe 3A between 60.

  The liquid return pipe 75 is provided with a liquid return valve device 76 that is controlled to be opened and closed by the control device C.

  Thereby, in the said Example 2, when evacuating, an operator connects the vacuum line 73 provided with the air pump etc. to the high voltage | pressure side piping 3A between the refrigerator unit and each showcase 60. FIG. Vacuuming is started by operating the control panel 71. When the evacuation is completed, the air pump is disconnected from the vacuum line 73, and the control device C opens the liquid pipe valve device 76 in a state where the compressors 11, 21, and 31 are stopped.

  Thereby, the refrigerant in the receiver tanks 40 and 50 can be returned to the showcase 60 in preference to the refrigerant collected in the refrigerator units 10, 20 and 30.

  In this embodiment, the refrigerant in each receiver tank 40, 50 flows into the liquid return pipe 75 from the refrigerant outlets 42, 52 via the refrigerant return pipes 45, 55, and the refrigerant flowing into the liquid return pipe 75 is Then, it flows into the showcase 60 from the outlet side of the liquid pipe valve device 64 interposed in the high pressure side pipe 3A.

  As a result, the refrigerant flowing out from the refrigerant outlets 42 and 52 of the receiver tanks 40 and 50 flows into the capillary tubes 46, 56 and 66, the low-pressure side pipes 16, 26 and 36, and the refrigerant recovery pipes 18, 28 and 38, etc. It is possible to quickly and smoothly return the refrigerant to the showcase 60 without the need to go through.

  In each of the above embodiments, the receiver tank 40 branches to the liquid outlets 12A, 22A, 32A of the refrigerator units 10, 20, 30 and the gas inlets 11A, 21A, 31A via the check valves 43, 53. The refrigerant outlets 41 and 51 are connected to the refrigerant outlets 42 and 52 via the capillary tubes 46, 56 and 66, and tank valve devices are provided respectively. For example, the refrigerant inlets 41 and 51 of the receiver tanks 40 and 50 are connected to the high-pressure side piping 3A between each refrigerator unit 10, 20, 30 and the usage-side equipment, and the refrigerant outlets 42 of the receiver tanks 40 and 50 are connected to the low-pressure side piping 3B. It is good also as a structure which connects 52 and flows in and out of a refrigerant | coolant collectively.

  Moreover, in each said Example, although the control apparatus C shall control all the refrigerator units 10, 20, and 30, it is not limited to this, A control apparatus is provided for every refrigerator unit, Control that optimizes the circulating refrigerant amount may be performed using any one of the refrigerator unit control devices as a main control device.

DESCRIPTION OF SYMBOLS 1 Refrigerating device 2 Refrigerant circuit 3 Refrigerant piping 3A High pressure side piping 10, 20, 30 Refrigerator unit 11, 21, 31 Compressor 11A, 21A, 31A Gas inlet 12, 22, 32 Heat exchanger (condenser)
12A, 22A, 32A Liquid outlet 13, 23, 33, 15, 25, 35 Valve device 14, 24, 34 High pressure side piping 16, 26, 36 Low pressure side piping 17, 27, 37 Tank valve device 18, 28, 38 Refrigerant recovery pipe 19, 29, 39 Refrigerant return pipe 40, 50 Receiver tank 41, 51 Refrigerant inlet 42, 52 Refrigerant outlet 43, 53 Check valve 44, 54 Refrigerant recovery pipe 45, 55 Refrigerant return pipe 46, 56, 66 Capillary tube (pressure reduction means)
47, 57, 67 Tank valve device 60 Showcase 61 Evaporator 62 Liquid electromagnetic valve 63 Expansion valve (pressure reduction device)
64 Liquid pipe valve device 69, 75 Liquid return pipe 70 Various sensors 71 Control panel 73 Vacuum line 76 Liquid return valve device

Claims (4)

In a refrigeration system comprising a plurality of refrigerator units each equipped with a compressor and connected in parallel to a user side device,
A refrigerant inlet is connected to the high pressure side via a check valve and a refrigerant outlet is connected to the low pressure side via a capillary tube to store the refrigerant, and
A tank valve device for controlling the inflow and outflow of the refrigerant into the tank;
A refrigeration apparatus comprising: a control device that controls the tank valve device based on an operating state, and controls the amount of refrigerant stored in the tank to control the amount of circulating refrigerant to an appropriate value.   A liquid pipe valve device connected to a high-pressure side pipe between the refrigerator unit and the use side device is provided, and the refrigerant flows into the tank by the tank valve device in a state where the liquid pipe valve device is closed. The refrigeration apparatus according to claim 1, wherein a refrigerant recovery operation for recovering the refrigerant in the tank is executable.   The refrigeration apparatus according to claim 1, further comprising a liquid return pipe that communicates an inlet side of the check valve and a refrigerant outlet of the tank.   A liquid return pipe that communicates a refrigerant outlet of the tank and a high-pressure side pipe on the outlet side of the liquid pipe valve device, and a liquid return valve device interposed in the liquid return pipe. The refrigeration apparatus according to claim 2.

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