JP2008275211A - Vapor compression-type refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor compression type refrigerating cycle capable of reducing a flowing-in ratio of a gas-liquid two-phase refrigerant to a refrigerant outflow tube of a gas-liquid separator, and improving stability in dryness of the refrigerant at a gas-liquid separator outlet. <P>SOLUTION: In this refrigerating cycle comprising a compressor, a radiator, a pressure reducer, an evaporator and the gas-liquid separator for separating the refrigerant flowing out from the evaporator into a gas-phase refrigerant and a liquid-phase refrigerant, and allowing the separated gas-phase refrigerant to flow out to a suction side of the compressor, a refrigerant inflow passage for allowing the refrigerant to flow into the gas-liquid separator is formed into the curved shape so that the refrigerant can be centrifugally separated into the gas-phase refrigerant and the liquid-phase refrigerant. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vapor compression refrigeration cycle suitable for use with a carbon dioxide refrigerant, and more particularly to a structure of a gas-liquid separator suitable for use in a vapor compression refrigeration cycle in a vehicle air conditioner.

  From the viewpoint of consideration of environmental problems, carbon dioxide refrigerant has been proposed as an alternative refrigerant in vehicle air conditioners (for example, Patent Document 1). Carbon dioxide refrigerant is non-toxic and non-flammable, but has a low critical temperature (about 31 ° C) and a transcritical cycle (supercritical refrigeration cycle) in which the high pressure side of the cycle becomes supercritical (about 7.4 MPa or higher) . Generally, since the coefficient of performance (COP: Coefficient of Performance) is poor compared to those using chlorofluorocarbon, it is required to improve this.

  As one of the methods, there is a method of exchanging heat between the high-pressure side refrigerant on the radiator outlet side and the low-pressure side refrigerant on the evaporator outlet side using an internal heat exchanger arranged in the cycle. As a result, the refrigerant temperature on the high-pressure side can be reduced, the enthalpy on the inlet side of the evaporator is reduced, and the enthalpy difference between the inlet side and the outlet side in the evaporator is increased, thereby improving the refrigeration coefficient of performance. Realized.

Furthermore, a configuration is also known in which a gas-liquid separator is installed in front of the low pressure side of the internal heat exchanger so that it can cope with fluctuations in the required refrigerant amount due to external environment changes. The gas-liquid separator is a liquid storage tank for taking in and out the refrigerant in the cycle, and has a function of separating the gas-phase refrigerant and the liquid-phase refrigerant. In this gas-liquid separator, the gas-liquid refrigerant is separated and the gas-phase refrigerant flows out of the refrigerant by disposing the inlet of the separated gas-phase refrigerant outlet pipe above the liquid-phase refrigerant interface (liquid surface). It is made to flow out of the pipe.
Japanese Patent Publication No. 7-18602

  However, when the environmental load fluctuates, the required amount of refrigerant in the vapor compression refrigeration cycle increases and decreases, so the amount of liquid phase refrigerant stored in the gas-liquid separator also increases and decreases. The gas-liquid two-phase refrigerant layer flowing into the gas-liquid separator from the refrigerant inflow pipe to the gas-liquid separator has an inlet of the refrigerant outflow pipe when the liquid level of the liquid-phase refrigerant stored in the gas-liquid separator rises. It will be formed nearby. From the relationship of the refrigerant density, a gas-liquid two-phase refrigerant layer is formed on the upper part of the liquid-phase refrigerant liquid surface, and a gas-phase refrigerant layer is formed on the uppermost part. If the inlet of the refrigerant outflow pipe is located within the range of the gas-liquid two-phase refrigerant layer, the gas-liquid two-phase refrigerant flows into the refrigerant outflow pipe, and the dryness of the refrigerant at the gas-liquid separator outlet is determined. There is a problem that stability is reduced. If the dryness of the refrigerant changes at this site, it is difficult to improve the refrigeration performance coefficient.

  Accordingly, an object of the present invention is to reduce the ratio of the gas-liquid two-phase refrigerant flowing into the refrigerant outflow pipe of the gas-liquid separator even when the environmental load fluctuates in order to solve the above problems, and at the gas-liquid separator outlet An object of the present invention is to provide a vapor compression refrigeration cycle in which the stability of the dryness of the refrigerant is improved.

  In order to solve the above problems, a vapor compression refrigeration cycle according to the present invention includes a compressor that sucks and compresses refrigerant, a radiator that dissipates the refrigerant compressed by the compressor, and heat that is dissipated by the radiator. A decompressor for decompressing the refrigerant, an evaporator for evaporating the refrigerant decompressed by the decompressor, and separating the separated refrigerant into a vapor phase liquid and a liquid phase refrigerant and separating the separated vapor phase refrigerant In a vapor compression refrigeration cycle provided with a gas-liquid separator that flows out to the suction side of the compressor, a refrigerant inflow passage through which the refrigerant flows into the gas-liquid separator, and the refrigerant inside the gas-phase refrigerant and the liquid phase It consists of what was formed in the curved shape which can be separated into a refrigerant | coolant. That is, the refrigerant inflow pipe or the refrigerant inflow passage forming body that forms the refrigerant inflow passage is formed in a curved pipe shape.

  In such a vapor compression refrigeration cycle, the refrigerant flowing from the evaporator side flows into the gas-liquid separator through the refrigerant inflow passage formed in a curved shape, but passes through the refrigerant inflow passage. In doing so, it is centrifuged into a gas phase refrigerant and a liquid phase refrigerant. More specifically, by utilizing the difference in density of the gas-liquid two-phase refrigerant that flows in, due to the centrifugal force acting on the refrigerant by the curved passage structure (due to the difference in inertial force based on the centrifugal force), The gas-phase refrigerant having a low density passes through the central portion of the refrigerant in the refrigerant inflow passage more toward the inner wall surface side in the refrigerant inflow passage, so that the gas-liquid separation action is promoted in the refrigerant inflow passage. . The refrigerant that has flowed through the refrigerant inflow passage flows into the main body of the gas-liquid separator, and the gas-liquid separation action, which is the original function of the gas-liquid separator, works. Therefore, the gas-liquid separation function as a whole of the gas-liquid separator is greatly enhanced, and the outflow of the gas-liquid two-phase refrigerant from the gas-liquid separator, in particular, the outflow of the liquid-phase refrigerant is suppressed. It becomes possible to stabilize the dryness of the refrigerant.

  In the vapor compression refrigeration cycle according to the present invention, the refrigerant inflow passage may be formed to have a passage cross-sectional area that increases from the inlet to the outlet. If comprised in this way, in addition to the said centrifugal separation effect | action, by a pipe expansion effect, the difference of the inertia force based on the density difference of a gas-liquid two-phase refrigerant | coolant WHEREIN: A high-density liquid phase refrigerant | coolant and a low-density gaseous-phase refrigerant | coolant are A difference in speed in the passage can be provided between them, and the gas-liquid separation action can be further promoted. Therefore, more efficient gas-liquid separation is performed in the refrigerant inflow passage, and the gas-liquid separation function of the entire gas-liquid separator is further greatly enhanced.

  The curved shape of the refrigerant inflow passage can be formed, for example, so as to extend in an involute shape or a pseudo involute shape that is close to the involute shape from the inlet to the outlet. However, it is not limited to this shape, and it is also possible to adopt a curved shape consisting of a simple arc shape.

  Moreover, it is preferable that the exit of the said refrigerant | coolant inflow passage is opened toward the direction along the circumferential direction of the internal peripheral surface of the container of a gas-liquid separator. With this configuration, the refrigerant that has flowed into the gas-liquid separator main body from the outlet of the refrigerant inflow passage can subsequently flow in the circumferential direction along the inner peripheral surface of the container, thereby receiving a centrifugal separation action. This further enhances the gas-liquid separation function.

  It is preferable that a collision separation plate for a gas-liquid two-phase flow of the refrigerant is provided inside the gas-liquid separator. By providing the collision separation plate, the liquid-phase refrigerant in the gas-liquid two-phase refrigerant in the gas-liquid separator collides with the collision separation plate to separate it from the gas-phase refrigerant, and the separated gas-phase refrigerant is efficiently removed. It becomes possible to flow out of the liquid separator. That is, it becomes possible to improve the gas-liquid separation performance in the gas-liquid separator body. In particular, at low loads where a gas-liquid two-phase refrigerant layer containing a relatively large amount of liquid phase refrigerant is formed, it is possible to efficiently separate the gas phase refrigerant from the gas phase refrigerant by colliding the liquid phase refrigerant having a large specific gravity with the collision separation plate. It becomes possible to do.

  The collision separation plate is preferably disposed at a position lower than the inlet portion in the gas-liquid separator of the refrigerant outflow pipe through which the separated gas-phase refrigerant flows out from the gas-liquid separator. With this arrangement, the gas-phase refrigerant after being separated by the collision separation plate as described above flows out of the gas-liquid separator more efficiently.

  Moreover, it is preferable that the collision separating plate is provided with a plurality of holes. With this configuration, the gas-liquid separator in the gas-liquid two-phase refrigerant efficiently collides with the collision separation plate, and the gas-phase refrigerant separated from the liquid-phase refrigerant passes through the plurality of holes to efficiently perform the gas-liquid separator. It is possible to drain from.

  In addition, the total cross-sectional area of the holes provided in the collision separation plate is either the cross-sectional area of the refrigerant inflow passage or the cross-sectional area of the refrigerant outflow pipe through which the separated gas-phase refrigerant flows out from the gas-liquid separator. It is preferable that it is set larger. With such a configuration, it is possible to keep the pressure loss when the refrigerant passes through the hole of the collision separation plate relatively low, and it is possible to keep the pressure loss of the gas-liquid separator as a whole low. Become.

  Moreover, it is preferable that the said collision separation board is arrange | positioned in the position higher than the liquid level of the liquid phase refrigerant | coolant stored in the said gas-liquid separator. The liquid level of the stored liquid-phase refrigerant varies depending on the load or the like, but is preferably disposed at a position higher than the highest liquid level position. With this configuration, the gas-liquid two-phase refrigerant layer formed below the collision separation plate can surely have a gas-liquid separation function by the collision separation plate.

  The collision separator plate has a structure that holds a pipe that forms the refrigerant inflow passage in the gas-liquid separator and a refrigerant outflow pipe that allows the separated gas-phase refrigerant to flow out from the gas-liquid separator. be able to. For example, a structure in which the collision separation plate and the refrigerant inflow pipe or the refrigerant outflow pipe are integrated by brazing, welding, or the like can be adopted. In such a configuration, the assembly strength between the pipe and the gas-liquid separator main body can be increased via the collision separator plate, and the reliability of the gas-liquid separator as a whole is improved.

  The vapor compression refrigeration cycle according to the present invention further includes an internal heat exchanger that exchanges heat between the refrigerant radiated by the radiator and the refrigerant flowing out of the gas-liquid separator; can do. By arranging an internal heat exchanger in the cycle, the high-pressure side refrigerant temperature can be reduced by heat exchange between the high-pressure side refrigerant in the cycle and the low-pressure side refrigerant on the evaporator outlet side. The refrigeration coefficient of performance can be improved by reducing the enthalpy on the side and increasing the enthalpy difference between the inlet side and the outlet side in the evaporator.

  The vapor compression refrigeration cycle according to the present invention is particularly suitable when the refrigerant used is carbon dioxide. Furthermore, the vapor compression refrigeration cycle according to the present invention is particularly suitable as a refrigeration cycle used in a vehicle air conditioner that is strongly demanded to improve the refrigeration performance coefficient.

  According to the vapor compression refrigeration cycle according to the present invention, the refrigerant inflow passage of the gas-liquid separator is formed into a curved shape, and the gas-liquid separation is performed by operating the centrifugal separation inside thereof, and further within the gas-liquid separator main body. By performing gas-liquid separation, the gas-liquid separation function of the entire gas-liquid separator can be greatly enhanced, and refrigerant can be prevented from flowing out of the gas-liquid separator in a gas-liquid two-phase state. Further, it is possible to stabilize the dryness of the refrigerant at the gas-liquid separator outlet and improve the cycle refrigeration performance coefficient. By optimizing the cross-sectional area change configuration and curved shape of the refrigerant inflow passage and the outlet opening direction of the refrigerant inflow passage, it becomes possible to further improve the gas-liquid separation function and further improve the refrigeration performance coefficient of the cycle. Can do.

  In addition, by providing a collision separation plate in the gas-liquid separator and optimizing its configuration, arrangement, piping with the gas-liquid separator piping, etc., the gas-liquid separation performance of the refrigerant can be further enhanced. The outflow of the phase refrigerant can be suppressed more efficiently, and the refrigeration coefficient of performance of the cycle can be further improved. Furthermore, it is possible to further improve the refrigeration performance coefficient by providing an internal heat exchanger.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 shows an example of a circuit configuration of a general vapor compression refrigeration cycle in a vehicle air conditioner, for example. In the configuration shown in FIG. 1, reference numeral 1 denotes a compressor that sucks and compresses refrigerant, and 2 denotes a radiator (gas cooler) that radiates the refrigerant compressed by the compressor 1 using an external heat exchange medium. From the internal heat exchanger 3 that further cools the refrigerant radiated by the radiator 2 (high pressure side), the decompressor 4 that decompresses the cooled refrigerant, the evaporator 5 that evaporates the decompressed refrigerant, and the evaporator 5 A gas-liquid separator 6 is provided for separating the separated refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant and causing the separated gas-phase refrigerant (low-pressure side) to flow out to the internal heat exchanger 3. These devices are sequentially connected by the refrigeration circuit 11. The arrows in FIG. 1 indicate the flow direction of the refrigerant.

  In such a vapor compression refrigeration cycle, the internal heat exchanger 3 can reduce the high-pressure side refrigerant pressure in a transcritical cycle in which the high-pressure side refrigerant pressure during the cycle operation is in a supercritical state, such as carbon dioxide refrigerant. This is because the high-pressure side refrigerant temperature can be reduced by exchanging heat between the high-pressure side refrigerant and the low-pressure side refrigerant. Furthermore, since the high-pressure side refrigerant temperature can be reduced, the enthalpy on the inlet side of the evaporator 5 can be reduced, and by increasing the enthalpy difference between the inlet and outlet in the evaporator 5, an improvement in the refrigeration performance coefficient can be expected. However, the internal heat exchanger 3 has the merit that the high-pressure side refrigerant temperature can be lowered, but increases the suction-side refrigerant temperature of the compressor 1. In the compression stroke of the compressor 1, the refrigerant theoretically changes in isentropy, but when the refrigerant temperature on the suction side of the compressor 1 rises, the slope of the isentropic line in the Mollier diagram becomes smaller. It also has a demerit that the power of the compressor 1 increases compared to when the suction side refrigerant temperature is low.

  Further, when a refrigerant having a high pressure on the high-pressure side, such as carbon dioxide, is used, it is difficult to provide a liquid storage tank on the high-pressure side due to problems such as ensuring pressure resistance. Further, in order to prevent a large amount of liquid refrigerant from being sucked into the compressor at the time of starting the compressor, it is preferable to provide a liquid reservoir tank on the refrigerant suction side to the compressor. It greatly affects the reliability. Therefore, it is common to install the gas-liquid separator 6 on the low pressure side as described above. The present invention aims to improve the refrigeration performance coefficient of the entire cycle through the improvement of the gas-liquid separator 6.

  In order to understand the improvement of the gas-liquid separator 6 in the present invention more easily, first, as an object for comparison, an example of the structure of the gas-liquid separator used in the conventional refrigeration cycle is shown in FIG. To explain. In FIG. 2, the same reference numerals as the reference numerals indicating the internal structure of an embodiment of the present invention to be described later are used for comparison with reference numerals indicating the internal structure of the gas-liquid separator.

  In FIG. 2, the gas-liquid separator 6 is configured to be able to cope with a necessary refrigerant amount fluctuation due to a change in the external environment. The gas-liquid separator 6 is a liquid storage tank for taking in and out the refrigerant in the cycle, and by separating the gas-liquid refrigerant by disposing the inlet of the refrigerant outflow pipe 22 above the liquid surface of the liquid phase refrigerant layer 26. It is a device that causes the gas-phase refrigerant to flow out from the refrigerant outflow pipe 22. Further, the lubricating oil that flows into the gas-liquid separator 6 together with the refrigerant is stored as the lowermost oil layer 27, and is returned to the compressor 1 through the refrigerant outflow pipe 22 from there. Actually, even if an oil separator or the like is used, it is difficult to separate 100% of the lubricating oil from the refrigerant, and the lubricating oil dissolved in the refrigerant circulates in the refrigeration cycle.

  A refrigerant inflow pipe 21 (refrigerant inflow passage) connected to the outlet refrigerant pipe of the evaporator 5 is provided on the upper surface of the gas-liquid separator 6, from which refrigerant and lubricating oil flow into the gas-liquid separator 6. Due to the difference in specific gravity, the inflowing refrigerant and lubricating oil accumulate the lubricating oil having a large specific gravity as the oil layer 27 at the bottom, and the liquid refrigerant having the next large specific gravity is formed as the liquid phase refrigerant layer 26 at the top of the oil layer 27. Stored. Further, a gas-liquid two-phase refrigerant layer 28 is located on the upper part, the gas phase refrigerant having the smallest specific gravity is formed as the gas phase refrigerant layer 25 on the uppermost part, and the gas phase refrigerant in the gas phase refrigerant layer 25 is transferred from the refrigerant outflow pipe 22. leak. At that time, a small amount of lubricating oil is sucked up from the oil return hole 24, and the lubricating oil accumulated in the gas-liquid separator 6 is returned to the compressor 1 through the internal heat exchanger 3. The refrigerant inflow pipe 21 and the refrigerant outflow pipe 22 are accommodated in a pressure vessel 23 as a gas-liquid separator body. Although illustration is omitted, since the oil return hole 24 has a small cross-sectional area and may be clogged with impurities in the refrigeration cycle, it is preferable to attach a filter.

  FIG. 3 shows a structure of a gas-liquid separator 20 according to an embodiment of the present invention, which is improved by the present invention with respect to such a conventional gas-liquid separator 6. Basically, as described in FIG. 2, a refrigerant inflow pipe 21 as a refrigerant inflow passage connected to the outlet refrigerant pipe of the evaporator 5 is provided on the upper surface of the main body of the gas-liquid separator 20, from which gas-liquid separation is performed. Refrigerant and lubricating oil flow into the vessel 20. Due to the difference in specific gravity, the inflowing refrigerant and lubricating oil accumulate lubricating oil having a large specific gravity in the bottom oil layer 27, and then a liquid refrigerant having the next largest specific gravity is formed as a liquid phase refrigerant layer 26 on the oil layer 27. Stored. Furthermore, a gas-liquid two-phase refrigerant layer 28 is located on the upper part, the gas phase refrigerant having the smallest specific gravity is formed as the gas phase refrigerant layer 25 at the uppermost part, and the gas phase refrigerant in the gas phase refrigerant layer 25 is transferred from the refrigerant outflow pipe 22. leak. At that time, a small amount of lubricating oil is sucked up from the oil return hole 24, and the lubricating oil accumulated in the gas-liquid separator 20 is returned to the compressor 1 through the internal heat exchanger 3. The refrigerant inflow pipe 21 and the refrigerant outflow pipe 22 are accommodated in a pressure vessel 23 as a gas-liquid separator body. In this case as well, although not shown, the oil return hole 24 has a small cross-sectional area and may be clogged with impurities in the refrigeration cycle, so it is preferable to attach a filter. In addition, the arrow in FIG. 3 has shown the flow of the refrigerant | coolant.

  The refrigerant inflow pipe 21 as the refrigerant inflow passage is formed in a curved shape capable of centrifuging the refrigerant into a gas phase refrigerant and a liquid phase refrigerant inside the passage from the inlet to the outlet 29. Is formed to have a shape along an involute curve from the inlet toward the outlet 29, for example. In this embodiment, the passage cross-sectional area of the refrigerant inflow pipe 21 as the refrigerant inflow passage is formed so as to increase from the inlet to the outlet 29. Furthermore, the outlet 29 of the refrigerant inflow pipe 21 as the refrigerant inflow passage is opened toward the direction along the circumferential direction of the inner peripheral surface of the pressure vessel 23 as the gas-liquid separator body, as shown in FIG. Has been.

  In this way, the refrigerant inflow passage is formed in a curved shape, and the cross-sectional area of the passage is increased from the inlet to the outlet, so that air is separated in the refrigerant inflow passage by centrifugal action. The separation of the gas-phase refrigerant and the liquid-phase refrigerant of the liquid two-phase refrigerant can be promoted. This utilizes the density difference between the gas-liquid two-phase refrigerant, and the low-density gas-phase refrigerant flows through the center of the passage and changes in speed with the liquid-phase refrigerant as the passage cross-sectional area changes. The liquid refrigerant having a high density flows on the inner wall surface side of the passage due to the inertial force due to the centrifugal force, and a speed difference is generated between the gas-phase refrigerant and the change in the cross-sectional area of the passage, thereby promoting gas-liquid separation. The refrigerant separated in this way and flowing into the gas-liquid separator main body from the outlet 29 of the refrigerant inflow pipe 21 flows along the circumferential direction of the pressure-resistant vessel 23, thereby undergoing a centrifugal separation action, and further the gas-phase refrigerant. And the liquid-phase refrigerant are separated, the liquid-phase refrigerant flows to the liquid-phase refrigerant layer 26, and the gas-phase refrigerant flows to the gas-phase refrigerant layer 25. As a result, the liquid-phase refrigerant stays in the lower layer of the pressure-resistant vessel 23, and the gas-phase refrigerant forms the gas-phase refrigerant layer 25 after passing through the pores 31 of the collision separation plate 30, and from there through the refrigerant outflow pipe 22. It flows out of the separator 20. As a result, the gas-liquid separator 20 as a whole performs extremely efficient gas-liquid separation, the outflow of the liquid-phase refrigerant and the gas-liquid two-phase refrigerant is suppressed, and the dryness of the refrigerant at the outlet of the gas-liquid separator 20 Is stabilized and the refrigeration performance coefficient of the cycle is improved.

  In this embodiment, the collision separation plate 30 is provided at a position higher than the liquid level of the liquid refrigerant layer 26 inside the gas-liquid separator 20, and the collision separation plate 30 is provided with a plurality of pores 31. ing. The total cross-sectional area of the pores 31 is set larger than either the cross-sectional area of the refrigerant inflow pipe 21 or the refrigerant outflow pipe 22. In particular, since the dryness of the refrigerant flowing into the gas-liquid separator 20 as a refrigerant state at a low load is small, the refrigerant containing a relatively large amount of liquid-phase refrigerant forms the gas-liquid two-phase refrigerant layer 28, but the collision By providing the pores 31 in the separation plate 30, the liquid phase refrigerant having a large specific gravity collides with the wall surface of the collision separation plate 30, the gas phase refrigerant passes through the pores 31, and the gas phase refrigerant and the liquid phase refrigerant are separated. Separated into each. At this time, since the collision separation plate 30 is located above the liquid surface of the liquid-phase refrigerant layer 26, the gas-liquid separation performance of the collision separation plate 30 is stably exhibited. By providing the collision separation plate 30 in this manner, it becomes possible to more efficiently separate the gas-liquid refrigerant in combination with the function of the curved refrigerant inflow passage described above, and to improve cycle stability. Further, by setting the total cross-sectional area of the pores 31 of the collision separation plate 30 to be larger than any of the cross-sectional areas of the refrigerant inflow pipe 21 or the refrigerant outflow pipe 22, the refrigerant can pass through the pores 31 of the collision separation plate 30. The pressure loss at the time of passing through can be kept low, and the entire pressure loss in the gas-liquid separator 20 can be kept low. The shape of the pores 31 provided in the collision separation plate 30 is not limited to a circle. Further, the positions of the pores 31 provided in the collision separation plate 30 are not particularly limited.

  For example, the collision separation plate 30 has a hole through which the refrigerant inflow pipe 21 and the refrigerant outflow pipe 22 penetrate in advance, and the collision separation plate 30, the refrigerant inflow pipe 21, and the refrigerant outflow pipe 22 collide by brazing or welding. It can be integrated with the separation plate 30. If integrated in this way, the assembly strength between the pipe and the gas-liquid separator 20 main body (pressure vessel 23) increases, which can contribute to the improvement of product reliability.

  As described above, in the gas-liquid separator 20 used in the vapor compression refrigeration cycle of the present invention, the refrigerant flowing into the gas-liquid separator main body is introduced at the inlet by the curved structure of the refrigerant inflow pipe 21 and further the pipe expansion structure. Since the gas-liquid separation is performed and the gas-liquid separation can be performed in the main body, the gas-liquid two-phase refrigerant is less likely to be mixed in the refrigerant outflow pipe 22, and the gas-phase refrigerant separated in the gas-liquid separator 20 is efficient. The gas-liquid separator 20 often flows out, the gas-liquid separator outlet refrigerant dryness can be stabilized, and the refrigeration performance coefficient of the cycle can be improved.

  Further, by providing the collision separation plate 30 in the gas-liquid separator 20, the specific gravity is large particularly at low load when the refrigerant containing a relatively large amount of liquid-phase refrigerant forms the gas-liquid two-phase refrigerant layer 28. The liquid phase refrigerant can collide with the wall surface of the collision separation plate 30 to be efficiently separated from the gas phase refrigerant, and the gas-liquid separation of the refrigerant can be performed more efficiently in combination with the curved structure of the refrigerant inflow passage. Stability can be improved. Further, by setting the total cross-sectional area of the pores 31 provided in the collision separation plate 30 to be larger than either the cross-sectional area of the refrigerant inflow pipe 21 or the refrigerant outflow pipe 22, the refrigerant causes the pores 31 of the collision separation plate 30 to be formed. The pressure loss at the time of passing can be reduced, and the pressure loss of the gas-liquid separator 20 as a whole can be reduced.

  Moreover, since the holes through which the refrigerant inflow pipe 21 and the refrigerant outflow pipe 22 penetrate are formed in the collision separation plate 30 in advance, the collision separation plate 30, the refrigerant inflow pipe 21 and the refrigerant outflow pipe 22 can be integrated. The assembly strength of each pipe and the gas-liquid separator main body can be increased to improve the reliability of the gas-liquid separator 20 as a product. Furthermore, since the refrigerant inflow pipe 21 and the refrigerant outflow pipe 22 are both on the upper surface side of the gas-liquid separator main body, when carbon dioxide is used as the refrigerant of the vehicle air conditioner, it is expected that the apparatus will be downsized and mounted. it can.

  The improved structure of the gas-liquid separator in the refrigeration cycle according to the present invention can be applied to any vapor compression refrigeration cycle, and is particularly suitable for use in a vapor compression refrigeration cycle in a vehicle air conditioner using a carbon dioxide refrigerant. Is.

It is an equipment distribution diagram showing an example of a general vapor compression refrigeration cycle. An example of the structure of the conventional gas-liquid separator shown for the comparison is shown, (B) is a longitudinal sectional view, and (A) is a transverse sectional view taken along line AA of FIG. (B). The structure of the gas-liquid separator which concerns on one Example of this invention is shown, (B) is a longitudinal cross-sectional view, (A) is a cross-sectional view which follows the AA line of figure (B).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Radiator 3 Internal heat exchanger 4 Pressure reducer 5 Evaporator 6, 20 Gas-liquid separator 11 Refrigerating circuit 21 Refrigerant inflow pipe 22 as refrigerant inflow passage Refrigerant outflow pipe 23 Pressure vessel 24 Oil return hole 25 Gas phase Refrigerant layer 26 Liquid-phase refrigerant layer 27 Oil layer 28 Gas-liquid two-phase refrigerant layer 29 Outlet 30 of refrigerant inflow passage Collision separation plate 31 Fine pore (hole)

Claims (14)

  A compressor that sucks and compresses the refrigerant; a radiator that dissipates the refrigerant compressed by the compressor; a decompressor that decompresses the refrigerant dissipated by the radiator; and evaporates the refrigerant decompressed by the decompressor A vapor compression type equipped with an evaporator and a gas-liquid separator that separates the refrigerant flowing out of the evaporator into a gas phase refrigerant and a liquid phase refrigerant and causes the separated gas phase refrigerant to flow out to the suction side of the compressor In the refrigeration cycle, the vapor compression passage characterized in that the refrigerant inflow passage through which the refrigerant flows into the gas-liquid separator is formed in a curved shape capable of separating the refrigerant into a gas phase refrigerant and a liquid phase refrigerant. Refrigeration cycle.   2. The vapor compression refrigeration cycle according to claim 1, wherein the refrigerant inflow passage is formed so that a cross-sectional area of the passage increases from an inlet to an outlet thereof.   The vapor compression refrigeration cycle according to claim 1 or 2, wherein the refrigerant inflow passage extends in an involute shape or a pseudo-involute shape close to the inlet from the inlet to the outlet.   The vapor compression refrigeration cycle according to any one of claims 1 to 3, wherein an outlet of the refrigerant inflow passage is opened in a direction along a circumferential direction of an inner peripheral surface of a container of the gas-liquid separator.   The vapor compression refrigeration cycle according to any one of claims 1 to 4, wherein a collision separation plate for a gas-liquid two-phase flow of refrigerant is provided inside the gas-liquid separator.   The said collision separation board is arrange | positioned in the position lower than the inlet_port | entrance part in the gas-liquid separator of the refrigerant | coolant outflow pipe which flows out the isolate | separated gaseous-phase refrigerant | coolant from the said gas-liquid separator. Vapor compression refrigeration cycle.   The vapor compression refrigeration cycle according to claim 5 or 6, wherein the collision separation plate is provided with a plurality of holes.   The total cross-sectional area of the holes provided in the collision separation plate is larger than either the cross-sectional area of the refrigerant inflow passage or the cross-sectional area of the refrigerant outflow pipe for allowing the separated gas-phase refrigerant to flow out from the gas-liquid separator. The vapor compression refrigeration cycle according to claim 7, which is set to be large.   The vapor compression refrigeration cycle according to any one of claims 5 to 8, wherein the collision separation plate is disposed at a position higher than a liquid level of a liquid phase refrigerant stored in the gas-liquid separator.   The vapor compression refrigeration cycle according to any one of claims 5 to 9, wherein the collision separation plate holds a pipe that forms the refrigerant inflow passage in the gas-liquid separator.   The said collision separation board is holding | maintaining the refrigerant | coolant outflow tube which flows out the isolate | separated gaseous-phase refrigerant | coolant from the inside of the said gas-liquid separator in the said gas-liquid separator. Vapor compression refrigeration cycle.   Furthermore, the vapor | steam in any one of Claims 1-11 provided with the internal heat exchanger which performs heat exchange between the refrigerant | coolant thermally radiated by the said heat radiator, and the refrigerant | coolant which flows out out of the said gas-liquid separator. Compression refrigeration cycle.   The vapor compression refrigeration cycle according to any one of claims 1 to 12, wherein the refrigerant is carbon dioxide.   The vapor compression refrigeration cycle according to any one of claims 1 to 13, comprising a refrigeration cycle used in a vehicle air conditioner.

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