JPWO2007123041A1 - Internal heat exchanger - Google Patents

Abstract

In the internal heat exchanger 10 that performs heat exchange between the high-temperature and high-pressure refrigerant A flowing from the radiator 2 into the decompression means 3 and the low-temperature and low-pressure refrigerant B flowing from the evaporator 4 into the compressor 1, An oil separating means 50 for separating the oil contained in the refrigerants A and B passing therethrough is provided at least one of the inlet part 11a of A and the inlet part 12a of the refrigerant B on the low temperature and low pressure side.

Description

  The present invention relates to an internal heat exchanger installed in a refrigeration cycle of a cooling device for a vehicle or a building.

  In recent years, natural refrigerants such as carbon dioxide with a low global warming coefficient have been used in the refrigeration cycle of this type of cooling device, and measures have been taken to reduce the environmental impact even when the refrigerant leaks to the outside. Yes.

  By the way, in the refrigeration cycle, lubricating oil for lubricating the compressor is discharged together with the refrigerant from the compressor.

  For this reason, it is inevitable that a part of the lubricating oil adheres as an oil film to the inner surface of the flow path of the heat exchanger incorporated in the refrigeration cycle. The amount of heat exchange with the wall is reduced.

  Therefore, for example, in JP-A-2-293570 (hereinafter referred to as Patent Document 1), in a refrigeration cycle having a compressor 101, a condenser 102, an accumulator 103, a decompression means 104, and an evaporator 105 as shown in FIG. A technique has been proposed in which oil separation means is provided in the refrigerant inflow chamber of the condenser 102 and the separated oil is returned to the compressor 101 through the oil return passage 108 via the pressure reducing valve 109.

  However, in the technique described in Patent Document 1, the liquid refrigerant may flow into the compressor 101.

  Accordingly, an object of the present invention is to provide an internal heat exchanger capable of preventing the reduction of the heat exchange amount by suppressing the oil film from adhering to the inner surface of the flow path and preventing the liquid refrigerant from flowing into the compressor. And

  The invention according to claim 1, which achieves the above object, releases a heat of the refrigerant circulating in the cycle to the outside and cools the refrigerant, and absorbs the external heat in the refrigerant circulating in the cycle. An evaporator that evaporates the refrigerant, a compressor that sucks and compresses the refrigerant flowing out of the evaporator and discharges it toward the radiator, and a decompression that decompresses the refrigerant flowing out of the radiator and introduces it into the evaporator A high-pressure side passage through which a high-temperature and high-pressure refrigerant flowing from the radiator to the decompression means flows, and a low-temperature and low-pressure refrigerant flowing from the evaporator to the suction side of the compressor An internal heat exchanger that exchanges heat between the high-temperature and high-pressure refrigerant and the low-temperature and low-pressure refrigerant, the inlet portion of the high-pressure side flow path and the low pressure Small number of side channel inlets Even Ku to one, characterized by providing an oil separating means for separating the oil contained in the refrigerant passing through.

  Further, according to a second aspect of the present invention, in the internal heat exchanger according to the first aspect, a high-pressure side inlet header and a low-pressure side inlet header are respectively provided at an inlet portion of the high-pressure side flow channel and an inlet portion of the low-pressure side flow channel. The oil separation means is provided in at least one of the high-pressure side inlet header and the low-pressure side inlet header.

  Further, according to a third aspect of the present invention, in the internal heat exchanger according to the first or second aspect, an oil return mechanism for sending the oil on one flow path side separated by the oil separation means to the other flow path side, It is provided on the downstream side of the oil separating means.

FIG. 1 is a circuit diagram showing an example of a conventional refrigeration cycle. FIG. 2 is a circuit diagram of a carbon dioxide refrigeration cycle provided with the internal heat exchanger according to the first embodiment of the present invention. FIG. 3: is a block diagram of the internal heat exchanger of 1st Embodiment of this invention, Comprising: (a) is a front view, (b) is II 'sectional drawing of (a). FIG. 4 is a configuration diagram of an internal heat exchanger according to a second embodiment of the present invention, in which (a) is a front view, (b) is a cross-sectional view taken along line II-II ′ of (a), and (c) is ( It is a side view when it sees from the arrow III of a). FIG. 5: is a block diagram of the internal heat exchanger of 3rd Embodiment of this invention, Comprising: (a) is a front view, (b) is IV-IV 'sectional drawing of (a), (c) is ( It is a side view when it sees from the arrow V of a). FIG. 6 is an exploded perspective view of the internal heat exchanger according to the fourth embodiment of the present invention. FIG. 7 is an exploded perspective view of the internal heat exchanger according to the fifth embodiment of the present invention.

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Here, the example which applied this invention to the carbon dioxide refrigerating cycle of the vehicle air conditioner is demonstrated.

(First embodiment)
FIG. 2 is a circuit diagram of a carbon dioxide refrigeration cycle including the internal heat exchanger of the first embodiment.

  This refrigeration cycle includes a compressor 1 for compressing refrigerant, a radiator 2 for exchanging heat between the high-temperature refrigerant boosted by the compressor 1 and outside air, and an expansion for decompressing the refrigerant cooled by the radiator 2. A valve (decompression unit) 3, an evaporator 4 that evaporates the refrigerant depressurized by the expansion valve 3, and a refrigerant that has passed through the evaporator 4 is gas-liquid separated to send only the gas-phase refrigerant to the compressor 1. An accumulator 5 and an internal heat exchanger 10 that exchanges heat between the high-pressure refrigerant cooled by the radiator 2 and the low-pressure refrigerant returning to the compressor 1 are provided.

  The compressor 1 obtains a driving force from a motor (not shown) or an engine, compresses a carbon dioxide refrigerant in a gas phase state (hereinafter, appropriately referred to as carbon dioxide or refrigerant), and discharges the refrigerant that has become high temperature and pressure. .

  The radiator 2 cools the temperature of the refrigerant to near the outside air temperature by dissipating the heat of the high-temperature and high-pressure refrigerant discharged from the compressor 1 to the outside air. The radiator 2 is blown with outside air by driving an electric fan or the like, for example. The high-temperature and high-pressure refrigerant is cooled to a predetermined temperature by exchanging heat between the high-temperature and high-pressure refrigerant passing through the radiator 2 and the blown outside air.

  The internal heat exchanger 10 further cools the refrigerant sent from the radiator 2 to the expansion valve 3 by exchanging heat between the refrigerant cooled by the radiator 2 and the low-temperature and low-pressure refrigerant evaporated by the evaporator 4. is doing.

  The expansion valve 3 expands (depressurizes) the medium-temperature and high-pressure refrigerant cooled by the internal heat exchanger 10 and sends it to the evaporator 4 as a low-temperature and low-pressure gaseous refrigerant.

  The evaporator 4 is a heat exchanger that exchanges heat between a low-temperature and low-pressure refrigerant decompressed by the expansion valve 3 and supply air from a blower fan (not shown). The refrigerant that has become low temperature and low pressure in the expansion valve 3 takes the heat of the supply air and evaporates (evaporates) when passing through the evaporator 4. Then, the supply air absorbed by the refrigerant in the evaporator 4 is cooled and dehumidified to be conditioned and blown into the passenger compartment.

  The accumulator (gas-liquid separator) 5 performs gas-liquid separation of the refrigerant discharged from the evaporator 4, sends out a gas-phase refrigerant (gas refrigerant) to the internal heat exchanger 10, and a liquid-phase refrigerant (liquid refrigerant) (Refrigerant) is temporarily stored.

  In FIG. 2, high-temperature and high-pressure carbon dioxide discharged from the compressor 1 undergoes heat exchange with air while passing through the radiator 2, and the temperature decreases. The carbon dioxide whose temperature has been lowered then passes through the internal heat exchanger 10, further exchanges heat with the low-temperature and low-pressure refrigerant returning to the compressor 1, and further sent to the expansion valve 3. When passing through the expansion valve 3, the carbon dioxide expands and the temperature decreases, and as a result, the temperature of the evaporator 4 provided on the downstream side of the expansion valve 3 decreases. Therefore, the air wind flowing through the evaporator 4 is cooled, and the water vapor contained in the air is removed to perform cooling and dehumidification.

  The low-temperature carbon dioxide (low-temperature and low-pressure side refrigerant B) that has passed through the evaporator 4 passes through the accumulator 5 and is then sent to the internal heat exchanger 10. In this internal heat exchanger 10 portion, the radiator 2 Heat exchange is performed with carbon dioxide (refrigerant A on the high-temperature and high-pressure side) that is still high in temperature and is returned to the compressor 1 for compression. The accumulator 5 also serves to prevent liquid carbon dioxide from being fed into the compressor 1.

  3A and 3B are configuration diagrams of the internal heat exchanger 10 in the first embodiment, in which FIG. 3A is a front view and FIG. 3B is a cross-sectional view taken along the line II ′ of FIG. The internal heat exchanger 10 exchanges heat between the high-temperature and high-pressure side refrigerant A flowing through the high-pressure side flow path 11 and the low-temperature and low-pressure side refrigerant B flowing through the low-pressure side flow path 12.

  In the present embodiment, each of the high-pressure channel 11 and the low-pressure channel 12 has a multi-hole tube portion 11c in which a plurality of substantially circular channels (not shown) through which a refrigerant flows are formed in parallel. 12c.

  Furthermore, in this embodiment, the high-pressure side inlet header 21 and the high-pressure side outlet header 22 are respectively provided at the inlet portion 11a and the outlet portion 11b of the high-pressure side flow channel 11, and the inlet portion 12a of the low-pressure side flow channel 12 and A low-pressure side inlet header 31 and a low-pressure side outlet header 32 are provided in the outlet portion 12b. These headers 21, 22, 31, and 32 are installed upright, and are joined to the end portions of the multi-hole pipe portions 11 c and 12 c of the high-pressure side channel 11 and the low-pressure side channel 12, respectively. The high pressure side inlet pipe 21a and the low pressure side inlet pipe 31a are connected to the upper ends (upstream side) of the high pressure side inlet header 21 and the low pressure side inlet header 31, respectively. Further, a high pressure side outlet pipe 22a and a low pressure side outlet pipe 32a are connected to lower ends (downstream side) of the high pressure side outlet header 22 and the low pressure side outlet header 32, respectively.

  Further, an oil separating means 50 is provided at an upper position inside the high pressure side inlet header 21 and the low pressure side inlet header 31. As the oil separating means 50, a mesh or bundle made of fibers of metals, resins, ceramics or the like, or a porous body made of similar materials can be used. For example, when a mesh is used as the oil separating means, the refrigerant flowing into the headers 21 and 31 is attached to the mesh when passing through the oil separating means. And separated.

  Since the oil separated by the oil separating means 50 has a density higher than that of the refrigerant, the oil moves downward, accumulates in the lower part of the inlet headers 21 and 31, and further contains a large number of high-pressure side passages 11 and low-pressure side passages 12. It flows to the outlet headers 22 and 32 through the flow path provided below the hole tube portions 11c and 12c. That is, the refrigerant flows through the upper flow path, and the oil flows through the lower flow path to the outlet headers 22 and 32. In this case, the flow path of the oil is limited to the flow path below the multi-hole pipe portions 11c and 12c, and the oil can be prevented from adhering to the inner surface of the flow path of the coolant. A decrease in the amount of heat exchange due to the adhesion of oil to the inner surface of the road can be prevented.

  Moreover, in the internal heat exchanger 10, since heat exchange is also performed in the flow path through which the oil flows, the liquid refrigerant dissolved in the oil when the oil flows from the low-pressure side inlet header 31 toward the outlet header 32. Evaporates. Therefore, mixing of the liquid refrigerant into the compressor 1 can be prevented.

  In addition, oil separation in the internal heat exchanger 10 is reduced as a result of oil separation, so that the oil return to the compressor 1 is improved, the lack of lubrication of the compressor 1 is eliminated, and the life of the compressor 1 is extended. Can do.

(Second Embodiment)
In the first embodiment, the example in which the adjacent headers 21, 32, 22, and 31 are spaced apart from each other has been described. However, the adjacent headers 21, 32, 22, and 31 are adjacent to each other with, for example, one partition wall. In such a case, it can be configured like the internal heat exchanger 10B of the second embodiment in FIG. 4A and 4B are configuration diagrams of the internal heat exchanger 10B according to the second embodiment, in which FIG. 4A is a front view, FIG. 4B is a sectional view taken along line II-II ′ in FIG. It is a side view when it sees from arrow view III.

  In the present embodiment, since the refrigerant is circulated in a counterflow manner, the high-pressure side inlet header 21 and the low-pressure side outlet header 32 are adjacent to each other, and the high-pressure side outlet header 22 and the low-pressure side inlet header 31 are adjacent to each other. .

  And in this internal heat exchanger 10B, the oil separation means 50 is provided in the upper position inside the high pressure side inlet header 21, and the oil separation means 50 is not provided in the low pressure side inlet header 31. On the other hand, oil chambers 26 and 36 are provided on the inner bottom portion downstream of the high-pressure side outlet header 22 and the inner bottom portion downstream of the low-pressure side inlet header 31 and separated from the upper side by partition walls 25 and 35, respectively. ing. These oil chambers 26 and 36 communicate with each other via a communication hole (for example, a minute hole) 28 having a pressure reducing function provided in a partition wall 27 that partitions both headers 22 and 31. The high-pressure side outlet pipe 22a is connected to the upper side of the partition wall 25 that partitions the oil chamber 26 at the lower part.

  In the internal heat exchanger 10B having this structure, the oil separated by the oil separating means 50 of the high-pressure side inlet header 21 is accumulated in the lower portion of the header 21, passes through the flow path below the multi-hole pipe portion 11c, It flows to the high-pressure side outlet header 22. The oil that has flowed into the oil chamber 26 below the high-pressure outlet header 22 flows into the oil chamber 36 below the low-pressure inlet header 31 through the communication hole 28 with a pressure reducing function. It flows from the chamber 36 to the low-pressure side outlet header 32 through a flow path below the multi-hole pipe portion 12. The refrigerant and oil are mixed in the low-pressure side outlet header 32, and the oil-mixed refrigerant discharged from the low-pressure side outlet pipe (not shown) flows to the compressor 1.

  In other words, in the present embodiment, the flow path below the multi-hole tube portion 11 c, the oil chamber 26, and the communication hole 28 function as an oil return mechanism located on the downstream side of the oil separating means 50.

  In the internal heat exchanger 10B according to the above-described embodiment, when the refrigerant passes through the multi-hole pipe portions 11c and 12c, that is, when the refrigerant flows from the high-pressure side inlet header 21 to the high-pressure side outlet header 22, and the low-pressure side inlet When flowing from the header 31 to the low-pressure side outlet header 32, the refrigerant and the oil flow in a state where they are separated into an upper layer and a lower layer, so that it is possible to suppress the oil from adhering to the inner surface of the flow path where the refrigerant flows. It is possible to prevent a decrease in the heat exchange amount of the internal heat exchanger 10B due to the adhesion of oil.

  Moreover, the fall of the heat exchange performance by adhesion of the oil with respect to the evaporator 4 (refer FIG. 2) connected between the high voltage | pressure side exit header 22 and the low voltage | pressure side inlet header 31 can also be prevented.

  Further, heat exchange is also performed in the portion (lower flow path) through which the oil flows in the internal heat exchanger 10B, so that the liquid refrigerant dissolved in the low-pressure side oil evaporates and prevents the liquid refrigerant from entering the compressor 1. be able to.

  In addition, oil separation in the internal heat exchanger 10B is reduced due to the oil separation, so that the oil return to the compressor 1 is improved, the lack of lubrication of the compressor 1 is eliminated, and the life of the compressor 1 can be extended.

(Third embodiment)
In the second embodiment, the counter flow type is shown, but the present invention can also be applied to a parallel flow method. FIG. 5 shows an internal heat exchanger 10C according to a third embodiment applied to the parallel flow method. 5A is a front view of the internal heat exchanger in the third embodiment, FIG. 5B is a cross-sectional view taken along the line IV-IV ′ of FIG. 5A, and FIG. 5C is a view when viewed from the arrow V of FIG. It is a side view.

  In the present embodiment, since the refrigerant is circulated in a parallel flow system, the high pressure side inlet header 21 and the low pressure side inlet header 31 are adjacent to each other, and the high pressure side outlet header 22 and the low pressure side outlet header 32 are adjacent to each other. .

  In the internal heat exchanger 10 </ b> C, the oil separating means 50 is provided at an upper position inside the high pressure side inlet header 21, and the oil separating means 50 is not provided in the low pressure side inlet header 31. On the other hand, oil chambers 26 and 36 are provided on the inner bottom portion that is downstream of the high-pressure side inlet header 21 and the inner bottom portion that is downstream of the low-pressure side inlet header 31. ing. These oil chambers 26 and 36 communicate with each other via a communication hole (for example, a minute hole) 28 having a pressure reducing function provided in a partition wall 27 that partitions both headers 21 and 31.

  In the internal heat exchanger 10C having this structure, the oil separated by the oil separating means 50 of the high-pressure inlet header 21 is accumulated in the oil chamber 26 below the header 21 and is directly passed through the communication hole 28 having a pressure reducing function. And flows into the oil chamber 36 of the low-pressure inlet header 31. Next, the oil chamber 36 flows to the low-pressure side outlet header 32 through a flow path below the multi-hole pipe portion 12. The refrigerant and oil are mixed in the low-pressure side outlet header 32, and the oil-mixed refrigerant discharged from the low-pressure side outlet pipe (not shown) flows to the compressor 1.

  That is, in this embodiment, the oil chamber 26 and the communication hole 28 function as an oil return mechanism.

  Also in the present embodiment described above, the same effects as those of the internal heat exchanger 10B of the second embodiment described above can be obtained.

  In the internal heat exchanger 10B of the second embodiment shown in FIG. 4, the high pressure side inlet header 21 and the low pressure side outlet header 32, and the high pressure side outlet header 22 and the low pressure side inlet header 31 are in close contact with each other. Therefore, heat exchange is also performed between the adjacent headers 21 and 32 and between the headers 22 and 31.

  Similarly, in the internal heat exchanger 10C of the third embodiment shown in FIG. 5, the high-pressure side inlet header 21 and the low-pressure side inlet header 31, and the high-pressure side outlet header 22 and the low-pressure side outlet header 32 are in close contact. Since they are adjacent (integrated in the illustrated example), heat exchange is also performed between the adjacent headers 21 and 31 and between the headers 22 and 32.

  In addition, the communication hole 28 with a pressure reducing function provided in the second and third embodiments can be substituted by providing an element having the same function outside the headers 21, 22, and 31. For example, a communication pipe with a pressure reducing function for communicating the oil chambers 26 and 36 may be provided outside the header.

  Further, considering that a communication pipe with a pressure reducing function may be provided outside the headers 21, 22, 31, 31, the high pressure / low pressure headers 21, 22, 31, 32 as shown in FIG. 3 are separated. It goes without saying that the structure of the oil chambers 26 and 36 and the communication pipe can be applied to the internal heat exchanger of the type.

(Fourth embodiment)
Next, an embodiment in which the oil return structure is simplified will be described. FIG. 6 is an exploded perspective view of the internal heat exchanger according to the fourth embodiment, and particularly shows an oil return structure provided in the high pressure side inlet header 21 and the low pressure side outlet header 32. Here, the description of the configuration and operational effects common to the other embodiments is omitted, and only the configuration and operational effects characteristic of the present embodiment will be described.

  In the internal heat exchanger 10D of the present embodiment, since the refrigerant is circulated in a counterflow manner as in the second embodiment, the high-pressure side inlet header 21 and the low-pressure side outlet header 32 are disposed adjacent to each other, and The high-pressure side outlet header and the low-pressure side inlet header are arranged adjacent to each other.

  In this internal heat exchanger 10D, an oil separation means (see FIG. 3B) (not shown) is provided at an upper position inside the high-pressure side inlet header 21. And the oil separation means is not provided in the low-pressure side inlet header (not shown).

  A patch end 41 and a plate 42 are provided at the lower ends of the adjacent high-pressure side inlet header 21 and low-pressure side outlet header 32 to connect two adjacent headers. The patch end 41 is formed in a box frame shape, in order to discharge the refrigerant from the bottom of the low pressure side outlet header 32 and the groove portion 41a communicating between the high pressure side inlet header 21 and the low pressure side outlet header 32 at the bottom. The outlet hole 41b is formed. The groove 41a is formed to have a substantially concave cross section, and its end communicates with the outlet hole 41b.

  In addition, a low-pressure side outlet pipe 32 a is connected to the outlet hole 41 b of the patch end 41. The patch end 41 can be formed by cutting, pressing, forging, or the like.

  By assembling the patch end 41 and the plate 42 to the lower ends of the high-pressure inlet header 21 and the low-pressure outlet header 32, the lower end of the high-pressure inlet header 21 is shielded, and the lower end of the low-pressure outlet header 32 The side outlet pipe 32a communicates with the groove 41a. At the same time, the adjacent high pressure side inlet header 21 and low pressure side outlet header 32 are connected and fixed by the patch end 41 and the plate 42.

  In the internal heat exchanger 10D according to the present embodiment, oil separated by an oil separation means (not shown) provided in the high-pressure side inlet header 21 is accumulated in the lower portion of the header 21 and passes through the groove 41a of the patch end 41 from here. It flows into the lower part of the low-pressure side outlet header 32. Then, the refrigerant and oil that have flowed through the multi-hole pipe portion 12 in the lower part of the low-pressure side outlet header 32 are mixed, and the oil-mixed refrigerant discharged from the low-pressure side outlet pipe 32 a is sent to the compressor 1.

  That is, in this embodiment, the patch end 41, the plate 42, and the groove 41a function as an oil return mechanism provided on the downstream side of the oil separating means.

  According to the internal heat exchanger 10D of the present embodiment as described above, the oil return can be performed with a simple structure by the patch end 41 and the plate 42, so that the number of parts can be reduced and the cost can be reduced.

  In the present embodiment, an example in which the oil return structure by the patch end 41 and the plate 42 is provided below the high-pressure side inlet header 21 and the low-pressure side outlet header 32 has been described. The same oil return structure may be provided in the inlet header, and the oil may be returned from the lower part of the low pressure side inlet header to the high pressure side outlet header. In this way, the oil return structure can be provided on either one of the header sides or both.

  In this embodiment, an example in which one groove 41a is formed on the bottom of the patch end 41 is shown, but a plurality of grooves 41a may be formed. Furthermore, it can also be configured as a groove portion with a decompression function by reducing the cross-sectional area.

(Fifth embodiment)
FIG. 7 is an exploded perspective view of the internal heat exchanger according to the fifth embodiment, and particularly shows an oil return structure provided in the high pressure side inlet header 21 and the low pressure side inlet header 32. Here, the description of the configuration and operational effects common to the other embodiments is omitted, and only the configuration and operational effects characteristic of this embodiment will be described.

  In the internal heat exchanger 10E of the present embodiment, since the refrigerant is circulated in a parallel flow manner as in the third embodiment, the high-pressure side inlet header 21 and the low-pressure side inlet header 32 are disposed adjacent to each other, as shown in the figure. The high-pressure side outlet header and the low-pressure side outlet header are arranged adjacent to each other.

  In this internal heat exchanger 10E, an oil separation means (not shown) (see FIG. 3B) is provided at an upper position inside the high-pressure side inlet header 21. The low pressure side inlet header 32 is not provided with oil separating means.

  A patch end 43 and a plate 42 are provided at the lower ends of the adjacent high-pressure side inlet header 21 and low-pressure side inlet header 32 to connect two adjacent headers. The patch end 43 is formed in a box frame shape, and a groove 43a having a substantially concave cross section that communicates between the high-pressure inlet header 21 and the low-pressure inlet header 32 is formed at the bottom.

  By assembling the patch end 43 and the plate 42 to the lower ends of the high-pressure side inlet header 21 and the low-pressure side inlet header 32, the lower ends of the high-pressure side inlet header 21 and the low-pressure side inlet header 32 are respectively shielded. Is communicated with the groove 43a at its lower end. At the same time, the adjacent high pressure side inlet header 21 and low pressure side inlet header 32 are connected and fixed by the patch end 43 and the plate 42.

  In the internal heat exchanger 10E according to the present embodiment, the oil separated by the oil separation means (not shown) provided in the high-pressure side inlet header 21 is accumulated in the lower part of the header 21 and passes through the groove 43a of the patch end 43 from here. The oil flows to the lower part of the low-pressure side inlet header 32, and further, this oil flows into the low-pressure side outlet header (not shown) through the flow path of the multi-hole pipe portion 12 below the low-pressure side inlet header 32. The refrigerant and oil are mixed in the low-pressure side outlet header, and the oil-mixed refrigerant discharged from the low-pressure side outlet pipe (not shown) is sent to the compressor 1.

  That is, in the present embodiment, the patch end 43, the plate 42, and the groove 43a function as an oil return mechanism provided on the downstream side of the oil separating means.

  Also in the internal heat exchanger 10E of the present embodiment described above, the oil return can be performed with a simple structure by the patch end 43 and the plate 42, so the number of parts can be reduced and the cost can be reduced.

  In the present embodiment, the example in which the oil return structure by the patch end 43 and the plate 42 is provided below the high-pressure side inlet header 21 and the low-pressure side inlet header 32 has been described. 7 or 6 may be provided to return the oil from the lower part of the high-pressure side outlet header to the low-pressure side outlet header. In this way, the oil return structure can be provided on either one of the header sides or both.

  In the present embodiment, an example in which one groove 43a is formed at the bottom of the patch end 43 is shown, but a plurality of grooves 43a may be formed. Furthermore, it can also be configured as a groove portion with a decompression function by reducing the cross-sectional area.

  According to the present invention, it is possible to provide an internal heat exchanger that can suppress the adhesion of an oil film to the inner surface of a flow path to prevent a decrease in the amount of heat exchange and prevent the liquid refrigerant from flowing into the compressor.

Claims (3)

A radiator that releases the heat of the refrigerant circulating in the cycle to cool the refrigerant, an evaporator that absorbs external heat into the refrigerant circulating in the cycle and evaporates the refrigerant, and the evaporator Equipped in a refrigeration cycle comprising a compressor that sucks and compresses the refrigerant that has flowed out and discharges it toward the radiator, and decompression means that decompresses the refrigerant that has flowed out of the radiator and introduces it into the evaporator, A high-pressure side passage through which high-temperature and high-pressure refrigerant flowing from the radiator to the decompression means flows, and a low-pressure side passage through which low-temperature and low-pressure refrigerant flowing from the evaporator to the suction side of the compressor flows. An internal heat exchanger that performs heat exchange between the high-temperature and high-pressure refrigerant and the low-temperature and low-pressure refrigerant,
Oil separation means for separating oil contained in the passing refrigerant is provided in at least one of the inlet portion of the high-pressure channel and the inlet portion of the low-pressure channel. Internal heat exchanger. A high-pressure side inlet header and a low-pressure side inlet header are respectively provided at the inlet portion of the high-pressure side channel and the inlet portion of the low-pressure side channel,
The internal heat exchanger according to claim 1, wherein the oil separation means is provided in at least one of the high-pressure side inlet header and the low-pressure side inlet header.   The oil return mechanism for sending the oil on one channel side separated by the oil separating means to the other channel side is provided on the downstream side of the oil separating means. Internal heat exchanger.

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