JP2008075955A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating device using an open type compressor capable of continuing operation by preventing intrusion of the atmosphere into a housing of the compressor even under such operating conditions as to have intake negative pressure. <P>SOLUTION: The refrigerating device has a refrigerant circuit 2 composed by connecting the compressor 3, a condenser 4, an expansion valve 9 and an evaporator 10 for cooling the inside of the cooling storage, sequentially by refrigerant piping 12, wherein the compressor 3 is constituted to project one end of a driving shaft to the outside of a housing and to be driven by an external drive source. The refrigerant circuit 2 is provided with by-pass circuits 15, 17 by-passing a part of a high pressure refrigerant which circulates through the refrigerant circuit, to the intake side of the compressor 3, and the by-pass circuits 15, 17 are provided with solenoid valves 16, 18 opened when the intake pressure of the compressor 3 is a set value or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus including a compressor configured to be driven by an external drive source such as an engine, and more particularly to a refrigeration apparatus suitable for being mounted on a refrigeration vehicle.

  Among refrigeration apparatuses, there are a refrigerant compressor that compresses refrigerant gas and a compressor that includes a hermetic compressor and a compressor that includes an open compressor. A hermetic compressor has a structure in which a motor for driving the compression mechanism is built in a hermetically sealed housing with a built-in compression mechanism. On the other hand, an open-type compressor does not have a motor and is compressed. One end of a drive shaft that drives the mechanism protrudes outside from the housing and is driven by an external drive source such as an engine. The latter open-type compressor is often used in a refrigeration apparatus, a vehicle air conditioner, an engine-driven air conditioner (GHP), and the like that are mounted on a vehicle and driven by a traveling engine or a sub-engine.

  In these refrigeration apparatuses or air conditioning apparatuses, in particular, in a so-called engine direct-coupled vehicle refrigeration apparatus that is driven by a vehicle traveling engine, the rotation speed of the compressor is independent of the refrigeration load. It depends on the engine speed. For this reason, for example, under conditions such as when the set temperature in the refrigerator is in a very low temperature range and the rotational speed of the compressor is high, the suction pressure of the compressor is reduced to below atmospheric pressure (negative pressure). There is.

If the operation under the suction negative pressure condition is continued, in the above-described open type compressor, the periphery of the drive shaft protruding from the housing is sealed with a lip seal. ) May cause air and moisture in the atmosphere to enter the housing from the lip seal portion.
If air and moisture in the atmosphere enter the housing of the compressor, abnormal discharge pressure increases due to compression of non-condensable gas, abnormal stop due to operation of the protective device, compression performance degradation, compressor failure, damage, etc. It becomes a factor. Moreover, with the passage of time, the deterioration of the properties of refrigerant and refrigerating machine oil, the generation of foreign matter, or the generation of rust, etc., will eventually lead to an inoperable state.

On the other hand, in order to save energy, the cooling capacity can be adjusted in the range of 0 to 100% with respect to the maximum cooling capacity, so that the opening degree of the electronic expansion valve can be adjusted in the range of 0 to 100% by the temperature controller. A refrigerating apparatus has been proposed (see Patent Document 1).
In this refrigeration system, when the opening of the electronic expansion valve is reduced to 0%, the suction pressure of the compressor becomes negative. Therefore, in Patent Document 1, a low-pressure expansion valve that opens when the suction pressure becomes negative, and a heat exchanger that exchanges heat with the refrigerant gas discharged from the compressor, between the outlet side of the condenser and the suction side of the compressor. The bypass circuit provided with these is provided. As a result, a part of the high-pressure liquid refrigerant is depressurized by the low-pressure expansion valve, led to the heat exchanger and gasified by heat exchange with the discharged refrigerant gas, and then bypassed to the suction side of the compressor. The negative pressure is avoided.
JP 2001-311567 A

However, Patent Document 1 suggests a refrigeration apparatus using an open-type compressor, or suggests a problem of air intrusion into the compressor housing at the time of suction negative pressure of the refrigeration apparatus. It does not suggest. This means that the pressure of the high-pressure liquid refrigerant is reduced using a special low-pressure expansion valve, the heat is exchanged with the discharged refrigerant gas in the heat exchanger, and gasified, and is bypassed to the suction side of the compressor as a low-pressure gas refrigerant. It is clear from that. In other words, in order to recover the negative suction pressure, it is not necessary to depressurize and use a low-pressure gas refrigerant. Rather, reducing the pressure is to reduce the recovery sensitivity of the suction negative pressure, which is not preferable. In addition, the use of an expensive low-pressure expansion valve or heat exchanger does not bring any benefit to the recovery of the suction negative pressure.
As described above, the actual situation is that no useful means for solving the problem of the suction negative pressure operation in the refrigeration apparatus using the open type compressor has yet been provided.

  The present invention has been made in view of such circumstances, and prevents the atmosphere from entering the housing of the compressor and continues the operation even under an operating condition that results in a negative suction pressure. An object of the present invention is to provide a refrigeration apparatus using an open type compressor.

In order to solve the above problems, the refrigeration apparatus of the present invention employs the following means.
That is, in the refrigeration apparatus according to the present invention, a compressor, a condenser, an expansion valve, and an evaporator for cooling the inside of the refrigerator are sequentially connected by a refrigerant pipe to form a refrigerant circuit, and the compressor is driven by In the refrigerating apparatus in which one end of the shaft projects outside the housing and is driven by an external drive source, a part of the high-pressure refrigerant circulating in the refrigerant circuit is supplied to the compressor in the refrigerant circuit. A bypass circuit for bypassing is provided on the suction side, and the bypass circuit is provided with an electromagnetic valve that is opened when the suction pressure of the compressor is equal to or lower than a set value.

  According to the present invention, the refrigerant circuit is provided with a bypass circuit that bypasses a part of the high-pressure refrigerant circulating in the refrigerant circuit to the suction side of the compressor, and the bypass circuit includes a suction pressure of the compressor. Since a solenoid valve that is opened when is below the set value is provided, when the compressor suction pressure drops below the set value (below atmospheric pressure) during operation, the solenoid valve is opened and the high pressure A part of the refrigerant is bypassed to the suction side of the compressor by the bypass circuit. Thereby, it can prevent that the suction pressure of a compressor falls below atmospheric pressure. Accordingly, it is possible to avoid the suction negative pressure operation in which the suction pressure of the compressor is equal to or lower than the atmospheric pressure, and to solve various problems caused by the air entering the compressor housing from the seal portion of the drive shaft. It is possible to improve the reliability of the refrigeration apparatus.

  Furthermore, in the refrigeration apparatus of the present invention, in the refrigeration apparatus, the bypass circuit includes a high-pressure liquid refrigerant bypass circuit that bypasses a part of the high-pressure liquid refrigerant circulating in the refrigerant circuit to the suction side of the compressor. It is characterized by being configured.

  According to the present invention, the bypass circuit is constituted by the high-pressure liquid refrigerant bypass circuit that bypasses a part of the high-pressure liquid refrigerant circulating in the refrigerant circuit to the suction side of the compressor. When the pressure falls below a set value (below atmospheric pressure), the solenoid valve is opened and a part of the high-pressure liquid refrigerant is bypassed to the suction side of the compressor by the high-pressure liquid refrigerant bypass circuit. As a result, it is possible to prevent the suction pressure of the compressor from decreasing below the atmospheric pressure and to avoid the suction negative pressure operation. Further, since the high-pressure liquid refrigerant is bypassed, the compressor can be cooled using the latent heat of vaporization by the relatively low-temperature liquid refrigerant, and the discharge temperature of the compressor can be lowered.

  Furthermore, in the refrigeration apparatus according to the present invention, in the above refrigeration apparatus, the bypass circuit includes a hot gas bypass circuit that bypasses a part of the high-pressure gas refrigerant circulating in the refrigerant circuit to the suction side of the compressor. It is characterized by being.

  According to the present invention, the bypass circuit is constituted by a hot gas bypass circuit that bypasses a part of the high-pressure gas refrigerant circulating in the refrigerant circuit to the suction side of the compressor, so that the suction pressure of the compressor during operation When the pressure drops below the set value (below atmospheric pressure), the solenoid valve is opened and a part of the high-pressure gas refrigerant is bypassed to the suction side of the compressor by the hot gas bypass circuit. As a result, the suction pressure of the compressor can be prevented from decreasing below the atmospheric pressure, and the suction negative pressure operation can be avoided. Further, since the high-pressure gas refrigerant is bypassed, the suction pressure recovery sensitivity can be increased, and the suction negative pressure can be quickly recovered to suppress a decrease in cooling capacity.

  In the refrigeration apparatus according to the present invention, a compressor, a condenser, an expansion valve, and an evaporator for cooling the inside of the refrigerator are sequentially connected by a refrigerant pipe to form a refrigerant circuit, and the compressor is driven In the refrigeration apparatus in which one end of the shaft projects outside the housing and is driven by an external drive source, the refrigerant circuit includes a part of the high-pressure liquid refrigerant circulating in the refrigerant circuit as the compression. A high-pressure liquid refrigerant bypass circuit for bypassing to the suction side of the machine, and a hot gas bypass circuit for bypassing a part of the high-pressure gas refrigerant circulating in the refrigerant circuit to the suction side of the compressor. The liquid refrigerant bypass circuit is provided with an electromagnetic valve that is opened when the suction pressure of the compressor is equal to or lower than a set value and the discharge pressure or discharge temperature is equal to or higher than the set value. The scan circuit, wherein the suction pressure of the compressor below the set value, and when the discharge pressure or discharge temperature is less than the set value, characterized in that the solenoid valve that is open is provided.

According to the present invention, the refrigerant circuit includes a high-pressure liquid refrigerant bypass circuit that bypasses a part of the high-pressure liquid refrigerant circulating in the refrigerant circuit to the suction side of the compressor, and a high-pressure gas circulating in the refrigerant circuit. A hot gas bypass circuit that bypasses a part of the refrigerant to the suction side of the compressor, and the liquid refrigerant bypass circuit has a compressor suction pressure equal to or lower than a set value and a discharge pressure or a discharge temperature set to a set value. An electromagnetic valve that is opened at the above time is provided, and the hot gas bypass circuit has an electromagnetic valve that is opened when the suction pressure of the compressor is lower than the set value and the discharge pressure or discharge temperature is lower than the set value. Since the valve is provided, when the suction pressure of the compressor drops below the set value (below atmospheric pressure) during operation, if the discharge pressure or discharge temperature is above the set value, it is provided in the high-pressure liquid refrigerant bypass circuit. Solenoid valve By the open, it is possible to bypass some of the high-pressure liquid refrigerant to the suction side of the compressor. Further, when the discharge pressure or the discharge temperature is lower than the set value, a part of the high-pressure gas refrigerant can be bypassed to the suction side of the compressor by opening the solenoid valve provided in the hot gas bypass circuit. it can. As a result, it is possible to reliably prevent the suction pressure of the compressor from dropping below the atmospheric pressure. Therefore, the suction negative pressure operation can be avoided, and various problems caused by the air entering the compressor housing from the seal portion of the drive shaft can be solved.
Moreover, since either the high pressure liquid refrigerant or the high pressure gas refrigerant can be selectively bypassed to the suction side of the compressor depending on the state of the discharge pressure or the discharge temperature when the suction pressure is reduced, the discharge pressure or the discharge temperature is high. In this case, the discharge temperature of the compressor can be quickly lowered by bypassing the high-pressure liquid refrigerant and cooling the compressor using the latent heat of vaporization with a relatively low-temperature liquid refrigerant. Further, when the discharge pressure or the discharge temperature is low, by bypassing the high-pressure gas refrigerant, it is possible to increase the recovery sensitivity of the suction pressure and quickly recover the suction negative pressure, thereby suppressing a decrease in cooling capacity. .

  According to the present invention, when the suction pressure of the compressor drops below a set value (below atmospheric pressure) during operation of the refrigeration system, a part of the high-pressure refrigerant is bypassed to the suction side of the compressor from the bypass circuit. Therefore, the suction pressure of the compressor can be prevented from dropping below the atmospheric pressure, so that the suction negative pressure operation where the suction pressure of the compressor is below the atmospheric pressure is avoided and the compressor is compressed from the seal portion of the drive shaft. Various problems caused by the air entering the machine housing can be solved. Therefore, the reliability of the refrigeration apparatus can be improved.

  Further, according to the present invention, either the high-pressure liquid refrigerant or the high-pressure gas refrigerant can be selectively bypassed to the compressor suction side depending on the state of the discharge pressure or discharge temperature when the suction pressure is reduced. Alternatively, when the discharge temperature is high, the refrigerant gas discharge temperature can be lowered by bypassing the high-pressure liquid refrigerant and cooling the compressor. Further, when the discharge pressure or the discharge temperature is low, by bypassing the high-pressure gas refrigerant, the recovery sensitivity of the suction pressure can be increased, the suction negative pressure can be quickly avoided, and the decrease in the cooling capacity can be suppressed. .

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a refrigerant circuit diagram of a refrigeration apparatus 1 according to the present embodiment. In the present embodiment, an engine direct-coupled vehicle refrigeration apparatus 1 mounted on a refrigerated vehicle and driven by a traveling engine of the vehicle is shown.
The refrigerant circuit 2 of the refrigeration apparatus 1 includes an open compressor 3 that compresses refrigerant gas, and a capacitor 4 that dissipates and condenses the high-temperature and high-pressure refrigerant gas discharged from the open compressor 3 by heat exchange with the outside air. , A receiver 5 that stores the liquid refrigerant condensed by the condenser 4, a dryer 6 filled with a desiccant that removes moisture in the refrigerant circuit 2, and a sight glass that monitors the state of the refrigerant circulating in the refrigerant circuit 2 7, a gas-liquid heat exchanger 8 for exchanging heat between the liquid refrigerant and the gas refrigerant evaporated by the evaporator 10, an expansion valve 9 for adiabatically expanding the liquid refrigerant, and the adiabatic expansion provided in the refrigerator. An evaporator 10 that evaporates the refrigerant by exchanging heat between the refrigerant and the internal air, and an accumulator 11 that separates liquid components in the evaporated gas refrigerant and sucks only the gas refrigerant into the compressor 3 in this order. Piping 1 In it constituted by connecting.

The open-type compressor 3 is a known open-type compressor 3 having a configuration in which a motor is not built in and one end of a drive shaft that drives the compression mechanism protrudes outside from the housing. This open type compressor 3 may be any type of compressor, and a drive shaft is driven via an electromagnetic clutch by a traveling engine (not shown).
The condenser 4 and the evaporator 10 are respectively provided with a condenser fan 13 that blows outside air to the condenser 4 and an evaporator fan 14 that circulates the internal air to the evaporator 12.

One end of the refrigerant circuit 2 is branched from a discharge pipe 12 </ b> A connected to the compressor 3, and the other end is connected to a suction pipe 12 </ b> C of the open compressor 3 to be discharged from the open compressor 3. A hot gas bypass circuit 15 for bypassing a part of the high-pressure refrigerant gas to the suction side of the open compressor 3 is provided. The hot gas bypass circuit 15 is provided with an electromagnetic valve 16.
Further, one end of the refrigerant circuit 2 is branched from the high-pressure liquid refrigerant pipe 12B between the condenser 4 and the expansion valve 9, and the other end is connected to the suction pipe 12C of the open compressor 3, so that the high-pressure liquid refrigerant A high-pressure liquid refrigerant bypass circuit 17 that bypasses a part of the refrigerant to the suction side of the open compressor 3 is provided. The high-pressure liquid refrigerant bypass circuit 17 is provided with an electromagnetic valve 18 and a flow rate adjusting capillary tube 19.

  A discharge pressure or discharge temperature sensor 20 that detects the pressure or temperature of the discharged refrigerant gas is provided in the discharge pipe 12 </ b> A of the open compressor 3. The suction pipe 12A of the open compressor 3 is provided with a suction pressure sensor 21 that detects the pressure of the sucked refrigerant gas. The detected values of the discharge pressure or discharge temperature sensor 20 and the suction pressure sensor 21 are input to the controller 22.

When the suction pressure detected by the suction pressure sensor 21 becomes a negative pressure equal to or lower than the atmospheric pressure, the controller 22 sets the discharge pressure or discharge temperature detected by the discharge pressure or discharge temperature sensor 20 to a set value (for example, the pressure is If it is 15 kg / cm ² ) or more, the solenoid valve 18 is opened and a part of the high-pressure liquid refrigerant is bypassed to the suction pipe 12C of the open compressor 3 via the high-pressure liquid refrigerant bypass circuit 17. Further, when the suction pressure is less than atmospheric pressure and the discharge pressure or discharge temperature is less than a set value (for example, the pressure is 15 kg / cm ² ), the solenoid valve 16 is opened and a part of the high-temperature high-pressure hot gas is removed. The configuration is such that the suction pipe 12 </ b> C of the open compressor 3 is bypassed via the hot gas bypass circuit 15.

Next, the operation of the refrigeration apparatus 1 according to the present embodiment will be described.
When the electromagnetic clutch (not shown) is turned on, the refrigeration apparatus 1 is driven by the open-type compressor 3 by the traveling engine. The refrigerant compressed by driving the open-type compressor 3 flows into the condenser 4 through the discharge pipe 12A, and is heat-exchanged with the outside air blown by the condenser fan 13 in the condenser 4 to be condensed and liquefied. This liquid refrigerant is temporarily stored in the receiver 5 through the liquid refrigerant pipe 12B. The refrigerant stored in the receiver 5 passes through the dryer 6 and the sight glass 7 and flows into the gas-liquid heat exchanger 8, where it is heat-exchanged with the low-pressure gas refrigerant from the evaporator 10 and cooled. The refrigerant cooled by the gas-liquid heat exchanger 8 reaches the expansion valve 9, where it is adiabatically expanded to become a low-temperature and low-pressure gas-liquid two-phase refrigerant and flows into the evaporator 10.

The refrigerant that has flowed into the evaporator 10 is heat-exchanged with the air in the refrigerator circulated by the evaporator fan 14, and cools and evaporates the air in the refrigerator. As the cooling air is circulated in the cabinet, the inside of the refrigerator is cooled to a predetermined temperature. The refrigerant evaporated in the evaporator 10 flows through the suction pipe 12 </ b> C, and is sucked into the compressor 3 through the gas-liquid heat exchanger 8 and the accumulator 11.
As described above, the cooling operation for cooling the inside of the refrigerator is performed by circulating the refrigerant in the refrigerant circuit 2.

In the refrigeration apparatus 1 described above, the open compressor 3 is driven at a rotational speed corresponding to the rotational speed of the traveling engine of the vehicle regardless of the refrigeration load. On the other hand, the inside of the refrigerator is cooled to a temperature set corresponding to the load.
Under such circumstances, particularly when the internal temperature is set to a very low temperature range and the rotational speed of the open compressor 3 becomes a high rotation range, the suction pressure of the open compressor 3 is set. Can sometimes be reduced to negative pressures below atmospheric pressure. In this case, in the open type compressor 3, since the periphery of the drive shaft protruding from the housing is sealed by the lip seal, air and moisture in the atmosphere may enter the housing through the seal portion.

  However, in the present embodiment, when the suction pressure becomes a negative pressure equal to or lower than the atmospheric pressure in the above situation, the suction pressure sensor 21 detects this, and at that time, the detection value of the discharge pressure or the discharge temperature sensor 20 is set. When the value is greater than or equal to the value, the solenoid valve 18 can be opened and a part of the high-pressure liquid refrigerant can be bypassed to the suction pipe 12C of the open compressor 3 via the high-pressure liquid refrigerant bypass circuit 17. Thereby, the suction negative pressure operation in which the suction pressure is equal to or lower than the atmospheric pressure can be avoided. In addition, due to the physical properties of the refrigerant, if the outside air temperature is high, the discharge pressure and discharge temperature of the compressor tend to increase. By bypassing the high-pressure liquid refrigerant, the latent heat of vaporization is utilized by the relatively low-temperature liquid refrigerant. Thus, the open type compressor 3 can be cooled, and the discharge temperature can be cooled so as not to exceed the limit temperature.

  Further, in the above, when the detected value of the discharge pressure or the discharge temperature sensor 20 is less than the set value, the solenoid valve 16 is opened and a part of the high-pressure gas refrigerant is opened via the hot gas bypass circuit 15. The suction pipe 12C can be bypassed. As a result, the suction negative pressure operation in which the suction pressure is equal to or lower than the atmospheric pressure can be avoided. In addition, if the outside air temperature is low due to the physical properties of the refrigerant, the discharge pressure and discharge temperature of the compressor also become low.In this case, by bypassing the high-pressure gas refrigerant, the suction pressure recovery sensitivity is increased, It is possible to quickly avoid the suction negative pressure and suppress the cooling capacity decrease. In this case, since the discharge pressure or discharge temperature of the compressor is relatively low, the discharge pressure or discharge temperature does not exceed the limit value even if high-temperature and high-pressure hot gas is bypassed.

Thus, according to the present embodiment, the following effects can be obtained.
Since suction negative pressure can be surely avoided, various problems caused by air and moisture in the atmosphere entering the housing of the open compressor 3 during suction negative pressure operation, that is, non-condensable gas Refrigeration system due to abnormal increase in discharge pressure due to compression of the compressor, abnormal stop due to the activation of the protection device, deterioration in compression performance, failure or damage of the compressor, deterioration of properties of refrigerant and refrigerator oil, generation of foreign matter, generation of rust, etc. The problem that 1 falls into an inoperable state can be solved beforehand, and the reliability of the refrigeration apparatus can be ensured.

  Further, since either the high-pressure liquid refrigerant or the high-pressure gas refrigerant can be selectively bypassed to the suction pipe 12C of the open compressor 3 depending on the state of the discharge pressure or the discharge temperature when the suction pressure is reduced, the discharge pressure or When the discharge temperature is high, by bypassing the high-pressure liquid refrigerant and cooling the open compressor 3, the refrigerant gas discharge temperature can be lowered so that the discharge temperature does not exceed the limit temperature. In addition, when the discharge pressure or the discharge temperature is low, by bypassing the high-pressure gas refrigerant, the recovery sensitivity of the suction pressure can be increased, the suction negative pressure can be quickly recovered, and the cooling capacity reduction can be suppressed.

  In the above embodiment, the discharge pressure or discharge temperature sensor 20 and the suction pressure sensor 21 do not need to be newly installed, and existing sensors installed in the refrigeration apparatus 1 can be used as they are.

It is a refrigerant circuit figure of the refrigerating device concerning one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerating device 2 Refrigerant circuit 3 Compressor 4 Capacitor 9 Expansion valve 10 Evaporator 12 Refrigerant piping 15 Hot gas bypass circuit 16 Solenoid valve 17 High pressure liquid refrigerant bypass circuit 18 Solenoid valve 20 Discharge pressure or discharge temperature sensor 21 Intake pressure sensor 22 Controller

Claims (4)

A compressor, a condenser, an expansion valve, and an evaporator for cooling the inside of the refrigerator are sequentially connected by a refrigerant pipe to form a refrigerant circuit,
In the refrigeration apparatus, the compressor has a configuration in which one end of a drive shaft projects outside the housing and is driven by an external drive source.
The refrigerant circuit is provided with a bypass circuit that bypasses a part of the high-pressure refrigerant circulating in the refrigerant circuit to the suction side of the compressor,
The bypass device is provided with a solenoid valve that is opened when a suction pressure of the compressor is equal to or lower than a set value.   The refrigeration according to claim 1, wherein the bypass circuit is configured by a high-pressure liquid refrigerant bypass circuit that bypasses a part of the high-pressure liquid refrigerant circulating in the refrigerant circuit to the suction side of the compressor. apparatus.   2. The refrigeration apparatus according to claim 1, wherein the bypass circuit includes a hot gas bypass circuit that bypasses a part of the high-pressure gas refrigerant circulating in the refrigerant circuit to a suction side of the compressor. . A compressor, a condenser, an expansion valve, and an evaporator for cooling the inside of the refrigerator are sequentially connected by a refrigerant pipe to form a refrigerant circuit,
In the refrigeration apparatus, the compressor has a configuration in which one end of the drive shaft projects outside the housing and is driven by an external drive source.
The refrigerant circuit includes a high-pressure liquid refrigerant bypass circuit that bypasses a part of the high-pressure liquid refrigerant circulating in the refrigerant circuit to the suction side of the compressor, and one of the high-pressure gas refrigerant circulating in the refrigerant circuit. A hot gas bypass circuit for bypassing the section to the suction side of the compressor,
The high-pressure liquid refrigerant bypass circuit is provided with an electromagnetic valve that is opened when the suction pressure of the compressor is equal to or lower than a set value and the discharge pressure or discharge temperature is equal to or higher than a set value.
The refrigeration apparatus, wherein the hot gas bypass circuit is provided with an electromagnetic valve that is opened when the suction pressure of the compressor is equal to or lower than a set value and the discharge pressure or the discharge temperature is lower than the set value.

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