(19)
(11)EP 3 926 255 A1

(12)EUROPEAN PATENT APPLICATION

(43)Date of publication:
22.12.2021 Bulletin 2021/51

(21)Application number: 21178113.3

(22)Date of filing:  08.06.2021
(51)International Patent Classification (IPC): 
F25B 13/00(2006.01)
F25B 43/00(2006.01)
(52)Cooperative Patent Classification (CPC):
F25B 13/00; F25B 43/00; F25B 2400/23
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
KH MA MD TN

(30)Priority: 16.06.2020 KR 20200073100

(71)Applicant: LG Electronics Inc.
Seoul 07336 (KR)

(72)Inventors:
  • CHO, Eunjun
    08592 Seoul (KR)
  • YOON, Pilhyun
    08592 Soul (KR)
  • HONG, Seongho
    08592 Seoul (KR)
  • PARK, Jungmin
    08592 Seoul (KR)
  • KIM, Yejin
    08592 Seoul (KR)

(74)Representative: Vossius & Partner Patentanwälte Rechtsanwälte mbB 
Siebertstraße 3
81675 München
81675 München (DE)


(56)References cited: : 
  
      


    (54)AIR CONDITIONER


    (57) An air conditioner of the present disclosure includes: a compressor which compresses a refrigerant; a condenser which condenses the refrigerant discharged from the compressor; an expansion valve which expands the refrigerant passed through the condenser; a gas-liquid separation pipe through which the refrigerant passed through the expansion valve flows; a gas-liquid separator, through which the refrigerant passed through the gas-liquid separation pipe is introduced, that separates and discharges the refrigerant introduced into the gas-liquid separator into a vapor refrigerant and a liquid refrigerant; and an evaporator which evaporates the liquid refrigerant discharged from the gas-liquid separator, wherein the vapor refrigerant discharged from the gas-liquid separator and the refrigerant passed through the evaporator are provided to the compressor, and the gas-liquid separation pipe comprises: a first part which extends long, and is connected to a refrigerant inflow pipe in which the expansion valve is installed; and a second part which extends in a direction crossing a length direction of the first part and is coupled to the first part, wherein at least one of the first part and the second part is connected to the gas-liquid separator.




    Description

    CROSS-REFERENCE TO RELATED APPLICATION



    [0001] This application claims the priority benefit of Korean Patent Application No. 10-2020-0073100, filed on June 16, 2020.

    BACKGROUND OF THE INVENTION


    1. Field of the invention



    [0002] The present disclosure relates to an air conditioner. In particular, the present disclosure relates to an air conditioner capable of increasing the separation rate of a vapor refrigerant and a liquid refrigerant by providing a gas-liquid separation pipe in the front end of a gas-liquid separator.

    2. Description of the Related Art



    [0003] In general, an air conditioner refers to an apparatus that cools and heats a room through compression, condensation, expansion and evaporation processes of refrigerant. If an outdoor heat exchanger of the air conditioner serves as a condenser, whereas an indoor heat exchanger serves as an evaporator, the room may be cooled. On the other hand, if the outdoor heat exchanger of the air conditioner serves as an evaporator, whereas the indoor heat exchanger serves as a condenser, the room may be heated.

    [0004] A conventional air conditioner includes a gas-liquid separator that receives a refrigerant that has passed through an expansion valve and separates and discharges the received refrigerant into a vapor refrigerant and a liquid refrigerant. In this case, the vapor refrigerant separated in the gas-liquid separator is injected into a compressor, and the liquid refrigerant separated in the gas-liquid separator may be supplied to an evaporator.

    [0005] However, if the vapor refrigerant and the liquid refrigerant are not sufficiently separated in the gas-liquid separator, there is a problem in that the liquid refrigerant is injected into the compressor to cause damage to the compressor.

    [0006] Recently, a lot of researches have been conducted on a method of increasing the separation rate of vapor refrigerant and liquid refrigerant in a gas-liquid separator.

    SUMMARY OF THE INVENTION



    [0007] An object of the present disclosure is to solve the above and other problems.

    [0008] Another object of the present disclosure is to provide an air conditioner capable of increasing a separation rate of a vapor refrigerant and a liquid refrigerant by providing a gas-liquid separation pipe in the front end of a gas-liquid separator.

    [0009] Another object of the present disclosure is to provide an air conditioner capable of securing the reliability of a compressor by preventing the liquid refrigerant from being discharged into a gas-liquid refrigerant pipe of a gas-liquid separator.

    [0010] Another object of the present disclosure is to provide various embodiments of a structure of gas-liquid separation pipe.

    [0011] In accordance with an aspect of the present invention, an air conditioner includes: a compressor which compresses a refrigerant; a condenser which condenses the refrigerant discharged from the compressor; an expansion valve which expands the refrigerant passed through the condenser; a gas-liquid separation pipe through which the refrigerant passed through the expansion valve flows; a gas-liquid separator, through which the refrigerant passed through the gas-liquid separation pipe is introduced, that separates and discharges the refrigerant introduced into the gas-liquid separator into a vapor refrigerant and a liquid refrigerant; and an evaporator which evaporates the liquid refrigerant discharged from the gas-liquid separator, wherein the vapor refrigerant discharged from the gas-liquid separator and the refrigerant passed through the evaporator are provided to the compressor, and the gas-liquid separation pipe comprises: a first part which extends long, and is connected to a refrigerant inflow pipe in which the expansion valve is installed; and a second part which extends in a direction crossing a length direction of the first part and is coupled to the first part, wherein at least one of the first part and the second part is connected to the gas-liquid separator.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0012] The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which:

    FIG. 1 is a diagram that shows a configuration of an air conditioner capable of switching between a cooling operation and a heating operation according to an embodiment of the present disclosure and a flow of a refrigerant, and explains an example in which a first gas-liquid separation pipe and a second gas-liquid separation pipe are provided and a vapor refrigerant separated by a gas-liquid separator is injected to a medium pressure stage of a compressor;

    FIGS. 2 to 9 are diagrams showing examples of gas-liquid separation pipes of an air conditioner according to embodiments of the present disclosure;

    FIG. 10 is a diagram that shows a configuration of an air conditioner capable of performing a cooling operation or a heating operation according to an embodiment of the present disclosure and a flow of a refrigerant, and explains an example in which a single gas-liquid separation pipe is provided and a vapor refrigerant separated by a gas-liquid separator is injected to a medium pressure stage of a compressor;

    FIG. 11 is a diagram that shows a configuration of an air conditioner capable of switching between a cooling operation and a heating operation according to an embodiment of the present disclosure and a flow of a refrigerant, and explains an example in which a first gas-liquid separation pipe and a second gas-liquid separation pipe are provided and a vapor refrigerant separated by a gas-liquid separator is injected to a low pressure stage of a compressor; and

    FIG. 12 is a diagram that shows a configuration of an air conditioner capable of performing a cooling operation or a heating operation according to an embodiment of the present disclosure and a flow of a refrigerant, and explains an example in which a single gas-liquid separation pipe is provided and a vapor refrigerant separated by a gas-liquid separator is injected to a low pressure stage of a compressor.


    DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS



    [0013] Description will now be given in detail according to exemplary embodiments disclosed herein, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components may be denoted by the same reference numbers, and description thereof will not be repeated. In general, suffixes such as "module" and "unit" may be used to refer to elements or components. Use of such suffixes herein is merely intended to facilitate description of the specification, and the suffixes do not have any special meaning or function. In the present disclosure, that which is well known to one of ordinary skill in the relevant art has generally been omitted for the sake of brevity. The accompanying drawings are used to assist in easy understanding of various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. It will be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. It will be understood that when an element is referred to as being "connected with" another element, there may be intervening elements present. In contrast, it will be understood that when an element is referred to as being "directly connected with" another element, there are no intervening elements present. A singular representation may include a plural representation unless context clearly indicates otherwise. Terms such as "includes" or "has" used herein should be considered as indicating the presence of several components, functions or steps, disclosed in the specification, and it is also understood that more or fewer components, functions, or steps may likewise be utilized.

    [0014] Referring to FIG. 1, an air conditioner 1 includes a compressor 2, an outdoor heat exchanger 4, an indoor heat exchanger 5, an expansion valve Va and Vb, a gas-liquid separator 6, and a gas-liquid separation pipe 11a and 11b. The expansion valve may include a first expansion valve Va and a second expansion valve Vb. The gas-liquid separation pipe may include a first gas-liquid separation pipe 11a and a second gas-liquid separation pipe 11b.

    [0015] The compressor 2 compresses the refrigerant introduced from an accumulator 7 and discharges a high-temperature and high-pressure refrigerant. Meanwhile, a first pipe P1 may be installed between the compressor 2 and the switching valve 3 to provide a flow path for refrigerant ranging from the compressor 2 to the switching valve 3. Here, the accumulator 7 may provide a vapor refrigerant to the compressor 2 through a twelfth pipe P12.

    [0016] A switching valve 3 may receive a refrigerant which is discharged from the compressor 2 and passed through the first pipe P1. In addition, the switching valve 3 may guide the refrigerant introduced through the first pipe P1 to the outdoor heat exchanger 4 or the indoor heat exchanger 5. For example, the switching valve 3 may be a four-way valve. Meanwhile, an eleventh pipe P11 may be installed between the switching valve 3 and the accumulator 7 to provide a flow path for a refrigerant ranging from the switching valve 3 to the accumulator 7.

    [0017] The outdoor heat exchanger 4 may heat-exchange the refrigerant and outdoor air. The direction of heat transfer between the refrigerant and outdoor air in the outdoor heat exchanger 4 may differ depending on the operation mode of the air conditioner, that is, depending on whether it is a cooling operation or a heating operation. An outdoor fan 4a is disposed in one side of the outdoor heat exchanger 4 to adjust the amount of air provided to the outdoor heat exchanger 4. For example, the outdoor fan 4a may be driven by an electric motor for outdoor fan. Meanwhile, a second pipe P2 may be installed between the switching valve 3 and the outdoor heat exchanger 4 to provide a flow path for refrigerant connecting the switching valve 3 and the outdoor heat exchanger 4.

    [0018] The indoor heat exchanger 5 may heat-exchange the refrigerant and indoor air. The direction of heat transfer between the refrigerant and the indoor air in the indoor heat exchanger 5 may differ depending on the operation mode of the air conditioner, that is, depending on whether it is a cooling operation or a heating operation. An indoor fan 5a is disposed in one side of the indoor heat exchanger 5 to adjust the amount of air provided to the indoor heat exchanger 5. For example, the indoor fan 5a may be driven by an electric motor for indoor fan. Meanwhile, a tenth pipe P10 may be installed between the switching valve 3 and the indoor heat exchanger 5 to provide a flow path for refrigerant connecting the switching valve 3 and the indoor heat exchanger 5.

    [0019] The first expansion valve Va and the second expansion valve Vb may be installed between the outdoor heat exchanger 4 and the indoor heat exchanger 5. In detail, the first expansion valve Va may be installed in a third pipe P3 facing the second pipe P2 across the outdoor heat exchanger 4. In addition, the second expansion valve Vb may be installed in a ninth pipe P9 facing the tenth pipe P10 across the indoor heat exchanger 5. The first expansion valve Va and the second expansion valve Vb may expand the refrigerant supplied from one of the outdoor heat exchanger 4 and the indoor heat exchanger 5 according to the operation mode of the air conditioner.

    [0020] The gas-liquid separator 6 may receive refrigerant expanded from the first expansion valve Va or the second expansion valve Vb. The gas-liquid separator 6 may separate the received refrigerant into a vapor refrigerant and a liquid refrigerant to discharge. For example, the gas-liquid separator 6 may be formed in a cylindrical shape extended long in the vertical direction. In this case, the liquid refrigerant, among two phase refrigerants that are expanded in the first expansion valve Va or the second expansion valve Vb and introduced into the gas-liquid separator 6, flows to the lower portion of the gas-liquid separator 6, while the vapor refrigerant may flow to the upper portion of the gas-liquid separator 6. At this time, the gas-liquid separator 6 may include a liquid refrigerant pipe, through which the liquid refrigerant is discharged, that is provided in the lower portion of the gas-liquid separator 6, and a vapor refrigerant pipe, through which the vapor refrigerant is discharged, that is provided in the upper portion of the gas-liquid separator 6.

    [0021] The first gas-liquid separation pipe 11a may be installed between the first expansion valve Va and the gas-liquid separator 6. In addition, the first gas-liquid separation pipe 11a may be connected to the first expansion valve Va through a third pipe P3, and connected to the gas-liquid separator 6 through a fourth pipe P4 and a fifth pipe P5. At this time, depending on the operation mode of the air conditioner, the refrigerant may flow into the gas-liquid separator 6 through a fourth pipe P4 and a fifth pipe P5, or the liquid refrigerant may be discharged from the gas-liquid separator 6 through the fifth pipe P5.

    [0022] The second gas-liquid separation pipe 11b may be installed between the second expansion valve Vb and the gas-liquid separator 6. In addition, the second gas-liquid separation pipe 11b may be connected to the second expansion valve Vb through a ninth pipe P9, and connected to the gas-liquid separator 6 through a seventh pipe P7 and an eighth pipe P8. At this time, depending on the operation mode of the air conditioner, the refrigerant may flow into the gas-liquid separator 6 through the seventh pipe P7 and the eighth pipe P8, and the liquid refrigerant may be discharged from the gas-liquid separator 6 through the seventh pipe P7.

    [0023] Meanwhile, a sixth pipe P6 may provide a flow path for refrigerant connecting the gas-liquid separator 6 and the compressor 2 as a vapor refrigerant pipe of the gas-liquid separator 6 described above. In this case, an injection valve Vi is installed in the sixth pipe P6 to open and close the flow path for refrigerant.

    <Cooling operation mode of air conditioner>



    [0024] Referring to the left drawing of FIG. 1, the low-temperature and low-pressure refrigerant flowing from the accumulator 7 to the compressor 2 through the twelfth pipe P12 may be compressed in the compressor 2 and discharged in a high-temperature and high-pressure state. The refrigerant discharged from the compressor 2 may be introduced into the outdoor heat exchanger 4 through the first pipe P1, the switching valve 3, and the second pipe P2 sequentially.

    [0025] As heat energy is transferred from the refrigerant to the outdoor air in the outdoor heat exchanger 4, the refrigerant may be condensed. At this time, the outdoor heat exchanger 4 may be referred to as a condenser. The refrigerant condensed while passing through the outdoor heat exchanger 4 may pass through the third pipe P3 and may be expanded in the first expansion valve Va up to a range corresponding to the medium pressure stage of the compressor 2. Here, the medium pressure stage of the compressor 2 may be understood as a pressure formed between the pressure (i.e. low pressure) of refrigerant flowing into the compressor 2 and the pressure (i.e. high pressure) of refrigerant discharged from the compressor 2. For example, the first expansion valve Va may be an electronic expansion valve EEV capable of adjusting the opening degree of the flow path of the third pipe P3.

    [0026] The refrigerant expanded in the first expansion valve Va may flow into the first gas-liquid separation pipe 11a in a two-phase state. A relatively large amount of vapor refrigerant among the two phase refrigerants introduced into the first gas-liquid separation pipe 11a flows into the gas-liquid separator 6 through the fourth pipe P4, and a relatively large amount of liquid refrigerant flows into the gas-liquid separator 6 through the fifth pipe P5, which will be described in more detail later.

    [0027] The gas-liquid separator 6 may separate and discharge the two phase refrigerants introduced into the gas-liquid separator 6 into a vapor refrigerant and a liquid refrigerant. The vapor refrigerant separated by the gas-liquid separator 6 may flow into the medium pressure stage of the compressor 2 through the sixth pipe P6. In this case, the injection valve Vi may be an EEV or a solenoid valve that opens and closes the sixth pipe P6. The liquid refrigerant separated by the gas-liquid separator 6 may flow into the second gas-liquid separation pipe 11b through the seventh pipe P7. The liquid refrigerant introduced into the second gas-liquid separation pipe 11b passes through the ninth pipe P9 and may expand in the second expansion valve Vb up to a range corresponding to the low pressure stage of the compressor 2. For example, the second expansion valve Vb may be an electronic expansion valve EEV capable of adjusting the opening degree of the flow path of the ninth pipe P9.

    [0028] The refrigerant expanded in the second expansion valve Vb may be introduced into the indoor heat exchanger 5 through the ninth pipe P9.

    [0029] As the heat energy of the indoor air is transferred from the indoor heat exchanger 5 to the refrigerant, the refrigerant may be evaporated. At this time, the indoor heat exchanger 5 may be referred to as an evaporator. Further, according to the heat exchange between the refrigerant and the indoor air, the temperature of the indoor air is lowered, so that the indoor space may be cooled. The refrigerant evaporated while passing through the indoor heat exchanger 5 flows into the accumulator 7 through the tenth pipe P10, the switching valve 3, and the eleventh pipe P11 sequentially so that a refrigerant cycle for the above-described cooling operation of air conditioner may be completed.

    <Heating operation mode of air conditioner>



    [0030] Referring to the right drawing of FIG. 1, the low-temperature and low-pressure refrigerant flowing from the accumulator 7 to the compressor 2 through the twelfth pipe P12 is compressed in the compressor 2 and discharged in a high-temperature and high-pressure state. The refrigerant discharged from the compressor 2 may be introduced into the indoor heat exchanger 5 through the first pipe P1, the switching valve 3, and the tenth pipe P10 sequentially.

    [0031] As heat energy is transferred from the refrigerant to the indoor air in the indoor heat exchanger 5, the refrigerant may be condensed. At this time, the indoor heat exchanger 5 may be referred to as a condenser. In addition, according to the heat exchange between the refrigerant and the indoor air, the temperature of the indoor air may increase to heat the indoor space. The refrigerant condensed while passing through the indoor heat exchanger 5 passes through the ninth pipe P9 and may be expanded in the second expansion valve Vb up to a range corresponding to the medium pressure stage of the compressor 2. Here, the medium pressure stage of the compressor 2 can be understood as a pressure formed between the pressure (i.e. low pressure) of the refrigerant flowing into the compressor 2 and the pressure (i.e. high pressure) of the refrigerant discharged from the compressor 2. For example, the second expansion valve Vb may be an electronic expansion valve EEV capable of adjusting the opening degree of the flow path of the ninth pipe P9.

    [0032] The refrigerant expanded in the second expansion valve Vb may flow into the second gas-liquid separation pipe 11b in a two-phase state. Among two phase refrigerants flowing into the second gas-liquid separation pipe 11b, a relatively large amount of vapor refrigerant may flow into the gas-liquid separator 6 through the eighth pipe P8, and a relatively large amount of liquid refrigerant may flow into the gas-liquid separator 6 through the seventh pipe P7, which will be described in more detail later.

    [0033] The gas-liquid separator 6 may separate and discharge the two phase refrigerants introduced into the gas-liquid separator 6 into a vapor refrigerant and a liquid refrigerant. The vapor refrigerant separated in the gas-liquid separator 6 may flow into the medium pressure stage of the compressor 2 through the sixth pipe P6. In this case, the injection valve Vi may be an EEV or a solenoid valve that opens and closes the sixth pipe P6. The liquid refrigerant separated in the gas-liquid separator 6 may flow into the first gas-liquid separation pipe 11a through the fifth pipe P5. The liquid refrigerant introduced into the first gas-liquid separation pipe 11a passes through the third pipe P3 and may expand in the first expansion valve Va up to a range corresponding to the low pressure stage of the compressor 2. For example, the first expansion valve Va may be an electronic expansion valve EEV capable of adjusting the opening degree of the flow path of the third pipe P3.

    [0034] The refrigerant expanded in the first expansion valve Va may flow into the outdoor heat exchanger 4 through the third pipe P3.

    [0035] As the heat energy of outdoor air is transferred from the outdoor heat exchanger 4 to the refrigerant, the refrigerant may be evaporated. At this time, the outdoor heat exchanger 4 may be referred to as an evaporator. The refrigerant evaporated while passing through the outdoor heat exchanger 4 flows into the accumulator 7 through the second pipe P2, the switching valve 3, and the eleventh pipe P11 sequentially, so that a refrigerant cycle for the above-described heating operation of air conditioner may be completed.

    [0036] Referring to FIGS. 1 and 2, the refrigerant expanded in the first expansion valve Va is first separated into a vapor refrigerant and a liquid refrigerant in the first gas-liquid separation pipe 11a, and may be secondarily separated into a vapor refrigerant and a liquid refrigerant in the gas-liquid separator 6. The refrigerant expanded in the second expansion valve Vb is first separated into a vapor refrigerant and a liquid refrigerant in the second gas-liquid separation pipe 11b, and may be secondarily separated into a vapor refrigerant and a liquid refrigerant in the gas-liquid separator 6.

    [0037] When the outdoor heat exchanger 4 serves as a condenser (refer to the left drawing of FIG. 1), the refrigerant that has passed through the outdoor heat exchanger 4 passes through the third pipe P3 and may be expanded in the first expansion valve Va.

    [0038] In this case, the refrigerant expanded in the first expansion valve Va may flow into the first gas-liquid separation pipe 11a through an inlet of the first gas-liquid separation pipe 11a connected to the third pipe P3. Here, the third pipe P3 may be referred to as a refrigerant inflow pipe. In addition, the refrigerant passing through the first gas-liquid separation pipe 11a may be introduced into the gas-liquid separator 6 through the outlet of the first gas-liquid separation pipe 11a connected to the fourth pipe P4 and the fifth pipe P5. Here, the fourth pipe P4 and the fifth pipe P5 are installed between the first gas-liquid separation pipe 11a and the gas-liquid separator 6, and may provide a flow path of refrigerant ranging from the first gas-liquid separation pipe 11a to the gas-liquid separator 6. In this case, the fourth pipe P4 may be referred to as a first refrigerant discharge pipe, and the fifth pipe P5 may be referred to as a second refrigerant discharge pipe.

    [0039] In addition, a first check valve 10a is installed in the fourth pipe P4, so that the flow of the refrigerant passing through the fourth pipe P4 can be restricted to a direction from the outlet of the first gas-liquid separation pipe 11a toward the gas-liquid separator 6. For another example, a solenoid valve, instead of the first check valve 10a, may be installed in the fourth pipe P4.

    [0040] In addition, the gas-liquid separator 6 may separate and discharge the refrigerant introduced through the fourth pipe P4 and the fifth pipe P5 into a vapor refrigerant and a liquid refrigerant. In detail, the vapor refrigerant discharged from the gas-liquid separator 6 may be introduced into the medium pressure stage of the compressor 2 through the sixth pipe P6 opened and closed by the injection valve Vi. The liquid refrigerant discharged from the gas-liquid separator 6 may flow into the inlet of the second gas-liquid separation pipe 11b through the seventh pipe P7. Here, the seventh pipe P7 is installed between the gas-liquid separator 6 and the second gas-liquid separation pipe 11b to provide a flow path of refrigerant ranging from the gas-liquid separator 6 to the second gas-liquid separation pipe 11b. In this case, the sixth pipe P6 may be referred to as a vapor refrigerant pipe, and the seventh pipe P7 may be referred to as a liquid refrigerant pipe.

    [0041] Further, the refrigerant passing through the second gas-liquid separation pipe 11b passes through the ninth pipe P9 and may be expanded in the second expansion valve Vb. In this case, the refrigerant expanded in the second expansion valve Vb may flow into the indoor heat exchanger 5 through the ninth pipe P9.

    [0042] When the indoor heat exchanger 5 serves as a condenser (refer to the right drawing of FIG. 1), the refrigerant that has passed through the indoor heat exchanger 5 passes through the ninth pipe P9 and may be expanded in the second expansion valve Vb.

    [0043] In this case, the refrigerant expanded in the second expansion valve Vb may flow into the second gas-liquid separation pipe 11b through an inlet of the second gas-liquid separation pipe 11b connected to the ninth pipe P9. Here, the ninth pipe P9 may be referred to as a refrigerant inflow pipe. In addition, the refrigerant passing through the second gas-liquid separation pipe 11b may be introduced into the gas-liquid separator 6 through the outlet of the second gas-liquid separation pipe 11b connected to the seventh pipe P7 and the eighth pipe P8. Here, the seventh pipe P7 and the eighth pipe P8 are installed between the second gas-liquid separation pipe 11b and the gas-liquid separator 6, thereby providing a flow path for refrigerant ranging from the second gas-liquid separation pipe 11b to the gas-liquid separator 6. In this case, the eighth pipe P8 may be referred to as a first refrigerant discharge pipe, and the seventh pipe P7 may be referred to as a second refrigerant discharge pipe.

    [0044] In addition, a second check valve 10b is installed in the eighth pipe P8, so that the flow of the refrigerant passing through the eighth pipe P8 can be restricted to a direction from the outlet of the second gas-liquid separation pipe 11b toward the gas-liquid separator 6. For another example, a solenoid valve, instead of the second check valve 10b, may be installed in the fourth pipe P4.

    [0045] In addition, the gas-liquid separator 6 may separate and discharge the refrigerant introduced through the seventh pipe P7 and the eighth pipe P8 into a vapor refrigerant and a liquid refrigerant. Specifically, the vapor refrigerant discharged from the gas-liquid separator 6 may be introduced into the medium pressure stage of the compressor 2 through the sixth pipe P6 opened and closed by the injection valve Vi. The liquid refrigerant discharged from the gas-liquid separator 6 may flow into the inlet of the first gas-liquid separation pipe 11a through the fifth pipe P5. Here, the fifth pipe P5 is installed between the gas-liquid separator 6 and the first gas-liquid separation pipe 11a, thereby providing a flow path of refrigerant ranging from the gas-liquid separator 6 to the first gas-liquid separation pipe 11a. In this case, the sixth pipe P6 may be referred to as a vapor refrigerant pipe, and the fifth pipe P5 may be referred to as a liquid refrigerant pipe.

    [0046] Further, the refrigerant passing through the first gas-liquid separation pipe 11a passes through the third pipe P3 and may be expanded in the first expansion valve Va. In this case, the refrigerant expanded in the first expansion valve Va may flow into the outdoor heat exchanger 4 through the third pipe P3.

    [0047] Meanwhile, the first gas-liquid separation pipe 11a and the second gas-liquid separation pipe 11b are common in that they provide a flow path for guiding the refrigerant expanded in the first expansion valve Va or the second expansion valve Vb to the gas-liquid separator 6, and the same structure may be applied to both pipes. Hereinafter, for brief description, in the case in which the outdoor heat exchanger 4 serves as a condenser (refer to the left drawing of FIG. 1), the first gas-liquid separation pipe 11a will be mainly described. In addition, a corresponding description can be applied to the description of the second gas-liquid separation pipe 11b, in the case where the indoor heat exchanger 5 serves as a condenser (refer to the right drawing of FIG. 1).

    [0048] The first gas-liquid separation pipe 11a includes a first part 111 and a second part 112. The first part 111 may be extended long and connected to the third pipe P3. The second part 112 may be extended in a direction crossing the length direction of the first part 111 and may be coupled to the first part 111. For example, the first part 111 may be extended horizontally along a virtual first extension line L11, and the second part 112 may be extended vertically along a virtual second extension line L12 orthogonal to the first extension line L11.

    [0049] One end of the first part 111 may be connected to the third pipe P3, and the other end of the first part 111 may be connected to the fourth pipe P4. One end of the second part 112 is formed between one end and the other end of the first part 111 and formed below the first part 111, and the other end of the second part 112 may be connected to the fifth pipe P5. For example, one end of the fourth pipe P4 may be connected to the other end of the first part 111, and the other end of the fourth pipe P4 may be horizontally connected to the upper side of the gas-liquid separator 6. For example, one end of the fifth pipe P5 may be connected to the other end of the second part 112 and the other end of the fifth pipe P5 may be horizontally connected to the lower side of the gas-liquid separator 6. Meanwhile, based on the gas-liquid separator 6, the seventh pipe P7 may be symmetrical with the fifth pipe P5, and the eighth pipe P8 may be symmetrical with the fourth pipe P4.

    [0050] In this case, the flow of the liquid refrigerant among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 111 may be relatively more concentrated in the other end of the second part 112 than the other end of the first part 111. Here, it can be understood that the liquid refrigerant is relatively more influenced by gravity than the vapor refrigerant, so that the flow is concentrated in the second part 112 located below the first part 111. On the contrary, the flow of the vapor refrigerant among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 111 may be relatively more concentrated in the other end of the first part 111 than the other end of the second part 112.

    [0051] Accordingly, the first gas-liquid separation pipe 11a may discharge a relatively larger amount of vapor refrigerant, among the two phase refrigerants flowed into the first gas-liquid separation pipe 11a, to the gas-liquid separator 6 through the fourth pipe P4, and may discharge a relatively larger amount of liquid refrigerant to the gas-liquid separator 6 through the fifth pipe P5. Thus, the gas-liquid separation efficiency in the gas-liquid separator 6 is increased, and the reliability of the compressor can be obtained by preventing the liquid refrigerant from being discharged through the sixth pipe P6. In addition, it is easy to manage the level of the liquid refrigerant, so that the performance or efficiency of the air conditioner can be improved.

    [0052] Referring to FIG. 3, one end of the fourth pipe P4' may be connected to the other end of the first part 111 (see FIG. 2), and the other end of the fourth pipe P4' may be vertically connected to the upper side of the gas-liquid separator 6. In this case, the first check valve 10a may be installed in the fourth pipe P4'. One end of the fifth pipe P5' may be connected to the other end of the second part 112 (see FIG. 2), and the other end of the fifth pipe P5' may be vertically connected to the lower side of the gas-liquid separator 6.

    [0053] Meanwhile, based on the gas-liquid separator 6, the seventh pipe P7' may be symmetrical with the fifth pipe P5', and the eighth pipe P8' may be symmetrical with the fourth pipe P4'.

    [0054] Referring to FIG. 4, the first gas-liquid separation pipe 11a' may include a short tube 113, 114 in addition to the first part 111' and the second part 112'.

    [0055] One end of the first part 111' may be connected to the third pipe P3 and the other end may be connected to the short tube 113, 114. One end of the second part 112' is formed between one end and the other end of the first part 111' and formed below the first part 111', and the other end of the second part 112' may be connected to the fifth pipe P5.

    [0056] One end of the short tube 113, 114 may be disposed inside the first part 111', and the other end may be connected to the fourth pipe P4. Specifically, the short tube 113, 114 may include a first tube 113 and a second tube 114 that have different diameters. The diameter Da of the first tube 113 may be larger than the diameter Db of the second tube 114. For example, the diameter Da of the first tube 113 may be the same as the diameter of the first part 111'. One end of the second tube 114 may be disposed inside the first part 111' while forming one end of the short tube 113, 114, and may be positioned spaced apart from the inner surface of the first part 111'. The other end of the second tube 114 may be connected to one end of the first tube 113, and the other end of the first tube 113 may be connected to the fourth pipe P4 while forming the other end of the short tube 113, 114.

    [0057] For example, the first tube 113 and the second tube 114 may be integrally formed. In this case, the short tube 113, 114 may be formed in a tapered shape whose diameter decreases as it progresses from the first tube 113 to the second tube 114.

    [0058] Meanwhile, the dryness of the two phase refrigerants flowing through the third pipe P3 via the first expansion valve Va may be formed to be relatively low. For example, the dryness of the two phase refrigerants flowing into the first gas-liquid separation pipe 11a' may be 0.4 or less. In this case, the vapor refrigerant Rg among the refrigerants flowing through the third pipe P3 may exist as a bubble state in the phase of liquid refrigerant Rf. In other words, among the refrigerants flowing through the third pipe P3, the vapor refrigerant Rg may flow while being spaced apart from the inner surface of the third pipe P3.

    [0059] In this case, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 111', the vapor refrigerant can be easily introduced to one end of the second tube 114 of the short tube 113, 114. In this case, the second part 112 ' may be overlapped with the second tube 114 in the vertical direction. In addition, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 111', the liquid refrigerant can be easily introduced to the second part 112' along the inner surface of the first gas-liquid separation pipe 11a' due to fluid force.

    [0060] Accordingly, the performance of the first gas-liquid separation pipe 11a' for separating and discharging the two phase refrigerants introduced into the first gas-liquid separation pipe 11a' into a vapor refrigerant and a liquid refrigerant may be improved. Thus, the gas-liquid separation efficiency in the gas-liquid separator 6 is increased, and the reliability of the compressor can be obtained by preventing the liquid refrigerant from being discharged through the sixth pipe P6. In addition, it is easy to manage the level of the liquid refrigerant, so that the performance or efficiency of the air conditioner can be improved.

    [0061] Referring to FIG. 5, the air conditioner 1 may include a first gas-liquid separation pipe 12a and a second gas-liquid separation pipe 12b. Hereinafter, for brief description, the first gas-liquid separation pipe 12a will be mainly described, and a corresponding description may be identically applied to the second gas-liquid separation pipe 12b.

    [0062] The first gas-liquid separation pipe 12a may include a first part 121 and a second part 122. The first part 121 may extend long and may be connected to a third pipe P31 in which the first expansion valve Va is installed. Here, the third pipe P31 may be referred to as a refrigerant inflow pipe. The second part 122 may extend in a direction crossing the length direction of the first part 121 and may be coupled to the first part 121. For example, the first part 121 may extend horizontally along a virtual first extension line L21, and the second part 122 may extend vertically along a virtual second extension line L22 orthogonal to the first extension line L21.

    [0063] One end of the first part 121 may be connected to the third pipe P31, and the other end may be connected to the fifth pipe P51. One end of the second part 122 may be formed between one end and the other end of the first part 121 and is formed above the first part 121, and the other end of the second part 122 may be connected to the fourth pipe P41. Here, the fourth pipe P41 may be referred to as a first refrigerant discharge pipe, and the fifth pipe P51 may be referred to as a second refrigerant discharge pipe. For example, one end of the fourth pipe P41 may be connected to the other end of the second part 122, and the other end of the fourth pipe P41 may be vertically connected to the upper side of the gas-liquid separator 6. For example, one end of the fifth pipe P51 may be connected to the other end of the first part 121, and the other end may be horizontally connected to the lower side of the gas-liquid separator 6. Meanwhile, based on the gas-liquid separator 6, the seventh pipe P71 may be symmetrical with the fifth pipe P51, and the eighth pipe P81 may be symmetrical with the fourth pipe P41.

    [0064] In this case, the flow of the liquid refrigerant, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 121, may be relatively more concentrated in the other end of the first part 121 than the other end of the second part 122. Here, it can be understood that the liquid refrigerant is relatively influenced by gravity and inertial force than the vapor refrigerant, so that the flow is concentrated in the first part 121 located below the second part 122. On the contrary, the flow of the vapor refrigerant, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 121, may be relatively more concentrated in the other end of the second part 122 than the other end of the first part 121.

    [0065] Accordingly, the first gas-liquid separation pipe 12a may discharge a relatively larger amount of vapor refrigerant, among the two phase refrigerants flowed into the first gas-liquid separation pipe 12a, to the gas-liquid separator 6 through the fourth pipe P4, and may discharge a relatively larger amount of liquid refrigerant to the gas-liquid separator 6 through the fifth pipe P51. Thus, the gas-liquid separation efficiency in the gas-liquid separator 6 is increased, and the reliability of the compressor can be obtained by preventing the liquid refrigerant from being discharged through the sixth pipe P6. In addition, it is easy to manage the level of the liquid refrigerant, so that the performance or efficiency of the air conditioner can be improved.

    [0066] Referring to FIG. 6, the air conditioner 1 may include a first gas-liquid separation pipe 13a and a second gas-liquid separation pipe 13b. Hereinafter, for brief description, the first gas-liquid separation pipe 13a will be mainly described, and a corresponding description may be identically applied to the second gas-liquid separation pipe 13b.

    [0067] The first gas-liquid separation pipe 13a may include a first part 131 and a second part 132. The first part 131 may be extended and connected to a third pipe P32 in which the first expansion valve Va is installed. Here, the third pipe P32 may be referred to as a refrigerant inflow pipe. The second part 132 may extend in a direction crossing the length direction of the first part 131 and may be coupled to the first part 131. For example, the first part 131 may extend vertically along a virtual first extension line L31, and the second part 132 may extend horizontally along a virtual second extension line L32 orthogonal to the first extension line L31.

    [0068] One end of the first part 131 may be connected to the third pipe P32, and the other end may be connected to the fourth pipe P42 in which the first check valve 10a is installed. One end of the second part 132 may be formed between one end and the other end of the first part 131 and formed in the right side of the first part 131, and the other end of the second part 132 may be connected to the fifth pipe P52. Here, the fourth pipe P42 may be referred to as a first refrigerant discharge pipe, and the fifth pipe P52 may be referred to as a second refrigerant discharge pipe. For example, one end of the fourth pipe P42 may be connected to the other end of the first part 131, and the other end of the fourth pipe P42 may be connected vertically to the upper portion of the gas-liquid separator 6. For example, one end of the fifth pipe P52 may be connected to the other end of the second part 132, and the other end may be vertically connected to the lower portion of the gas-liquid separator 6. Meanwhile, based on the gas-liquid separator 6, the seventh pipe P72 may be symmetrical with a fifth pipe P52, and the eighth pipe P82 may be symmetrical with a fourth pipe P42.

    [0069] Meanwhile, the first gas-liquid separation pipe 13a may include a short tube 113', 114' in addition to the first part 131 and the second part 132.

    [0070] One end of the short tube 113', 114' may be disposed inside the first part 131, and the other end may be connected to a fourth pipe P42. Specifically, the short tube 113', 114' may include a first tube 113' and a second tube 114' that have different diameters. The diameter Da' of the first tube 113' may be larger than the diameter Db' of the second tube 114'. For example, the diameter Da' of the first tube 113' may be the same as the diameter of the first part 131. One end of the second tube 114' is disposed inside the first part 131 while forming one end of the short tube 113', 114', and may be positioned spaced apart from the inner surface of the first part 131. The other end of the second tube 114' is connected to one end of the first tube 113', and the other end of the first tube 113' may be connected to the fourth pipe P42 while forming the other end of the short tube 113', 114'.

    [0071] For example, the first tube 113' and the second tube 114' may be integrally formed. In this case, the short tube 113', 114' may have a tapered shape whose diameter decreases as it progresses from the first tube 113' to the second tube 114'.

    [0072] Meanwhile, the dryness of the two phase refrigerants flowing through the third pipe P32 via the first expansion valve Va may be formed to be relatively low. For example, the dryness of the two phase refrigerants flowing into the first gas-liquid separation pipe 13a may be 0.4 or less. In this case, the vapor refrigerant Rg among the refrigerants flowing through the third pipe P32 may exist as a bubble state in the phase of liquid refrigerant Rf. In other words, among the refrigerants flowing through the third pipe P32, the vapor refrigerant Rg may flow while being spaced apart from the inner surface of the third pipe P32.

    [0073] In this case, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 131, the vapor refrigerant can be easily introduced to one end of the second tube 114' of the short tube 113', 114'. In addition, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 131, the liquid refrigerant can be easily introduced to the second part 132 along the inner surface of the first gas-liquid separation pipe 13a due to fluid force.

    [0074] Accordingly, the performance of the first gas-liquid separation pipe 13a for separating and discharging the two phase refrigerants introduced into the first gas-liquid separation pipe 13a into a vapor refrigerant and a liquid refrigerant may be improved. Thus, the gas-liquid separation efficiency in the gas-liquid separator 6 is increased, and the reliability of the compressor can be obtained by preventing the liquid refrigerant from being discharged through the sixth pipe P6. In addition, it is easy to manage the level of the liquid refrigerant, so that the performance or efficiency of the air conditioner can be improved.

    [0075] Referring to FIG. 7, the air conditioner 1 may include a first gas-liquid separation pipe 14a and a second gas-liquid separation pipe 14b. Hereinafter, for brief description, the first gas-liquid separation pipe 14a will be mainly described, and a corresponding description may be identically applied to the second gas-liquid separation pipe 14b.

    [0076] The first gas-liquid separation pipe 14a may include a first part 141 and a second part 142, 143. The first part 141 may extend long and may be connected to a third pipe P33 in which the first expansion valve Va is installed. Here, the third pipe P33 may be referred to as a refrigerant inflow pipe. The second part 142, 143 may extend in a direction crossing the length direction of the first part 141 and may be coupled to the first part 141. For example, the first part 141 may extend horizontally along a virtual first extension line L41, and the second part 142, 143 may extend vertically along a virtual second extension line L42 or L43 orthogonal to the first extension line L41.

    [0077] One end of the first part 141 may be connected to the third pipe P33, and the other end may be connected to the second part 142, 143. One end of the second part 142, 143 may be connected to the fourth pipe P43 in which the first check valve 10a is installed, and the other end of the second part 142, 143 may be connected to a fifth pipe P53. Here, the fourth pipe P43 may be referred to as a first refrigerant discharge pipe, and the fifth pipe P51 may be referred to as a second refrigerant discharge pipe. That is, the other end of the first part 141 may be formed between one end and the other end of the second part 142, 143 and may be connected to the left side of the second part 142, 143. In this case, the second parts 142 and 143 may include a second-first part 142 which is positioned above the first part 141 while forming one end of the second part, and a second-second part 143 which is positioned below the first part 141 while forming the other end of the second part.

    [0078] For example, one end of the fourth pipe P43 may be connected to the second-first part 142, and the other end of the fourth pipe P43 may be vertically connected to the upper side of the gas-liquid separator 6. For example, one end of the fifth pipe P53 may be connected to the second-second part 143 and the other end of the fifth pipe P53 may be horizontally connected to the lower side of the gas-liquid separator 6. Meanwhile, based on the gas-liquid separator 6, the seventh pipe P73 may be symmetrical with the fifth pipe P53, and the eighth pipe P83 may be symmetrical with the fourth pipe P43.

    [0079] In this case, the flow of the liquid refrigerant, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 141, may be relatively more concentrated in the second-second part 143 than the second-first part 142. Here, it can be understood that the liquid refrigerant is more influenced by gravity than the vapor refrigerant, so that the flow is concentrated in the second-second part 143 located below the second-first part 142. On the contrary, the flow of the vapor refrigerant, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 141, may be relatively more concentrated in the second-first part 142 than the second-second part 143.

    [0080] Accordingly, the first gas-liquid separation pipe 14a may discharge a relatively larger amount of vapor refrigerant, among the two phase refrigerants flowed into the first gas-liquid separation pipe 14a, to the gas-liquid separator 6 through the fourth pipe P43, and may discharge a relatively larger amount of liquid refrigerant to the gas-liquid separator 6 through the fifth pipe P53. Thus, the gas-liquid separation efficiency in the gas-liquid separator 6 is increased, and the reliability of the compressor can be obtained by preventing the liquid refrigerant from being discharged through the sixth pipe P6. In addition, it is easy to manage the level of the liquid refrigerant, so that the performance or efficiency of the air conditioner can be improved.

    [0081] Referring to FIG. 8, the air conditioner 1 may include a first gas-liquid separation pipe 15a and a second gas-liquid separation pipe 15b. Hereinafter, for brief description, the first gas-liquid separation pipe 15a will be mainly described, and a corresponding description may be identically applied to the second gas-liquid separation pipe 15b.

    [0082] The first gas-liquid separation pipe 15a may include a first part 151 and a second part 152, 153. The first part 131 may be extended and connected to a third pipe P34 in which the first expansion valve Va is installed. Here, the third pipe P34 may be referred to as a refrigerant inflow pipe. The second part 152, 153 may extend in a direction crossing the length direction of the first part 151 and may be coupled to the first part 151. For example, the first part 151 may extend obliquely in the vertical direction along a virtual first extension line L51, and the second part 152, 153 may extend vertically along a virtual second extension line L52 or L53 crossing the first extension line L51.

    [0083] One end of the first part 151 may be connected to the third pipe P34 and the other end may be connected to the second part 152, 153. One end of the second part 152, 153 may be connected to the fourth pipe P44 in which the first check valve 10a is installed, and the other end of the second part 152, 153 may be connected to the fifth pipe P54. Here, the fourth pipe P44 may be referred to as a first refrigerant discharge pipe, and the fifth pipe P54 may be referred to as a second refrigerant discharge pipe. That is, the other end of the first part 151 is formed between one end and the other end of the second part 152, 153 and may be connected to the left side of the second part 152, 153. In this case, the second part 152, 153 may include a second-first part 152 which forms an acute angle with the first part 151 while forming one end of the second part, and a second-second part 153 which forms an obtuse angle with the first part 151 while forming the other end of the second part. In other words, the second-first part 152 may extend upwardly along the second-first extension line L52 forming an acute angle (theta s) with the first extension line L51, and the second-second part 153 may extend downwardly along the second-second extension line L53 forming an obtuse angle (theta 1) with the first extension line L51.

    [0084] For example, one end of the fourth pipe P44 may be connected to the second-first part 152 and the other end of the fourth pipe P44 may be vertically connected to the upper side of the gas-liquid separator 6. For example, one end of the fifth pipe P54 may be connected to the second-second part 153, and the other end of the fifth pipe P54 may be horizontally connected to the lower side of the gas-liquid separator 6. Meanwhile, based on the gas-liquid separator 6, the seventh pipe P74 may be symmetrical with the fifth pipe P54, and the eighth pipe P84 may be symmetrical with the fourth pipe P44.

    [0085] In this case, the flow of the liquid refrigerant, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 151, may be relatively more concentrated in the second-second part 153 than the second-first part 152. Here, it can be understood that the liquid refrigerant is more influenced by gravity and inertial force than the vapor refrigerant, so that the flow is concentrated in the second-second part 153 located below the second-first part 152. On the contrary, the flow of the vapor refrigerant, among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 151, may be relatively more concentrated in the second-first part 152 than the second-second part 153.

    [0086] Accordingly, the first gas-liquid separation pipe 15a may discharge a relatively larger amount of vapor refrigerant, among the two phase refrigerants flowed into the first gas-liquid separation pipe 15a, to the gas-liquid separator 6 through the fourth pipe P44, and may discharge a relatively larger amount of liquid refrigerant to the gas-liquid separator 6 through the fifth pipe P54. Thus, the gas-liquid separation efficiency in the gas-liquid separator 6 is increased, and the reliability of the compressor can be obtained by preventing the liquid refrigerant from being discharged through the sixth pipe P6. In addition, it is easy to manage the level of the liquid refrigerant, so that the performance or efficiency of the air conditioner can be improved.

    [0087] Referring to FIG. 9, the air conditioner 1 may include a first gas-liquid separation pipe 16a and a second gas-liquid separation pipe 16b. Hereinafter, for brief description, the first gas-liquid separation pipe 16a will be mainly described, and a corresponding description may be identically applied to the second gas-liquid separation pipe 16b.

    [0088] The first gas-liquid separation pipe 16a may include a first part 161 and a second part 162, 163. The first part 161 has a straight section and a curved section, and may be connected to a third pipe P35 in which the first expansion valve Va is installed. Here, the third pipe P35 may be referred to as a refrigerant inflow pipe. The second part 162, 163 may be coupled to the first part 151. For example, the first part 161 may include a first-first part 161-1, a first-second part 161-2, and a first-third part 161-3. In this case, the first-first part 161-1 may extend vertically along a virtual first-first extension line L61-1. In addition, the first-second part 161-2 is connected to the first-first part 161-1, and may be formed to be curved along a virtual first-second line L61-2 having a constant radius of curvature R based on the center point C. In addition, the first-third part 161-3 is connected to the first-second part 161-2, and may extend horizontally along a virtual first-third extension line L61-3. For example, the second part 162, 163 may extend vertically along a virtual second extension line L62 or L63 orthogonal to the third extension line L61-3.

    [0089] One end of the first part 161 may be connected to the third pipe P35, and the other end may be connected to the second part 162, 163. One end of the second part 162, 163 may be connected to the fourth pipe P45 in which the first check valve 10a is installed, and the other end of the second part 162, 163 may be connected to the fifth pipe P55. Here, the fourth pipe P45 may be referred to as a first refrigerant discharge pipe, and the fifth pipe P55 may be referred to as a second refrigerant discharge pipe. That is, the other end of the first part 161 is formed between one end and the other end of the second part 162, 163, and may be connected to the left side of the second part 162, 163. In this case, the second part 162, 163 may include a second-first part 162 which is positioned above the first-third part 161-3 while forming one end of the second part, and a second-second part 163 which is positioned below the first-third part 161-3 while forming the other end of the second part.

    [0090] For example, one end of the fourth pipe P45 may be connected to the second-first part 162 and the other end may be vertically connected to the upper side of the gas-liquid separator 6. For example, one end of the fifth pipe P55 may be connected to the second-second part 163, and the other end may be horizontally connected to the lower side of the gas-liquid separator 6. Meanwhile, based on the gas-liquid separator 6, the seventh pipe P75 may be symmetrical with the fifth pipe P55, and the eighth pipe P85 may be symmetrical with the fourth pipe P45.

    [0091] In this case, the flow of the liquid refrigerant among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 161 may be relatively more concentrated in the second-second part 163 than the second-first part 162. Here, it can be understood that the liquid refrigerant is more influenced by gravity and centrifugal force than the vapor refrigerant, so that the flow is concentrated in the second-second part 163 located below the second-first part 162. On the contrary, the flow of the vapor refrigerant among the two phase refrigerants that are expanded in the first expansion valve Va and flowed into one end of the first part 161 may be relatively more concentrated in the second-first part 162 than the second-second part 163.

    [0092] Accordingly, the first gas-liquid separation pipe 16a may discharge a relatively larger amount of vapor refrigerant, among the two phase refrigerants flowed into the first gas-liquid separation pipe 16a, to the gas-liquid separator 6 through the fourth pipe P45, and may discharge a relatively larger amount of liquid refrigerant to the gas-liquid separator 6 through the fifth pipe P55. Thus, the gas-liquid separation efficiency in the gas-liquid separator 6 is increased, and the reliability of the compressor can be obtained by preventing the liquid refrigerant from being discharged through the sixth pipe P6. In addition, it is easy to manage the level of the liquid refrigerant, so that the performance or efficiency of the air conditioner can be improved.

    [0093] Referring to FIG. 10, unlike the explanation described with reference to FIG. 1 and the like, the air conditioner 1 may perform only one of a cooling operation and a heating operation. In this case, the air conditioner 1 may not be provided with the switching valve 3.

    [0094] For example, the air conditioner 1 may perform only a cooling operation. In this case, the low-temperature and low-pressure refrigerant flowing from the accumulator 7 to the compressor 2 through the twelfth pipe P12 may be compressed in the compressor 2 and discharged in a high-temperature and high-pressure state. The refrigerant discharged from the compressor 2 may flow into the outdoor heat exchanger 4 through the first pipe P1. Here, the outdoor heat exchanger 4 may serve as a condenser.

    [0095] The refrigerant condensed while passing through the outdoor heat exchanger 4 may pass through the third pipe P3 and may be expanded in the first expansion valve Va up to a range corresponding to the medium pressure stage of the compressor 2. The refrigerant expanded in the first expansion valve Va may flow into the gas-liquid separator 6 through the first gas-liquid separation pipe 11a, the fourth pipe P4, and the fifth pipe P5.

    [0096] The gas-liquid separator 6 may separate and discharge the refrigerant introduced into the gas-liquid separator 6 into a vapor refrigerant and a liquid refrigerant. The vapor refrigerant separated by the gas-liquid separator 6 may be introduced into the medium pressure stage of the compressor 2 through the sixth pipe P6 in which the injection valve Vi is installed. The liquid refrigerant separated in the gas-liquid separator 6 may pass through the seventh pipe P7 and may be expanded in the second expansion valve Vb up to a range corresponding to the low pressure stage of the compressor 2.

    [0097] The refrigerant expanded in the second expansion valve Vb may flow into the indoor heat exchanger 5 through the seventh pipe P7. Here, the indoor heat exchanger 5 may serve as an evaporator.

    [0098] The refrigerant which is evaporated while passing through the indoor heat exchanger 5 is introduced into the accumulator 7 through the tenth pipe P10, so that a refrigerant cycle for the above-described cooling operation of the air conditioner may be completed.

    [0099] Referring to FIG. 11, unlike the explanation described with reference to FIG. 1 and the like, the vapor refrigerant separated in the gas-liquid separator 6 may flow into the low pressure stage of the compressor 2 through the sixth pipe P6'.

    [0100] Referring to the left drawing of FIG. 11, for example, the air conditioner 1 may perform a cooling operation. In this case, the outdoor heat exchanger 4 may serve as a condenser, and the indoor heat exchanger 5 may serve as an evaporator.

    [0101] The refrigerant which is condensed while passing through the outdoor heat exchanger 4 may pass through the third pipe P3 and may be expanded in the first expansion valve Va up to a range corresponding to the low pressure stage of the compressor 2. The refrigerant expanded in the first expansion valve Va may flow into the gas-liquid separator 6 through the first gas-liquid separation pipe 11a, the fourth pipe P4, and the fifth pipe P5.

    [0102] The gas-liquid separator 6 may separate and discharge the refrigerant introduced into the gas-liquid separator 6 into a vapor refrigerant and a liquid refrigerant. The vapor refrigerant separated in the gas-liquid separator 6 may be introduced into the low pressure stage of the compressor 2 through the sixth pipe P6' in which the injection valve Vi is installed. Here, one end of the sixth pipe P6' may be connected to the gas-liquid separator 6, and the other end may be connected to the twelfth pipe P12. The liquid refrigerant separated in the gas-liquid separator 6 may flow into the ninth pipe P9 through the seventh pipe P7 and the second gas-liquid separation pipe 11b.

    [0103] The second expansion valve Vb opens the ninth pipe P9, and the refrigerant may flow into the indoor heat exchanger 5 through the ninth pipe P9.

    [0104] The refrigerant which is evaporated while passing through the indoor heat exchanger 5 may pass through the tenth pipe P10, the switching valve 3, and the eleventh pipe P11 sequentially and may flow into the accumulator 7, so that a refrigerant cycle for the above-described cooling operation of air conditioner can be completed.

    [0105] Referring to the right drawing of FIG. 11, for example, the air conditioner 1 may perform a heating operation. In this case, the indoor heat exchanger 5 may serve as a condenser, and the outdoor heat exchanger 4 may serve as an evaporator.

    [0106] The refrigerant which is condensed while passing through the indoor heat exchanger 5 may pass through the ninth pipe P9 and may be expanded in the second expansion valve Vb up to a range corresponding to the low pressure stage of the compressor 2. The refrigerant expanded in the second expansion valve Vb may flow into the gas-liquid separator 6 through the second gas-liquid separation pipe 11b, the seventh pipe P7, and the eighth pipe P8.

    [0107] The gas-liquid separator 6 may separate and discharge the refrigerant introduced into the gas-liquid separator 6 into a vapor refrigerant and a liquid refrigerant. The vapor refrigerant separated in the gas-liquid separator 6 may be introduced into the low pressure stage of the compressor 2 through the sixth pipe P6' in which the injection valve Vi is installed. The liquid refrigerant separated in the gas-liquid separator 6 may flow into the third pipe P3 through the fifth pipe P5 and the first gas-liquid separation pipe 11a.

    [0108] The first expansion valve Va opens the third pipe P3, and the refrigerant may flow into the outdoor heat exchanger 4 through the third pipe P3.

    [0109] The refrigerant which is evaporated while passing through the outdoor heat exchanger 4 may pass through the second pipe P2, the switching valve 3, and the eleventh pipe P11 sequentially to flow into the accumulator 7, so that a refrigerant cycle for the above-described heating operation of air conditioner can be completed.

    [0110] Referring to FIG. 12, unlike the explanation described with reference to FIG. 11, the air conditioner 1 may perform only one of a cooling operation and a heating operation. In this case, the air conditioner 1 may not be provided with the switching valve 3.

    [0111] For example, the air conditioner 1 may perform only a cooling operation. In this case, the low-temperature and low-pressure refrigerant flowing from the accumulator 7 to the compressor 2 through the twelfth pipe P12 may be compressed in the compressor 2 and discharged in a high-temperature and high-pressure state. The refrigerant discharged from the compressor 2 may flow into the outdoor heat exchanger 4 through the first pipe P1. Here, the outdoor heat exchanger 4 may serve as a condenser.

    [0112] The refrigerant which is condensed while passing through the outdoor heat exchanger 4 may pass through the third pipe P3 and may be expanded in the first expansion valve Va up to a range corresponding to the low pressure stage of the compressor 2. The refrigerant expanded in the first expansion valve Va may flow into the gas-liquid separator 6 through the first gas-liquid separation pipe 11a, the fourth pipe P4, and the fifth pipe P5.

    [0113] The gas-liquid separator 6 may separate and discharge the refrigerant introduced into the gas-liquid separator 6 into a vapor refrigerant and a liquid refrigerant. The vapor refrigerant separated in the gas-liquid separator 6 may be introduced into the low pressure stage of the compressor 2 through the sixth pipe P6' in which the injection valve Vi is installed. The liquid refrigerant separated in the gas-liquid separator 6 may flow into the indoor heat exchanger 5 through the seventh pipe P7 opened by the second expansion valve Vb. Here, the indoor heat exchanger 5 may serve as an evaporator.

    [0114] The refrigerant which is evaporated while passing through the indoor heat exchanger 5 is introduced into the accumulator 7 through the tenth pipe P10, so that a refrigerant cycle for the above-described cooling operation of air conditioner may be completed.

    [0115] According to an aspect of the present disclosure, provided is an air conditioner including: a compressor which compresses a refrigerant; a condenser which condenses the refrigerant discharged from the compressor; an expansion valve which expands the refrigerant passed through the condenser; a gas-liquid separation pipe through which the refrigerant passed through the expansion valve flows; a gas-liquid separator, through which the refrigerant passed through the gas-liquid separation pipe is introduced, that separates and discharges the refrigerant introduced into the gas-liquid separator into a vapor refrigerant and a liquid refrigerant; and an evaporator which evaporates the liquid refrigerant discharged from the gas-liquid separator, wherein the vapor refrigerant discharged from the gas-liquid separator and the refrigerant passed through the evaporator are provided to the compressor, and the gas-liquid separation pipe comprises: a first part which extends long, and is connected to a refrigerant inflow pipe in which the expansion valve is installed; and a second part which extends in a direction crossing a length direction of the first part and is coupled to the first part, wherein at least one of the first part and the second part is connected to the gas-liquid separator.

    [0116] According to another aspect of the present disclosure, one end of the first part is connected to the refrigerant inflow pipe, and one end of the second part is coupled to a lower side of the first part between one end and the other end of the first part.

    [0117] According to another aspect of the present disclosure, the air conditioner further includes: a first refrigerant discharge pipe which is installed between the other end of the first part and the gas-liquid separator; and a second refrigerant discharge pipe which is installed between the other end of the second part and the gas-liquid separator, wherein the first part extends in a horizontal direction, and the second part extends in a vertical direction.

    [0118] According to another aspect of the present disclosure, the air conditioner further includes a short tube having one end disposed inside the first part and the other end connected to the first refrigerant discharge pipe, wherein the short tube includes a first tube which forms the other end of the short tube and has a first diameter; and a second tube which forms one end of the short tube and has a second diameter smaller than the first diameter.

    [0119] According to another aspect of the present disclosure, the second tube is located spaced apart from an inner surface of the first part, and the second part overlaps the second tube in a vertical direction.

    [0120] According to another aspect of the present disclosure, one end of the first part is connected to the refrigerant inflow pipe, and one end of the second part is coupled to an upper side of the first part between one end and the other end of the first part.

    [0121] According to another aspect of the present disclosure, the air conditioner further includes a first refrigerant discharge pipe which is installed between the other end of the second part and the gas-liquid separator; and a second refrigerant discharge pipe which is installed between the other end of the first part and the gas-liquid separator, wherein the first part extends in a horizontal direction, and the second part extends in a vertical direction.

    [0122] According to another aspect of the present disclosure, one end of the first part is connected to the refrigerant inflow pipe, and one end of the second part is coupled to one side of the first part between one end and the other end of the first part.

    [0123] According to another aspect of the present disclosure, the air conditioner further includes a first refrigerant discharge pipe which is installed between the other end of the first part and the gas-liquid separator; a second refrigerant discharge pipe which is installed between the other end of the second part and the gas-liquid separator; and a short tube having one end disposed inside the first part and the other end connected to the first refrigerant discharge pipe, wherein the first part extends in a vertical direction, and the second part extends in a horizontal direction, wherein the short tube includes a first tube which forms the other end of the short tube and has a first diameter; and a second tube which forms one end of the short tube and has a second diameter smaller than the first diameter.

    [0124] According to another aspect of the present disclosure, one end of the first part is connected to the refrigerant inflow pipe, and the other end of the first part is coupled to one side of the second part between one end and the other end of the second part.

    [0125] According to another aspect of the present disclosure, the air conditioner further includes a first refrigerant discharge pipe installed between one end of the second part and the gas-liquid separator; and a second refrigerant discharge pipe installed between the other end of the second part and the gas-liquid separator, wherein the first part extends in a horizontal direction, the second part extends in a vertical direction, and one end of the second part is located above the other end of the second part.

    [0126] According to another aspect of the present disclosure, the air conditioner further includes a first refrigerant discharge pipe which is installed between one end of the second part and the gas-liquid separator; and a second refrigerant discharge pipe which is installed between the other end of the second part and the gas-liquid separator, wherein the first part extends in a direction of being inclined in a vertical direction, the second part extends in a vertical direction, and one end of the second part is located above the other end of the second part.

    [0127] According to another aspect of the present disclosure, the air conditioner further includes a first refrigerant discharge pipe which is installed between one end of the second part and the gas-liquid separator; and a second refrigerant discharge pipe which is installed between the other end of the second part and the gas-liquid separator, wherein the first part further includes: a first-first part which forms one end of the first part, and extends in a vertical direction; a first-second part which is connected to the first-first part, and has a constant curvature; and a first-third part which is connected to the first-second part, forms the other end of the first part, and extends in a horizontal direction, wherein the second part extends in the vertical direction, and one end of the second part is located above the other end of the second part.

    [0128] According to another aspect of the present disclosure, the expansion valve further includes a first expansion valve which is installed between the condenser and the gas-liquid separator; and a second expansion valve installed between the evaporator and the gas-liquid separator, wherein the gas-liquid separation pipe further includes a first gas-liquid separation pipe installed between the first expansion valve and the gas-liquid separator; and a second gas-liquid separation pipe installed between the second expansion valve and the gas-liquid separator.

    [0129] According to another aspect of the present disclosure, the air conditioner further includes a liquid refrigerant pipe, which is installed between the gas-liquid separator and the evaporator, through which the liquid refrigerant separated in the gas-liquid separator flows; a vapor refrigerant pipe, which is installed between the gas-liquid separator and the compressor, through which the vapor refrigerant separated in the gas-liquid separator flows; and an injection valve installed in the vapor refrigerant pipe.

    [0130] The effect of the air conditioner according to the present disclosure will be described as follows.

    [0131] According to at least one embodiment of the present disclosure, it is possible to provide an air conditioner capable of increasing a separation rate of a vapor refrigerant and a liquid refrigerant by providing a gas-liquid separation pipe in the front end of a gas-liquid separator.

    [0132] According to at least one embodiment of the present disclosure, it is possible to provide an air conditioner capable of securing the reliability of a compressor by preventing the liquid refrigerant from being discharged into a gas-liquid refrigerant pipe of a gas-liquid separator.

    [0133] According to at least one embodiment of the present disclosure, it is possible to provide various embodiments of a structure of gas-liquid separation pipe.


    Claims

    1. An air conditioner comprising:

    a compressor (2) which compresses a refrigerant;

    a condenser (4, 5) which condenses the refrigerant discharged from the compressor (2);

    an expansion valve (Va, Vb) which expands the refrigerant passed through the condenser (4, 5);

    a gas-liquid separation pipe (11a, 11b) through which the refrigerant passed through the expansion valve flows;

    a gas-liquid separator (6), through which the refrigerant passed through the gas-liquid separation pipe (11a, 11b) is introduced, that separates and discharges the refrigerant introduced into the gas-liquid separator (6) into a vapor refrigerant and a liquid refrigerant; and

    an evaporator (5, 4) which evaporates the liquid refrigerant discharged from the gas-liquid separator (6),

    wherein the vapor refrigerant discharged from the gas-liquid separator (6) and the refrigerant passed through the evaporator (5, 4) are provided to the compressor (2), and

    the gas-liquid separation pipe (11a) comprises:

    a first part (111, 121, 131, 141, 151, 161) which extends long, and is connected to a refrigerant inflow pipe (P3) in which the expansion valve (Va) is installed; and

    a second part (112, 122, 132, 142, 152, 162) which extends in a direction crossing a length direction of the first part (111, 121, 131, 141, 151, 161) and is coupled to the first part (111, 121, 131, 141, 151, 161),

    wherein at least one of the first part (111, 121, 131, 141, 151, 161) and the second part (112, 122, 132, 142, 152, 162) is connected to the gas-liquid separator (6).


     
    2. The air conditioner of claim 1, wherein one end of the first part (111) is connected to the refrigerant inflow pipe (P3), and
    one end of the second part (112) is coupled to a lower side of the first part (111) between one end and the other end of the first part (111).
     
    3. The air conditioner of claim 2, further comprising:

    a first refrigerant discharge pipe (P4) which is disposed between the other end of the first part (111) and the gas-liquid separator (6); and

    a second refrigerant discharge pipe (P5) which is disposed between the other end of the second part (112) and the gas-liquid separator (6),

    wherein the first part (111) extends in a horizontal direction, and

    the second part (112) extends in a vertical direction.


     
    4. The air conditioner of claim 3, further comprising a short tube (113, 114) having one end disposed inside the first part (111) and the other end connected to the first refrigerant discharge pipe (P4),
    wherein the short tube (113, 114) comprises:

    a first tube (113) which forms the other end of the short tube and has a first diameter (Da); and

    a second tube (114) which forms one end of the short tube and has a second diameter (Db) smaller than the first diameter (Da).


     
    5. The air conditioner of claim 4, wherein the second tube (113) is located spaced apart from an inner surface of the first part (111), and
    the second part (112) overlaps the second tube (114) in a vertical direction.
     
    6. The air conditioner of claim 1, wherein one end of the first part (121) is connected to the refrigerant inflow pipe, and
    one end of the second part (122) is coupled to an upper side of the first part (121) between one end and the other end of the first part (121).
     
    7. The air conditioner of claim 6, further comprising:

    a first refrigerant discharge pipe (P41) which is installed between the other end of the second part (122) and the gas-liquid separator (6); and

    a second refrigerant discharge pipe (P51) which is installed between the other end of the first part (121) and the gas-liquid separator (6),

    wherein the first part (121) extends in a horizontal direction, and

    the second part (122) extends in a vertical direction.


     
    8. The air conditioner of claim 1, wherein one end of the first part (131) is connected to the refrigerant inflow pipe (P32), and
    one end of the second part (132) is coupled to one side of the first part (131) between one end and the other end of the first part (131).
     
    9. The air conditioner of claim 8, further comprising:

    a first refrigerant discharge pipe (P42) which is installed between the other end of the first part (131) and the gas-liquid separator (6);

    a second refrigerant discharge pipe (P52) which is installed between the other end of the second part (132) and the gas-liquid separator (6); and

    a short tube (113', 114') having one end disposed inside the first part (131) and the other end connected to the first refrigerant discharge pipe (P42),

    wherein the first part (131) extends in a vertical direction, and

    the second part (132) extends in a horizontal direction,

    wherein the short tube (113', 114') comprises:

    a first tube (113') which forms the other end of the short tube and has a first diameter (Da'); and

    a second tube (114') which forms one end of the short tube and has a second diameter (Db') smaller than the first diameter (Da').


     
    10. The air conditioner of claim 1, wherein one end of the first part (141, 151, 161) is connected to the refrigerant inflow pipe (P33, P34, P35), and
    the other end of the first part (141, 151, 161) is coupled to one side of the second part (142, 143, 152, 153, 162, 163) between one end and the other end of the second part (142, 143, 152, 153, 162, 163).
     
    11. The air conditioner of claim 10, further comprising:

    a first refrigerant discharge pipe (P43, P44, P45) installed between one end of the second part (142, 152, 162) and the gas-liquid separator (6); and

    a second refrigerant discharge pipe (P53, P54, P55) installed between the other end of the second part (143, 153, 63) and the gas-liquid separator (6),

    wherein the first part (141, 151, 161) extends in a horizontal direction,

    the second part (142, 143, 152, 153, 162) extends in a vertical direction, and

    one end of the second part (142, 152, 162) is located above the other end of the second part (143, 153, 163).


     
    12. The air conditioner of claim 10, or 11, further comprising:

    a first refrigerant discharge pipe (P44) which is installed between one end of the second part (152, 153) and the gas-liquid separator (6); and

    a second refrigerant discharge pipe (P54) which is installed between the other end of the second part (152, 153) and the gas-liquid separator (6),

    wherein the first part (151) extends in a direction of being inclined in a vertical direction,

    the second part (152, 153) extends in a vertical direction, and

    one end of the second part (152) is located above the other end of the second part (153).


     
    13. The air conditioner of claim 10, or 11, further comprising:

    a first refrigerant discharge pipe (P45) which is disposed between one end of the second part (162, 163) and the gas-liquid separator (6); and

    a second refrigerant discharge pipe (P55) which is disposed between the other end of the second part (162, 163) and the gas-liquid separator (6),

    wherein the first part (161) further comprises:

    a first-first part (161-1) which forms one end of the first part (161), and extends in a vertical direction;

    a first-second part (161-2) which is connected to the first-first part (161-1), and has a constant curvature; and

    a first-third part (161-3) which is connected to the first-second part (161-2), forms the other end of the first part (161), and extends in a horizontal direction,

    wherein the second part (162, 163) extends in the vertical direction, and

    one end of the second part (162, 163) is located above the other end of the second part (162, 163).


     
    14. The air conditioner of any one of claims 1 to 13, wherein the expansion valve further comprises:

    a first expansion valve (Va) which is disposed between the condenser (4) and the gas-liquid separator (6); and

    a second expansion valve (Vb) disposed between the evaporator (5) and the gas-liquid separator (6),

    wherein the gas-liquid separation pipe further comprises:

    a first gas-liquid separation pipe (11a) disposed between the first expansion valve (Va) and the gas-liquid separator (6); and

    a second gas-liquid separation pipe (11b) disposed between the second expansion valve (Vb) and the gas-liquid separator (6).


     
    15. The air conditioner of any one of claims 1 to 14, further comprising:

    a liquid refrigerant pipe, which is disposed between the gas-liquid separator (6) and the evaporator (5), through which the liquid refrigerant separated in the gas-liquid separator (6) flows;

    a vapor refrigerant pipe (P6, P6'), which is disposed between the gas-liquid separator (6) and the compressor (2), through which the vapor refrigerant separated in the gas-liquid separator (6) flows; and

    an injection valve (Vi) disposed in the vapor refrigerant pipe (P6, P6').


     




    Drawing








































    Search report









    Search report




    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description