JPH0669662U - Damage prevention mechanism of compressor in refrigeration system - Google Patents

Abstract

(57) [Summary] [Purpose] To suppress the increase of refrigerant bypass amount in the refrigeration system,
Prevent damage to the compressor. [Composition] The compressor 14, the condenser 16, the liquid receiver 18, the expansion means 10, the evaporator 12, and the condenser and the liquid receiver are always communicated with each other, and when the condensation pressure decreases, the compressor and the liquid receiver are connected. Condensing pressure regulator 22 that switches to the communication side, and capillary tube 30 that bypasses the liquid receiver to the suction side of the compressor are provided. In the system, the connection part for bypassing the capillary tube to the receiver is selected at an approximately intermediate position between the high limit Hm and the low limit Lm of the refrigerant storage level of the receiver, and the level in the receiver is high. When it is, the amount of bypass from the receiver to the compressor is increased to prevent overheating of the compressor, and when the level in the receiver is at the lower limit, the receiver is connected to the compressor. The cooling amount of the compressor is stopped by reducing the bypass amount to the compressor.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a mechanism for preventing damage to a compressor in a refrigeration system, and more specifically, when the condensing pressure of an air-cooled condenser is reduced, the vaporized refrigerant from the compressor is fed to a receiver side by a condensing pressure regulator. Switching from the refrigeration system or condenser to raise the condensing pressure, and to prevent the compressor from overheating by bypassing the liquefied cooling medium from the receiver to the suction side of the compressor by means of a capillary tube. In a refrigeration system in which the liquefied refrigerant is bypassed by a capillary tube to the suction side of the compressor to prevent overheating of the compressor, the bypass amount of the liquefied refrigerant is suppressed from increasing in the winter when the outside temperature is low. The present invention relates to a mechanism capable of suitably preventing damage to the compressor.

[0002]

[Prior art]

 4 and 5 are schematic views showing a refrigeration system of an ice making machine or a refrigerator according to the related art. Taking the refrigeration system of an ice maker as an example, this refrigeration system includes an expansion means 10 such as an expansion valve that expands a high-pressure liquefied refrigerant into a vaporized refrigerant, and heat of vaporization taken when the liquefied refrigerant vaporizes. The evaporator 12 that performs the cooling action by the compressor 12, the compressor 14 that sends the vaporized refrigerant that has performed the cooling action in the evaporator 12 to the condenser in a compressed state, and the vaporized refrigerant that is compressed by the compressor 14 is condensed. A condenser 16 that serves as a liquefied refrigerant and a liquid receiver 18 that partially stores the condensed liquefied refrigerant and that supplies the liquefied refrigerant to the expansion means 10 via the pipe 32 are incorporated. A fan 20 is attached to the condenser 16 so that the fan 20 rotates to perform forced air cooling. In this way, when the condenser 16 is of the air-cooled type, it is possible to use an ice maker in an environment where the outside air temperature significantly decreases, such as in the winter, or to separate the condenser 16 such as the separate type so that strong winds are generated. When used under the appropriate conditions, the condensation capacity of the condenser 16 will be improved. However, on the other hand, the condensing pressure in the condenser 16 decreases, so that the evaporator 12 may not exhibit a sufficient refrigerating capacity.

In preparation for such a decrease in the condensation pressure, the refrigeration system is provided with a compression pressure regulator 22 which is a kind of switching valve. The condensing pressure regulator 22 has three ports B, C, and R as shown in FIGS. 4 and 5, and the port B among them is bypassed to the discharge side of the compressor 14 via a pipe 24. Connected. Further, the port C is connected to the outlet side of the condenser 16 via the pipe 26, and the pipe 28 led out from the port R is opened to the liquid receiver 18 from above. Then, the port C and the port R of the condensing pressure regulator 22 communicate with each other, and the high-pressure liquefied refrigerant condensed in the condenser 16 is supplied to the liquid receiver 18. However, as described above, when the ice making machine is used in an environment where the outside air temperature is lowered, such as in winter, the condensation pressure in the condenser 16 is lowered, and the sufficient refrigerating capacity cannot be exerted. When the condensing pressure decreases in this way, a diaphragm (not shown) built in the condensing pressure adjuster 22 responds to close the port C and the port R and to close the port B and the port R. To communicate. Therefore, the high-temperature, high-pressure vaporized refrigerant compressed by the compressor 14 is supplied to the liquid receiver 18 bypassing the conduit 24 without passing through the condenser 16. As a result, the liquefied refrigerant stays inside the condenser 16 (is not sent out), and the condensing pressure, which has dropped, starts to rise. When this condensing pressure becomes equal to or higher than the set pressure of the condenser 16, the diaphragm (not shown) reversely operates to re-establish communication between the port C and the port R, so that the condensing pressure is adjusted to an optimum value. The refrigerating capacity of the evaporator 12 is restored.

Further, in the above-mentioned refrigeration system, when the outside air temperature rises, for example, in the summer, the heat radiation condition in the compressor 14 may deteriorate and the compressor 14 may overheat. Further, when the condensation pressure in the condenser 16 becomes high, the compression ratio in the compressor 14 becomes large, and in this case also, the compressor 14 overheats. Therefore, in order to prevent overheating of the compressor, a capillary tube 30 that bypass-connects the liquid receiver 18 and the suction side of the compressor 14 is incorporated in the refrigeration system. That is, the liquefied refrigerant in the liquid receiver 18 flows into the suction side of the compressor 14 through the capillary tube 30 and is vaporized there, so that the heat of vaporization is taken away as in the case of the evaporator, and The machine 14 is cooled to prevent overheating.

[0005]

[Problems to be solved by the device]

 As described above, by providing the condensing pressure regulator 22 in the refrigeration system, it is possible to prevent the condensing pressure in the condenser 16 from decreasing even when the outside air temperature is low, such as in winter. Further, by providing the refrigeration system with the capillary tube 30 that bypasses the liquid receiver 18 and the compressor 14, overheating of the compressor 14 can be prevented. However, in the refrigeration system in which the condensing pressure regulator 22 and the capillary tube 30 are arranged, the following disadvantages occur particularly in winter. That is, in the winter when the outside air temperature greatly decreases, when the condensation pressure in the condenser 16 decreases, the condensation pressure regulator 22 operates, and as described above with reference to FIG. 4, the ports B and R are connected to each other. Increase condensing pressure. This prevents the cooling capacity of the evaporator 12 from decreasing, but on the other hand, since the high-pressure vaporized refrigerant from the compressor 14 is directly supplied to the receiver 18, the receiver 18 stores it. The liquefied refrigerant thus produced is forcibly sent out through the pipe 32. Therefore, there is a drawback that the amount of the liquefied refrigerant bypassed from the capillary tube 30 to the compressor 14 increases and the compressor 14 is cooled more than necessary. Further, when the liquefied refrigerant bypassed from the capillary tube 30 and the vaporized refrigerant coming from the evaporator 12 are mixed in a large amount (gas-liquid mixed phase state) and flow into the compressor 14, the compressor 14 is excessively large. It also points out the drawbacks that lead to damage under load.

Further, when the refrigeration system is provided with an overheat prevention mechanism for bypassing the liquefied refrigerant to the suction side of the compressor 14 by the capillary tube 30, it is not always a requirement to provide the condensation pressure regulator 22. However, as in the refrigeration system shown in FIG. 6, in the configuration in which the valve body for turning on / off the refrigerant inflow is not attached to the capillary tube 30, since the liquefied cooling medium is always bypassed to the inflow side of the compressor 14, When the outside air temperature becomes low, liquid backing occurs and the compressor deviates from the usable range. Therefore, as in the refrigeration system shown in FIG. 7, the capillary tube 30 is provided with an electromagnetic valve 40 for turning on / off the refrigerant flow, and the electromagnetic valve 40 is proposed to be opened / closed by a temperature sensor 42 provided in the compressor 14, for example. Has also been done. For example, in FIG. 7, when the temperature sensor 42 detects that the temperature of the compressor 14 exceeds the set value, the solenoid valve 40 is opened and the liquefied refrigerant is bypassed to the inflow side of the compressor 14 via the capillary tube 30. Thus, the compressor 14 is prevented from overheating. Conversely, when the temperature sensor 42 detects that the temperature of the compressor 14 has dropped below the set value, the electromagnetic valve 40 is closed to stop the bypass of the liquefied refrigerant, so that the temperature of the compressor 14 is prevented from dropping. However, the temperature sensor 42 has a reset width in order to reduce the number of times the solenoid valve 40 is started and stopped. Therefore, in the vicinity of the bypass switching point of the liquefied cooling medium where the outside air temperature changes, the number of times the solenoid valve 40 is started and stopped increases and the refrigerating capacity fluctuates. Moreover, the solenoid valve 40 is an expensive refrigerating machine component, which is one of the factors that increase the manufacturing cost. When the replacement is required due to a failure, all the refrigerant in the refrigerating system must be released to the atmosphere. However, it is pointed out that it is economically disadvantageous and is not preferable from the viewpoint of environmental protection.

[0007]

[The purpose of the device]

 In view of the above-mentioned drawbacks inherent in the refrigeration system according to the prior art, the present invention has been proposed in order to solve the above-mentioned disadvantages. When the condensing pressure of the air-cooled condenser is reduced, the compressor is The condensed refrigerant from the receiver is switched to the receiver side by the condensing pressure regulator to increase the condensing pressure, and the liquefied refrigerant from the receiver is bypassed by the capillary tube to the suction side of the compressor to compress the compressed refrigerant. In a refrigeration system designed to prevent overheating of a compressor, to provide a means for suppressing an increase in the amount of bypass of the liquefied refrigerant in winter when the outside air temperature is low, thereby appropriately preventing damage to the compressor. With the goal. Another object of the present application is to liquefy a liquefied refrigerant in a refrigeration system equipped with a compressor overheat prevention mechanism that bypasses the liquefied refrigerant to the suction side of the compressor without using an electromagnetic valve that is an expensive refrigerator part. Another object of the present invention is to provide a means that enables refrigerant bypass control and that does not need to discharge the refrigerant in the refrigeration system even when repairing a failure.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems and preferably achieve the first object, the present invention provides a compressor for compressing a vaporized cooling medium, a condenser for condensing the compressed vaporized refrigerant into a liquefied refrigerant, and A receiver that stores a part of the liquefied refrigerant, an expansion means that expands the liquefied cooling medium that comes from this receiver to become a vaporized refrigerant, and a cooling action performed by this vaporized refrigerant before An evaporator that returns to the suction side of the compressor, a condenser pressure regulator that always connects the condenser and the liquid receiver, and switches to the communication side between the compressor and the liquid receiver when the condensation pressure decreases. And a capillary tube that bypasses the liquid receiver to the suction side of the compressor, and there is a level difference in the storage level of the liquefied refrigerant in the liquid receiver depending on the switching state of the condensation pressure regulator. In the refrigeration system that is set to generate, the capillary tube is The connection part bypassed to the liquid receiver is selected at an approximately intermediate position between the high limit and the low limit of the refrigerant storage level in the liquid receiver, and the condensing pressure regulator is connected to the condenser and the liquid receiver. When the refrigerant storage level in the receiver is at the high limit, the bypass amount of vaporized refrigerant from the receiver to the compressor is increased to prevent overheating of the compressor. When the condensing pressure regulator is switched to the communication side between the compressor and the liquid receiver and the refrigerant storage level in the liquid receiver is at the lower limit, the liquid from the liquid receiver to the compressor is It is characterized in that the bypass amount of the vaporized refrigerant is reduced to stop the cooling of the compressor.

Also, in order to solve the above-mentioned problems and achieve the second object, another invention of the present application is a compressor for compressing a vaporized refrigerant, and condensing the compressed vaporized refrigerant into a liquefied refrigerant. A condenser, an expansion means for expanding the liquefied refrigerant from the condenser into a vaporized refrigerant, and an evaporator for returning the vaporized refrigerant to the suction side of the compressor after performing a cooling action by the vaporized refrigerant. And a capillary tube for bypassing the condenser to the suction side of the compressor, in a refrigeration system, an electric heater is attached to the capillary tube, and the energization of the electric heater is controlled to control the capillary tube. The feature is that the amount of bypass of the liquefied refrigerant in the pipe can be changed.

[0010]

【Example】

 Next, a compressor damage prevention mechanism in a refrigeration system according to the present invention will be described below with reference to the accompanying drawings by way of a preferred embodiment. FIG. 1 is a circuit diagram of a refrigeration system including a damage prevention mechanism for a compressor according to an embodiment, and the basic circuit is the same as that described with reference to FIGS. 4 and 5. Therefore, the same components will be designated by the same reference numerals. In this embodiment, a connecting portion for bypassing the capillary tube 30 to the liquid receiver 18 is selected at a substantially intermediate position between the high limit and the low limit of the refrigerant storage level in the liquid receiver 18, whereby the compressor is The damage of 14 can be prevented appropriately. The reason for having such a configuration depends on the following findings by the inventor. The liquid receiver 18 in the refrigeration system described above corresponds to the level of the liquefied refrigerant stored in the liquid receiver 18 when the outside air temperature is high, such as in the summer, and when the outside air temperature is low, such as the winter. There is a difference. That is, as shown in the example of winter in FIG. 4, when the condensing pressure regulator 22 is switched and the ports B and R communicate with each other, the vaporized refrigerant from the compressor 14 goes directly to the receiver 18, The liquefied refrigerant will remain in the condenser 14. Therefore, the storage level of the liquefied refrigerant in the liquid receiver 18 is reduced by the amount of the liquefied refrigerant accumulated in the condenser 14 (the low refrigerant storage level in the liquid receiver 18 is indicated by the symbol Lm). Further, as shown in the example of summer in FIG. 5, when the condensation pressure regulator 22 does not operate and the port C and the port R communicate with each other, the storage level of the liquefied refrigerant in the receiver 18 is high. Is held (the high refrigerant storage level in the liquid receiver 18 is indicated by the symbol Hm).

When the condensing pressure regulator 22 is used as described above, the refrigerant level in the receiver 18 is at the high limit Hm in the summer and at the low limit Lm in the winter as shown in FIG. . Therefore, if the connecting portion of the capillary tube 30 to the receiver 18 is selected at a position approximately midway between the high limit Hm and the low limit Lm, the liquefied refrigerant in the receiver 18 causes a problem in the capillary tube 30 in the summer. However, the liquefied refrigerant cannot flow into the capillary tube 30 in winter. For example, in the summer when the compressor 14 easily overheats and needs to be cooled, the opening of the capillary tube 30 connected to the receiver 18 is below the high limit Hm and communicates with the liquefied refrigerant layer. There is. Therefore, the amount by which the liquefied refrigerant bypasses the capillary tube 30 increases, and the compressor 14 is cooled appropriately. Further, in the winter when the compressor 14 does not need to be cooled, the opening of the capillary tube 30 connected to the liquid receiver 18 is located above the lower limit Lm and communicates with the vaporized refrigerant layer. Therefore, the amount of the liquefied refrigerant bypassing the capillary tube 30 is extremely reduced, and the compressor 14 is not cooled. Particularly, in the conventional refrigeration system described in FIG. 4, a large amount of the liquefied refrigerant bypasses the capillary tube 30 in winter, and the vaporized refrigerant and the liquefied refrigerant are supplied to the compressor 14 in a mixed state, and the compressor 14 However, the present embodiment solves this drawback.

Next, FIG. 2 shows a modification of the embodiment according to FIG. 1, in which an electric heater 34 is attached to the capillary tube 30 so that the bypass amount of the refrigerant can be supplementarily controlled. It was done. For example, the electric heater 34 is wound around the capillary tube 30 and connected to the bypass control circuit 38. A temperature sensor 36 provided in the compressor 14 is connected to the control circuit 38. Then, the bypass control circuit 38 controls the amount of heat generated by the electric heater 34 according to the temperature information of the compressor 14 detected by the temperature sensor 36. As an example, the temperature sensor 36 monitoring the temperature of the compressor 14 inputs the temperature information to the bypass control circuit 38. The control circuit 38 performs control such that the output voltage to the electric heater 34 decreases as the temperature detected by the temperature sensor 36 increases, and the output voltage to the electric heater 34 increases as the detected temperature decreases. Therefore, when the outside air temperature is high and the compressor 14 is easily overheated like in summer, the temperature detected by the temperature sensor 36 becomes high. Therefore, the output voltage to the electric heater 34 becomes low, and the amount of heat generated by the heater 34 is suppressed. Then, vaporization (gasification) of the liquefied refrigerant passing through the capillary tube 30 is reduced, the bypass amount of the refrigerant is increased, and the compressor 14 is cooled, so that overheating is prevented. On the contrary, in winter, the temperature detected by the temperature sensor 36 becomes low, so that the output voltage to the electric heater 34 becomes high, and heat generation in the heater 34 is accelerated. Then, the liquefied refrigerant is turned into flash gas to increase the passage resistance, and the specific volume of the refrigerant in the capillary tube 30 is significantly increased, so that the bypass amount is decreased and the situation of unnecessary cooling of the compressor 14 is avoided. It

FIG. 3 shows another embodiment of the present invention, in which an electric heater 34 is attached to the capillary tube 30 so that the bypass amount of the refrigerant can be controlled. That is, the electric heater 34 connected to the bypass control circuit 38 is wound around the capillary tube 30, and the temperature sensor 36 directly attached to the casing of the compressor 14 is input-connected to the control circuit 38. Then, the bypass control circuit 38 controls the amount of heat generated by the electric heater 34 according to the temperature information of the compressor 14 detected by the temperature sensor 36. The contents of the control include a method of increasing / decreasing the output voltage to the electric heater 34 in inverse proportion to the detected temperature of the temperature sensor 36, and a comparison of the detected temperature of the temperature sensor 36 with a set value, There is a method of turning on / off the power supply to the electric heater 34 as the threshold value.

First, the control contents will be described. The temperature sensor 36 monitors the casing temperature of the compressor 14, and inputs the temperature information to the bypass control circuit 38. The control circuit 38 performs control such that the higher the temperature detected by the temperature sensor 36, the lower the output voltage to the electric heater 34, and the lower the detected temperature, the higher the output voltage to the electric heater 34. For example, when the outside air temperature is high and the compressor 14 easily overheats, such as in summer, the temperature detected by the temperature sensor 36 increases. Therefore, the output voltage to the electric heater 34 becomes low, and the amount of heat generated by the heater 34 is suppressed. Then, the vaporization (gasification) of the liquefied refrigerant passing through the capillary tube 30 is reduced and the bypass amount of the refrigerant is increased. Therefore, the compressor 14 can be cooled to prevent overheating. On the contrary, when it is not necessary to cool the compressor 14 as in the winter, the temperature detected by the temperature sensor 36 becomes low, so that the output voltage to the electric heater 34 becomes high and heat generation in the heater 34 is accelerated. Then, the liquefied refrigerant is turned into flash gas to increase the passage resistance, and the specific volume of the refrigerant in the capillary tube 30 is significantly increased. As a result, the bypass amount is decreased, and the compressor 14 is unnecessarily cooled. Avoided.

Next, the control contents will be described. The temperature detected by the temperature sensor 36 is always compared with a temperature value preset in the bypass control circuit 38. When the compressor 14 is likely to overheat and the temperature detected by the temperature sensor 36 becomes higher than the set value as in the summer, the electric heater 34 is not energized. Then, the liquefied refrigerant passes through the capillary tube 30 and flows into the compressor 14, where it is vaporized to cool the compressor 14. When it is not necessary to cool the compressor 14 as in the winter, the temperature detected by the temperature sensor 36 becomes lower than the set value and the electric heater 34 is energized. That is, the liquefied refrigerant is turned into flash gas to increase the passage resistance, and the specific volume of the refrigerant in the capillary tube 30 is significantly increased. As a result, the amount of bypass is reduced, and unnecessary cooling of the compressor 14 is avoided. In each of the cases 1 and 2, the temperature sensor 36 is provided in the compressor 14 to directly detect the compressor temperature. However, by providing the temperature sensor 36 on the discharge side of the compressor 14, discharge from the compressor 14 is performed. You may make it detect the temperature of the vaporized refrigerant. The position where the electric heater 34 is attached to the capillary tube 30 may be set near the outlet of the capillary tube 30 or may be set near the inlet of the capillary tube 30. At this time, if the electric heater 34 is provided near the latter pipe inlet, the liquefied refrigerant becomes flash gas and the passage resistance increases, and the bypass amount decreases. As described above, according to the embodiment shown in FIG. 3, in the refrigeration system provided with the compressor overheat prevention mechanism for bypassing the liquefied refrigerant to the suction side of the compressor by the capillary tube, the solenoid valve which is an expensive refrigerating machine component is used. It is possible to bypass the liquefied refrigerant without using it, and at the same time, it is not necessary to discharge the refrigerant in the refrigeration system even when repairing a failure, which is economical.

[0016]

[Effect of device]

 According to the compressor damage prevention mechanism in the refrigeration system of the present invention, when the condensation pressure of the air-cooled condenser decreases, the vaporized refrigerant from the compressor is switched to the receiver side by the condensation pressure regulator and condensed. The liquefied refrigerant from the refrigeration system or the condenser, which raises the pressure and prevents the compressor from overheating by bypassing the liquefied refrigerant from the receiver to the suction side of the compressor by the capillary tube, In a refrigeration system that prevents overheating of the compressor by bypassing it on the suction side of the compressor with a capillary tube, it is possible to suppress an increase in the bypass amount of the liquefied refrigerant in the winter when the outside temperature is low, and thus the compression It is possible to preferably prevent damage to the machine.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a refrigeration system including a compressor damage prevention mechanism according to an embodiment.

FIG. 2 is a circuit diagram of a refrigeration system according to a modification of the embodiment shown in FIG.

FIG. 3 is a circuit diagram of a refrigeration system including a compressor damage prevention mechanism according to another embodiment of the present invention.

FIG. 4 is a circuit diagram showing a refrigeration system of an ice making machine according to a conventional technique.

FIG. 5 is a circuit diagram showing a refrigeration system of an ice making machine according to a conventional technique.

FIG. 6 is a circuit diagram of a refrigeration system in which a valve body for turning on / off a refrigerant inflow is not attached to the capillary tube.

FIG. 7 is a circuit diagram of a refrigeration system in which a capillary tube is provided with a valve element for turning on / off a refrigerant inflow.

[Explanation of symbols]

10 expansion means, 12 evaporator, 14 compressor,
16 condenser, 18 liquid receiver, 22 condensation pressure regulator, 30 capillary tube, 34 electric heater, H
m high limit, Lm low limit

Claims (2)

[Scope of utility model registration request] 1. A compressor (14) for compressing a vaporized refrigerant and a condenser (1) for condensing the compressed vaporized refrigerant into a liquefied refrigerant.
6), a liquid receiver (18) that stores a part of this liquefied refrigerant, an expansion means (10) that expands the liquefied refrigerant coming from this liquid receiver (18) into a vaporized refrigerant, and this vaporization After performing a cooling action by the refrigerant, an evaporator (12) that returns the vaporized refrigerant to the suction side of the compressor (14), and always the condenser (16) and the liquid receiver (18).
And a condensing pressure regulator (22) that switches to the communicating side of the compressor (14) and the liquid receiver (18) when the condensing pressure decreases,
A condenser pipe (30) for bypassing the liquid receiver (18) to the suction side of the compressor (14), and the condensing pressure regulator
According to the switching state of (22), in a refrigeration system in which a difference in height occurs in the storage level of the liquefied refrigerant in the liquid receiver (18), the capillary tube (30) to the liquid receiver (18). The connection part to be bypassed is selected at a substantially intermediate position between the high limit (Hm) and the low limit (Lm) of the refrigerant storage level in the liquid receiver (18), and the condensation pressure regulator (22) is the condenser. (16) and receiver (18)
When the refrigerant storage level in the liquid receiver (18) is in a high limit (Hm), the vaporized refrigerant bypasses from the liquid receiver (18) to the compressor (14). To prevent the compressor (14) from overheating, and the condensing pressure regulator (22) includes the compressor (14) and a liquid receiver.
(18) is switched to the communication side, when the refrigerant storage level in the liquid receiver (18) is at the lower limit (Lm), from the liquid receiver (18) to the compressor (14) A mechanism for preventing damage to a compressor in a refrigeration system, characterized in that cooling of the compressor (14) is stopped by reducing a bypass amount of vaporized refrigerant. 2. A compressor (14) for compressing a vaporized refrigerant and a condenser (1) for condensing the compressed vaporized refrigerant into a liquefied refrigerant.
6), expansion means (10) for expanding the liquefied refrigerant from this condenser (16) into a vaporized refrigerant, and after performing a cooling action by this vaporized refrigerant, the vaporized refrigerant is compressed by the compressor (14). The evaporator (12) for returning to the suction side of the compressor and the condenser (16) for the compressor (14)
In a refrigeration system including a capillary tube (30) to be bypassed to the suction side of the, by attaching an electric heater (34) to the capillary tube (30), by controlling the energization of the electric heater (34), A mechanism for preventing damage to a compressor in a refrigeration system, wherein a bypass amount of a liquefied refrigerant in a capillary tube (30) can be changed.