JP2006177228A - Rotary two-stage compressor and air conditioner using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce refrigerant leakage loss by suppressing the swing of a roller in a high pressure compression element. <P>SOLUTION: This rotary two-stage compressor is provided, in a sealed container, with a rotary shaft having two eccentric parts; a rotary compression element wherein a low pressure compression element and a high pressure compression element with rollers provided in compression chambers respectively and put in revolving motion by the eccentric rotation of the eccentric parts are provided through an intermediate partition plate; and intermediate passages connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element and separated from the internal space of the sealed container. When the heights of the eccentric part and roller of the low pressure compression element are set to h1, H1 respectively and the heights of the eccentric part and roller of the high pressure compression element are set to h2, H2 respectively, H1>H2 and (h1/H1)≤(h2/H2) are to be satisfied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotary two-stage compressor used in an air conditioner having a refrigeration cycle and an air conditioner using the same.

  Conventionally, as a rotary two-stage compressor used in a refrigeration cycle applied to an air conditioner, for example, a structure disclosed in Japanese Patent Application Laid-Open No. 60-128990 (hereinafter referred to as Patent Document 1) is known. The compressor in this prior art is provided with an electric motor composed of a stator and a rotor at the upper part inside a sealed container. The rotating shaft connected to the electric motor has two eccentric portions. As a compression mechanism corresponding to these eccentric portions, a high-pressure compression element and a low-pressure compression element are provided inside the sealed container in order from the electric motor side.

  Each compression element revolves the roller by the eccentric rotation of the eccentric portion of the rotation shaft. The eccentric portions have a phase difference of 180 °, and the phase difference of the compression process of each compression element is 180 °. That is, the compression process of the two compression elements is in antiphase. These eccentric portions are connected by an intermediate shaft having a substantially circular cross-sectional shape.

  The gas refrigerant, which is a working fluid, is sucked into the low pressure compression element at a low pressure Ps, is compressed, and rises to an intermediate pressure Pm. The gas refrigerant discharged at the intermediate pressure Pm is discharged into the intermediate flow path. Next, the gas refrigerant having the intermediate pressure Pm is sucked into the high pressure compression element through the intermediate flow path and compressed to the high pressure Pd.

  The high-pressure Pd gas refrigerant discharged from the compressor is condensed by the condenser and then decompressed to the low pressure Ps by the expansion mechanism. After that, it evaporates in an evaporator to become a gas refrigerant and is sucked into the low pressure compression element.

  As a structure of such a rotary two-stage compressor in which the internal pressure of the hermetic container is high pressure Pd, for example, a structure disclosed in Patent Document 1 is known. The conventional rotary two-stage compressor compresses the gas refrigerant stepwise from the low pressure Ps to the intermediate pressure Pm by the low pressure compression element and from the intermediate pressure Pm to the high pressure Pd by the high pressure compression element.

  The relationship between the eccentric part of the rotating shaft and the geometrical shape of the roller is not particularly described, and is the same as that of a general single-stage rotary compressor. In the drawing of Patent Document 1, the height of the roller and the eccentric portion of the low-pressure compression element is equal to the height of the roller and the eccentric portion of the low-pressure compression element, respectively. For reference, the height of the cylinder and the height of the roller are almost the same.

JP-A-60-128990 (page 5, FIG. 1)

  On the other hand, in a general single-stage rotary compressor, the relationship between the ratio between the eccentric part and the height of the roller and the power consumption is disclosed in Patent Document 2, for example. Depending on the ratio (h / H) between the height h of the eccentric part and the height H of the roller, the refrigerating capacity and the power consumption change. This is due to the sliding loss between the cylindrical inner surface of the roller and the cylindrical outer surface of the eccentric portion, and between the roller and the cylinder as the roller swings in the height direction, and between the upper and lower end surfaces of the roller and the end plate or middle. This is because the amount of refrigerant leakage from between the partition plates changes.

  When the rotary type two-stage compressor described in the prior art is used for an air conditioner, it often operates under a pressure condition of (high pressure Pd−intermediate pressure Pm)> (intermediate pressure Pm−low pressure Ps). Therefore, the gas load received by the roller and the eccentric portion is different between the low pressure compression element and the high pressure compression element, and particularly, the gas load at the high pressure compression element becomes high. For this reason, there is a problem that the roller of the high pressure compression element swings greatly, and the amount of refrigerant leakage increases here.

  Further, since the gas load is different between the high pressure compression element and the low pressure compression element, the intermediate shaft between the two eccentric portions of the rotating shaft is likely to be deformed, and the roller swing is increased, resulting in an increase in the amount of refrigerant leakage. there were.

  Moreover, in an air conditioner to which a compressor having such a problem is applied, it may be difficult to exhibit desired performance with respect to input, and there is a problem that the coefficient of performance COP decreases.

  An object of the present invention is to solve the above-described problems and to suppress the swing of a roller of a rotary two-stage compressor to reduce the amount of refrigerant leakage. Moreover, it exists in preventing a performance fall as an air conditioner.

  In order to achieve the above object, a rotary compressor according to the present invention includes an electric motor in a sealed container, a rotating shaft driven by the electric motor and having two eccentric parts, and a roller that revolves due to the eccentric rotation of the eccentric part. A rotary compression element in which a compression element for low pressure and a compression element for high pressure respectively provided in a compression chamber are provided via an intermediate partition plate; a compression chamber for the compression element for low pressure; and a compression chamber for the compression element for high pressure An intermediate flow path separated from the internal space of the sealed container to be connected. The pressure in the sealed container is the pressure of the discharge gas compressed by the high pressure compression element, and the height of the eccentric part and the roller in the low pressure compression element are h1 and H1, respectively, and the eccentricity in the high pressure compression element. The height of the part and the roller was set to h2 and H2, respectively, and the roller shape of each compression element and the geometric shape of the eccentric part were related as H1> H2 and (h1 / H1) ≦ (h2 / H2).

  In order to further suppress the fluctuation of the high pressure compression element, the eccentric distance of the eccentric part of the low pressure compression element from the rotary shaft is E1, and the eccentric part of the high pressure compression element from the rotary shaft is E1. When the eccentric distance is E2, each eccentric distance is related as E1> E2.

  Further, in order to reduce the amount of refrigerant leakage around the roller due to the deformation of the intermediate shaft, the phase difference in the compression process between the low pressure compression element and the high pressure compression element is approximately 180 °, and the low pressure compression element is eccentric. The intermediate shaft that connects between the center portion and the eccentric portion of the high-pressure element has a step in the axial direction, and the center of gravity of the intermediate shaft on the low-pressure compression element side and the high-pressure compression element side is the eccentricity of each eccentric portion. The bending rigidity may be improved by decentering in the direction.

  In particular, in order to increase the bending rigidity of the intermediate shaft on the high pressure side, the eccentric distance between the compression element for low pressure and the compression element for high pressure is E1> E2, and the cross-sectional area and bending rigidity of the intermediate shaft on the high pressure compression element side are Increased over the low pressure compression element side.

  Furthermore, in the gas injection cycle in which the gas load of the compression element for high pressure becomes higher, it is possible to improve the reliability and performance by reducing the refrigerant leakage amount by using the rotary compressor of the present invention described above. It becomes.

  According to the present invention, in the compressor, it is possible to reduce the refrigerant leakage loss due to the rocking of the roller and to reduce the power consumption. In particular, it is possible to reduce refrigerant leakage loss due to the swing of the roller of the high pressure compression element.

  Moreover, in an air conditioner, power consumption can be reduced and performance improvement can be obtained.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a rotary two-stage compressor 1 of the present embodiment, and FIG. The compressor 1 includes a sealed container 13 including a bottom portion 21, a lid portion 12, and a body portion 22. An electric motor 14 having a stator 7 and a rotor 8 is provided above the inside of the sealed container 13. The rotating shaft 2 connected to the electric motor 14 includes two eccentric portions 5 and is pivotally supported by the main bearing 9 and the auxiliary bearing 19a. The two eccentric portions 5 are connected by an intermediate shaft 41 having a step 44 in the axial direction. The main bearing 9, the high-pressure compression element 20b, the intermediate partition plate 15, the low-pressure compression element 20a, the end plate portion 19b, and the auxiliary bearing 19a provided with the end plate portion 9a are sequentially arranged with respect to the rotating shaft 2 from the electric motor 14 side. The provided intermediate container 19 is laminated and integrated with a fastening element 36 such as a bolt.

  The end plate portion 9 a is fixed to the inner wall of the body portion 22 by welding and supports the main bearing 9. The end plate portion 19b is supported by the auxiliary bearing 19a. In this embodiment, the end plate portion 19b is fixed by the fastening element 36, but may be fixed to the body portion 22 by welding.

  Each compression element 20a and 20b is comprised like FIG. 1, FIG. In the low-pressure compression element 20a, a compression chamber 23a is composed of an end plate portion 19b, a cylindrical cylinder 10a, a cylindrical roller 11a fitted to the outer periphery of the eccentric portion 5a, and an intermediate partition plate 15. In the high-pressure compression element 20b, a compression chamber 23b is constituted by the main bearing 9, the cylindrical cylinder 10b, the cylindrical roller 11b fitted to the outer periphery of the eccentric portion 5b, and the intermediate partition plate 15. The compression chambers 23a and 23b are in contact with the outer periphery of the rollers 11a and 11b in which a flat vane 18 connected to an urging force applying means such as a coil spring rotates in accordance with the eccentric motion of the eccentric portions 5a and 5b. While moving forward and backward, the compression chambers 23a and 23b are divided into a compression space and a suction space.

  The compression element 20 drives the roller 11 when the eccentric part 5 rotates eccentrically. As shown in FIGS. 1 and 2, the eccentric portion 5a and the eccentric portion 5b have a phase difference of 180 °, and the phase difference in the compression process of the compression elements 20a and 20b is 180 °. That is, the compression process of the two compression elements is in opposite phase.

  The flow of the gas refrigerant which is a working fluid is represented by an arrow in FIG. The low-pressure Ps gas refrigerant supplied through the pipe 31 is sucked into the low-pressure compression element 20a from the suction port 25a connected to the pipe 31, and is compressed to the intermediate pressure Pm by the eccentric rotation of the roller 11a. When the discharge valve 28a that opens when the pressure in the compression chamber 23a reaches a preset pressure opens at the intermediate pressure Pm, the gas refrigerant that has reached the intermediate pressure Pm is discharged into the discharge space 33 that communicates with the discharge port 26a. . The discharge space 33 is a space separated from the sealed space 29 in the sealed container 13 by the intermediate container 19 and the flat cover 35, and the internal pressure thereof is basically the intermediate pressure Pm. The intermediate flow path 30 is a flow path that connects the discharge port 26c from the discharge space 33 and the suction port 25b. The gas refrigerant having the pressure Pm discharged from the discharge port 26a opened by the discharge valve 28a is discharged into the discharge space 33, and then passes through the intermediate flow path 30 and communicates with the pressure chamber 23b of the high-pressure element 20b. To.

  Next, the gas refrigerant having the intermediate pressure Pm passing through the intermediate flow path 30 and sucked into the high pressure compression element 20b from the suction port 25b is compressed to the high pressure Pd by the revolution of the roller 11b. When the discharge valve 28b that opens when the pressure in the compression chamber 23b reaches a preset pressure opens at high pressure Pd, the gas refrigerant is discharged from the discharge port 26b to the sealed space 29 that is the internal space of the sealed container 13. The high-pressure Pd gas refrigerant discharged into the sealed space 29 passes through the gap of the electric motor 14 and is discharged from the discharge pipe 27.

  In FIG. 3, the enlarged view of the compression element 20 part of the rotary compressor 1 of this embodiment is shown. In the two-stage compression method in which the refrigerant is compressed stepwise, the amount of pressing (stroke volume) of the high pressure compression element 20b is smaller than the amount of pressing of the low pressure compression element 20a.

  The compressor 1 is for a general air conditioner, and the ratio of the high pressure compression element 20b, the low pressure compression element 20a, and the amount of pressing is set to a predetermined value range of 0.65 to 0.85. In many cases, the ratio of the pressing amount is operated under a pressure condition of (high pressure Pd−intermediate pressure Pm)> (intermediate pressure Pm−low pressure Ps). That is, the gas load in the high pressure compression element 20b is larger than the gas load in the low pressure compression element 20a.

  The pressing amount of each compression element 20 is set by the inner diameter φD of the cylinder 10, the height H of the cylinder 10 or the roller 11, and the eccentric distance E from the center of the rotating shaft 2 of the eccentric portion 5. The inner diameter φD of each cylinder 10 is the same in the low pressure compression element 20a and the high pressure compression element 20b. The reason why the inner diameter φD of each cylinder 10 is set to the same value is to unify the part processing jig, the part processing apparatus, the measuring apparatus, and the assembly apparatus of each cylinder. The height H2 of the cylinder 10b or the roller 11b was made lower than the height H1 of the cylinder 10a or the roller 11a. Further, the eccentric distance E2 may be smaller than the eccentric distance E1 in order to set a desired pressing amount.

  The roller 11 was formed into a substantially cylindrical shape by processing a cast member by cutting or polishing. The corners between the upper and lower end surfaces and the inner surface of the roller 11 are tapered to reduce the weight. However, the taper 42 is provided in a range where the sliding surface with the eccentric portion 5 is not reduced. The height of the roller 11 is almost the same as the height of the cylinder 10 although there is a difference of several μm to several tens of μm.

  The height H2 of the roller 11b was as low as 0.8 times the height H1 of the roller 11a. The outer diameter of the roller 11 is determined from the relationship between the ratio of the pressing amount of each compression element 20 and the height H of each roller 11 and the eccentric distance E of the eccentric portion 5.

  In this embodiment, the outer diameter of the roller 11b of the high pressure compression element 20b is larger than the outer diameter of the roller 11a of the low pressure compression element 20a.

  The rotating shaft 2 is a cast member processed by cutting or polishing. The eccentric portion 5 has a substantially cylindrical shape located at an eccentric distance E from the rotation center of the rotating shaft 2. As described above, the eccentric distance E2 is smaller than the eccentric distance E1. The center of the eccentric part 5 in the height direction and the center of the roller 11 in the height direction were substantially matched.

  Next, in the present embodiment, the height h2 of the eccentric portion 5b is set lower than the height h1 of the eccentric portion 5a. When the height of each compression element 20 was compared, it was set as (h1 / H1) ≦ (h2 / H2). Specifically, (h1 / H1) was 0.48, (h2 / H2) was 0.58, and (h2 / H2) was 1.2 times (h1 / H1). (H1 / H1) was set in the range of 0.4 to 0.8 in consideration of the sliding loss and the refrigerant leakage loss around the roller 11.

  FIG. 4 shows the AA cross section of FIG. 3, and FIG. 5 shows the BB cross section. The intermediate shaft 41 has a step 44 in the axial direction of the rotating shaft 2. The intermediate shaft 41 has a cross section of a region surrounded by an arc having a radius r from the rotation center O of the rotating shaft 2 and an arc having a radius R from the center C of the eccentric portion 5. That is, the center of gravity of the cross section of the intermediate shaft 41 is decentered toward the center C rather than the center O.

  Since the radius r is processed when the rotary shaft 2 is processed, and the radius R is processed when the eccentric portion 5 is processed, there is no significant increase in processing steps. However, the radius r is smaller than the radius of the central hole 40 provided in the intermediate partition plate 15 as shown in FIG. 3 so that the intermediate partition plate 15 and the intermediate shaft 41 do not contact each other.

  Further, S1> t> S2 as shown in FIG. 3 so that the eccentric portion 5 and the intermediate partition plate 15 do not come into contact with each other during assembly. Here, S1 is the height on the low pressure compression element 20a side from the step 44 of the intermediate shaft 41, S2 is the height on the high pressure compression element 20b side from the step 44 of the intermediate shaft 41, and t is the thickness of the intermediate partition plate 15. is there. Here, S1> t, but it is sufficient that at least one S is larger than t as in S2> t.

  Since the height H2 of the cylinder 10b is lower than the height H1 of the cylinder 10a, that is, the cylinder 10b is flattened, the differential pressure (Pd−Pm) of the high pressure compression element 20b is reduced to the low pressure side differential pressure (Pm−Ps). ), The swinging of the roller 11b is suppressed.

  Furthermore, since (h2 / H2) is made larger than (h1 / H1) after setting (h1 / H1) to an appropriate range, the swing of the roller 11b is further suppressed. Further, since E2 <E1 with respect to the eccentric distance, the roller 11b has a smaller revolution distance than the roller 11a, and the swing is suppressed. Furthermore, the roller 11 is tapered to reduce the weight, so that the swinging is further suppressed.

  Further, since the cross-sectional area of the intermediate shaft 41 is made larger than the cross-sectional area of the rotary shaft 2 and the bending rigidity is increased, the intermediate shaft 41 is deformed even if the gas load applied to the eccentric portion 5a and the eccentric portion 5b is unbalanced. Since it is difficult to swing, the swing of the roller 11 is suppressed.

  Further, as can be seen by comparing FIG. 4 and FIG. Since the cross-sectional area and bending rigidity of the intermediate shaft 41 on the high pressure side can be increased as compared with those on the low pressure side, the influence on the gas load is relatively strong, and the swing of the roller 11b can be suppressed.

  Here, if the height of the eccentric portion 5 is enlarged and a clearance groove 47 is provided as shown in FIG. 6, the swing of the roller 11 is further suppressed. However, also in FIG. 6, (h1 / H1) is in the range of 0.4 to 0.8, and (h1 / H1) ≦ (h2 / H2). In FIG. 6, the value corresponding to the height h of the eccentric portion 5 is the sum of the heights h ′ and h ″ of the sliding surfaces of the roller 11 and the eccentric portion 5.

  With the above configuration, the compressor of the present embodiment suppresses the swing of the roller and reduces the refrigerant leakage amount.

  Next, FIG. 7 shows a cycle configuration when the compressor of the present embodiment is used in a gas injection cycle. The high-pressure Pd refrigerant gas discharged from the rotary two-stage compressor 1 according to the embodiment of the present invention is condensed by the condenser 3 and then expanded by the first expansion mechanism 4 so that the pressure reaches the intermediate pressure Pm. Depressurized. The decompressed refrigerant gas is separated into a gas refrigerant and a liquid refrigerant by the gas-liquid separator 6. The separated liquid refrigerant is further depressurized to a low pressure Ps by the second expansion mechanism 4 downstream of the gas-liquid separator 6 and then evaporated by the evaporator 16 to become a gas refrigerant. The low-pressure Ps gas refrigerant is sucked into the low-pressure compression element 20a from the pipe 31 and the suction port 25a, and is compressed to the intermediate pressure Pm by the revolution of the roller 11a fitted to the eccentric portion 5a. Is done.

  The gas refrigerant in the intermediate flow path 30 is mixed with the gas refrigerant having an intermediate pressure Pm guided from the injection flow path 17 in which the gas-liquid separator 6 and the intermediate flow path 30 communicate with each other. Thereafter, the gas refrigerant having the intermediate pressure Pm sucked into the high pressure compression element 20b from the suction port 25b is compressed to the high pressure Pd by the revolution of the roller 11b fitted to the eccentric portion 5b, and discharged from the discharge pipe 27. Is done.

  In such an injection cycle, the gas refrigerant having low heat transfer performance is bypassed to the intermediate flow path 30 in the evaporator 16, so that the excessive circulation flow to the low pressure compression element 20 a is reduced to reduce the compression work, and the refrigeration Improve cycle performance coefficient COP. In addition, a two-way valve 34 for opening and closing the flow path 17 is provided in the middle of the injection flow path 17. When the two-way valve 34 is opened, an injection cycle is established, and when the two-way valve 34 is closed, the normal refrigeration cycle shown in FIG. A switchable configuration may be used. Further, instead of the two-way valve 34, an expansion valve capable of adjusting the flow rate may be used.

  In a refrigeration cycle of a general air conditioner to which this embodiment is not applied, as described in the embodiment of the rotary compressor, the differential pressure (high pressure Pd−intermediate pressure Pm) applied to the high pressure compression element 20b is low pressure. It becomes higher than the differential pressure (intermediate pressure Pm−low pressure Ps) applied to the compression element 20a, and the roller 11b is more likely to swing.

  In the gas injection cycle shown in FIG. 7, the refrigerant flows into the intermediate flow path 30 from the injection flow path 17 so that the refrigerant is increased in the high pressure compression element. For this reason, the load on the roller 11b of the high pressure compression element 20b is increased and is more likely to swing. That is, although the gas injection cycle ideally improves the coefficient of performance COP, there is a problem that it is easily affected by refrigerant leakage loss due to the swing of the roller 11b.

  In such a gas injection cycle, when the rotary type two-stage compressor 1 of the present embodiment is used, it is possible to reduce the refrigerant leakage loss accompanying the swing of the roller 11b. The effect is more remarkable in the gas injection cycle than in the normal refrigeration cycle. Therefore, the refrigeration cycle of this embodiment can realize a gas injection cycle that is closer to the ideal, and can improve the coefficient of performance COP of the refrigeration cycle.

1 is a longitudinal sectional view of a rotary two-stage compressor showing an embodiment of the present invention. 1 is a configuration diagram of a rotary two-stage compressor showing an embodiment of the present invention. The fragmentary sectional view of the rotary type two-stage compressor which shows one Embodiment of this invention. AA sectional drawing of FIG. BB sectional drawing of FIG. The longitudinal cross-sectional view of the intermediate shaft and roller which show the application example of one Embodiment of this invention. The block diagram of the refrigerating cycle which shows one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Rotary shaft, 5 ... Eccentric part, 9 ... Main bearing, 10 ... Cylinder, 11 ... Roller, 15 ... Intermediate partition plate, 17 ... Injection flow path, 20 ... Compression element, 30 ... Intermediate flow path 41 ... Intermediate shaft.

Claims (4)

  A low-pressure compression element and a high-pressure compression element each having an electric motor in a hermetic container, a rotating shaft driven by the electric motor and having two eccentric parts, and a roller that revolves by the eccentric rotation of the eccentric part, respectively. A rotary compression element provided via an intermediate partition plate, an intermediate flow path separated from the internal space of the sealed container connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element, The pressure in the hermetic container is the pressure of the discharge gas compressed by the high pressure compression element, and the height of the eccentric part and the roller in the low pressure compression element is h1. , H1 and the height of the eccentric part and the roller in the compression element for high pressure are h2 and H2, respectively, and H1> H2 and (h1 / H1) ≦ (h2 / H2).   2. The rotary two-stage compressor according to claim 1, wherein an eccentric distance of the eccentric portion of the low pressure compression element from the rotation shaft is E1, and an eccentric distance of the eccentric portion of the high pressure compression element from the rotation shaft is E1. A rotary two-stage compressor in which E2 is E2 and the relationship of the eccentric distance is E1> E2.   3. The rotary type two-stage compressor according to claim 2, wherein a phase difference in a compression process between the low pressure compression element and the high pressure compression element is approximately 180 °, and the eccentric portion of the low pressure compression element and the high pressure element The intermediate shaft has a step in the axial direction, and the center of gravity of the low-pressure compression element side step portion and the high-pressure compression element side step portion is close to each other. A rotary type two-stage compressor in which an eccentric portion is eccentric in an eccentric direction, and a cross-sectional area on the high-pressure compression element side is larger than a cross-sectional area of the low-pressure compression element. A rotary compressor, a condenser for condensing the high-pressure gas refrigerant discharged from the rotary compressor, a first expansion mechanism for expanding the condensed liquid refrigerant to an intermediate pressure, and an expanded intermediate pressure In an air conditioner that sequentially connects a second expansion mechanism that expands the refrigerant to a low pressure and an evaporator that evaporates the refrigerant.
The rotary compressor includes a motor in a hermetic container, a rotary shaft driven by the motor and having two eccentric parts, and a roller that revolves by the eccentric rotation of the eccentric part in a compression chamber. A rotary compression element in which an element and a high pressure compression element are provided via an intermediate partition plate, and an internal space of the sealed container connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element The pressure in the sealed container is the pressure of the discharge gas compressed by the high pressure compression element, and the height of the eccentric part and the roller in the low pressure compression element are h1 and H1, respectively. And the heights of the eccentric part and the roller in the compression element for high pressure are h2 and H2, respectively, and H1> H2 and (h1 / H1) ≦ (h2 / H2), and a refrigerant is provided downstream of the first expansion mechanism. The gas refrigerant Gas-liquid separator and an air conditioner having an injection passage communicating with said intermediate passage and the gas-liquid separator for separating the liquid refrigerant.

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