Refrigerating device

Abstract

To provide a refrigerating device that can prevent a compressor from stopping immediately after starting up.SOLUTION: A refrigerating device includes a compressor 10 for compressing a refrigerant, a condenser 11 performing condensation of the refrigerant compressed by the compressor 10, and a chiller 14 in which the refrigerant liquefied by the condenser 11 is evaporated, the compressor 10, the condenser 11 and the chiller 14 being connected by pipings 16, 17, 18, 19, 20. A solenoid valve 23 for opening and closing a refrigerant flow passage is disposed in the piping 19 through which the refrigerant flows from the condenser 11 to the chiller 14. A second receiver tank 24 capable of storing liquid refrigerant, and a non-return valve 25 are disposed in the pipings 18, 19 between the solenoid valve 23 and the condenser 11. After starting of the compressor 10, the liquid refrigerant stored in the second receiver tank 24 is supplied to the chiller 14 until the liquid refrigerant on the condenser side is supplied to the second receiver tank 24.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a refrigeration device in which a compressor, a condenser, and a cooler are connected by pipes so that a refrigerant circulates.

Background Art

[0002] In Patent Document 1, a condenser unit including a compressor and a condenser and a cooler unit including a cooler are separately arranged, and a refrigerant discharge port of the compressor and a refrigerant suction port of the cooler are connected by a high-pressure pipe, and a refrigerant discharge port of the cooler and a refrigerant suction port of the compressor are connected by a low-pressure pipe. A refrigeration device is disclosed. Further, in the refrigeration device, a solenoid valve is inserted between an expansion valve inserted in the high-pressure pipe and the compressor, and a low-pressure switch is provided in the low-pressure pipe, and the compressor is configured to be stopped by a pump-down operation. In the pump-down operation, when stopping the compressor, the solenoid valve is closed to close the refrigeration circuit and the operation of the compressor is continued, and the refrigerant in the cooler and the low-pressure pipe is carried to the condenser unit side, so that when the pressure in the low-pressure pipe decreases to a certain value or less, the low-pressure switch operates to stop the compressor. By performing such a pump-down operation, effects such as reduction of the load on the compressor at the time of starting the compressor, prevention of return of liquid refrigerant, and improvement of defrosting efficiency can be obtained. When driving the compressor stopped by the pump-down operation, the solenoid valve is opened, and when the low-pressure pressure rises and balances with the high-pressure pressure in the high-pressure pipe, the low-pressure switch returns and the compressor starts.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the refrigeration device, the liquid refrigerant in the refrigeration circuit tends to gather from the higher temperature side to the lower temperature side, and also tends to gather from the higher physical height side to the lower physical height side. Therefore, depending on various conditions such as the temperature difference around the cooler unit and the condenser unit, and the height difference in the installation positions of the condenser unit and the cooler unit, when the compressor stops due to pump-down operation, a phenomenon occurs where a large amount of the liquid refrigerant in the refrigeration circuit accumulates on the condenser unit side. At this time, only gaseous refrigerant in a vapor state remains in the cooler unit and the high-pressure piping. When the solenoid valve is opened to drive the compressor in this state, although the low-pressure pressure rises, equalizes with the high-pressure pressure, and the low-pressure switch returns, causing the compressor to start, it takes time for the liquid refrigerant accumulated on the condenser unit side to reach the expansion valve. As a result, the gaseous refrigerant becomes insufficient, and the once-risen low-pressure pressure drops to the pressure at which the low-pressure switch operates, resulting in the problem that the compressor stops immediately after starting.

[0005] In view of the above-described problems inherent in the prior art, the present invention has been proposed to preferably solve these problems, and an object thereof is to provide a refrigeration device capable of preventing the compressor from stopping immediately after starting.

Means for Solving the Problem

[0006] To overcome the above problems and achieve the intended purpose, the first means is In a refrigeration device in which a compressor (10) for compressing refrigerant, a condenser (11) for condensing the refrigerant compressed by the compressor (10), and a cooler (14) in which the refrigerant liquefied by the condenser (11) is vaporized are connected by pipes (16, 17, 18, 19, 20), An on-off valve (23) provided in a pipe (19) for flowing the refrigerant from the condenser (11) to the cooler (14) to open and close the refrigerant flow path, A refrigerant storage means (24) provided in a pipe (18) between the on-off valve (23) and the condenser (11) and capable of storing liquid refrigerant, The gist is that a check valve (25) is provided in a pipe (18) between the refrigerant storage means (24) and the condenser (11) to regulate the backflow of the liquid refrigerant to the condenser side. According to this configuration, since the refrigerant storage means and the check valve are provided on the condenser side of the on-off valve provided in the pipe connecting the condenser and the cooler, when the compressor is stopped by the pump-down operation, the liquid refrigerant can be stored in the refrigerant storage means. When driving the compressor stopped by the pump-down operation, it is possible to prevent the gas refrigerant from being insufficient due to the liquid refrigerant stored in the refrigerant storage means, and prevent the compressor from stopping immediately after starting. Further, when the compressor starts, an appropriate cooling operation can be performed by the liquid refrigerant stored in the refrigerant storage means, so that the time lag until an appropriate cooling operation is started after the start of the compressor can be shortened.

[0007] The gist of the second means is that the refrigerant storage means (24) is configured to be able to store an amount of liquid refrigerant that can supply liquid refrigerant to the cooler until the liquid refrigerant from the condenser side is supplied to the refrigerant storage means (24) when the compressor (10) starts with the refrigerant flow path opened by the on-off valve (23). According to this configuration, after the compressor starts, until the liquid refrigerant is supplied from the condenser side to the refrigerant storage means, the cooling operation can be performed by the liquid refrigerant stored in the refrigerant storage means, so that after the compressor starts, the appropriate cooling operation can be continued without interruption.

Advantages of the Invention

[0008] According to the refrigeration device of the present invention, it is possible to prevent the compressor from stopping immediately after starting due to a shortage of gas refrigerant.

Brief Description of the Drawings

[0009]

Figure 1

Modes for Carrying Out the Invention

[0010] Next, the refrigeration device according to the present invention will be described below with reference to the accompanying drawings by giving preferred embodiments.

Embodiment

[0011] The refrigeration device of the embodiment shown in FIG. 1 includes a condenser unit 12 including a compressor 10 that pumps refrigerant and a condenser 11 that cools and condenses the refrigerant pumped by the compressor 10, and an expansion valve (pressure reducing means) 13 that expands the refrigerant and a cooler unit 15 including a cooler 14 that cools the surroundings by evaporating the refrigerant expanded by the expansion valve 13. The condenser unit 12 and the cooler unit 15 are connected by pipes 16, 17, 18, 19, 20 so that the refrigerant circulates. Further, the condenser unit 12 includes a cooling fan 21 that air-cools the condenser 11 and a first receiver tank 22 that can temporarily store the liquid refrigerant condensed by the condenser 11. Specifically, in the condenser unit 12, the discharge port 10a of the compressor 10 is connected to the inlet 11a of the condenser 11 by a first pipe 16, and the outlet 11b of the condenser 11 is connected to the inlet 22a of the first receiver tank 22 by a second pipe 17. The outlet 17a of the second pipe 17 is located at the upper part inside the tank, and the inlet 18a of a third pipe 18, which will be described later and is connected to the outlet 22b of the first receiver tank 22, is located near the bottom of the tank. The liquid refrigerant supplied from the second pipe 17 and stored in the tank is supplied to the cooler unit 15 via the third pipe 18.

[0012] As shown in FIG. 1, the cooler unit 15 has a pipe 18, 19 through which refrigerant flows from the condenser unit 12 to the inlet 14a of the cooler 14, the expansion valve 13, a solenoid valve (on-off valve) 23 for opening and closing the refrigerant flow path, a second receiver tank 24 as a refrigerant storage means for temporarily storing liquid refrigerant, and a check valve 25 for regulating the flow of refrigerant to the condenser unit side, which are arranged in order from the cooler unit side to the condenser unit side. Specifically, a third pipe 18 connected to the outlet 22b of the first receiver tank 22 is connected to the inlet 24a of the second receiver tank 24, and a check valve 25 is provided in the third pipe 18. The liquid refrigerant stored in the first receiver tank 22 is supplied to the second receiver tank 24 through the third pipe 18 via the check valve 25. Also, a solenoid valve 23 and an expansion valve 13 are provided in series in a fourth pipe 19 connecting the outlet 24b of the second receiver tank 24 and the inlet 14a of the cooler 14. The outlet 18b of the third pipe 18 connected to the inlet 24a of the second receiver tank 24 is located at the upper part inside the tank, and the inlet 19a of the fourth pipe 19 connected to the outlet 24b of the second receiver tank 24 is located near the bottom of the tank. The liquid refrigerant supplied from the third pipe 18 and stored in the tank is supplied to the expansion valve 13 through the fourth pipe 19 via the solenoid valve 23. The solenoid valve 23 is electrically controlled to open and close, allowing the passage of refrigerant in the open state and prohibiting it in the closed state. Also, a fifth pipe 20 connected to the outlet 14b of the cooler 14 is connected to the suction port 10b of the compressor 10. The second receiver tank 24 is configured to be able to store an amount of liquid refrigerant that can supply the cooler 14 with liquid refrigerant until liquid refrigerant from the condenser unit side (condenser side) is supplied to the second receiver tank 24 when the compressor 10 is started with the solenoid valve 23 in the open state (the state where the refrigerant flow path is open). That is, the second receiver tank 24 is configured to be able to store an amount of liquid refrigerant corresponding to the refrigerant circulation amount for the time required for the liquid refrigerant to reach from the condenser unit 12 to the cooler unit 15.Note that the time required for the liquid refrigerant to reach the cooler unit 15 from the condenser unit 12 varies depending on the distance between the condenser unit 12 and the cooler unit 15. Therefore, the storage amount of the liquid refrigerant that can be stored in the second receiver tank 24 is set to the refrigerant circulation amount corresponding to the distance between the two units 12 and 15.

[0013] As shown in FIG. 1, the refrigeration device of the embodiment includes a low-pressure switch (pressure detection means) 26 that operates and returns according to a change in the internal pressure (low-pressure) of the fifth pipe 20. The refrigeration device is configured to be capable of performing a pump-down operation for controlling the operation of the compressor 10 by the low-pressure switch 26 and the electromagnetic valve 23. In the pump-down operation, while the operation of the compressor 10 is continued, the electromagnetic valve 23 is closed by an operation stop signal (such as the OFF of the stop switch), and when the low-pressure drops to the operation stop pressure and the low-pressure switch 26 operates, the operation of the compressor 10 is stopped. When driving the compressor 10 stopped by the pump-down operation, the electromagnetic valve 23 is opened, and when the low-pressure rises to the operation start pressure and the low-pressure switch 26 returns, the compressor 10 is started.

[0014] 〔Operation of the Embodiment〕 Next, the operation of the refrigeration device according to the embodiment will be described.

[0015] During normal cooling operation in which the refrigeration device operates the compressor 10 with the electromagnetic valve 23 open, the refrigerant circulates between the cooler unit 15 and the condenser unit 12 while the second receiver tank 24 remains in a full liquid state.

[0016] In the pump-down operation for stopping the compressor 10, the solenoid valve 23 is closed, and the operation of the compressor 10 continues with the refrigeration circuit closed between the second receiver tank 24 and the expansion valve 13. As a result, the refrigerant in the cooler 14 and the fifth pipe 20 is supplied to the condenser 11 via the compressor 10, and the low-pressure in the fifth pipe 20 decreases. When the low-pressure decreases to the operation stop pressure, the low-pressure switch 26 operates and the compressor 10 is stopped and controlled. By such a pump-down operation, effects such as reduction of the load on the compressor 10 at the time of the next startup of the compressor 10, prevention of return of liquid refrigerant, and increase in defrosting efficiency can be obtained. Further, in the refrigeration apparatus of the embodiment, when the compressor 10 is operating with the refrigeration circuit closed, the refrigerant in the refrigeration circuit from the solenoid valve 23 to the check valve 25 does not flow backward to the condenser unit side due to the check valve 25. Therefore, when the compressor 10 is stopped by the pump-down operation, the second receiver tank 24 is maintained in a full liquid state.

[0017] When driving the compressor 10 stopped by pump-down operation, the solenoid valve 23 is opened before starting the compressor 10. When the solenoid valve 23 is opened, the gas refrigerant in the cooler 14 and the fourth pipe 19 moves to the fifth pipe 20 so that the internal pressure (high-pressure) of the fourth pipe 19 and the low-pressure of the fifth pipe 20 are balanced, and when the low-pressure of the fifth pipe 20 rises to the starting operation pressure, the low-pressure switch 26 returns and the compressor 10 starts. Since the second receiver tank 24 is in a full liquid state, the liquid refrigerant stored in the second receiver tank 24 is supplied to the cooler 14 via the expansion valve 13 by the operation of the compressor 10, and the gas refrigerant vaporized in the cooler 14 is sucked into the compressor 10 via the fifth pipe 20. Therefore, the low-pressure does not drop below the starting operation pressure due to refrigerant shortage (shortage of gas refrigerant), and it is prevented that the low-pressure switch 26 operates immediately after starting the compressor 10 and the compressor 10 stops. Also, immediately after starting the compressor 10, an appropriate cooling operation is performed by the liquid refrigerant stored in the second receiver tank 24, and when the liquid refrigerant in the second receiver tank 24 runs out, the liquid refrigerant is supplied from the condenser unit 12 (first receiver tank 22) to the cooler unit 15 (second receiver tank 24), so that the appropriate cooling operation continues without interruption.

[0018] In the refrigeration device of the embodiment, a second receiver tank 24 and a check valve 25 are provided in the cooler unit 15, so that when the compressor 10 that has stopped by the pump-down operation is started, the liquid refrigerant stored in the second receiver tank 24 at the time of the stop of the compressor 10 can be supplied to the cooler 14 via the expansion valve 13. Therefore, it is possible to prevent the low-pressure pressure that has once risen to the operating start pressure from dropping to the operating stop pressure due to refrigerant shortage when the solenoid valve 23 is opened, and prevent the low-pressure switch 26 from operating and the compressor 10 from stopping immediately after startup. Further, after the compressor 10 is started, an appropriate cooling operation can be performed with the liquid refrigerant stored in the second receiver tank 24 of the cooler unit 15, so that the time lag until an appropriate cooling operation is started after the startup of the compressor 10 can be shortened. That is, compared with a conventional refrigeration device in which an appropriate cooling operation is not started until the liquid refrigerant from the condenser unit 12 side is supplied to the cooler unit 15 after the startup of the compressor 10, the time lag until an appropriate cooling operation is started can be shortened. In particular, even when the installation environment is poor where the separation distance and the height difference between the condenser unit 12 and the cooler unit 15 are outside the specified range in the refrigeration device, it is possible to prevent the compressor 10 from stopping immediately after startup and the time lag until an appropriate cooling operation is started from becoming long. Further, the second receiver tank 24 stores an amount of liquid refrigerant that can be supplied to the cooler 14 until the liquid refrigerant from the condenser side (first receiver tank 22) is supplied after the startup of the compressor 10. Therefore, after the startup of the compressor 10, an appropriate cooling operation can be continued without interruption.

[0019] 〔Modification Example〕 The present application is not limited to the configurations of the above-described embodiments and the like, and other configurations can be appropriately adopted. Further, not limited to the following modification examples, various embodiments can be adopted for the configurations described in the embodiments and the like within the scope of the gist of the present invention. (1) In the embodiment, the refrigerant storage means is a receiver tank, but if the liquid refrigerant can be temporarily stored, a chamber or the like in which a part of the pipe is thickened can be adopted. (2) In the embodiment, the pump-down operation is configured to be performed by a low-pressure switch that operates and returns according to the change in the low-pressure. However, instead of the low-pressure switch, a pressure sensor (pressure detection means) capable of detecting the low-pressure can be used. When the pressure sensor detects the operation stop pressure, the compressor is stopped, and when the pressure sensor detects the operation start pressure, the compressor is started. (3) In the embodiment, a first receiver tank is provided in the condenser unit. However, the first receiver tank can be omitted, and a configuration can be adopted in which the condenser and the second receiver tank are directly connected by a third pipe. (4) In the embodiment, an expansion valve is used as the decompression means for the refrigerant. However, it is also possible to use a capillary tube instead of the expansion valve.

Explanation of symbols

[0020] 10 Compressor, 11 Condenser, 14 Cooler, 16 First pipe (pipe) 17 Second pipe (pipe), 18 Third pipe (pipe), 19 Fourth pipe (pipe) 20 Fifth pipe (pipe), 23 Solenoid valve (on-off valve) 24 Second receiver tank (refrigerant storage means), 25 Check valve

Claims

Claim 1 In a refrigeration device in which a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, and an evaporator in which the refrigerant liquefied by the condenser is vaporized are connected by piping, a shut-off valve provided in the piping through which the refrigerant flows from the condenser to the evaporator and that opens and closes the refrigerant flow path; a refrigerant storage means provided in the piping between the shut-off valve and the condenser and capable of storing liquid refrigerant; a check valve provided in the piping between the refrigerant storage means and the condenser and that regulates backflow of the liquid refrigerant to the condenser side, and a refrigeration device characterized by the above. Claim 2 The refrigeration device according to claim 1, wherein the refrigerant storage means is configured to be able to store an amount of liquid refrigerant that can supply liquid refrigerant to the evaporator until liquid refrigerant from the condenser side is supplied to the refrigerant storage means when the compressor starts up with the refrigerant flow path opened by the shut-off valve.

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