JP3326835B2 - Refrigeration cycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle of an intermittent injection cycle type incorporated in, for example, a refrigerating apparatus or a refrigerating apparatus.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open Publication No.
In Publication No. 0, as shown in FIG. 12, a refrigerant compressor 101, a refrigerant condenser 102, a first decompression device 103, a gas-liquid separator 104, a second decompression device 105, and a refrigerant evaporator 106 are sequentially connected. A refrigeration cycle 100 has been proposed. The refrigeration cycle 100 connects the refrigerant gas side of the gas-liquid separator 104 and the suction side of the refrigerant compressor 101 with each other.
The second pressure reducing device 105 is connected to the refrigerant evaporator 106 by a bypass 107 which bypasses the refrigerant evaporator 106, and an electromagnetic valve 108 for opening and closing the bypass 107 is disposed in the bypass 107.
Further, a check valve 109 for preventing backflow of the refrigerant from the bypass passage 107 to the downstream side of the refrigerant evaporator 106 is provided.

However, in the conventional refrigeration cycle 100, when the first decompression device 103 provided on the distillation side of the gas-liquid separator 104 is a fixed throttle such as a capillary tube, the bypass passage 107 by intermittent injection is used.
The intermediate pressure resulting from the flow rate difference between the flow rate of the refrigerant flowing through the inside and the flow rate of the refrigerant flowing through the refrigerant evaporator 106, that is, the pressure inside the gas-liquid separator 104 greatly fluctuates, and the refrigeration capacity is reduced. . Therefore, in order to solve the problem, the present inventors disclosed in Japanese Patent Application No. 3-32295 (filed on December 6, 1991: a related technology that is not a known technology) the refrigeration cycle 200 shown in FIG. Suggested.

[0004] The refrigeration cycle 200 includes a refrigerant compressor 2.
01, refrigerant condenser 202, two parallel refrigerant flow paths 23
1, two decompression units 233 and 2
34, a first pressure reducing device 203, a gas-liquid separator 204,
The second pressure reducing device 205 and the refrigerant evaporator 206 are sequentially connected in a ring shape. In the refrigeration cycle 200, the refrigerant gas side of the gas-liquid separator 204 and the suction side of the refrigerant compressor 201 are connected by a bypass 207, and the bypass 207
Valve 208 for intermittently opening and closing the valve, the second pressure reducing device 205
Solenoid valve 210 for opening and closing a refrigerant passage 209 provided with a refrigerant evaporator 206 and an electromagnetic valve 21 for opening and closing a refrigerant passage 232
1 is arranged.

[0005] Then, the solenoid valve 208 is opened, and the solenoid valve 2 is opened.
When the refrigerant flows into the bypass passage 207 by closing the valve 10, the electromagnetic valve 211 is opened to flow the refrigerant through both of the refrigerant flow paths 231 and 232, and the refrigerant is depressurized by the two decompression units 233 and 234. I have to. When the electromagnetic valve 208 is closed and the electromagnetic valve 210 is opened to allow the refrigerant to flow into the refrigerant channel 209, the electromagnetic valve 211 is closed and the refrigerant channel 231 is closed.
The refrigerant is caused to flow only in the refrigerant, and the refrigerant is depressurized only in one decompression unit 233.

[0006]

However, in the refrigeration cycle 200 shown in FIG.
3 is composed of two refrigerant flow paths 231 and 232 and two decompression units 233 and 234, so that the structure of the first decompression device 203 is complicated and expensive.

In the refrigeration cycle 200, in the refrigerant evaporator mode in which the refrigerant is supplied to the refrigerant evaporator 206, the gas-liquid two-phase refrigerant decompressed by the decompression unit 233 flows into the gas-liquid separator 204, The gas-liquid separator 2 is kept in balance with the liquid refrigerant flowing out to the evaporator 206.
Although the amount of the liquid refrigerant in the chamber 04 is stabilized, the amount of the refrigerant gas flowing into the gas-liquid separator 204 also increases. For this reason, as shown in the time chart of FIG.
4, the intermediate pressure (PM2) of the refrigeration cycle 200 slightly increases, and as shown in the Mollier diagram of FIG. 5, the enthalpy width between the inlet and the outlet of the refrigerant evaporator 206 becomes Δi2. It decreases more like Δi1. Therefore, there is a problem that the effect of improving the refrigeration capacity of the refrigeration cycle 200 is reduced. The present invention
It is an object of the present invention to provide a refrigeration cycle in which the structure of the first pressure reducing device is simplified, and the refrigeration capacity is further improved by keeping the intermediate pressure constant.

[0008]

SUMMARY OF THE INVENTION The present invention provides a refrigerant compressor,
A refrigerant condenser, a first decompression device, a gas-liquid separator, a second decompression device, and a refrigerant evaporator are connected in a ring shape, and the gas-liquid is further removed by a bypass that bypasses the second decompression device and the refrigerant evaporator. In a refrigeration cycle connecting the refrigerant gas side of the separator and the suction side of the refrigerant compressor, the refrigeration cycle is connected between the downstream side of the refrigerant condenser and the upstream side of the first pressure reducing device, A receiver that separates refrigerant gas and liquid refrigerant and sends only liquid refrigerant to the first decompression device, and a refrigerant flow path that connects the inside of the receiver and the inside of the gas-liquid separator via the first decompression device. Channel opening and closing means for opening and closing,
A first path for sending the refrigerant in the gas-liquid separator to the suction side of the refrigerant compressor through the second pressure reducing device and the refrigerant evaporator, and a refrigerant in the gas-liquid separator through the bypass path; A path switching means for switching a second path to be sent to the suction side of the first path, and closing the flow path opening / closing means when the path is switched to the first path by the path switching means;
And a control means for opening the flow path opening / closing means when the path is switched to the second path by the path switching means.

[0009]

When the path is switched to the first path by the path switching means, the refrigerant flow path is closed by the flow path opening / closing means. For this reason, the liquid refrigerant condensed and liquefied by the refrigerant condenser and flowed into the receiver does not flow out to the gas-liquid separator side, but is accumulated in the receiver, so that the amount of the liquid refrigerant in the receiver increases. On the other hand, the liquid refrigerant in the gas-liquid separator flows out toward the second pressure reducing device, so that the amount of the liquid refrigerant in the gas-liquid separator decreases and the volume of the refrigerant gas increases. For this reason, the pressure in the gas-liquid separator, that is, the intermediate pressure of the refrigeration cycle tends to decrease, but since the liquid refrigerant in the gas-liquid separator evaporates by the reduced pressure, the intermediate pressure of the refrigeration cycle increases. Be kept constant.

When the path is switched to the second path by the path switching means, the refrigerant flow path is opened by the flow path opening / closing means. Therefore, the liquid refrigerant accumulated in the receiver is
It flows out toward the first decompression device, is decompressed when passing through the second decompression device, becomes a gas-liquid two-phase refrigerant, and flows into the gas-liquid separator. The liquid refrigerant flowing into the gas-liquid separator does not flow out to the refrigerant evaporator side but accumulates in the gas-liquid separator, so that the amount of the liquid refrigerant in the gas-liquid separator increases. On the other hand, since the refrigerant gas in the gas-liquid separator flows out to the suction side of the refrigerant compressor through the bypass, the amount of the refrigerant gas in the gas-liquid separator decreases. For this reason, the intermediate pressure of the refrigeration cycle is kept constant.

[0011]

Next, a refrigerating cycle according to the present invention will be described with reference to FIGS. 1 to 11. [Structure of First Embodiment] FIGS. 1 to 7 show a first embodiment of the present invention. FIG. 1 is a view showing a refrigeration cycle, and FIGS. 2 and 3 are views showing a main part of the refrigeration cycle. The refrigeration cycle 1 is an intermittent gas injection cycle system, and is incorporated in a refrigeration apparatus or a refrigerator. In the refrigeration cycle 1, a refrigerant compressor 2, a refrigerant condenser 3, a receiver 4, a first decompression device 5, a gas-liquid separator 6, a second decompression device 7, and a refrigerant evaporator 8 are sequentially connected in a ring shape. . The liquid refrigerant side of the receiver 4 and the upstream side of the gas-liquid separator 6 are connected by a refrigerant flow path 9 in which the first pressure reducing device 5 is arranged. In addition, the refrigerant gas side of the gas-liquid separator 6 and the suction side of the refrigerant compressor 2 are connected by a bypass path 11 that bypasses a refrigerant flow path 10 in which the second pressure reducing device 7 and the refrigerant evaporator 8 are arranged. .

When the electromagnetic clutch 12 is energized (turned on), the refrigerant compressor 2 is driven to rotate by an internal combustion engine (not shown) or the like, and compresses the refrigerant gas sucked from the gas-liquid separator 6 and the refrigerant evaporator 8. Then, the high-temperature and high-pressure refrigerant gas is discharged toward the refrigerant condenser 3. The refrigerant condenser 3 is connected to the discharge side of the refrigerant compressor 2, and condenses and liquefies the refrigerant gas flowing from the refrigerant compressor 2 by exchanging heat with air sent by the electric fan 13. The receiver 4 is connected to the downstream side of the refrigerant condenser 3 and separates the refrigerant flowing from the refrigerant condenser 3 into a refrigerant gas and a liquid refrigerant.
To supply only liquid refrigerant. The first pressure reducing device 5 is connected to the downstream side of the receiver 4 and adiabatically expands the refrigerant flowing from the receiver 4 by a fixed throttle such as a capillary tube or an orifice and sends the gas-liquid two-phase refrigerant to the gas-liquid separator 6. . The gas-liquid separator 6 is connected to the downstream side of the first decompression device 5, separates the refrigerant flowing from the first decompression device 5 into refrigerant gas and liquid refrigerant, and directly converts the refrigerant gas to the suction side of the refrigerant compressor 2. And the liquid refrigerant is supplied to the second decompression device 7.

The second pressure reducing device 7 is connected to the liquid refrigerant side of the gas-liquid separator 6, adiabatically expands the refrigerant flowing from the gas-liquid separator 6, and sends the gas-liquid two-phase refrigerant to the refrigerant evaporator 8. This second
A normal temperature-operated expansion valve is used for the pressure reducing device 7. The refrigerant evaporator 8 is disposed in a freezer or a refrigerator, and is connected between a suction side of the refrigerant compressor 2 and a downstream side of the second decompression device 7. The refrigerant evaporator 8 evaporates and evaporates the liquid refrigerant flowing from the second decompression device 7 by exchanging heat with the internal air sent by the electric fan 14. An electromagnetic valve 15 for intermittently opening and closing the refrigerant flow path 9 is disposed in the refrigerant flow path 9 between the downstream side of the first pressure reducing device 5 and the upstream side of the gas-liquid separator 6. This solenoid valve 1
5 is a flow path opening / closing means of the present invention,
Is controlled by the control device 20 (see FIG. 4).
When the solenoid valve 15 is opened, the connection between the receiver 4 and the gas-liquid separator 6 is connected, and when the valve is closed, the connection between the receiver 4 and the gas-liquid separator 6 is cut off.

An electromagnetic valve 16 intermittently opens and closes the refrigerant flow path 10 in the refrigerant flow path 10 between the liquid refrigerant side of the gas-liquid separator 6 and the upstream side of the second pressure reducing device 7. Are arranged. In the bypass path 11, the bypass path 11
The solenoid valve 17 which opens and closes intermittently is arranged. These solenoid valves 16 and 17 are path switching means of the present invention, and are controlled to be energized by the control device 20 (see FIG. 4) of the refrigeration cycle 1. When the electromagnetic valve 16 is opened and the electromagnetic valve 17 is closed, the refrigerant path of the refrigeration cycle 1 is such that the refrigerant in the gas-liquid separator 6 is sent to the suction side of the refrigerant compressor 2 through the refrigerant flow path 10. One path (indicated by a solid arrow in FIG. 1)
18 are formed. Also, the solenoid valve 16 closes, and the solenoid valve 1
When the valve 7 is opened, the refrigerant path of the refrigeration cycle 1 is a second path for sending the refrigerant in the gas-liquid separator 6 through the bypass path 11 to the suction side of the refrigerant compressor 2 (indicated by a broken arrow in FIG. 1). 19 is formed.

FIG. 4 is a diagram showing the control device 20 of the refrigeration cycle 1, and FIG. 5 is a time chart showing the operation of the control device 20 of the refrigeration cycle 1. The control device 20 is a control means of the present invention, and is supplied with power from a battery 22 via a refrigerating switch 21. This control device 20
In accordance with an electric signal output from the refrigeration switch 21 and the in-compartment temperature sensor 23, energization (ON) and stop (OFF) of energization of the relay coils 24 to 26 are controlled. The relay switch 27 which is opened and closed by turning on and off the relay coil 24 includes the electromagnetic clutch 12 and the electric fan 13,
14 are electrically connected. The solenoid valve 16 is electrically connected to a relay switch 28 that is opened and closed when the relay coil 25 is turned on and off. Relay coil 26
Solenoid valves 15 and 17 are electrically connected to a relay switch 29 that is opened and closed by turning on and off the switch.

[Operation of First Embodiment] Next, the operation of the refrigeration cycle 1 will be briefly described with reference to FIGS. Here, FIG. 6 is a Mollier diagram showing the state points of the refrigerant in the refrigerant circuit of the refrigeration cycle 1 in FIG. 1, and the states of the refrigerants A to F on the refrigerant circuit of the refrigeration cycle in FIG. 6 corresponds to A to F on the Mollier diagram. When the freezing switch 21 is closed and the internal temperature detected by the internal temperature sensor 23 is higher than the set temperature, the relay coil 24 is turned on and the relay switch 27 is closed. Therefore, as shown in the time chart of FIG.
The electromagnetic clutch 12 and the electric fans 13 and 14 are turned on, and the refrigeration cycle 1 starts operating.

Here, when the control device 20 turns on the relay coil 25 and turns off the relay coil 26, the relay switch 28 is closed and the relay switch 29 is opened. Therefore, as shown in the time chart of FIG. 5, the solenoid valve 16 is opened, and the solenoid valves 15, 17 are closed. In the case of the refrigerant evaporator mode (see FIG. 5) in which such refrigerant flows through the refrigerant flow path 10, the refrigerant gas (state point A) compressed by the refrigerant compressor 2 discharges the refrigerant gas (state point A). , Gradually flows into the refrigerant condenser 3. Then, the refrigerant is condensed and liquefied in the refrigerant condenser 3 (from state point A to state point B) and flows into the receiver 4. The refrigerant flowing into the receiver 4 is separated into a refrigerant gas and a liquid refrigerant. However, as shown in FIG. 2, since the refrigerant flow path 9 is shut off by the solenoid valve 15, the refrigerant gradually flows into the receiver 4. Will be accumulated.

Since the refrigerant flow passage 10 is opened by the electromagnetic valve 16, the liquid refrigerant (state point D) in the gas-liquid separator 6 gradually flows out due to the suction force of the refrigerant compressor 2. Is adiabatically expanded when passing through the second pressure reducing device 7 (state point D → state point E). Since the refrigerant does not flow into the gas-liquid separator 6 from the refrigerant flow path 9, as shown in FIG. 2, when the liquid refrigerant flows out of the gas-liquid separator 6 to the refrigerant flow path 10, the gas-liquid The amount of the liquid refrigerant in the separator 6 gradually decreases, and the volume of the refrigerant gas increases. For this reason, the pressure in the gas-liquid separator 6, that is, the intermediate pressure (PM1) of the refrigeration cycle 1 tends to decrease, but the liquid refrigerant in the gas-liquid separator 6 evaporates and vaporizes by the reduced amount. The intermediate pressure (PM1) of the refrigeration cycle 1 is kept constant. Thereafter, the gas-liquid two-phase refrigerant having a small enthalpy i flows into the refrigerant evaporator 8 and takes heat from the surrounding air to evaporate (state point E → state point F). Is performed. Then, the refrigerant gas flowing out of the refrigerant evaporator 8 is sucked into the refrigerant compressor 2.

Conversely, the controller 20 controls the relay coil 2
When 5 is turned off and the relay coil 26 is turned on, the relay switch 28 is opened and the relay switch 29 is closed. Therefore, as shown in the time chart of FIG. 5, the solenoid valve 16 is closed, and the solenoid valves 15, 17 are opened. In the injection mode in which the refrigerant flows in the bypass passage 11 (see FIG. 5), the refrigerant gas (state A) compressed by the refrigerant compressor 2 is supplied to the refrigerant condenser 3
, And flows into the receiver 4 after being condensed and liquefied (from state point A to state point B). In addition, as shown in FIG. 3, since the refrigerant flow path 9 is opened by the electromagnetic valve 15, only the liquid refrigerant flows out of the receiver 4. The liquid refrigerant flowing out of the receiver 4 is adiabatically expanded when passing through the first pressure reducing device 5 (state point B → state point C). Then, the gas-liquid two-phase refrigerant flowing into the gas-liquid separator 6 from the first pressure reducing device 5 is separated into a refrigerant gas and a liquid refrigerant. The liquid refrigerant flowing into the gas-liquid separator 6 gradually accumulates. However, since the electromagnetic valve 16 is closed and the electromagnetic valve 17 is opened, the liquid refrigerant is stored in the gas-liquid separator 6. The inflowing refrigerant gas (state point F1) is supplied to the bypass 1
1 and is directly sucked into the suction side of the refrigerant compressor 2. Therefore, the amount of the liquid refrigerant in the gas-liquid separator 6 gradually increases,
The amount of refrigerant gas gradually decreases.

[Effects of the First Embodiment] In this embodiment, the refrigerant flows into the gas-liquid separator 6 only in the injection mode, and the liquid refrigerant accumulated in the gas-liquid separator 6 in the refrigerant evaporator mode. The refrigerant evaporator 8 evaporates and evaporates. For this reason, although the amount of the liquid refrigerant in the gas-liquid separator 6 fluctuates, the pressure in the gas-liquid separator 6, that is, the intermediate pressure of the refrigeration cycle 1 is kept low (PM1 <PM2).
The enthalpy width (Δi2) can be made large. In the refrigeration cycle 200 of the related art, the fluctuation amount of the intermediate pressure (PM2) was 0.08 MPa, but in the refrigeration cycle 1 of the present invention, the fluctuation amount of the intermediate pressure (PM1) was 0.03 MPa. As shown in the time chart, since the intermediate pressure (PM1) is stable, the refrigeration capacity is improved by 7% compared to the refrigeration cycle 200. Since the receiver 4 is also added to control the amount of refrigerant charged in the refrigeration cycle 1, the amount of refrigerant charged can be visually controlled by a sight glass (not shown) attached to the receiver 4. In addition, since the first pressure reducing device 5 is simplified also in the configuration of the refrigeration cycle 1, there is an effect that the component configuration is simplified.

[Structure of the Second Embodiment] FIGS. 8 to 11 show a second embodiment of the present invention. FIG. 8 is a diagram showing a refrigeration cycle. FIG. 9 is a diagram showing the control device 20 of the refrigeration cycle 1, and FIG. 10 is a time chart showing the operation of the control device 20 of the refrigeration cycle 1. The control device 20 of this embodiment is configured to control the relay coils 24, 25, 41, 42 and the abnormal lamp 4
3 is controlled to energize (ON) and stop (OFF) energization. The intermediate pressure sensor 40 is attached to the gas-liquid separator 6, and controls an ON signal when the refrigerant pressure P in the gas-liquid separator 6 drops below a predetermined pressure (x: for example, 0.1 MPa to 0.2 MPa). Output to the device 20. Further, the intermediate pressure sensor 40 outputs an off signal to the control device 20 when the refrigerant pressure P in the gas-liquid separator 6 rises above a predetermined pressure x. The solenoid valve 15 is electrically connected to a relay switch 44 that is opened and closed by turning on and off the relay coil 41. The solenoid valve 17 is electrically connected to a relay switch 45 that is opened and closed by turning on and off the relay coil 42. The abnormality lamp 43 is a display unit that notifies the user that the circulation amount of the refrigerant in the refrigeration cycle 1 is insufficient.

[Operation of the Second Embodiment] Next, the operation of this embodiment will be briefly described with reference to FIGS.
Here, FIG. 11 is a flowchart showing a main program of the control device 20 of the refrigeration cycle 1. Note that the flowchart of FIG. 11 is executed when the relay coil 25 is turned on and the relay coil 42 is turned off, that is, when the solenoid valve 16 is opened and the solenoid valve 17 is closed. First, the refrigerant pressure P in the gas-liquid separator 6 detected by the intermediate pressure sensor 40
Is lower than a predetermined pressure x. In this embodiment, it is determined whether an ON signal is output from the intermediate pressure sensor 40 (step S1). If the determination result in step S1 is No, the relay coil 41 is turned off so as to close the solenoid valve 15 (step S1).
2). Then return.

If the result of the determination in step S1 is Yes, the relay coil 4 is opened so that the solenoid valve 15 is opened.
1 is turned on (step S3). Thereby, when the refrigerant pressure P in the gas-liquid separator 6 falls below a predetermined pressure x, as shown in the time chart of FIG.
5 is opened, the liquid refrigerant accumulated in the receiver 4 passes through the first pressure reducing device 5 to become a gas-liquid two-phase refrigerant, and flows into the gas-liquid separator 6. Therefore, if the circulation amount of the refrigerant in the refrigeration cycle 1 is an appropriate value, the refrigerant pressure P in the gas-liquid separator 6 increases, and the predetermined pressure x can be maintained.

Then, it is determined whether or not a predetermined time (y: for example, 10 seconds to 60 seconds) has elapsed since the solenoid valve 15 was opened (step S4). If the determination result of step S4 is No, the control of step S1 is executed. If the determination result in step S4 is Yes, the abnormal lamp 43 is turned on and turned on (step S4).
5) Turn off the relay coils 24, 25, 41, 42, stop the operation of the refrigerant compressor 2 and the electric fans 13, 14 and close the solenoid valves 15 to 16 to stop the operation of the device. (Step S6).

[Effects of the Second Embodiment] As described above, in this embodiment, as shown in the time chart of FIG.
When the refrigerant pressure P in the gas-liquid separator 6 drops below a predetermined pressure x, the solenoid valve 15 installed in the refrigerant flow path 9 between the receiver 4 and the first pressure reducing device 5 is opened, After the refrigerant pressure P in the liquid separator 6 returns to the predetermined pressure x, the solenoid valve 15
Is closed. Therefore, the gas-liquid separator 6
By keeping the internal refrigerant pressure P at a predetermined pressure x, it is possible to prevent a decrease in the flow rate of the refrigerant passing through the second pressure reducing device 7 and flowing into the refrigerant evaporator 8, thereby preventing a decrease in the refrigeration capacity of the refrigeration cycle 1. can do.

When the flow rate of the refrigerant flowing into the refrigerant evaporator 8 decreases, the lubricating oil (refrigerant oil) of the refrigerant compressor 2 that circulates in the refrigeration cycle 1 together with the refrigerant. The refrigerant stagnates in the refrigerant flow path 46 between the outlet side of the refrigerant compressor 2 and the suction side of the refrigerant compressor 2, and the amount of lubricating oil flowing into the refrigerant compressor 2 decreases.
By preventing a decrease in the flow rate of the refrigerant flowing into the
A decrease in the amount of lubricating oil flowing into the refrigerant compressor 2 can be prevented, and the reliability of the refrigerant compressor 2 can be improved. In addition, the solenoid valve 15
If the refrigerant pressure P in the gas-liquid separator 6 does not return to the predetermined pressure x even when the valve is opened, it can be determined that the circulation amount of the refrigerant in the refrigeration cycle 1 is insufficient (for example, gas leakage). The shortage of the refrigerant can be detected at an early stage by turning on the abnormal lamp 43,
The reliability of the refrigeration cycle 1 can be further improved.

[Modification] In the present embodiment, the present invention is incorporated in a refrigerator or a refrigerator, but the present invention may be incorporated in a cooling device. Further, the present invention may be applied to a refrigeration cycle having means for switching the flow direction of the refrigerant in the refrigeration cycle. In the present embodiment, the electromagnetic valves 16 and 17 are used as the path switching means, but other means such as a three-way valve may be used as the path switching means.

[0028]

According to the present invention, the structure of the first pressure reducing device can be simplified, and the refrigeration capacity of the refrigeration cycle can be further improved by keeping the intermediate pressure of the refrigeration cycle constant.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration cycle used in a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation of the refrigeration cycle used in the first embodiment of the present invention.

FIG. 3 is an operation explanatory view of a refrigeration cycle used in the first embodiment of the present invention.

FIG. 4 is an electric circuit diagram of a refrigeration cycle control device used in the first embodiment of the present invention.

FIG. 5 is a time chart showing the operation of the control device of the refrigeration cycle used in the first embodiment of the present invention.

FIG. 6 is a Mollier diagram of a refrigeration cycle used in the first embodiment of the present invention.

FIG. 7 is a time chart showing an intermediate pressure of the refrigeration cycle used in the first embodiment of the present invention.

FIG. 8 is a refrigerant circuit diagram of a refrigeration cycle used in a second embodiment of the present invention.

FIG. 9 is an electric circuit diagram of a refrigeration cycle control device used in a second embodiment of the present invention.

FIG. 10 is a time chart showing the operation of the control device of the refrigeration cycle used in the second embodiment of the present invention.

FIG. 11 is a flowchart showing a main program of a control device for a refrigeration cycle used in a second embodiment of the present invention.

FIG. 12 is a refrigerant circuit diagram of a conventional refrigeration cycle.

FIG. 13 is a refrigerant circuit diagram of a refrigeration cycle according to the related art.

FIG. 14 is a time chart showing an intermediate pressure of a refrigeration cycle according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Refrigerant compressor 3 Refrigerant condenser 4 Receiver 5 1st decompression device 6 Gas-liquid separator 7 2nd decompression device 8 Refrigerant evaporator 9 Refrigerant flow path 10 Refrigerant flow path 11 Bypass path 15 Solenoid valve (flow path opening / closing) Means) 16 solenoid valve (path switching means) 17 solenoid valve (path switching means) 18 first path 19 second path 20 control device (control means) 40 intermediate pressure sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 1/00

Claims (2)

(57) [Claims] 1. A refrigerant compressor, a refrigerant condenser, a first decompression device, a gas-liquid separator, a second decompression device, and a refrigerant evaporator are connected in a ring shape, and further, the second decompression device and the refrigerant evaporator are connected. A refrigeration cycle in which the refrigerant gas side of the gas-liquid separator and the suction side of the refrigerant compressor are connected by a bypass path that bypasses the refrigeration cycle: (a) a downstream side of the refrigerant condenser and the first A receiver connected between the upstream side of the pressure reducing device and separating the refrigerant gas and the liquid refrigerant and sending only the liquid refrigerant to the first pressure reducing device; (b) inside the receiver and inside the gas-liquid separator; The first
Flow path opening / closing means for opening / closing a refrigerant flow path connected via a pressure reducing device; and (c) transferring the refrigerant in the gas-liquid separator to the suction side of the refrigerant compressor through the second pressure reducing device and the refrigerant evaporator. Path switching means for switching between a first path for sending and a second path for sending the refrigerant in the gas-liquid separator to the suction side of the refrigerant compressor through the bypass path; and (d) the first path by the path switching means. Control means for closing the flow path opening / closing means when being switched to the second path, and opening the flow path opening / closing means when being switched to the second path side by the path switching means. And refrigeration cycle. 2. The refrigeration cycle according to claim 1, wherein the control means has an intermediate pressure sensor for detecting a refrigerant pressure in the gas-liquid separator, and the refrigerant pressure detected by the intermediate pressure sensor is A refrigeration cycle wherein the flow passage opening / closing means is opened when the pressure drops below a predetermined pressure.