JP3448794B2 - Refrigeration equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the reliability of a refrigerating device used in, for example, a low temperature product case in a supermarket, a refrigerator or a freezer.

[0002]

2. Description of the Related Art FIG. 12 is a view showing a refrigerant piping system of a conventional refrigerating apparatus, for example, one described in a construction / service manual (January 1995 version) issued by Mitsubishi Electric Corporation. In the figure, 1 is a refrigerant compressor, 2 is an oil separator, 3 is a condenser, 4 is a liquid reservoir containing the liquid refrigerant condensed in the condenser 3, and 5 is a liquid refrigerant contained in the liquid reservoir 4. Liquid pipe for delivery, 6 is a pressure reducing device, 7 is an evaporator, 8 is a gas-liquid separator, and 9 is a suction pipe connecting the gas-liquid separator 8 and the refrigerant compressor 1. Further, 10 is a suction operation valve, and 11 is a discharge operation valve, which are mainly used when performing services such as evacuation in the market (for example, equipment shipping destination). The suction operation valve 10 is directly connected to the main body of the refrigerant compressor 1. Further, the suction operation valve 10
Is provided with a service port 10a, which is used when a service is provided in the market. In the above, the main parts which comprise the refrigerant circuit in a refrigerating device were shown. There are some other associated pipes, but the description is omitted here.

The conventional refrigeration system is constructed as described above,
For example, the refrigerant charged in a gas state from the service port 10a of the suction operation valve 10 connected to the refrigerant compressor 1 is compressed by the refrigerant compressor 1 to have high temperature and high pressure, and the oil separator 2 causes high temperature and high pressure gas and oil. Is separated into The high-temperature and high-pressure refrigerant sent from the oil separator 2 is condensed in the condenser 3 and liquefied, and this liquid refrigerant is stored in the liquid reservoir 4. The liquid refrigerant sent from the liquid reservoir 4 through the liquid pipe 5 is decompressed by the decompression device 6 into a gas-liquid two-phase state, heat-exchanged with the outside air in the evaporator 7 to be gasified, and the gas-liquid separator 8 After passing through the suction pipe 9 and returning to the refrigerant compressor 1, the above cycle is repeated. Also,
The liquid refrigerant that has not been completely evaporated in the evaporator 7 due to changes in operating conditions and the like is stored in the gas-liquid separator 8, and the gas refrigerant separated here is returned to the refrigerant compressor 1 via the suction pipe 9, Repeat the cycle as above. In addition, the operating conditions, for example, the evaporation temperature of the refrigerant in the evaporator 7 is -30 ° C to
When the temperature is as low as 45 ° C., the temperature of the refrigerant sent from the gas-liquid separator 8 is extremely lowered, so that frost or freezing may occur at a portion where the gas-liquid separator 8 or the suction pipe 9 comes into contact with the outside air. .

[0004]

Since the conventional refrigeration system is constructed as described above, there are cases where the liquid refrigerant directly returns to the suction side of the refrigerant compressor 1 due to changes in operating conditions. The compressor 1 may be damaged by the compression of the liquid refrigerant. Further, when charging the refrigerant in the market, the service port 10a of the suction operation valve 10 connected to the refrigerant compressor 1
There is a problem in that the liquid refrigerant may be filled from the inside, which damages the refrigerant compressor 1. Then, the dew condensation water is frozen on the surface of the gas-liquid separator 8 which comes into contact with the outside air,
Since it further reaches and grows up to the suction pipe 9 from the gas-liquid separator 8 to the refrigerant compressor 1, the outer diameter of the suction pipe 9 may be substantially increased when the frozen portion is included. At that time, there was a problem that the natural frequency of the suction pipe 9 resonated in agreement with the motion frequency, and the suction pipe 9 was broken in some cases. Further, in the conventional refrigeration system, since the installation area of the gas-liquid separator 8 and the liquid reservoir 4 is relatively large, there is a problem that the cost of the entire product increases.

The present invention has been made to solve the above-mentioned conventional problems, and in order to further improve the reliability of the refrigeration system, the liquid refrigerant is charged from the suction operation valve and the liquid refrigerant is returned during operation. It is an object of the present invention to obtain a refrigeration system that prevents damage to the refrigerant compressor and enables proper operation. Further, another object of the present invention is to obtain a refrigeration system that prevents pipe breakage due to freezing from the gas-liquid separator to the suction pipe, enables proper operation, and is inexpensive.

[0006]

In order to achieve the above object, a refrigerating apparatus according to the present invention comprises a refrigerant compressor, a condenser,
In a refrigerating device having a refrigerant circuit in which a pressure reducing device, an evaporator, a gas-liquid separator and the like are sequentially connected by piping, a refrigerant flow rate control valve provided in a suction pipe connecting the gas-liquid separator and the refrigerant compressor, and a refrigerant. An oil temperature detector provided in the compressor for detecting the oil temperature in the refrigerant compressor, and a first controller for controlling the opening of the refrigerant flow control valve based on the oil temperature detected by the oil temperature detector are provided. It is a prepared configuration.

Further, in a refrigerating apparatus having a refrigerant circuit in which a refrigerant compressor, a condenser, a pressure reducing device, an evaporator, a gas-liquid separator and the like are sequentially connected by piping, a suction connecting the gas-liquid separator and the refrigerant compressor. A refrigerant flow rate control valve provided in the pipe, an oil temperature detector provided in the refrigerant compressor to detect the oil temperature in the refrigerant compressor, and a pressure detector provided in the intake pipe to detect the pressure in the intake pipe, The oil temperature superheat amount, which is the difference between the saturation temperature of the refrigerant corresponding to the pressure detected by the pressure detector and the oil temperature detected by the oil temperature detector, is calculated, and the refrigerant is calculated based on the oil temperature superheat amount. And a second controller for controlling the opening of the flow control valve.

Further, in a refrigerating apparatus having a refrigerant circuit in which a refrigerant compressor, a condenser, a pressure reducing device, an evaporator, a gas-liquid separator and the like are sequentially connected by piping, a suction connecting the gas-liquid separator and the refrigerant compressor. A first solenoid valve provided in the pipe, at least one parallel pipe connected to the suction pipe in parallel with the first solenoid valve, a second solenoid valve provided in the parallel pipe, and a second solenoid valve in series Based on the oil temperature detected by the oil temperature detector, which is provided in the parallel pipe and has a smaller diameter than the suction pipe, the oil temperature detector which is provided in the refrigerant compressor and detects the oil temperature in the refrigerant compressor, And a fourth controller for appropriately controlling the opening and closing of the first solenoid valve and the second solenoid valve.

[0009]

[0010]

[0011]

[0012]

[0013]

In the refrigerating apparatus according to the present invention, as the oil temperature in the refrigerant compressor detected by the oil temperature detector decreases, the first controller decreases the opening degree of the refrigerant flow control valve in the suction pipe. The control is performed to reduce the inflow of the liquid refrigerant into the refrigerant compressor.

The second controller calculates the oil temperature superheat amount which is the difference between the oil temperature in the refrigerant compressor and the refrigerant saturation temperature corresponding to the pressure in the suction pipe, and this oil temperature superheat amount is calculated. Based on the above, when the oil temperature superheat amount is low, the second controller controls the opening degree of the refrigerant flow control valve to be small to prevent the liquid refrigerant from flowing into the refrigerant compressor.

Further, the fourth controller appropriately opens and closes the first solenoid valve of the suction pipe and the second solenoid valve of the parallel pipe based on the oil temperature detected by the oil temperature detector of the refrigerant compressor. Control. Therefore, the liquid refrigerant selectively flows into the suction pipe and the parallel pipe in accordance with the amount of the liquid refrigerant flowing into the suction pipe corresponding to the oil temperature.

[0016]

[0017]

[0018]

[0019]

[0020]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. 1 is a refrigerant piping system diagram showing Embodiment 1 of the present invention, and reference numerals 1 to 11 are the same as the constituent elements of the conventional apparatus described in FIG. 12, and therefore detailed description thereof will be omitted. In FIG. 1, 12 is an oil temperature detector that is embedded in the lower part of the body of the refrigerant compressor 1 and detects the temperature of the lubricating oil in the refrigerant compressor 1, and 13 is a suction connecting the gas-liquid separator 8 and the refrigerant compressor 1. A refrigerant flow rate control valve provided in the middle of the pipe 9 for adjusting the refrigerant flow rate by variably opening the valve, and 14 is a control for controlling the opening degree of the refrigerant flow rate control valve 13 based on the oil temperature detected by the oil temperature detector 12. It is a device (an example of a first controller).

This refrigerating apparatus is constructed as described above, and the high temperature and high pressure refrigerant compressed by the refrigerant compressor 1 is separated into the high temperature and high pressure gas and the oil by the oil separator 2. The high-temperature and high-pressure refrigerant sent from the oil separator 2 is condensed in the condenser 3 and liquefied, and this liquid refrigerant is stored in the liquid reservoir 4. The liquid refrigerant sent from the liquid reservoir 4 through the liquid pipe 5 is decompressed by the decompression device 6 into a gas-liquid two-phase state, heat-exchanged with the outside air in the evaporator 7 to be gasified, and the gas-liquid separator 8, After passing through the suction pipe 9 and returning to the refrigerant compressor 1, the above cycle is repeated. Further, the liquid refrigerant that has not been completely evaporated in the evaporator 7 due to changes in operating conditions and the like is stored in the gas-liquid separator 8, and the gas separated here is passed through the suction pipe 9 to the refrigerant compressor 1. Return and repeat the cycle as above. By the way, the liquid refrigerant may be directly sent to the refrigerant compressor 1 without being gas-liquid separated by the gas-liquid separator 8. At this time, the liquid refrigerant passes through the suction pipe 9 and collects in the lower portion of the refrigerant compressor 1 main body. Lubricating oil for lubricating the parts inside the refrigerant compressor 1 is held therein, but they are mixed by the inflow of the liquid refrigerant.
Then, the viscosity of the lubricating oil decreases, and the sliding portion in the refrigerant compressor 1 cannot be sufficiently lubricated, which may lead to a failure. Since the liquid refrigerant has a very low temperature (for example, -40 ° C to
(0 ° C.), the temperature of the mixed liquid of the liquid refrigerant and the lubricating oil decreases. Therefore, in this embodiment, the temperature of the lubricating oil held in the refrigerant compressor 1 is detected by the oil temperature detector 12, and the opening of the refrigerant flow control valve 13 is determined according to the detected oil temperature. It has become. FIG. 2 is a diagram showing the relationship between the oil temperature detected by the oil temperature detector and the opening of the refrigerant flow control valve.
Here, the opening of the refrigerant flow control valve 13 is 100% when fully opened.
, And fully closed is expressed as 0%. For example, the valve opening is reduced as the oil temperature decreases. That is, by reducing the valve opening degree, the amount of the liquid refrigerant flowing through the refrigerant flow control valve 13 and flowing into the refrigerant compressor 1 is reduced. By the control by the controller 14 as described above, it is possible to prevent the failure of the refrigerant compressor 1 due to the return of the liquid refrigerant and to smoothly operate the refrigeration system.

Example 2. In the first embodiment, the oil temperature detector 12
The opening degree of the refrigerant flow control valve 13 is determined and controlled based on the oil temperature detected by
As shown in, a pressure detector 15 for detecting the pressure in the suction pipe 9 is provided. The controller 14 (an example of a second controller) determines the difference between the oil temperature detected by the oil temperature detector 12 and the saturation temperature of the refrigerant corresponding to the suction pipe pressure detected by the pressure detector 15. The oil temperature superheat amount is calculated, and the opening degree of the refrigerant flow control valve 13 is controlled based on the oil temperature superheat amount value or the oil temperature value. For example, if the value of the oil temperature superheat amount is less than 10 deg, the controller 14 always reduces the opening degree of the refrigerant flow control valve 13 regardless of the oil temperature. FIG. 3 is a diagram showing the relationship between the oil temperature superheat amount and the opening degree of the refrigerant flow control valve. Here, the opening degree of the refrigerant flow control valve 13 is 100% when fully opened and 0% when fully closed.
It is expressed as. For example, when the value of the oil temperature superheat amount is less than 10 deg, the opening degree of the refrigerant flow control valve 13 is 50%, and when it is 10 deg or more, 100% (fully open). That is, when the oil temperature superheat amount is not sufficiently secured, the liquid refrigerant may be laid in the oil, and thus the liquid refrigerant return to the refrigerant compressor 1 may be reduced more reliably than in the first embodiment. Therefore, the failure of the refrigerant compressor 1 can be prevented.

Example 3. Fourth Embodiment FIG. 4 is a sectional view of a main part of a suction pipe showing a third embodiment of the present invention. In FIG. 4, reference numeral 16 is a liquid level detector provided in the suction pipe 9 connecting the gas-liquid separator 8 and the refrigerant compressor 1 and detecting the liquid refrigerant flowing into the suction pipe 9. The controller 14 (an example of a third controller) controls the opening degree of the refrigerant flow control valve 13 based on the liquid level of the liquid refrigerant detected by the liquid level detector 16. That is, in the case of excessive liquid return such that the liquid refrigerant flows as a jet flow, the liquid level detector 16 detects the liquid level of the liquid refrigerant and reduces the opening degree of the refrigerant flow control valve 13 to a predetermined value. , To prevent the liquid refrigerant from flowing into the refrigerant compressor 1.
By the control by the controller 14 as described above, it is possible to prevent the failure of the refrigerant compressor 1 and smoothly operate the refrigeration system.

Example 4. [Embodiment 4] FIG. 5 is a main part piping system diagram in the vicinity of an intake pipe showing Embodiment 4 of the present invention. In FIG. 5, 17 is a first solenoid valve provided in a suction pipe 9 connecting the gas-liquid separator 8 and the refrigerant compressor 1, and 19, 19 and 19 are provided in the suction pipe 9 in parallel with the first solenoid valve 17. Three parallel pipes connected to each other, 18, 18, 18 are second solenoid valves provided in each parallel pipe 19, and 20, 21, 22 are provided in each parallel pipe 19 in series with the second solenoid valve 18, respectively. The first, second, and third capillaries having a pipe inner diameter smaller than that of the suction pipe 9;
Reference numeral 14 denotes a controller (an example of a fourth controller) that controls opening / closing of the first solenoid valve 17 and each second solenoid valve 18 based on the oil temperature detected by the oil temperature detector 12 (see FIG. 1). is there. Here, the first capillary tube 20, the second capillary tube 21, and the third capillary tube 22 have substantially the same tube inner diameter. The length of each capillary is set such that the first capillary 20 has the longest length, the second capillary 21 has the longest, and the third capillary 22 has the shortest. Therefore, when the refrigerant flows, the flow rate passing through the first capillary tube 20 is the smallest, and the flow rate increases in the order of the second capillary tube 21 and the third capillary tube 22. Next, the operation will be described. When the liquid refrigerant flows from the gas-liquid separator 8 through the suction pipe 9 into the refrigerant compressor 1, the controller 14 opens and closes the second electromagnetic valve 18 based on the temperature detected by the oil temperature detector 12. Specifically, as shown in the relationship diagram of FIG. 6, if the temperature detected by the oil temperature detector 12 is 0 ° C. or higher, it is determined that there is no liquid refrigerant return, and the first solenoid valve 17 is opened. Control is performed so that all three second solenoid valves 18 are closed. Further, the temperature detected by the oil temperature detector 12 is -10 ° C to 0 ° C.
Then, the first solenoid valve 17 is closed and the second solenoid valve 18 on the side of the third capillary tube 22 is opened. The other second solenoid valve 18 is closed. In other words, it is judged that there is a liquid refrigerant return, and the third capillary tube 2
By passing 2 through, the liquid refrigerant return to the refrigerant compressor 1 is reduced. When the temperature detected by the oil temperature detector 12 is -10 ° C or lower, the second capillary 21
Side, the second solenoid valve 18 on the first capillary tube 20 side is opened. That is, it is determined that the lower the temperature detected by the oil temperature detector 12, the greater the liquid refrigerant return, and the liquid refrigerant return to the refrigerant compressor 1 is reduced by passing the longer one of the capillaries. By controlling the controller 14 as described above, the same effect as that of the above-described embodiment can be expected.

Example 5. Fifth Embodiment FIG. 7 is a configuration diagram of essential parts near a refrigerant compressor showing a fifth embodiment of the present invention. In FIG.
Reference numeral 10 denotes a suction operation valve which is provided on the refrigerant suction side of the refrigerant compressor 1 and which allows the refrigerant to be taken in and out of the outside. 10 a denotes a suction operation valve 1.
0 is a charge port provided by branching from 0, 23A is a first take-out pipe connected to the charge port 10a using a flare nut 26, and 23 is provided at the tip of the first take-out pipe 23A and an external vacuuming means (shown in the figure). (Omitted) and a check joint that is detachably connected to the check joint, and 24 is a non-return valve that is installed in the first take-out pipe 23A between the refrigerant compressor 1 and the check joint 23 and allows gas flow only in the direction toward the check joint 23. It is a valve. That is, a vacuum-dedicated pipe is formed mainly by the configuration including the first extraction pipe 23A, the check joint 23, and the check valve 24.
Therefore, it is impossible to inadvertently fill the refrigerant from the suction operation valve 10 in the market. Further, the first extraction pipe 23A is connected to the flare nut 2 from the charge port 10a of the suction operation valve 10.
6 is connected so that replacement of the refrigerant compressor 1 is not hindered.

Example 6. [Embodiment 6] FIG. 8 is a configuration diagram of essential parts near a gas-liquid separator showing Embodiment 6 of the present invention. In FIG.
Reference numeral 23B is a second extraction pipe connected to the main body of the gas-liquid separator 8. Here, a check joint 23 detachably connected to an external refrigerant filling means (not shown) is provided at the tip of the second extraction pipe 23B, and is a dedicated pipe for refrigerant filling. In this case, the second outlet pipe 23B is connected to the charge port 27 provided by branching from the main body of the gas-liquid separator 8 using the flare nut 26,
There is no hindrance to the replacement of the gas-liquid separator 8.
As shown in FIG. 9, the check joint 23 may be provided at the tip of the second extraction pipe 23C directly welded to the refrigerant suction side pipe 25 of the gas-liquid separator 8. This also has no direct hindrance to the replacement of the gas-liquid separator 8.

Example 7. FIG. 10 is a refrigerant piping system diagram showing Embodiment 7 of the present invention. In FIG. 10, the evaporator 7
The refrigerant in the gas-liquid two-phase state that has passed through flows into the gas-liquid separator 8, but if the proportion of the liquid refrigerant is higher than that of the gas refrigerant, the refrigerant returns to the refrigerant compressor 1 and causes a failure. Therefore, in this embodiment, the liquid reservoir 4 is arranged in close contact with the lower stage of the gas-liquid separator 8 so that heat can be conducted. The liquid reservoir 4 and the gas-liquid separator 8 are integrally structured, and the high temperature side is configured as the liquid reservoir 4 and the low temperature side is configured as the gas liquid separator 8 so that heat can be exchanged between them. ing. Therefore, this heat exchange makes it possible to vaporize the liquid refrigerant in the gas-liquid separator 8 and prevent the liquid from returning to the refrigerant compressor 1. Further, by this heat exchange, as shown in FIG. 11, the ice around the portion 8a where the gas-liquid separator 8 comes into contact with the outside air, in particular, the suction pipe 9 can also be melted, so that resonance damage can be prevented in advance.
And since these are an integral structure, the installation area which occupies in a refrigerating device becomes smaller than the conventional one, and it leads to reduction of manufacturing cost.

[0028]

As described above, according to the present invention, the refrigerant compressor is provided with the oil temperature detector, and as the oil temperature detected by the oil temperature detector decreases, the refrigerant flow control valve of the suction pipe. Since the opening degree is controlled to be small, the inflow of the liquid refrigerant into the refrigerant compressor can be reduced, and the refrigerant compressor can be prevented from malfunctioning, so that the refrigeration system can be operated smoothly.

Further, the refrigerant compressor is provided with an oil temperature detector,
The suction pipe is equipped with a pressure detector to calculate the oil temperature superheat amount, which is the difference between the oil temperature and the refrigerant saturation temperature corresponding to the pressure in the suction pipe, and the oil temperature superheat amount is calculated based on this oil temperature superheat amount. When the temperature superheat amount is low, the opening of the refrigerant flow control valve is controlled to be small.
The refrigerant compressor can be more reliably prevented from malfunctioning, and the refrigeration system can be operated smoothly.

Further, a first solenoid valve is provided in the suction pipe, and a parallel pipe having a second solenoid valve and a capillary tube connected in parallel with the suction pipe is provided, and based on the oil temperature detected by the oil temperature detector of the refrigerant compressor. The first solenoid valve and the second solenoid valve are controlled to be opened / closed appropriately, that is, the liquid refrigerant is selectively supplied to the suction pipe and the parallel pipe in accordance with the amount of the liquid refrigerant flowing into the suction pipe corresponding to the oil temperature. Since the flow of the liquid refrigerant into the refrigerant compressor is reduced, the refrigerant compressor can be prevented from malfunctioning, and the refrigeration system can be operated smoothly.

[0031]

[0032]

[0033]

[0034]

[Brief description of drawings]

FIG. 1 is a refrigerant pipe system diagram showing a first embodiment of the present invention.

FIG. 2 is a relationship diagram of the oil temperature and the opening degree of the refrigerant flow control valve showing the first embodiment of the present invention.

FIG. 3 is a relationship diagram of an oil temperature superheat amount and an opening degree of a refrigerant flow rate control valve, showing a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part of an intake pipe showing a third embodiment of the present invention.

FIG. 5 is a main part piping system diagram in the vicinity of an intake pipe showing a fourth embodiment of the present invention.

FIG. 6 is a relationship diagram of an oil temperature and an open / closed state of a second solenoid valve according to a fourth embodiment of the present invention.

FIG. 7 is a main part configuration diagram in the vicinity of a refrigerant compressor showing a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of essential parts near a gas-liquid separator showing a sixth embodiment of the present invention.

FIG. 9 is a main part configuration diagram in the vicinity of a gas-liquid separator showing another example of the sixth embodiment of the present invention.

FIG. 10 is a refrigerant piping system diagram showing Embodiment 7 of the present invention.

FIG. 11 is a schematic cross-sectional view showing a gas-liquid separator and a liquid reservoir having an integral structure according to Embodiment 7 of the present invention.

FIG. 12 is a refrigerant piping system diagram showing a conventional refrigeration system.

[Explanation of symbols]

1 Refrigerant compressor, 3 Condenser, 4 Liquid reservoir, 6 Pressure reducing device, 7 Evaporator, 8 Gas-liquid separator, 9 Suction pipe, 10
Intake operation valve, 12 Oil temperature detector, 13 Refrigerant flow control valve, 14 Controller, 15 Pressure detector, 16 Liquid level detector, 17 First solenoid valve, 18 Second solenoid valve, 19 Parallel piping, 20 First Capillaries, 21 second capillaries, 22
Third capillary, 23 check joint, 23A first take-out pipe, 23B second take-out pipe, 23C second take-out pipe, 24 check valve, 25 refrigerant suction side pipe.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Ishii 6-5-66 Tehira, Wakayama City Mitsubishi Electric Corporation Wakayama Works (56) Reference JP-A-5-87428 (JP, A) JP-A 4-217754 (JP, A) JP-A-3-207971 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 1/00 304 F25B 43/00 F25B 45/00

Claims (3)

(57) [Claims] 1. A refrigeration system having a refrigerant circuit in which a refrigerant compressor, a condenser, a decompression device, an evaporator, a gas-liquid separator and the like are sequentially connected by piping, and the gas-liquid separator and the refrigerant compressor are connected to each other. A refrigerant flow rate control valve provided in the suction pipe, an oil temperature detector provided in the refrigerant compressor for detecting the oil temperature in the refrigerant compressor, and based on the oil temperature detected by the oil temperature detector. A refrigeration apparatus comprising: a first controller that controls an opening of the refrigerant flow rate control valve. 2. A refrigeration system having a refrigerant circuit in which a refrigerant compressor, a condenser, a pressure reducing device, an evaporator, a gas-liquid separator, etc. are sequentially connected by piping, and the gas-liquid separator is connected to the refrigerant compressor. Refrigerant flow control valve provided in the suction pipe, an oil temperature detector provided in the refrigerant compressor for detecting the oil temperature in the refrigerant compressor, and a pressure in the suction pipe provided in the suction pipe A pressure detector, and calculating the oil temperature superheat amount which is the difference between the saturation temperature of the refrigerant corresponding to the pressure detected by the pressure detector and the oil temperature detected by the oil temperature detector, and A second controller that controls the opening degree of the refrigerant flow control valve based on the oil temperature superheat amount. 3. A refrigeration apparatus having a refrigerant circuit in which a refrigerant compressor, a condenser, a decompression device, an evaporator, a gas-liquid separator and the like are sequentially connected by piping, and the gas-liquid separator and the refrigerant compressor are connected to each other. A first solenoid valve provided in the suction pipe, at least one parallel pipe connected to the suction pipe in parallel with the first solenoid valve, a second solenoid valve provided in the parallel pipe, A capillary tube that is provided in the parallel pipe in series with the second solenoid valve and has a smaller diameter than the suction pipe, an oil temperature detector that is provided in the refrigerant compressor and detects the oil temperature in the refrigerant compressor, and the oil. A refrigeration system comprising: a first controller that appropriately controls opening and closing of the first electromagnetic valve and the second electromagnetic valve based on an oil temperature detected by a temperature detector.