JP2018009707A - Refrigerant flow passage switching unit and air conditioner with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerant flow passage switching unit that enables a stable operation by preventing a refrigerant from stagnating and also prevents water from leaking by attaining secure heat insulation.SOLUTION: A refrigerant flow passage switching unit comprises: a high-pressure header 15 and a gas pipe 11a connecting with a discharge side of a compressor installed in an outdoor unit 2; a high-pressure valve 9 opened and closed to control circulation of a refrigerant circulating in the high-pressure header 15 and gas pipe 11a; a low-pressure header 6 and a gas pipe 11b branching off from the gas pipe 11a and connecting with a suction side of the compressor installed in the outdoor unit 3; a low-pressure valve 10 opened and closed to control circulation of the refrigerant circulating in the low-pressure header 6 and gas pipe 11b, and provided at the same position with the high-pressure value 9 in a height direction; and a gas pipe 11c further branching off from said branch to connect with a heat exchanger installed in an indoor unit 3, and having a part extending downward toward the heat exchanger.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a refrigerant flow switching unit and an air conditioner including the refrigerant flow switching unit, and in particular, a refrigerant flow switching unit capable of suppressing a height dimension and suppressing refrigerant from being accumulated therein and an air conditioner including the refrigerant flow switching unit. About.

  There is known a so-called multi-type air conditioner in which an indoor unit is provided for each room, and cooling and heating can be independently and simultaneously operated in each indoor unit. Such an air conditioner is used in, for example, buildings and commercial facilities. In the multi-type air conditioner, cooling and heating in each indoor unit can be changed by controlling the flow direction of the refrigerant for each indoor unit.

  In the multi-type air conditioner, a refrigerant flow path switching unit for switching the flow direction of the refrigerant to each indoor unit is provided between the outdoor unit and the plurality of indoor units. The refrigerant flow switching unit includes a collective type in which a plurality of indoor units are connected to one refrigerant flow switching unit, and one (total plural) refrigerant flow switching for each indoor unit. Two types are known, the individual type with which the unit is provided. Among these, in particular, the former collective refrigerant flow switching unit is connected to a high-pressure gas pipe and a low-pressure gas pipe connected to the outdoor unit, and a gas pipe connected to each indoor unit. A high-pressure valve is provided in the middle of the high-pressure gas pipe, and a low-pressure valve is provided in the middle of the low-pressure gas pipe. By controlling the opening and closing of these valves, the refrigerant flow in each indoor unit is controlled. The direction is controllable.

  The air conditioner employs a structure in which the refrigerant is less likely to stay so that the so-called “refrigerant stagnation”, which is a phenomenon of refrigerant accumulation, does not occur when the indoor unit is thermo-off or stopped. Thereby, the stagnation of the refrigerant is prevented and a stable operation is possible. Therefore, it is preferable that the refrigerant flow switching unit has a structure in which the refrigerant does not easily stay.

  There is a technique described in Patent Document 1 related to a technique for preventing the refrigerant from staying in the flow path switching unit. Patent Document 1 discloses a refrigerant flow path switching unit that is arranged between a heat source unit that forms a refrigerant circuit and a utilization unit and switches the flow of refrigerant, and is connected to an intake gas communication pipe extending from the heat source unit. A first refrigerant pipe, a second refrigerant pipe connected to a high / low pressure gas communication pipe extending from the heat source unit, a third refrigerant pipe connected to a gas pipe extending to the utilization unit, and the first refrigerant pipe; A connection part connected to the second refrigerant pipe and the third refrigerant pipe, connecting the first refrigerant pipe, the second refrigerant pipe, and the third refrigerant pipe, and arranged in the first refrigerant pipe. A first switching valve provided, and a second switching valve disposed in the second refrigerant pipe, wherein the second switching valve is disposed at a position higher than the first switching valve, The third refrigerant pipe is at the lowest height. It has a bottom, wherein connected to said connecting portion at the bottom, the refrigerant flow path switching unit is described.

Japanese Patent Laid-Open No. 2015-114049

  A cold refrigerant flows through piping and the like constituting the refrigerant flow switching unit. Therefore, in order to prevent dew condensation on the surface of the pipe or the like, a heat insulating material is often disposed around the pipe or the like. However, the connection structure such as piping is complicated. Therefore, for example, the pipes and the like constituting the refrigerant flow path switching unit are accommodated in a casing, and the casing is filled with a foaming agent as a heat insulating material to be solidified, whereby the entire pipes and the like are insulated. It will be.

  Here, in the refrigerant flow switching unit described in Patent Document 1, the position of the second motor operated valve Ev2 (high pressure valve) provided on the first header 55 side on the high pressure side is the second header 56 on the low pressure side or It is higher than the position of the first electric valve Ev1 (low pressure valve) provided on the third header 57 side (see particularly FIG. 6). And if the position of the 2nd motor operated valve Ev2 is higher than the position of the 1st motor operated valve Ev1 like the art of patent documents 1, the size of the height direction of a refrigerant channel change unit will become large. . In connection with this, the dimension of the height direction of the housing | casing for accommodating the piping etc. which comprise a refrigerant flow path switching unit also becomes large.

  And if the dimension of the height direction of a housing | casing becomes large, the volume of the space filled with a foaming agent will become large. If it does so, the quantity of the foaming agent with which the inside of a housing | casing is filled will increase, and it will become easy to mix air in the inside of a housing | casing at the time of filling with a foaming agent. And if air mixes, a bubble will arise in the heat insulating material after solidification, and if this bubble part faces piping etc., dew condensation water may arise in this part. And this dew condensation water causes a water leak.

  The present invention has been made in view of the above problems, and the problem to be solved by the present invention is to prevent the stagnation of the refrigerant and enable stable operation, and to perform reliable heat insulation. A refrigerant flow path switching unit capable of preventing water leakage and an air conditioner including the same.

  As a result of intensive studies for solving the above problems, the present inventors have found that the above problems can be solved as follows. That is, the gist of the present invention includes a plurality of usage-side units and heat source-side units that can be independently cooled and heated, and a refrigeration cycle is formed between the plurality of usage-side units and the heat source-side unit. Refrigerant flow path switching that is provided in the air conditioner that is disposed between the plurality of use side units and the heat source side unit to control the flow direction of the refrigerant to the plurality of use side units. A first refrigerant pipe connected to a discharge side of a compressor provided in the heat source side unit, and a refrigerant passage provided in the first refrigerant pipe and flowing through the first refrigerant pipe by opening and closing. A first on-off valve for controlling the flow, a second refrigerant pipe branched from the first refrigerant pipe and connected to the suction side of the compressor provided in the heat source side unit, and provided in the second refrigerant pipe, Open and close And controlling the flow of the refrigerant flowing through the second refrigerant pipe, the second on-off valve provided at the same position in the height direction as the first on-off valve, the first refrigerant pipe, and the A third refrigerant pipe further branched from the branch with the second refrigerant pipe, connected to a heat exchanger provided in the use side unit, and having a portion extending downward in a direction toward the heat exchanger. The present invention relates to a refrigerant flow path switching unit. The other means for solving will be described later in the mode for carrying out the invention.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing the stay of a refrigerant | coolant and enabling stable driving | operation, a refrigerant | coolant flow path switching unit which can perform reliable heat insulation and can prevent water leakage, and an air conditioner provided with the same are provided. be able to.

It is a systematic diagram of an air conditioner provided with the refrigerant flow path switching unit of this embodiment. It is a top view which shows the connection form of each piping which comprises the refrigerant | coolant flow path switching unit of this embodiment. It is a side view which shows the connection form of each piping which comprises the refrigerant | coolant flow path switching unit of this embodiment.

  Hereinafter, a form (this embodiment) for carrying out the present invention will be described with reference to the drawings. In addition, each figure is typical, and in order to make it easy to grasp the present invention, a part of the members is omitted or simplified as appropriate, or the internal structure is shown as long as the gist of the present invention is not impaired. It may be visualized for this purpose.

  FIG. 1 is a system diagram of an air conditioner 100 including a refrigerant flow path switching unit 1 of the present embodiment. The air conditioner 100 is a cooling / heating simultaneous type multi-type air conditioner capable of simultaneously operating cooling and heating for each indoor unit 3. The air conditioner 100 includes a refrigerant flow switching unit 1, an outdoor unit 2, a plurality of indoor units 3 (3 a, 3 b, 3 c, 3 d), a high pressure that connects the refrigerant flow switching unit 1 and the outdoor unit 2. The gas pipe 4, the low-pressure gas pipe 5 and the liquid pipe 6, and gas pipes 7 (7 a, 7 b, 7 c, 7 d) connecting the refrigerant flow switching unit 1 and the plurality of indoor units 3 are provided. Among these, the high pressure gas pipe 4 is also called a discharge gas pipe, and the low pressure gas pipe 5 is also called an intake gas pipe. And since the refrigerant | coolant flow path switching unit 1 and the outdoor unit 2 are connected by three piping of the high pressure gas pipe 4, the low pressure gas pipe 5, and the liquid pipe 6, the air-conditioning conditioner 100 is what is called a three-pipe system. Is an air conditioner.

  Although not shown, the outdoor unit 2 includes a compressor that compresses the refrigerant supplied to the refrigerant flow switching unit 1, an outdoor heat exchanger that performs heat exchange between the outdoor air and the refrigerant, The outdoor expansion valve for expanding the refrigerant before or after the heat exchange in the outdoor heat exchanger (depending on whether the cooling main body or the heating main body is expanded) and the refrigerant flow path are switched depending on whether the cooling main body or the heating main body is different. A four-way valve is provided. The high-pressure gas pipe 4 is connected to the discharge side of the compressor provided in the outdoor unit 2. On the other hand, the low-pressure gas pipe 5 and the liquid pipe 6 are connected to the suction side of the compressor.

  Further, although not shown in the figure, the indoor unit 3 includes an indoor heat exchanger that performs heat exchange between indoor air and a refrigerant, and before or after heat exchange in the indoor heat exchanger (indoor And an indoor expansion valve that expands the refrigerant (depending on the operation mode of the unit). Incidentally, a gas pipe 7 is connected to the indoor heat exchanger.

  And these are mutually connected by piping and the refrigerating cycle is formed between the outdoor unit 2 and the indoor unit 3 because a refrigerant | coolant flows through the inside of the said piping. In particular, in the refrigerant flow path switching unit 1 disposed between the outdoor unit 2 and the indoor unit 3, the flow direction of the refrigerant supplied from the outdoor unit 2 to the indoor unit 3 is controlled, so that the indoor unit 3 Independently, cooling and heating can be operated simultaneously.

  Specifically, in the indoor unit 3 that performs the cooling operation, the flow path is controlled so that the liquid refrigerant in the liquid pipe 6 flows through the indoor unit 3. Then, the liquid refrigerant flowing through the indoor unit 3 is expanded (depressurized) by the indoor expansion valve to become a low-temperature gas refrigerant, and then heat is exchanged with indoor air in the indoor heat exchanger, thereby cooling the room. Is done. The gas refrigerant that has exchanged heat in the indoor heat exchanger is returned to the low-pressure gas pipe 5. In the indoor unit 3 that performs the heating operation, the flow path is controlled so that the gas refrigerant in the high-pressure gas pipe 4 flows to the indoor unit 3. The high-temperature gas refrigerant flowing through the indoor unit 3 heats the room by exchanging heat with the indoor air in the indoor heat exchanger. The liquid refrigerant condensed by heat exchange in the indoor heat exchanger is returned to the liquid pipe 6.

  FIG. 2 is a top view showing a connection form of each pipe constituting the refrigerant flow path switching unit 1 of the present embodiment. In the refrigerant flow switching unit 1, the high-pressure gas pipe 4 and the low-pressure gas pipe 5 are connected in parallel to the gas pipes 7 a to 7 d via the high-pressure header 15 and the low-pressure header 16. Further, the high-pressure gas pipe 4 and the high-pressure header 15 are connected via a connection portion 13. Further, the low-pressure gas pipe 5 and the low-pressure header 16 are connected via a connection portion 14. A strainer 20 is provided in each of the high-pressure header 15 and the low-pressure header 16. The strainer 20 removes foreign matters in the flowing refrigerant. And these are all accommodated in the housing | casing 1a which comprises the refrigerant | coolant flow path switching unit 1. FIG. Further, a circuit board (not shown) for controlling the driving of the high-pressure valve electromagnetic coil 17 and the low-pressure valve electromagnetic coil 18 (both will be described later in detail with reference to FIG. 3) is housed on the side of the housing 1a. An electric box 1b is provided.

  A connection configuration of each pipe constituting the refrigerant flow path switching unit 1 and a configuration of each apparatus constituting the refrigerant flow path switching unit 1 will be described with reference to FIG.

  FIG. 3 is a side view showing a connection form of each pipe constituting the refrigerant flow path switching unit 1 of the present embodiment. The high-pressure header 15 connected to the high-pressure gas pipe 4 described with reference to FIG. 2 is provided with a high-pressure valve 9 on the substantially right side when viewed from the high-pressure gas pipe 4 and its connecting portion 13. Incidentally, a gas pipe 11a described later is connected to the lower side of the high-pressure valve 9. The high-pressure header 15 and the high-pressure valve 9 are connected at the connection portion 9a. The high pressure valve 9 is an electromagnetic valve, and the opening and closing of the high pressure valve 9 is controlled by a high pressure valve electromagnetic coil 17 disposed above the high pressure valve 9. Specifically, the opening and closing of the high-pressure valve 9 is controlled by controlling the energization of the high-pressure valve electromagnetic coil 17. Then, by controlling the opening and closing of the high-pressure valve 9, the flow of the high-pressure gas refrigerant from the high-pressure gas pipe 4 is controlled.

  Further, the low-pressure header 15 connected to the low-pressure gas pipe 5 described with reference to FIG. 2 is provided with a low-pressure valve 10 on the upper right side when viewed from the low-pressure gas pipe 5 and its connecting portion 14. Incidentally, the low-pressure valve 10 is connected to a gas pipe 11b described later at the connecting portion 10a. The low pressure valve 10 is an electromagnetic valve, and the opening and closing of the low pressure valve 10 is controlled by a low pressure valve electromagnetic coil 18 disposed above the low pressure valve 10. Specifically, opening / closing of the low-pressure valve 10 is controlled by controlling energization of the low-pressure valve electromagnetic coil 18. The flow of the low-pressure gas refrigerant from the low-pressure gas pipe 5 is controlled by controlling the opening and closing of the low-pressure valve 10.

  In the refrigerant flow path control unit 1 of the present embodiment, the high pressure valve 9 and the low pressure valve 10 have the same specifications and the same size (shape). The high-pressure valve electromagnetic coil 17 and the low-pressure valve electromagnetic coil 18 have the same specifications and the same size (shape). Here, the same specification means that the performance such as the relationship between the opening degree and the flow rate is the same. The same shape here means that the outer shape is the same, and the same height and width are the same in a side view. Therefore, the same specification and the same size (shape) means, for example, those of the same manufacturer and the same model number. The integrated body of the high-pressure valve 9 and the high-pressure valve electromagnetic coil 17 and the integrated body of the low-pressure valve 10 and the low-pressure valve electromagnetic coil 18 are arranged at the same position in the height direction. Therefore, in FIG. 3, a broken line connecting the upper end of the high pressure valve electromagnetic coil 17 and the upper end of the low pressure valve electromagnetic coil 18 and a broken line connecting the lower end of the high pressure valve 9 and the lower end of the low pressure valve 10 are parallel. (Although details will be described later, “parallel” here is a concept including “substantially parallel”).

  Since the high-pressure valve 9 and the low-pressure valve 10 are in such a positional relationship, since either one of the valves does not protrude upward, the upper surface (ceiling) of the housing 1a can be lowered. Therefore, it is possible to prevent a useless space from being generated inside the housing 1a, and to reduce the amount of the foaming agent as the heat insulating material 19 (described later) to be filled therein. Therefore, air can be sufficiently prevented from being mixed when the foaming agent is filled, and more reliable heat insulation can be achieved to prevent the formation of condensed water.

  A gas pipe 11a extends below the high-pressure valve 9, and a pipe branches in the left-right direction at a branching portion 22 existing at the lower end of the pipe. Of the pipes that branch off at the branch portion 22, the pipe that extends to the right is the gas pipe 11b, and the pipe that extends to the left is the gas pipe 11c. Among these, the side of the gas pipe 11b is a side toward the low-pressure valve 10. The low-pressure gas pipe 5 and the indoor unit 3 are connected mainly via the low-pressure header 16 and the gas pipes 11b and 11c. On the other hand, the side of the gas pipe 11 c is the side toward the indoor unit 3. The high-pressure gas pipe 4 and the indoor unit 3 are connected mainly via the high-pressure header 15 and the gas pipes 11a and 11c.

  The gas pipe 11b extending to the right side from the branch portion 22 has a portion extending upward in the vertical direction in addition to a portion extending to the horizontal portion. Specifically, the gas pipe 11b is configured to extend from the branch portion 22 to the right in the horizontal direction, then upward in the vertical direction, and further toward the right at the upper end thereof. Therefore, as a whole, the gas pipe 11b that constitutes from the branch portion 22 to the low pressure valve 10 extends upward. Thereby, a flow path is controlled so that the flow direction of the refrigerant | coolant to the outdoor expansion valve in the outdoor unit 2 may be only one direction.

  Further, the gas pipe 11 c extending to the left from the branch portion 22 is formed in the horizontal direction in the vicinity of the branch portion 22. However, in addition to the portion formed in the horizontal direction, the gas pipe 11c includes a portion having an inclination that goes down to the left (in the direction of the indoor heat exchanger of the indoor unit 3). And the gas pipe 7 connected to the indoor unit 3 is connected via the connection part 22 in the edge part of the horizontal part arrange | positioned on the left side of the part which has the downward inclination. By doing in this way, when the air conditioner 100 is thermo-off or stopped, the refrigerant present in the pipe of the refrigerant flow switching unit 1 is naturally in the indoor unit by the inclined part that goes down the gas pipe 11c. It will flow toward 3. Therefore, the refrigerant is prevented from staying inside the refrigerant flow path switching unit 1.

  And the strainer 20 is provided in the part which has the inclination which falls in the gas pipe 11c. As described above, the strainer 20 removes foreign matters in the flowing refrigerant. By arranging the strainer 20 with an inclination, the refrigerant is prevented from staying in the strainer 20.

  In addition, a heat insulating material 19 is disposed inside the housing 1a so as to cover all other members below the high-pressure valve electromagnetic coil 17 and the low-pressure valve electromagnetic coil 18. The heat insulating material 19 is, for example, urethane foam. The heat insulating material 19 is formed by filling urethane foam (foaming agent) through an opening (not shown) or the like formed on the surface of the housing 1a and solidifying it after housing piping or the like inside the housing 1a. The

  The position in the height direction of the connecting portion 21 (the position of the lowest one-dot chain line in FIG. 3), the position in the height direction of the branch portion 22 (the position of the middle one-dot chain line in FIG. 3), and the height of the connecting portion 10a. Each member is arranged so as to be higher in this order from the position in the vertical direction (the position of the uppermost one-dot chain line in FIG. 3). That is, as shown in FIG. 3, the position in the height direction of the branch portion 22 of the gas pipes 11b and 11c is longer than the position in the height direction of the connecting portion 21 between the gas pipe 11c and the gas pipe 7. It is only high. Further, the height direction positions of the connection portion 9a in the high pressure valve 9 and the connection portion 10a in the low pressure valve 10 are higher than the position in the height direction of the branch portion 22 of the gas pipes 11b and 11c by a length B. It has become. Since the high-pressure valve 9 and the low-pressure valve 10 have the same specifications and the same size (shape) as described above, the heights of the connecting portion 9a and the connecting portion 10a are the same.

  In this way, when the air conditioner 100 is thermo-off or stopped, the refrigerant in the refrigerant flow path switching unit 1 is transferred to the indoor unit 3 through the connection portion 21 and the gas pipe 7 arranged at the lowermost position. Will head. Therefore, stagnation of the refrigerant hardly occurs, and stable operation is possible even when the air conditioner 100 is operated again. In addition to refrigerant, refrigerating machine oil is less likely to stay, so that corrosion of piping and the like can be suppressed.

  Furthermore, the height direction positions of the connection portion 9a and the connection portion 10a are the same, and the height direction positions of the high pressure valve 9 and the low pressure valve 10 are the same. The dimension of the switching unit 1 in the height direction can be reduced. Therefore, the filling amount of the foaming agent can be reduced when the foaming agent constituting the heat insulating material 19 is filled. Thereby, mixing of air is prevented at the time of filling, and reliable heat insulation can be performed. Therefore, generation of condensed water can be suppressed and water leakage can be prevented.

  Although the present embodiment has been described with reference to the drawings as appropriate, the present embodiment is not limited to the above example.

  For example, the gas pipe 11c has an inclination that goes down in the direction toward the left direction (indoor heat exchanger) as a form that extends downward toward the indoor heat exchanger of the indoor unit 3, but the form that extends downward. If there is, you can do anything. For example, the gas pipe 11c may be formed by connecting a first pipe extending in the horizontal direction, a second pipe extending in the vertical direction, and a third pipe extending in the horizontal direction in this order. In this case, the connection part 21 is connected to the left end of the first pipe, the second pipe is connected to the right end of the first pipe, and the left end of the third pipe is connected to the upper end of the second pipe. The branch portion 22 is connected to the right end of the third pipe.

  In addition, for example, the strainer 20 provided in the gas pipe 11c is provided in a portion having an inclination descending in the left direction, but in addition to or provided in this portion. Instead, the strainer 20 may be provided in a horizontally extending portion other than the portion. By providing the strainer 20 in the horizontal portion, the processing becomes easy.

  Further, for example, the high-pressure valve 9 and the low-pressure valve 10 have the same specifications and the same size (shape), but this need not be the case. That is, even if the specifications and sizes are different, if the upper ends of the two valves (which may be the upper ends of the electromagnetic coils) are at the same height (may be substantially the same height), the dimensions in the height direction of the housing 1a. The effects of the present invention are exhibited.

  Further, although the high pressure valve 9 and the low pressure valve 10 are arranged so as to be at the same position in the height direction, they do not need to be located at the same height direction (that is, the broken line shown in FIG. For example, a slight deviation (that is, the broken lines shown in FIG. 3 are substantially parallel, for example) is allowed within a range that does not significantly impair the effects of the present invention.

DESCRIPTION OF SYMBOLS 1 Refrigerant flow path switching unit 1a Case 1b Electric box 2 Outdoor unit (heat source side unit)
3, 3a, 3b, 3c, 3d Indoor unit (use side unit)
4 High-pressure gas pipe (first refrigerant pipe)
5 Low pressure gas pipe (second refrigerant pipe)
6 Liquid pipes 7, 7a, 7b, 7c, 7d Gas pipe (third refrigerant pipe)
9 High pressure valve (first on-off valve)
10 Low pressure valve (first on-off valve)
11a Gas pipe (first refrigerant pipe)
11b Gas pipe (second refrigerant pipe)
11c Gas pipe (third refrigerant pipe)
12 Gas pipe 13 connecting high pressure valve and low pressure valve 13 Connection section 14 Connection section 15 High pressure header (first refrigerant pipe)
16 Low pressure header (second refrigerant piping)
17 High-pressure valve electromagnetic coil 18 Low-pressure valve electromagnetic coil 19 Heat insulating material 20 Strainer 22 Branch part (branch)
100 air conditioner

Claims (6)

Provided in an air conditioner that includes a plurality of use side units that can be cooled and heated independently and a heat source side unit, and in which a refrigeration cycle is formed between the plurality of use side units and the heat source side unit. A refrigerant flow switching unit for controlling a flow direction of the refrigerant to the plurality of usage-side units by being arranged between the plurality of usage-side units and the heat source-side unit,
A first refrigerant pipe connected to a discharge side of a compressor provided in the heat source side unit;
A first on-off valve that is provided in the first refrigerant pipe and controls the flow of the refrigerant flowing through the first refrigerant pipe by opening and closing;
A second refrigerant pipe branched from the first refrigerant pipe and connected to the suction side of the compressor provided in the heat source side unit;
The second refrigerant pipe provided in the second refrigerant pipe controls the flow of the refrigerant flowing through the second refrigerant pipe by opening and closing, and is provided at the same position in the height direction as the first on-off valve. A valve,
A third refrigerant having a portion further branched from the branch of the first refrigerant pipe and the second refrigerant pipe and connected to a heat exchanger provided in the use side unit and extending downward in a direction toward the heat exchanger. And a refrigerant flow path switching unit.   2. The refrigerant flow switching unit according to claim 1, wherein the downwardly extending portion formed in the third refrigerant pipe is a portion having an inclination downward toward the heat exchanger.   The refrigerant flow path switching unit according to claim 1 or 2, wherein the third refrigerant pipe is provided with a strainer for removing foreign matters in the flowing refrigerant at a portion extending downward. . The third refrigerant pipe includes a portion extending horizontally in addition to the portion extending downward,
The refrigerant flow path switching unit according to claim 1 or 2, wherein a strainer that removes foreign matters in the flowing refrigerant is provided in the horizontally extending portion.   The refrigerant channel switching unit according to claim 1 or 2, wherein the first on-off valve and the second on-off valve have the same specifications and the same size. A plurality of user-side units capable of cooling and heating independently,
A heat source side unit in which a refrigeration cycle is formed with the plurality of usage side units;
A first refrigerant pipe connected to a discharge side of a compressor provided in the heat source side unit, and a first refrigerant pipe provided in the first refrigerant pipe for controlling the flow of the refrigerant flowing through the first refrigerant pipe by opening and closing. One open / close valve, a second refrigerant pipe branched from the first refrigerant pipe and connected to the suction side of the compressor provided in the heat source side unit, and provided in the second refrigerant pipe, opening and closing the above Controlling the flow of the refrigerant flowing through the second refrigerant pipe, the second on-off valve provided at the same position in the height direction as the first on-off valve, the first refrigerant pipe and the second refrigerant pipe And a third refrigerant pipe having a portion extending downward in a direction toward the heat exchanger, further branched from the branch and connected to a heat exchanger provided in the use side unit, and the plurality of use sides Unit and the heat source side unit By being disposed between, characterized in that and a refrigerant flow path switching unit for controlling the flow direction of the refrigerant to the plurality of utilization side units, the air conditioner.

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