KR100609169B1 - Cascade refrigerating cycle - Google Patents

Abstract

The cascade refrigeration cycle according to the present invention includes a compressor in which a mixed refrigerant in which a second refrigerant having a high boiling point and a first refrigerant having a low boiling point is mixed is compressed; A condenser for condensing the compressed mixed refrigerant; A gas-liquid separator in which the liquid phase second refrigerant and the gaseous first refrigerant are separated and discharged from the condensed mixed refrigerant; A deflator including a heat exchanger in a low temperature state and a suction pipe through which the mixed refrigerant is sucked into the heat exchanger in order to separate the gaseous second refrigerant into a liquid phase from the gaseous mixed separator separated from the gas-liquid separator; A heat exchanger in which a first refrigerant in a gaseous phase that has passed through the deflector and the second refrigerant that is expanded and changed to a low temperature are heat-exchanged; And an evaporator in which the first refrigerant heat-exchanged by the heat exchanger is evaporated after being expanded and a low temperature environment is formed around the evaporator.

Since the mixed refrigerant separation process of the cascade refrigeration cycle can be performed more fully by the deflector according to the present invention, there is an advantage that the coefficient of performance of the refrigeration cycle is increased, in particular, the second refrigerant by the deflector The advantage is that only the first refrigerant of pure gaseous phase, which is completely excluded, is discharged.

Deflector, Refrigeration Cycle

Description

Cascade refrigerating cycle

1 is a cycle flow diagram of a cascade refrigeration cycle according to the spirit of the present invention.

2 is a view for explaining the flow of the first refrigerant having a low boiling point.

3 is a view for explaining the flow of a second high boiling point refrigerant separated by the gas-liquid separator;

4 is a view for explaining the flow of a second high boiling point refrigerant not separated by the gas-liquid separator;

5 is a T-S diagram illustrating a flow state of a second refrigerant.

6 is a T-S diagram illustrating a flow state of a first refrigerant.

7 is a cross-sectional view of the deflector according to the spirit of the present invention.

8 is a cross-sectional view taken along the line II ′ of FIG. 7;

<Explanation of symbols for the main parts of the drawings>

11 compressor 12 condenser 13 gas-liquid separator

14 deflator 15 heat exchanger 16 first expander

17: evaporator 18: second inflator

40: main body 45: heat exchanger

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cascade refrigeration cycle, wherein a mixed refrigerant is compressed by a single compressor, and to a cascade refrigeration cycle in which the efficiency of the refrigeration cycle is enhanced. More particularly, it relates to a cascade refrigeration cycle that can be configured to a lower temperature evaporator.

Typical refrigeration cycles consist of compression, condensation, expansion, and evaporation, and refrigeration is performed by allowing heat to be absorbed while the refrigerant evaporates in the evaporator during the evaporation process. However, although a general refrigeration cycle can obtain a sub-zero low temperature atmosphere such as a refrigerator, there is a disadvantage in that it is impossible to obtain ultra low temperatures of minus 100 degrees Celsius, which is required by industry.

Under these backgrounds, the Kleemenko cycle has been proposed as a proposed refrigeration cycle for commercially obtaining ultra-low temperatures of below 100 degrees Celsius. The Klimenco cycle is a refrigeration cycle named after the proposer, which was proposed by "APKleemenko" to "Proceedings Ⅹth international Congress on refrigeration, copenhagen, 1, 34-39 (1959), Pergamon Press, London". It is the starting point of the flow casing refrigeration cycle. Of course, there may be a variety of refrigeration cycles to achieve an extremely low temperature, but the present invention is of major interest in improving the structure of the Klimenco cycle.

In brief, the Climenco cycle will be condensed after a mixture of the first refrigerant having a low boiling point and the second refrigerant having a relatively high boiling point is compressed by a single compressor. After the condensation is performed, the first refrigerant maintains the gas phase and the second refrigerant turns into a liquid phase. Thereafter, while the first refrigerant in the gas phase and the second refrigerant in the liquid phase pass through the gas-liquid separator, the first refrigerant in the gas phase and the second refrigerant in the liquid phase are separated from each other, and flow through different pipes.

The second refrigerant is continuously expanded and evaporated, and the first refrigerant is condensed by cold air generated during the evaporation process of the second refrigerant, and after the condensation is completed, the second refrigerant is expanded through the expansion valve. Later, it is evaporated by an evaporator. Therefore, the first refrigerant may be evaporated while passing through the evaporator to absorb heat from the outside, and the outside of the evaporator may form an ultra low temperature environment of minus 100 degrees by the heat absorbed.

In summary, the Klymenco cycle is characterized in that the mixed refrigerant is compressed and condensed by a single compressor and a condenser, and the first refrigerant having a low boiling point is condensed by a second refrigerant having a high boiling point, whereby the first refrigerant is It is characterized by the fact that the environment to be evaporated can be created in the atmosphere of the cryogenic environment.

However, the refrigerant condensed through the condenser in the conventional Klimenko cycle has a problem that the second refrigerant having a high boiling point does not completely condense even though it passes through the condenser. Therefore, even after passing through the condenser, the second refrigerant in the gaseous phase remains in the second refrigerant, and eventually, during the process of separating the liquid phase second refrigerant and the gaseous first refrigerant by the gas-liquid separator. In addition, there is a problem that the second refrigerant in the gas phase flows together with the first refrigerant in the gas phase. In other words, there is a disadvantage that the efficiency of the gas-liquid separator is not high.

Due to this problem, the evaporator in which the first refrigerant flows does not reach an ultra low temperature, has a disadvantage in that the temperature is increased to some extent, and in the end, a problem in which an ultra low temperature state as desired by a user cannot be realized.

In addition, there is a disadvantage that the irreversible loss inside the refrigeration cycle is increased by flowing the second refrigerant together with the first refrigerant to be evaporated.

The present invention has been proposed in order to solve the above problems, an object of the present invention is to propose a cascade refrigeration cycle to improve the efficiency of the refrigeration cycle by allowing the separation process of the mixed refrigerant to be carried out more completely.

In addition, a cascade refrigeration cycle in which the second refrigerant having a high boiling point must flow in the pipeline, thereby increasing the purity of the second refrigerant, thereby reducing the irreversible loss and lowering the temperature of the low temperature environment. The purpose is to propose.

In addition, an object of the present invention is to propose a cascade refrigeration cycle in which the performance coefficient of the cascade refrigeration cycle is improved by allowing the gaseous mixed refrigerant to be separated more completely.

The cascade refrigeration cycle according to the present invention for achieving the above object is a compressor in which a mixed refrigerant is mixed, the second refrigerant having a high boiling point and the first refrigerant having a low boiling point is mixed; A condenser for condensing the compressed mixed refrigerant; A gas-liquid separator in which the liquid phase second refrigerant and the gaseous first refrigerant are separated and discharged from the condensed mixed refrigerant; A deflator including a heat exchanger in a low temperature state and a suction pipe through which the mixed refrigerant is sucked into the heat exchanger in order to separate the gaseous second refrigerant into a liquid phase from the gaseous mixed separator separated from the gas-liquid separator; A heat exchanger in which a first refrigerant in a gaseous phase that has passed through the deflector and the second refrigerant that is expanded and changed to a low temperature are heat-exchanged; And an evaporator in which the first refrigerant heat-exchanged by the heat exchanger is evaporated after being expanded and a low temperature environment is formed around the evaporator.

According to another aspect of the present invention, the cascade refrigeration cycle is characterized in that a mixed refrigerant in which a single is compressed by a compressor and condensed by a single condenser is separated by a gas-liquid separator so that the second refrigerant is used for condensation of the first refrigerant. In the cascade refrigeration cycle, the second refrigerant having a high boiling point contained in the first refrigerant having a low boiling point separated from the gas-liquid separator by suction of gaseous mixed refrigerant separated from the gas-liquid separator is the first refrigerant. Deflector for separating from the; A low temperature heat exchanger provided inside the deflector; And a suction pipe extending from the inside of the deflector to the low temperature heat exchanger side in order for the mixed refrigerant of the gaseous phase separated from the gas-liquid separator to be sucked in the direction of the heat exchanger.

By the configuration of the present invention as proposed it is possible to obtain the effect of improving the overall efficiency of the refrigeration cycle. In addition, since the evaporator side of the refrigeration cycle can be implemented at a lower temperature, there is an advantage that the application range of the refrigeration cycle can be wider.

Hereinafter, with reference to the drawings propose a specific embodiment of the present invention. However, the spirit of the present invention is not limited to the embodiments presented, and those skilled in the art who understand the spirit of the present invention may add other embodiments within the scope of the same idea to the addition, modification, deletion, addition, change of position, and the like. It may be easily proposed by the present invention, but this will also be included within the scope of the present invention idea.

1 is a cycle flowchart of a cascade refrigeration cycle according to the spirit of the present invention.

Referring to FIG. 1, the cascade refrigeration cycle to which the idea of the present invention is applied includes a compressor 11 in which a first refrigerant having a low boiling point and a second refrigerant having a high boiling point are mixed together; The gas-liquid separator which separates the condenser 12 in which the mixed refrigerant compressed by the compressor 11 is condensed, and the second refrigerant in the liquid phase, which has a high boiling point, and the first refrigerant in the gas phase, having a low boiling point, are separated from the condensed mixed refrigerant ( 13), and a dephlegmator (classification condenser, classifier, reflux condenser) 14 to allow the second refrigerant in the gas phase not separated during the passage through the gas-liquid separator 13 to be separated once again into a liquid phase. A second expansion valve 18 through which the liquid second refrigerant is expanded, and a heat exchanger 15 through which the expanded second refrigerant and the first refrigerant exchange heat, such that the second refrigerant is evaporated and the first refrigerant is condensed. With heat exchange A first first expansion valve 16, the refrigerant condensed by the expansion window, the first containing the evaporator 17 the refrigerant is evaporated.

In detail, the first refrigerant is a refrigerant having a low boiling point, and the second refrigerant is a refrigerant having a high boiling point. Therefore, the second refrigerant can be operated as a heat exchange fluid to condense the first refrigerant after it is expanded. For example, various kinds of nitrogen compounds and fluorine compounds may be used. However, any kind of refrigerant suitable for the use temperature of the casing refrigeration cycle may be applied regardless of the kind of material.

In detail, the first refrigerant in the gas phase and the second refrigerant in the gas phase flow into the refrigerant flowing into the deflector 14. At this time, the second refrigerant is a second refrigerant that is not completely separated into liquid by the gas-liquid separator 13, and is completely converted into liquid by a heat exchanger inside the deflector 14 to be separated from the first refrigerant. In the heat exchanger placed inside the deflector 14, a first refrigerant that is evaporated to a low temperature flows, and a second refrigerant is completely changed into a liquid phase by the low temperature of the first refrigerant. On the other hand, despite the separation by the gas-liquid separator 13, the flow of the second refrigerant together with the first refrigerant does not reach the level necessary for the temperature of the condenser 12 to completely condense the liquid into the liquid. It may be because.

As described, the deflector 14 applied to the present invention is a second refrigerant which is not separated by the gas-liquid separator 13, that is, the first discharged from the gas-liquid separator 13 together with the first refrigerant in the gas phase. 2 It is a device to separate the refrigerant completely into the liquid phase. As a result, the purity of the second refrigerant flowing into the second expander 18 may reach almost 100%. As such, when the purity of the second refrigerant is increased by the deflector 14, more heat is exchanged by the heat exchanger 15, and more heat is absorbed by the evaporator 17. The environment of the evaporator can be made into a lower temperature environment.

Hereinafter, the flow of the refrigerant flowing in each pipe line will be described in order of the first refrigerant, the second refrigerant separated by the gas-liquid separator, and the second refrigerant not separated by the gas-liquid separator. 2 is a view for explaining the flow of the first refrigerant, Figure 3 is a view for explaining the flow of the second refrigerant separated by the gas-liquid separator, Figure 4 is a second refrigerant not separated by the gas-liquid separator It is a figure explaining the flow of.

First, referring to FIG. 2, the flow path 1 of the first refrigerant having a low boiling point is compressed in the compressor 11 and condensed in the condenser 12. However, even when condensed by the condenser 12, the first refrigerant is maintained in the gas phase without phase change to the liquid phase because the boiling point is low, the first refrigerant in the gas phase is introduced into the deflector (14). At this time, the second refrigerant in the gaseous phase that has not been condensed may also flow into the deflector 14.

After the second refrigerant is completely separated by the deflector 14, the first refrigerant is introduced into the heat exchanger 15. Of course, the first refrigerant is condensed by the deflector 14, of course. The first refrigerant in the gaseous phase is expanded by the first expansion valve 16 after the heat exchange is performed by the heat exchanger 15. Then, after the expansion is introduced into the evaporator 17, the surrounding environment of the evaporator 17 is formed to a low temperature environment. The surrounding environment of the evaporator 17 may reach a cryogenic environment desired by the user.

After the predetermined heat is absorbed by the evaporator 17, the heat is introduced into the heat exchanger of the deflector 14 and operated as a low temperature fluid for heat exchange. This is because low temperature cold air is maintained even after the first refrigerant is evaporated by the evaporator 17.

Then, the first refrigerant is heat exchanged by the deflector 14 and then combined with the second refrigerant to go back into the compressor 11 again.

In addition, referring to FIG. 3, the flow of the second refrigerant passage 2 separated by the gas-liquid separator will be described. The process of passing the second refrigerant through the compressor 11 and the condenser 12 is the same as the first refrigerant. However, there is a difference in that a large amount of the second refrigerant is liquefied while passing through the condenser 12. Therefore, after the second liquid in the liquid flows into the gas-liquid separator 13 and is discharged through the conduit through which the liquid is discharged, the heat exchange is carried out by the heat exchanger 15 after being expanded in the second expansion valve 18. Is performed. When the heat exchanger 15 is viewed as the second refrigerant, it can be easily assumed that the heat exchanger 15 serves as an evaporator.

After the heat exchange is performed by the heat exchanger 15 to condense the first refrigerant, the heat exchanger 15 combines with the first refrigerant and moves to the compressor 11.

In addition, referring to FIG. 4, the flow path 3 of the second refrigerant not separated by the gas-liquid separator will be described. As with the second refrigerant phase-changed into liquid by the condenser 12, the compressor 11 and the condenser will be described. After passing through (12), the gas-liquid separator 13 flows into the deflector 14 together with the first refrigerant.

The second refrigerant introduced into the deflector 14 is combined with the second refrigerant separated by the gas-liquid separator 13 after being completely phase-changed into a liquid by the heat exchanger inside the deflector 14. Thereafter, the flow of the second refrigerant is as described previously.

As described, since the second refrigerant having a high boiling point is used for heat exchange of the heat exchanger 15 after it has been completely phase-changed into a liquid, the first refrigerant can be more condensed and, ultimately, evaporated in the evaporator 17. The first refrigerant may have the advantage of being able to be formed at a lower temperature. Thus, the liquid phase purity of the second refrigerant can be increased because the second refrigerant is completely phase-changed into the liquid by the deflector 14 and flows through the cycle.

Hereinafter, the states of the first refrigerant and the second refrigerant flowing in the cascade refrigeration cycle will be described in detail with reference to the T-S diagram. In order to make the description clear, the state of the refrigerant flowing in the respective flow paths is indicated by Arabic numerals in FIG. 1, and the Arabic numerals correspond to the Arabic numerals of FIGS. 5 and 6. It is explained.

FIG. 5 is a T-S diagram illustrating a flow state of the second refrigerant, and a flow state of the second refrigerant will be described with reference to FIG. 5.

First, the second refrigerant (7 states), which are heat-exchanged by the heat exchanger 15 and changed to the gaseous phase, is combined with the second refrigerant (13 states) and then flows into the compressor 11. After being compressed by the compressor 11 (1 state), it is condensed by the condenser 12 (2 state). However, since the low temperature environment is hardly formed in the condenser 12 so that the second refrigerant can be completely condensed, the second refrigerant is kept in the state of wet steam (two states).

In the wet steam state, the liquid second refrigerant is separated by the gas-liquid separator 13 and immediately flows into the second expansion valve 18, but the second refrigerant in the gas phase flows into the deflector 14. The temperature is further lowered to condense completely into the liquid second coolant (four states).

The second liquid phase (2 states) of the liquid phase and the second liquid phase (4 states) of the liquid phase changed into the liquid phase by the deflector 14 are combined to form a single second refrigerant state 5 among the second refrigerants of the wet steam. State). As shown in the T-S diagram, the five states exist between any of the two states and the four states.

After being expanded through the second expansion valve 18 in the single second refrigerant state (5 states) to further decrease the temperature (6 states), heat exchange with the first refrigerant is performed by the heat exchanger 15. (7 states) Then, after the heat exchange is performed, it is reintroduced into the compressor 1 after being combined with the first refrigerant (13 states).

As described, the cascade refrigeration cycle of the present invention allows more heat to be exchanged by the heat exchanger 15 by the defragmenter 14.

In detail, in the case where there is no deflector 14, the expansion of the second refrigerant passing through the gas-liquid separator 13 directly in the state (2 state) of the second refrigerant (changes from 2 state to 6-1 state) is performed. In the case where the second refrigerant (5 states) in which the second liquid (4 states) of the liquid phase separated by the deflector 14 and the second refrigerant (2 states) passing through the gas-liquid separator 13 are expanded (From 5 states to 6 states), more heat can be absorbed by the heat exchanger 15. In FIG. 5, the absorption heat of the first absorption heat 20 is increased.

In addition, when more heat is absorbed by the heat exchanger 15, since more heat is also released by the first refrigerant, it will naturally be predictable that the heat exchange efficiency of the first refrigerant is improved.

FIG. 6 is a T-S diagram illustrating a flow state of the first refrigerant, and a flow state of the first refrigerant will be described with reference to FIG. 6.

First, the first refrigerant (12 states) in the gaseous phase heat exchanged by the deflector 14 is combined with the second refrigerant (13 states), and then flows into the compressor 11 and is compressed (1 states). The compressed first refrigerant is condensed in the condenser 12 (2 states), but even when condensed by the condenser 12, since the first refrigerant has a low boiling point, the gaseous state is maintained without phase change to liquid, Flow into the deflector 14. The temperature is further lowered in the deflector 14, but the first refrigerant remains in a liquid state even when the temperature is lowered by the deflector 14 (8 states).

Thereafter, heat is desorbed to the second refrigerant side while passing through the heat exchanger 15 to condense to a liquid state (9 states), and after being expanded by the first expansion valve 16 (10 states), the evaporator 17. Evaporate during the process (11 states). As such, since heat is absorbed from the outside of the evaporator 17 while passing through the evaporator 17, heat around the evaporator 17 may be absorbed to form a low temperature atmosphere.

The cold air remaining even after being evaporated by the evaporator 17 is introduced into the deflector 14 so that the second refrigerant is completely changed into a liquid phase (12 states), and then combined with the second refrigerant (13). State), and flows back into the compressor (11). The cycle described above causes the first refrigerant to circulate.

On the other hand, in the absence of the deflector 14, as described above, the second refrigerant is not completely introduced into the liquid phase, and much heat is not released. Therefore, the first refrigerant may not change to a complete liquid phase because heat exchange is not completely performed even if heat exchange is performed with the second refrigerant. Therefore, when it is maintained in the state of wet steam (state 9-1), and passes through the first expansion valve 16 in this state, the state of wet steam becomes a state where the gas is relatively large (state 10-1). Therefore, since much heat is not absorbed even while passing through the evaporator 17, the periphery of the evaporator 17 is at a higher temperature than the case where the deflector 14 is present.

As a result, when the deflector 14 is present, as much heat as the second absorption heat 21 is absorbed through the evaporator 17 as compared with the case where the deflector 14 is not present. If more heat is absorbed through the evaporator 17, the performance coefficient of the cascade refrigeration cycle may be increased, and the temperature around the evaporator 17 may be further lowered.

In addition, the first absorption heat 20 and the second absorption heat 21 may be the same.

On the other hand, the T-S diagram has been described on the assumption that there is no irreversibility, the specific state of the refrigerant may be changed as the state of irreversibility increases. In addition, the state of the refrigerant may be divided into a liquid phase, a wet steam, and a gas phase while circulating inside the cycle. In the case of a wet steam state, the gas phase component and the liquid component may vary depending on a specific case when the cascade refrigeration cycle is applied. Could be In addition, in order to increase the efficiency of the heat exchanger, a plurality of heat exchangers may be placed in parallel.

Hereinafter, the configuration of the defragmenter 14 will be described in detail.

7 is a cross-sectional view of the deflector applied to the present invention.

Referring to FIG. 7, the deflector 14 is introduced into the main body 40 and the main body 40 which extends in a vertical direction in an empty state, and flows into or flows out of the main body 40. A plurality of pipes to be provided, and the heat exchanger 45 is placed inside the main body 40 to create a low-temperature environment inside the main body 40.

In more detail, the conduit includes a cold air suction pipe 44 through which cold cold air flows into the heat exchanger 45, and a cold air discharge pipe 46 through which cold air warmed from the heat exchanger 45 flows out. The cold air suction pipe 44 flows into the cold first refrigerant flowing out of the evaporator 17, and the cold air discharged from the cold air discharge pipe 46 flows into the compressor 11 in a state of high temperature.

In addition, a suction pipe 41 into which the mixed refrigerant in which the first refrigerant and the second refrigerant are mixed flows into the inner space of the main body 40, and a liquid in which the second refrigerant cooled again inside the main body 40 is discharged. A discharge pipe 47 and a gas discharge pipe 43 through which the first refrigerant in the gaseous phase which is not cooled despite the low temperature atmosphere of the main body 40 is discharged. A nozzle portion 42 is formed at an end of the suction pipe 41 to guide the first refrigerant and the second refrigerant to the heat exchange device 45 at a certain speed through the nozzle portion 42, thereby providing 2 There is an advantage that the refrigerant can be quickly cooled to a liquid phase. If the nozzle portion 42 is not formed, it is because there is a possibility that a second refrigerant that does not contact the heat exchanger 45 may be generated even when discharged from the suction pipe 41. However, if the entire refrigerant discharged from the suction pipe 41 can reach the heat exchanger 45 evenly and accurately, the nozzle unit 42 may not be formed. For example, the suction end of the suction pipe 41 may be inserted into the heat exchanger 45.

On the other hand, the gas discharge pipe 43 is placed on the upper side of the main body 40 in order to prevent the flow of the second liquid refrigerant, the pipe is opened toward the upper direction of the main body 40. In order to prevent the liquid from reaching the inlet of the gas discharge tube 43, a separator 48 is provided below the end of the gas discharge tube 43. The separation plate 48 prevents turbulence inside the main body 40 from being transmitted to the gas discharge tube 43 so that the first refrigerant in the gas phase is smoothly exhausted, and the second refrigerant in the liquid phase inside the main body 40 splashes to form a gas. This is to prevent the flow into the discharge tube 43.

FIG. 8 is a cross-sectional view taken along line II ′ of FIG. 7, and referring to FIG. 8, the separator 48 is formed in a substantially circular shape, and a gas discharge tube 43 passes through the center portion. In addition, a plurality of slits 49 are formed to penetrate through the separator plate 48 so that the first refrigerant in the gaseous phase accommodated in the main body 40 flows into the gas discharge tube 43.

With reference to the configuration of the deflector as described above, the operation of the deflector 14 will be described in detail. First, the first coolant evaporated from the evaporator 17 flows into the heat exchanger 45 to maintain the inside of the main body 40 at a low temperature. In addition, since the nozzle part 42 faces the heat exchanger 45, the first and second refrigerants in the gaseous phase discharged through the nozzle part 42 are discharged directly toward the heat exchanger 45, The gaseous second refrigerant may be immediately cooled and changed into a liquid phase. However, the first refrigerant in the gaseous phase discharged from the nozzle portion 42 does not change into a liquid phase even when it comes into contact with the heat exchanger 45 because the boiling point is low.

The second refrigerant phase-changed into the liquid phase is dropped by its own weight and discharged through the liquid discharge tube 47, and the first refrigerant in which the gas phase is maintained is discharged through the gas discharge tube 43.

In addition, the separator 48 is placed so that the second refrigerant does not flow into the gas discharge pipe 43. The separation plate 48 serves to prevent the mixed refrigerant sprayed from the nozzle unit 42 from being splashed and delivered to the gas discharge pipe 43. The constant flow rate of the refrigerant discharged by the gas discharge pipe 43 is prevented from allowing the turbulence discharged from the nozzle portion 42 to be formed inside the main body 45 to be transmitted to the upper space of the main body 40. It is improved and the turbulent flow prevents the liquid second refrigerant from rising. However, since the plurality of slits 49 are formed in the separator 48, the first refrigerant in the gas phase may smoothly flow into the upper space of the main body 40 on which the gas discharge pipe 43 is placed.

On the other hand, the gas passing through the gas-liquid separator 13 flows through the suction pipe 41, and the first refrigerant discharged through the discharge pipe 43 flows into the heat exchanger 15 and discharges the liquid. As described above, the second refrigerant discharged through the pipe 47 is introduced into the second expansion valve 18.

According to the present invention, since the mixed refrigerant separation process of the casing refrigeration cycle can be performed more completely, the performance coefficient of the refrigeration cycle is increased.

In particular, by increasing the purity of the first refrigerant having a low boiling point, irreversible loss is reduced, and the low temperature state of the low temperature atmosphere in which the evaporator is placed can be made lower, so that the cascade refrigeration cycle can be operated in a wider range of low temperature environment. There is an advantage that can be applied.

In addition, since the gas and the liquid can be smoothly separated by the internal configuration of the deflector, the efficiency is further improved. In particular, a separator is formed inside the deflector so that only the first refrigerant in a pure gaseous phase in which the second refrigerant is completely excluded can be discharged, thereby improving the performance coefficient of the refrigeration cycle.

In addition, since the suction end of the suction pipe faces the heat exchanger inside the deflector, the second refrigerant having a high boiling point discharged from the suction pipe can be completely liquefied.

Claims (12)

A compressor in which a mixed refrigerant in which a second boiling point having a high boiling point and a first refrigerant having a low boiling point is mixed is compressed; A condenser for condensing the compressed mixed refrigerant; A gas-liquid separator in which the liquid phase second refrigerant and the gaseous first refrigerant are separated and discharged from the condensed mixed refrigerant; A deflator including a heat exchanger in a low temperature state and a suction pipe through which the mixed refrigerant is sucked into the heat exchanger in order to separate the gaseous second refrigerant into a liquid phase from the gaseous mixed separator separated from the gas-liquid separator; A heat exchanger in which a first refrigerant in a gaseous phase that has passed through the deflector and the second refrigerant that is expanded and changed to a low temperature are heat-exchanged; And Cascade refrigeration cycle comprising an evaporator which is evaporated after the expansion of the first refrigerant heat-exchanged by the heat exchanger, a low-temperature environment around. The method of claim 1, Cascade refrigeration cycle in which the heat exchanger, the low-temperature first refrigerant evaporated by the evaporator flows in / out. The method of claim 1, Casing refrigeration cycle including a nozzle portion at the end of the suction pipe to the mixed refrigerant is injected toward the heat exchange device. The method of claim 1, Cascade refrigeration cycle is formed on the lower side of the deflector including a liquid discharge pipe outflow of the second refrigerant of the phase change liquid phase. The method of claim 1, A cascade refrigeration cycle is formed on the deflector and includes a gas discharge pipe through which the first refrigerant in the gas phase flows out. The method of claim 1, Cascade refrigeration cycle is provided inside the deflector is provided with a separator plate formed with a plurality of slits for passing only the first refrigerant in the gas phase. The method of claim 1, Cascade refrigeration cycle is provided inside the deflector is provided with a separator to prevent the propagation of turbulence. The method according to claim 6 or 7, Cascade refrigeration cycle through the gas discharge pipe through which the first refrigerant of the gas phase is discharged in the center of the separation plate. In a cascade refrigeration cycle in which a mixed refrigerant compressed by a single compressor and condensed by a single condenser is separated by a gas-liquid separator so that the second refrigerant is used for condensation of the first refrigerant, A deflector for sucking the gaseous mixed refrigerant separated by the gas-liquid separator so that the second high-boiling refrigerant included in the first low-boiling refrigerant separated from the gas-liquid separator is separated from the first refrigerant; A low temperature heat exchanger provided inside the deflector; And The cascade refrigeration cycle further comprises a suction pipe extending from the inside of the deflector to the low temperature heat exchanger side in order to suck the gaseous mixed refrigerant separated from the gas-liquid separator toward the heat exchanger. . The method of claim 9, Cascade refrigeration including a gas discharge tube provided above the deflector to discharge the first refrigerant in the gas phase, and a liquid discharge tube provided below the deflector to discharge the second refrigerant in the gas phase. cycle. The method of claim 9, Cascade refrigeration cycle is formed on the upper side of the heat exchanger to form a separation plate to prevent the passage of the second liquid refrigerant. The method of claim 9, Casing refrigeration cycle is formed at the end of the suction pipe nozzle portion for injecting the mixed refrigerant to the heat exchange device side.

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