Refrigerant distributing pipe, and air conditioner

Abstract

To provide a refrigerant distributing pipe capable of suppressing an actual distribution flow rate of a refrigeration oil being deviated from a target flow rate, and to provide an air conditioner.SOLUTION: A refrigerant distributing pipe is used for a refrigerant pipe for connecting a plurality of outdoor units and indoor units having a compressor, and distributes a fluid including a refrigerant for air conditioning and a refrigeration oil for lubrication of the compressor to the plurality of outdoor units. The refrigerant distributing pipe includes: an inflow pipe where a fluid flows in; a first outflow pipe for allowing the fluid to flow out of the outdoor unit; and a second outflow pipe for allowing the fluid to flow out of the outdoor unit different from the outdoor unit which is the flow-out destination from the first outflow pipe. In the first outflow pipe, a back pressure in the opposite direction from the circulation direction of the fluid is larger than the second outflow pipe, and the cross-section ratio of the first outflow pipe and the second outflow pipe is set in such a manner that the ratio of the value of the first outflow pipe to the value of the second outflow pipe is larger in comparison with the target distribution ratio of the fluid between the first outflow pipe and the second outflow pipe.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a refrigerant distribution pipe and an air conditioning apparatus. [Background technology]

[0002] In air conditioners equipped with indoor units, outdoor units, and refrigerant circuits, multiple outdoor units may be installed in parallel. Refrigerant oil is used to lubricate the sliding parts of the compressor in each outdoor unit to prevent burnout. As the refrigerant circulates through the refrigeration circuit, the refrigerant oil adheres to and accumulates in the heat exchanger and refrigerant pipes outside the compressor. For this reason, the refrigerant must be circulated through the refrigerant pipes, and this accumulated refrigerant oil must be periodically recovered into the compressors of each outdoor unit. It is desirable for the refrigerant oil to be recovered evenly from each outdoor unit, and distribution pipes are provided in the refrigerant pipes to distribute the refrigerant oil at an appropriate flow rate. For example, the distribution pipe disclosed in Patent Document 1 has an extension section that extends one end of a pipe with an approximately circular cross section, and a first branch pipe and a second branch pipe that are arranged side by side within this extension section and branch off in two directions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-2679 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when using the distribution pipe disclosed in Patent Document 1, etc., depending on the installation posture and shape of the distribution pipe, the actual distribution flow rate of refrigeration oil through the distribution pipe may deviate significantly from the target distribution flow rate (hereinafter referred to as the "target flow rate").

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a refrigerant distribution pipe and an air conditioning apparatus that can prevent the actual distribution flow rate of refrigeration oil from deviating from the target flow rate. [Means for solving the problem]

[0006] In order to solve the above problems, the refrigerant distribution pipe of the present disclosure is used in a refrigerant pipe connecting multiple outdoor units with compressors and indoor units, and distributes a fluid containing an air-conditioning refrigerant and a refrigeration oil for lubricating the compressors to the multiple outdoor units, and is provided with an inlet pipe into which the fluid flows, a first outlet pipe through which the fluid flows out to the outdoor units, and a second outlet pipe through which the fluid flows out to an outdoor unit different from the outdoor unit to which the fluid flows from the first outlet pipe, wherein the first outlet pipe has a higher back pressure in the direction opposite to the flow direction of the fluid than the second outflow pipe, and the cross-sectional area ratio of the first outflow pipe to the second outflow pipe is set so that the ratio of the value of the first outflow pipe to the value of the second outflow pipe is larger than the target distribution ratio of the fluid between the first outflow pipe and the second outflow pipe.

[0007] The air conditioning apparatus according to the present disclosure includes the refrigerant pipe including the refrigerant distribution pipe, a plurality of the outdoor units, and the indoor units. [Effects of the Invention]

[0008] According to the refrigerant distribution pipe and air conditioner of the present disclosure, it is possible to prevent the actual distributed flow rate of refrigeration oil from deviating from the target flow rate. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an overall configuration diagram of an air conditioning apparatus according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view of a refrigerant distribution pipe according to the first embodiment of the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5] FIG. 10 is a plan view of a refrigerant distribution pipe according to a modified example of the first embodiment of the present disclosure. [Figure 6] FIG. 6 is a cross-sectional view of a refrigerant distribution pipe according to a second embodiment of the present disclosure. [Figure 7] FIG. 10 is a diagram showing a case where a refrigerant distribution pipe according to a comparative example to the second embodiment of the present disclosure is used. [Figure 8] 10A and 10B are diagrams illustrating the effects of the refrigerant distribution pipe according to the second embodiment of the present disclosure. [Figure 9] FIG. 10 is a cross-sectional view of a refrigerant distribution pipe according to a third embodiment of the present disclosure. [Figure 10] FIG. 11 is a diagram showing a case where a refrigerant distribution pipe according to a comparative example to the third embodiment of the present disclosure is used. [Figure 11] 10A to 10C are diagrams illustrating the effects of the refrigerant distribution pipe according to the third embodiment of the present disclosure. [Figure 12] FIG. 11 is a cross-sectional view of a refrigerant distribution pipe according to a modified example of the third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment (Configuration of air conditioning device) A refrigerant distribution pipe 10 and an air conditioner 100 according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 4. FIG. As shown in Fig. 1, the air conditioning apparatus 100 includes an indoor unit 1, an outdoor unit 2, a refrigerant pipe 3, and a control unit 4. The air conditioning apparatus 100 of this embodiment is a so-called multi-air conditioner in which multiple indoor units 1 are provided. The air conditioning apparatus 100 is used, for example, in a building. Similarly to the indoor units 1, multiple outdoor units 2 are provided. In the following, an example will be described in which three indoor units 1 and three outdoor units 2 are provided.

[0011] Each indoor unit 1 includes a cooling expansion valve (not shown) and an indoor heat exchanger (not shown), and each outdoor unit 2 includes a compressor 2a, an outdoor heat exchanger (not shown), and a heating expansion valve (not shown).

[0012] The refrigerant pipes 3 connect multiple indoor units 1 and multiple outdoor units 2. A fluid F, such as an air-conditioning refrigerant, flows through the refrigerant pipes 3. The refrigerant pipes 3 include a gas pipe 3a and a liquid pipe 3b. Both the gas pipe 3a and the liquid pipe 3b connect the indoor units 1 and the outdoor units 2. During normal operation, gas refrigerant flows through the gas pipe 3a, and liquid refrigerant flows through the liquid pipe 3b. Here, normal operation refers to cooling operation and heating operation when the oil return operation, which will be described later, is not performed.

[0013] The gas pipe 3a includes an indoor gas pipe 5, a main pipe 6, a refrigerant distribution pipe 10, and an outdoor branch pipe 7. In this embodiment, two refrigerant distribution pipes 10 are provided. One of the two refrigerant distribution pipes 10 is designated as a first refrigerant distribution pipe 10a, and the other is designated as a second refrigerant distribution pipe 10b.

[0014] The indoor gas pipe 5 connects the indoor units 1 to the main pipe 6, and the main pipe 6 connects the indoor gas pipe 5 to the first refrigerant distribution pipe 10a. The main pipe 6 is a straight pipe having a length of, for example, 500 mm or more.

[0015] The outdoor branch pipe 7 is connected to the main pipe 6 via a refrigerant distribution pipe 10. In this embodiment, the outdoor branch pipe 7 includes a first outdoor branch pipe 7a and a second outdoor branch pipe 7b. Three first outdoor branch pipes 7a are provided, and one of these first outdoor branch pipes 7a extends from one outdoor unit 2 and is connected to the first refrigerant distribution pipe 10a. The other two first outdoor branch pipes 7a extend from the remaining two outdoor units 2, respectively, and are connected to the second refrigerant distribution pipe 10b. The second outdoor branch pipe 7b connects the second refrigerant distribution pipe 10b and the first refrigerant distribution pipe 10a. The second outdoor branch pipe 7b is a straight pipe having a length of, for example, 500 mm or more.

[0016] The air conditioner 100 described above can perform cooling operation to cool the indoor air and heating operation to heat the indoor air. During cooling operation, the outdoor heat exchanger functions as a condenser, and the indoor heat exchanger functions as an evaporator. The compressor 2a, the outdoor heat exchanger, the cooling expansion valve, and the indoor heat exchanger form a refrigerant circuit.

[0017] During cooling operation, high-temperature, high-pressure gas refrigerant discharged from the compressor 2a of the outdoor unit 2 is sent to the outdoor heat exchanger, where it condenses and liquefies by exchanging heat with outdoor air. This liquid refrigerant flows into the indoor unit 1 via liquid pipe 3b. The liquid refrigerant then undergoes adiabatic expansion as it passes through the cooling expansion valve, and is then sent to the indoor heat exchanger, where it evaporates by cooling the indoor air. The refrigerant that has absorbed heat and become gas in the indoor heat exchanger flows into the outdoor unit 2 via gas pipe 3a and is sent to the compressor 2a.

[0018] During heating operation, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator. The compressor 2a, the indoor heat exchanger, the heating expansion valve, and the outdoor heat exchanger form a refrigerant circuit.

[0019] During heating operation, a four-way valve (not shown) provided in the outdoor unit 2 is switched to a different direction from that during cooling operation. Refrigerant discharged from the compressor 2a of the outdoor unit 2 flows through the gas pipe 3a into the indoor heat exchanger of the indoor unit 1, where it condenses and liquefies by releasing heat to the indoor air. This liquid refrigerant flows through the liquid pipe 3b into the outdoor unit 2. The liquid refrigerant then undergoes adiabatic expansion as it passes through the heating expansion valve of the outdoor unit 2, and is then sent to the outdoor heat exchanger, where it evaporates by absorbing heat from the outdoor air. This gas refrigerant is then sent to the compressor 2a of the outdoor unit 2.

[0020] Furthermore, refrigeration oil is used in the compressor 2a of the outdoor unit 2 in the air conditioner 100 to lubricate the sliding parts inside the compressor 2a. The refrigeration oil prevents burnout in the compressor 2a. A portion of this refrigeration oil flows through the refrigerant circuits, such as the indoor heat exchanger and outdoor heat exchanger, together with the refrigerant discharged from the compressor 2a, and is then recovered back into the compressor 2a.

[0021] If this refrigeration oil adheres to the heat exchanger or the inner walls of the refrigerant pipes 3 as it flows through the refrigerant circuit, it will impede heat transfer and reduce the amount of refrigeration oil returned to the compressor 2a, resulting in insufficient lubrication of the compressor 2a. Therefore, in the air conditioning apparatus 100 of this embodiment, in order to recover the refrigeration oil that has adhered and accumulated on the heat exchanger or the inner walls of the refrigerant pipes 3, a so-called oil return operation is performed to periodically recover refrigeration oil to the compressor 2a side.

[0022] In the oil return operation, the control unit 4 controls the flow rate of the refrigerant so that the compressors 2a in all the outdoor units 2 draw in and discharge the same flow rate of refrigerant. This allows refrigeration oil to be collected evenly in all the outdoor units 2.

[0023] The oil return operation will be described below. During cooling operation, the control unit 4 starts the refrigeration oil recovery operation at a specified timing. During cooling, the refrigeration oil recovery operation involves reducing the rotation speed of the indoor unit 1 fan (not shown) and increasing the opening of the flow control valve (not shown) beyond a specified value. As a result, the amount of evaporation in the indoor heat exchanger is reduced, allowing the refrigerant to circulate in a liquid phase. The refrigeration oil adhering to the indoor heat exchanger and the walls of the gas pipe 3a, etc., is then recovered together with the liquid refrigerant into an accumulator (not shown) on the outdoor unit 2 side, and the refrigeration oil is returned to the compressor 2a through the accumulator's oil return pipe.

[0024] On the other hand, during heating operation, the control unit 4 starts the refrigeration oil recovery operation at a specified timing. During refrigeration oil recovery operation during heating, the fan of the indoor unit 1 is first stopped to stop the indoor air conditioning. Then, to circulate the refrigerant in the same direction as during cooling operation, the four-way valve is switched to a direction different from that used during normal heating operation. Then, high-temperature, high-pressure gas refrigerant compressed by the compressor 2a of the outdoor unit 2 is guided to the outdoor heat exchanger, where it is condensed and liquefied into liquid refrigerant. This liquid refrigerant flows into the liquid pipe 3b and is guided to the indoor unit 1 via the liquid pipe 3b. The liquid refrigerant does not undergo heat exchange in the indoor heat exchanger, but instead passes through the gas pipe 3a and is guided back to the outdoor unit 2 in its liquid state. The liquid refrigerant that has flowed into the outdoor unit 2 passes through the accumulator and is returned to the compressor 2a. This allows the refrigeration oil that has diffused in the indoor heat exchanger and liquid pipe 3b to be returned to the compressor 2a.

[0025] In this way, during oil return operation, not only the refrigerant but also the refrigerating machine oil flows through the refrigerant pipes 3. In other words, the fluid F flowing through the refrigerant pipes 3 contains the refrigerant and the refrigerating machine oil, and by evenly distributing this fluid F to each outdoor unit 2, it is possible to evenly supply the refrigerating machine oil to each outdoor unit 2. In this embodiment, in order to more evenly distribute the fluid F containing the air-conditioning refrigerant and refrigerating machine oil, the refrigerant distribution pipe 10 has the following configuration.

[0026] (Refrigerant distribution pipe configuration) Next, the configuration of the refrigerant distribution pipe 10 will be described. The refrigerant distribution pipe 10 is used in the refrigerant pipe 3 connecting the indoor unit 1 and multiple outdoor units 2, each having a compressor 2a, and is a piping component that distributes a fluid F containing an air-conditioning refrigerant and a refrigeration oil for lubricating the compressors 2a to the multiple outdoor units 2. The fluid F flowing through the refrigerant distribution pipe 10 is assumed to be primarily a liquid (liquid phase), but the fluid F may also contain a gas (gas phase). The fluid F flowing through the refrigerant distribution pipe 10 may also be composed of only a liquid phase or only a gas phase. As described above, two refrigerant distribution pipes 10 are provided in this embodiment, and the one directly connected to one main pipe 6 is designated as the first refrigerant distribution pipe 10a, and the other is designated as the second refrigerant distribution pipe 10b.

[0027] The first refrigerant distribution pipe 10a and the second refrigerant distribution pipe 10b have the same configuration. Therefore, the configuration of the refrigerant distribution pipe 10 will be described using the first refrigerant distribution pipe 10a as an example, and the description of the configuration of the second refrigerant distribution pipe 10b will be omitted as appropriate.

[0028] As shown in FIG. 2, the first refrigerant distribution pipe 10a includes an inlet pipe 11, a connection part 12, a first outlet pipe 13, and a second outlet pipe . In the following description of each component such as the inlet pipe 11, the connection portion 12, the first outlet pipe 13, and the second outlet pipe 14, as a general rule, "cross section" means the cross section of the flow path space through which the fluid F flows, and is perpendicular to the flow direction of the fluid F, and "cross-sectional area" means the cross-sectional area of ​​the flow path space through which the fluid F flows.

[0029] The inlet pipe 11 opens to the indoor unit 1 side. A fluid F containing a refrigerant and a lubricating refrigeration oil flows into the inlet pipe 11 during oil return operation. The inlet pipe 11 of the first refrigerant distribution pipe 10a is connected to the main pipe 6. The inlet pipe 11 is a straight pipe that extends linearly in one direction. In this embodiment, the inlet pipe 11 is a circular pipe with a circular cross section.

[0030] The connecting portion 12 extends in one direction from the end of the inlet pipe 11 . Hereinafter, the extension direction De of the connection portion 12 will be simply referred to as the "extension direction De." Furthermore, one of the directions perpendicular to the extension direction De will be referred to as the "first direction D1," and the direction perpendicular to the extension direction De and the first direction D1 will be referred to as the "second direction D2." In this embodiment, the connection portion 12 extends linearly in the same direction as the inlet pipe 11. That is, the inlet pipe 11 extends in the extension direction De.

[0031] The fluid F that has flowed into the inlet pipe 11 flows through the connecting portion 12. The connecting portion 12 connects the inlet pipe 11 to the first outlet pipe 13 and the second outlet pipe 14. The connecting portion 12 has an inlet portion 12a, a tapered portion 12b, and a branch portion 12c.

[0032] The inlet portion 12a is provided at the end of the connecting portion 12 on the inlet pipe 11 side in the extension direction De. The inlet portion 12a has an inlet opening 15 connected to the inlet pipe 11. The inlet opening 15 opens in the extension direction De and communicates with the inlet pipe 11. The fluid F is supplied to the inlet opening 15 from the inlet pipe 11.

[0033] The tapered portion 12b extends from the inlet portion 12a in the extension direction De to the opposite side to the inlet pipe 11. When viewed from the second direction D2, the tapered portion 12b is formed in a tapered shape (trapezoidal shape) that gradually widens in the first direction D1 as it moves away from the inlet portion 12a in the extension direction De.

[0034] Branch portion 12c is provided at the end of connecting portion 12 opposite to inlet pipe 11 in extension direction De. Branch portion 12c has first branch pipe 12c1, second branch pipe 12c2, and connecting wall 12d. First branch pipe 12c1 and second branch pipe 12c2 are provided side by side in first direction D1. First branch pipe 12c1 and second branch pipe 12c2 both extend in extension direction De and communicate with tapered portion 12b. Connecting wall 12d is provided between first branch pipe 12c1 and second branch pipe 12c2 in first direction D1.

[0035] The first branch pipe 12c1 has a first outlet opening 16 at an end opposite the tapered portion 12b in the extension direction De. The second branch pipe 12c2 has a second outlet opening 17 at an end opposite the tapered portion 12b in the extension direction De. The first outlet opening 16 and the second outlet opening 17 are arranged side by side in the first direction D1.

[0036] The fluid F that flows into the connecting portion 12 through the inlet opening 15 flows out of the connecting portion 12 through the first outlet opening 16 and the second outlet opening 17. A first outlet pipe 13 is connected to the first outlet opening 16, and a second outlet pipe 14 is connected to the second outlet opening 17. The first outlet pipe 13 and the second outlet pipe 14 are provided on the opposite side of the connecting portion 12 from the inlet pipe 11 in the extension direction De.

[0037] The first outlet pipe 13 communicates with the connecting portion 12 at a first outlet opening 16, and allows the fluid F that has flowed in from the inlet pipe 11 to flow out to the outdoor unit 2. The first outlet pipe 13 of this embodiment is a curved pipe that is shaped like an L when viewed from the second direction D2. The first outlet pipe 13 is a curved pipe that has a first straight pipe portion 18, a first curved portion 19, and a second straight pipe portion 20.

[0038] The first straight pipe section 18 extends linearly from the connecting section 12 in the extension direction De. The first curved section 19 is provided at the end of the first straight pipe section 18 opposite the connecting section 12 in the extension direction De. In other words, the first curved section 19 is located downstream of the first straight pipe section 18. The first curved section 19 curves in the first direction D1 so as to move away from the second outlet opening 17 as the first curved section 19 moves away from the first straight pipe section 18 in the extension direction De. The second straight pipe section 20 extends linearly from the first curved section 19 in the first direction D1.

[0039] The second outlet pipe 14 communicates with the connection portion 12 at a second outlet opening 17, and is arranged alongside the first outlet pipe 13 in the first direction D1. The second outlet pipe 14 causes the fluid F that has flowed in from the inlet pipe 11 to flow out to an outdoor unit 2 different from the outdoor unit 2 to which the fluid is directed from the first outlet pipe 13. The second outflow pipe 14 of this embodiment is a straight pipe extending in the extension direction De.

[0040] In this embodiment, the first outflow pipe 13 and the second outflow pipe 14 are both circular pipes with a circular cross section. Also, as shown in Fig. 3, the center 22 of the cross section of the first outflow pipe 13 and the center 23 of the cross section of the second outflow pipe 14 are located at the same position in the second direction D2 with respect to the center 21 of the inflow pipe 11. Here, the center 21 of the cross section of the inflow pipe 11 is the center of gravity of the cross-sectional shape of the inflow pipe 11, the center 22 of the first outflow pipe 13 is the center of gravity of the cross-sectional shape of the first outflow pipe 13, and the center 23 of the cross section of the second outflow pipe 14 is the center of gravity of the cross-sectional shape of the second outflow pipe 14. In the first refrigerant distribution pipe 10a, the first outflow pipe 13 is connected to the first outdoor branch pipe 7a extending from one outdoor unit 2, and the second outflow pipe 14 is connected to the second outdoor branch pipe 7b that connects the first refrigerant distribution pipe 10a and the second refrigerant distribution pipe 10b. Furthermore, the second refrigerant distribution pipe 10b is connected to the remaining two outdoor units 2 via two first outdoor branch pipes 7a.

[0041] The second refrigerant distribution pipe 10b has the same configuration as the first refrigerant distribution pipe 10a as described above. That is, the second refrigerant distribution pipe 10b includes an inlet pipe 11, a connection part 12, a first outlet pipe 13, and a second outlet pipe 14. However, the second refrigerant distribution pipe 10b differs from the first refrigerant distribution pipe 10a in the following points.

[0042] In the second refrigerant distribution pipe 10b, the first outflow pipe 13 and the second outflow pipe 14 are both connected to first outdoor branch pipes 7a extending from the remaining two outdoor units 2, respectively.

[0043] As described above, in both the first refrigerant distribution pipe 10a and the second refrigerant distribution pipe 10b, the first outflow pipe 13 is a curved pipe having the first curved section 19 on the downstream side, and the second outflow pipe 14 is a straight pipe extending in a straight line. Therefore, in the first outflow pipe 13, the fluid F flowing in from the connection section 12 collides with the wall surface of the first curved section 19 and is subjected to pressure, so the back pressure in the opposite direction to the flow direction of the fluid F is greater in the first outflow pipe 13 than in the second outflow pipe 14.

[0044] Here, the cross-sectional area of ​​the first outflow pipe 13 is S1, and the cross-sectional area of ​​the second outflow pipe 14 is S2. Furthermore, the target distribution amount of the fluid F to the first outflow pipe 13 is X1, and the target distribution amount of the fluid F to the second outflow pipe 14 is X1. At this time, in each refrigerant distribution pipe 10, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is set so that the ratio of the value of the first outflow pipe 13 to the value of the second outflow pipe 14 is larger than the target distribution ratio (X1:X2) of the fluid F between the first outflow pipe 13 and the second outflow pipe 14. In other words, the ratio is set so that (S1 / S2)>(X1 / X2).

[0045] Specific values ​​of the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 for each of the first refrigerant distribution pipe 10a and the second refrigerant distribution pipe 10b will be described below.

[0046] In the first refrigerant distribution pipe 10a, the fluid F flowing through the first outflow pipe 13 is guided to one outdoor unit 2, and the fluid F flowing through the second outflow pipe 14 is guided to two outdoor units 2. For this reason, in the first refrigerant distribution pipe 10a, the target distribution ratio (X1:X2) of the fluid F between the first outflow pipe 13 and the second outflow pipe 14 is set to, for example, the same as the ratio of the numbers of the outdoor units 2 to which the fluid is discharged, and is X1:X2 = 1:2. In other words, X1 / X2 = 1 / 2.

[0047] On the other hand, in the first refrigerant distribution pipe 10a, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is set to S1 / S2>1 / 2. For example, as shown in Figures 2 and 3, it is set to S1:S2=1:1.

[0048] In the second refrigerant distribution pipe 10b, the fluid F flowing through the first outflow pipe 13 is guided to one outdoor unit 2, and the fluid F flowing through the second outflow pipe 14 is guided to one outdoor unit 2. For this reason, in the second refrigerant distribution pipe 10b, the target distribution ratio (X1:X2) of the fluid F between the first outflow pipe 13 and the second outflow pipe 14 is set to, for example, the same as the ratio of the numbers of the outdoor units 2 to which the fluid is discharged, and is X1:X2 = 1:1. In other words, X1 / X2 = 1 / 1.

[0049] On the other hand, in the first refrigerant distribution pipe 10a, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is set to S1 / S2>1 / 1. For example, as shown in Figures 2 and 4, it is set to S1:S2=2:1.

[0050] (Action and effect) The refrigerant distribution pipe 10 having the above configuration can exhibit the following effects.

[0051] The refrigerant distribution pipe 10 of this embodiment is used in the refrigerant pipe 3 connecting multiple outdoor units 2 each having a compressor 2a to an indoor unit 1, and distributes a fluid F containing an air-conditioning refrigerant and a refrigerating machine oil for lubricating the compressor 2a to the multiple outdoor units 2. The refrigerant distribution pipe 10 includes an inlet pipe 11 into which the fluid F flows, a first outlet pipe 13 through which the fluid F flows to an outdoor unit 2, and a second outlet pipe 14 through which the fluid F flows from the first outlet pipe 13 to an outdoor unit 2 different from the destination outdoor unit 2. The first outlet pipe 13 has a higher back pressure in the direction opposite to the flow direction of the fluid F than the second outlet pipe 14. The cross-sectional area ratio (S1:S2) of the first outflow pipe 13 to the second outflow pipe 14 is set so that the ratio of the value of the first outflow pipe 13 is larger than the target distribution ratio (X1:X2) of the fluid F between the first outflow pipe 13 and the second outflow pipe 14.

[0052] This makes it easier for the fluid F to flow into the first outflow pipe 13, which has a large back pressure. Therefore, the fluid F can be distributed to the first outflow pipe 13 and the second outflow pipe 14 at a distribution ratio close to the target distribution ratio (X1:X2). Therefore, it is possible to prevent the actual distributed flow rate of refrigeration oil from deviating from the target distributed flow rate (hereinafter referred to as the "target flow rate").

[0053] In this embodiment, the first outflow pipe 13 is a curved pipe having a first curved portion 19 on the downstream side, and the second outflow pipe 14 is a straight pipe that extends linearly.

[0054] This increases the options for the shape of the first outflow pipe 13. Here, the first curved portion 19 increases the back pressure that the fluid F receives in the first outflow pipe 13, making it difficult for the fluid F to flow into the first outflow pipe 13. However, as described above, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is set so that the ratio of the value of the first outflow pipe 13 is large, so the fluid F easily flows into the first outflow pipe 13, which has a large back pressure. Therefore, while increasing the options for the shape of the first outflow pipe 13, the fluid F can be distributed to the first outflow pipe 13 and the second outflow pipe 14 at a distribution ratio close to the target distribution ratio (X1:X2). Therefore, it is possible to prevent the actual distributed flow rate of refrigeration oil from deviating from the target flow rate while improving convenience.

[0055] In the first refrigerant distribution pipe 10a of this embodiment, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is set to 1:1.

[0056] This allows the distribution ratio of the fluid F between the first outflow pipe 13 and the second outflow pipe 14 to be close to 1:2.

[0057] In the second refrigerant distribution pipe 10b of this embodiment, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is set to 2:1.

[0058] This allows the distribution ratio of the fluid F between the first outflow pipe 13 and the second outflow pipe 14 to be close to 1:1. The cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is not limited to 1:1 or 2:1, and can be changed appropriately depending on the flow rate of the fluid F. In order to make the distribution ratio (X1:X2) of the fluid F between the first outflow pipe 13 and the second outflow pipe 14 1:1, it is preferable that the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 be 2:1. However, for example, when the cross-sectional area S2 of the second outflow pipe 14 is 1, the cross-sectional area S1 of the first outflow pipe 13 may be 1.2 to 3.

[0059] <Modification of the first embodiment> Next, a modified example of the first embodiment will be described with reference to FIG. In this modification, the first refrigerant distribution pipe 10a and the second refrigerant distribution pipe 10b have the same configuration. The configuration of this modification will be described below using the first refrigerant distribution pipe 10a as an example.

[0060] As shown in FIG. 5, in this modification, the second outflow pipe 14 is a curved pipe having a third straight pipe portion 41, a second curved portion 42, and a fourth straight pipe portion 43.

[0061] The third straight pipe section 41 extends linearly from the connecting section 12 in the extension direction De. The second curved section 42 is provided at the end of the third straight pipe section 41 opposite the connecting section 12 in the extension direction De. In other words, the second curved section 42 is located downstream of the third straight pipe section 41. The second curved section 42 curves in the first direction D1 so as to move away from the first outlet opening 16 as it moves away from the third straight pipe section 41 in the extension direction De. The fourth straight pipe section 43 extends linearly from the second curved section 42.

[0062] Both the first outflow pipe 13 and the second outflow pipe 14 are curved pipes, but the curvature of the first curved section 19 of the first outflow pipe 13 is greater than the curvature of the second curved section 42 of the second outflow pipe 14. Therefore, the pressure that the fluid F flowing through the first outflow pipe 13 receives when it collides with the wall surface of the first curved section 19 is greater than the pressure that the fluid F flowing through the second outflow pipe 14 receives when it collides with the wall surface of the second curved section 42. In other words, the back pressure in the opposite direction to the flow direction of the fluid F is greater in the first outflow pipe 13 than in the second outflow pipe 14.

[0063] (Action and effect) The refrigerant distribution pipe 10 having the above configuration can exhibit the following effects.

[0064] In this modification, the first outflow pipe 13 is a curved pipe having a first curved portion 19 on the downstream side, and the second outflow pipe 14 is a curved pipe having a second curved portion 42 on the downstream side. The curvature of the first curved portion 19 is greater than the curvature of the second curved portion 42.

[0065] This further increases the options for the shapes of the first outflow pipe 13 and the second outflow pipe 14. Because the curvature of the first curved portion 19 is greater than that of the second curved portion 42, the back pressure that the fluid F receives in the first outflow pipe 13 is greater than that in the second outflow pipe 14. This makes it difficult for the fluid F to flow into the first outflow pipe 13. However, as described above, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13 and the second outflow pipe 14 is set so that the ratio of the value of the first outflow pipe 13 is greater. This makes it easier for the fluid F to flow into the first outflow pipe 13, which has a greater back pressure. This increases the options for the shapes of the first outflow pipe 13 and the second outflow pipe 14, while allowing the fluid F to be distributed to the first outflow pipe 13 and the second outflow pipe 14 at a distribution ratio close to the target distribution ratio (X1:X2). This further improves convenience and prevents the actual distributed flow rate of refrigeration oil from deviating from the target flow rate.

[0066] In the first embodiment, examples where the back pressure of the first outflow pipe 13 is greater than the back pressure of the second outflow pipe 14 have been described, such as when the first outflow pipe 13 is a curved pipe and the second outflow pipe 14 is a straight pipe, or when the curvature of the first curved portion 19 of the first outflow pipe 13 is greater than the curvature of the second curved portion 42 of the second outflow pipe 14. However, the present invention is not limited to these examples. For example, even if both the first outflow pipe 13 and the second outflow pipe 14 are straight pipes, the back pressure of the first outflow pipe 13 will be greater than the back pressure of the second outflow pipe 14 even if there is a curved portion downstream of and near the first outflow pipe 13.

[0067] In the first embodiment, the cross sections of the inlet pipe 11, the first outlet pipe 13, and the second outlet pipe 14 in the flow direction are circular, but this is not limiting. The cross sections of the inlet pipe 11, the first outlet pipe 13, and the second outlet pipe 14 in the flow direction may be polygonal, or may be irregularly shaped with a protruding or recessed portion.

[0068] Second Embodiment A refrigerant distribution pipe 210 and an air conditioning apparatus 100 according to a second embodiment of the present disclosure will be described below with reference to Figures 6 to 8. Configurations similar to those in the first embodiment will be given the same names and symbols as in the first embodiment, and descriptions thereof will be omitted as appropriate. In this embodiment, the first refrigerant distribution pipe 210a and the second refrigerant distribution pipe 210b have the same configuration. The configuration of this embodiment will be described below using the first refrigerant distribution pipe 210a as an example.

[0069] 6, the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 are located on one side in the second direction D2 with respect to the center 15a of the cross section of the inlet opening 15. Here, the center 15a of the cross section of the inlet opening 15 is the center of gravity of the cross section of the inlet opening 15, the center 16a of the cross section of the first outlet opening 16 is the center of gravity of the cross section of the first outlet opening 16, and the center 17a of the cross section of the second outlet opening 17 is the center of gravity of the cross section of the second outlet opening 17. In this embodiment, the cross sections of the first outlet opening 16 and the second outlet opening 17 are formed in a circular shape.

[0070] Furthermore, the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 are located closer to the center 15a of the inlet opening 15 in the first direction D1 than the ends 11a1 on both sides of the outer wall surface 11a of the inlet pipe 11. In the illustrated example, the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 are located closer to the center 15a of the inlet opening 15 than the outer wall surface 11a of the inlet pipe 11 (more radially inward from the outer wall surface 11a of the inlet pipe 11) when viewed from the extension direction De. Note that the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 may be located farther from the center 15a of the cross section of the inlet opening 15 than the outer wall surface 11a of the inlet pipe 11 (more radially outward from the outer wall surface 11a of the inlet pipe 11) when viewed from the extension direction De. Furthermore, in the first direction D1, the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 may be located outside the tangent to the outer wall surface 11a at the end 11a1 or on the tangent to the outer wall surface 11a at the end 11a1 when viewed from the extension direction De.

[0071] Furthermore, the center 21 of the cross section of the inlet pipe 11 is located on the other side of the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 throughout the entire inlet pipe 11 in the second direction D2.

[0072] Furthermore, the center 222 of the cross section of the first outlet pipe 213 is located on one side in the second direction D2 of the center 15a of the cross section of the inlet opening 15 throughout the first outlet pipe 213. Furthermore, the center 223 of the cross section of the second outlet pipe 214 is located on one side in the second direction D2 of the center 15a of the cross section of the inlet opening 15 throughout the second outlet pipe 214. Here, the center 21 of the cross section of the inlet pipe 11 is the center of gravity of the cross-sectional shape of the inlet pipe 11, the center 222 of the first outlet pipe 213 is the center of gravity of the cross-sectional shape of the first outlet pipe 213, and the center 223 of the cross section of the second outlet pipe 214 is the center of gravity of the cross-sectional shape of the second outlet pipe 214. In this embodiment, the entire first outlet pipe 213 and the entire second outlet pipe 214 are located on one side in the second direction D2 of the center 21 of the cross section of the inlet pipe 11.

[0073] Furthermore, in this embodiment, at the branch portion 12c of the connection portion 12, the connection wall 12d is curved so as to protrude toward the center 15a of the inlet opening 15 in the second direction D2 as viewed from the extension direction De. Therefore, the first outlet pipe 13 and the second outlet pipe 14 are disposed closer to the inlet pipe 11 in the first direction D1. More specifically, near the connection portion 12, the center 222 of the cross section of the first outlet pipe 213 and the center 223 of the cross section of the second outlet pipe 214 are located closer to the center 21 of the inlet pipe 11 than the ends 11a1 on both sides of the outer wall surface 11a of the inlet pipe 11 in the first direction D1. In the illustrated example, near the connection portion 12, the center 222 of the cross section of the first outlet pipe 213 and the center 223 of the cross section of the second outflow pipe 214 are located closer to the center 21 of the inlet pipe 11 than the outer wall surface 11a of the inlet pipe 11 as viewed from the extension direction De (radially inward from the outer wall surface 11a of the inlet pipe 11).

[0074] In this embodiment, at the connection portion 12, the center 15a of the inlet opening 15 and the center 21 of the cross section of the inlet pipe 11 overlap in the extension direction De, the center 16a of the first outlet opening 16 and the center 22 of the cross section of the first outlet pipe 13 overlap in the extension direction De, and the center 17a of the second outlet opening 17 and the center 23 of the cross section of the second outlet pipe 14 overlap in the extension direction De.

[0075] (Action and effect) The refrigerant distribution pipe 210 having the above configuration can exhibit the following effects.

[0076] In this embodiment, the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 are located on one side of the center 15a of the cross section of the inlet opening 15 in the second direction D2.

[0077] As a comparative example, consider a conventional refrigerant distribution pipe 210R as shown in FIG. 7. This refrigerant distribution pipe 210R includes an inlet pipe 11R, a connection portion 12R, a first outlet pipe 213R, and a second outlet pipe 214R. The center 16aR of the cross section of the first outlet opening 16R and the center 17aR of the cross section of the second outlet opening 17R are located at the same position in the second direction D2 relative to the center 15aR of the inlet opening 15. In this refrigerant distribution pipe 210R, at the connection portion 12R, the center 15aR of the cross section of the inlet opening 15R and the center 21R of the cross section of the inlet pipe 11R overlap in the extension direction De, the center 16aR of the cross section of the first outlet opening 16R and the center 222R of the cross section of the first outlet pipe 213R overlap in the extension direction De, and the center 17aR of the cross section of the second outlet opening 17R and the center 223R of the cross section of the second outlet pipe 14R overlap in the extension direction De. Therefore, the center 222R of the cross section of the first outflow pipe 213R and the center 223R of the cross section of the second outflow pipe 214R are located at the same position in the second direction D2 with respect to the center 21R of the inflow pipe 211R. Such a refrigerant distribution pipe 210R is usually installed so that the inflow pipe 11R is along a horizontal plane.

[0078] When the refrigerant distribution pipe 210R is not filled with the fluid F, for example, if the refrigerant distribution pipe 210R is installed at an angle so that the first direction D1 intersects with a horizontal plane, the liquid level S of the fluid F will be inclined with respect to the first direction D1 as shown in Fig. 7. Also, if the downstream side of the first outflow pipe 213R is a curved pipe, the fluid F will be subjected to back pressure in the curved pipe in the opposite direction to the flow direction, and the liquid level S of the fluid F will be inclined with respect to the first direction D1.

[0079] When the liquid level S of the fluid F is inclined with respect to the first direction D1, the amount of the fluid F distributed between the first outflow pipe 213R and the second outflow pipe 214R becomes significantly unbalanced. As a result, in the conventional refrigerant distribution pipe 210R, the actual distributed flow rate of the refrigeration oil significantly deviates from the target distributed flow rate. In addition, Figure 7 illustrates both the case where the liquid level S of the fluid F is a high liquid level HS and the case where the liquid level S is a low liquid level LS, and in both cases, the amount of fluid F distributed between the first outflow pipe 13R and the second outflow pipe 14R is significantly biased.

[0080] In contrast, according to the present embodiment, when the refrigerant distribution pipe 210 is installed so that the inlet pipe 11 is aligned along a horizontal plane, both the first outflow pipe 213 and the second outflow pipe 214 can be arranged vertically below the inflow pipe 11. As a result, even if the liquid level S of the fluid F is inclined with respect to the first direction D1 as shown in FIG. 8 , unevenness in the amount of fluid F distributed between the first outflow pipe 213 and the second outflow pipe 214 is suppressed. Whether the liquid level S of the fluid F is high HS or low LS, unevenness in the amount of fluid F distributed between the first outflow pipe 213 and the second outflow pipe 214 is suppressed. Therefore, unevenness in the amount of refrigeration oil supplied to each outdoor unit 2 can be suppressed. This further suppresses deviation of the actual distributed flow rate of refrigeration oil from the target flow rate.

[0081] In this embodiment, the entire first outlet pipe 213 and the entire second outlet pipe 214 are located on one side of the center 15a of the cross section of the inlet opening 15 in the second direction D2.

[0082] This further reduces the unevenness in the amount of fluid F distributed between the first outflow pipe 213 and the second outflow pipe 214. This further reduces the unevenness in the amount of refrigerating machine oil supplied to each outdoor unit 2. This further reduces the deviation of the actual distributed flow rate of refrigerating machine oil from the target flow rate.

[0083] In this embodiment, at the connection portion 12, the center 222 of the cross section of the first outflow pipe 213 and the center 223 of the cross section of the second outflow pipe 214 are located closer to the center 21 of the cross section of the inflow pipe 11 in the first direction D1 than the ends 11a1 on both sides of the outer wall surface 11a of the inflow pipe 11.

[0084] This further reduces the unevenness in the amount of fluid F distributed between the first outflow pipe 213 and the second outflow pipe 214. This further reduces the unevenness in the amount of refrigerating machine oil supplied to each outdoor unit 2. This further reduces the deviation of the actual distributed flow rate of refrigerating machine oil from the target flow rate.

[0085] In the second embodiment, the cross sections of the inlet pipe 11, the first outlet pipe 213, and the second outlet pipe 214 in the flow direction are circular, but this is not limited to this. In the second embodiment, the cross sections of the inlet pipe 11, the first outlet pipe 213, and the second outlet pipe 214 in the flow direction may be polygonal or may be distorted with a protruding or recessed portion. In this case, too, the center 21 of the cross section of the inlet pipe 11 is the center of gravity of the cross section of the inlet pipe 11, the center 222 of the first outlet pipe 213 is the center of gravity of the cross section of the first outlet pipe 213, and the center 223 of the cross section of the second outlet pipe 214 is the center of gravity of the cross section of the second outlet pipe 214.

[0086] <Third embodiment> A refrigerant distribution pipe 310 and an air conditioning apparatus 100 according to a third embodiment of the present disclosure will be described below with reference to Figures 9 to 12. Configurations similar to those in the above embodiment will be given the same names and symbols as in the above embodiment, and descriptions thereof will be omitted as appropriate.

[0087] 9, in the refrigerant distribution pipe 310 of this embodiment, the first outlet pipe 313 and the second outlet pipe 314 are rectangular pipes. The shapes of the first outlet pipe 313 and the second outlet pipe 314 will be described using the second refrigerant distribution pipe 310b as an example, and description of the first refrigerant distribution pipe 310a will be omitted as appropriate.

[0088] In a cross-sectional view perpendicular to the extension direction De, the cross section of the first outflow pipe 313 and the cross section of the second outflow pipe 314 are formed into a rectangular shape having one side extending in the second direction D2. Furthermore, the first outflow pipe 313 is formed so that both ends of the first outflow pipe 313 in the second direction D2 overlap with both ends of the inflow pipe 11 in the second direction D2 in the extension direction De. Similarly, the second outflow pipe 314 is formed so that both ends of the second outflow pipe 314 in the second direction D2 overlap with both ends of the inflow pipe 11 in the second direction D2 in the extension direction De.

[0089] Furthermore, in the second refrigerant distribution pipe 310b, similarly to the first embodiment, the cross-sectional area S1 of the first outflow pipe 313 is designed to be larger than the cross-sectional area S2 of the second outflow pipe 314. More specifically, while the dimensions L2a, L2b in the second direction D2 of both the first outflow pipe 313 and the second outflow pipe 314 are maintained, the dimension L1a in the first direction D1 of the first outflow pipe 313 is made larger than the dimension L1b in the first direction D1 of the second outflow pipe 314.

[0090] (Action and effect) The refrigerant distribution pipe 310 having the above configuration can exhibit the following effects.

[0091] In this embodiment, the first outflow pipe 313 and the second outflow pipe 314 are rectangular pipes, and when viewed in a cross section perpendicular to the extension direction De, the cross section of the first outflow pipe 313 and the cross section of the second outflow pipe 314 are shaped like a rectangle along the first direction D1 and the second direction D2.

[0092] As a comparative example, consider a conventional refrigerant distribution pipe 310R as shown in Fig. 10. In this refrigerant distribution pipe 310R, the cross sections of the first outflow pipe 313R and the second outflow pipe 314R are circular when viewed in a cross section perpendicular to the extension direction De. This type of refrigerant distribution pipe 310R is usually installed so that the inflow pipe 11R is aligned along a horizontal plane.

[0093] 10, when the liquid level S of the fluid F changes, the cross-sectional area ratio of the fluid F between the first outflow pipe 313R and the second outflow pipe 314R changes. Therefore, in the conventional refrigerant distribution pipe 310R, the actual distributed flow rate of the refrigeration oil significantly deviates from the target flow rate.

[0094] In contrast, according to this embodiment, by installing the refrigerant distribution pipe 310 so that the inlet pipe 11 is along a horizontal plane, the first outlet pipe 313 and the second outlet pipe 314 can be arranged so that the rectangular cross section of the first outlet pipe 313 and the rectangular cross section of the second outlet pipe 314 extend in the vertical direction, as shown in Fig. 11. This makes it possible to maintain a constant cross-sectional area ratio of the fluid F between the first outlet pipe 313 and the second outlet pipe 314, even if the liquid level S of the fluid F changes. This further prevents the actual distributed flow rate of refrigeration oil from deviating from the target flow rate.

[0095] 12, the configuration of the third embodiment may be combined with not only the first embodiment but also the second embodiment. That is, the first outflow pipe 313 and the second outflow pipe 314 may be formed into a rectangular shape as described above, and in each refrigerant distribution pipe 10, the cross-sectional area ratio (S1:S2) between the first outflow pipe 313 and the second outflow pipe 314 may be set so that the ratio of the value of the first outflow pipe 313 to the value of the second outflow pipe 314 is larger than the target distribution ratio (X1:X2) of the fluid F between the first outflow pipe 313 and the second outflow pipe 314. Furthermore, the center 16a of the cross section of the first outflow opening 16 and the center 17a of the cross section of the second outflow opening 17 may be located on one side of the center 15a of the cross section of the inflow opening 15 in the second direction D2. Furthermore, the entire first outflow pipe 313 and the entire second outflow pipe 314 may be located on one side of the center 15a of the cross section of the inflow opening 15 in the second direction D2. Furthermore, the center 16a of the cross section of the first outlet opening 16 and the center 17a of the cross section of the second outlet opening 17 may be located closer to the center 15a of the cross section of the inlet opening 15 than the ends 11a1 on both sides of the outer wall surface 11a of the inlet pipe 11 in the first direction D1.

[0096] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure. In the above embodiment, an example has been described in which three indoor units 1 and three outdoor units 2 are provided, but this is not limited to this. As long as multiple outdoor units 2 are provided, the number of indoor units 1 and outdoor units 2 installed can be changed as appropriate. For example, two indoor units 1 and two outdoor units 2 may be provided. When there are two outdoor units 2, only one second refrigerant distribution pipe 10b, 210b, 310b may be provided as the refrigerant distribution pipe 10, 210, 310.

[0097] <Additional Notes> The refrigerant distribution pipe and the air conditioning apparatus described in each embodiment can be understood, for example, as follows.

[0098] (1) The refrigerant distribution pipe 10, 210, 310 according to the first aspect is used in a refrigerant pipe 3 connecting a plurality of outdoor units 2 each having a compressor 2a to an indoor unit 1, and distributes a fluid F containing an air-conditioning refrigerant and a refrigerating machine oil for lubricating the compressor 2a to the plurality of outdoor units 2, and includes an inlet pipe 11 into which the fluid F flows, a first outlet pipe 13, 213, 313 from which the fluid F flows out to the outdoor units 2, and a second outlet pipe 13, 213, 313 from which the fluid F flows out to the outdoor units 2 different from the outdoor units 2 to which the fluid F flows out from the first outlet pipe 13, 213, 313. 4, 214, 314, and the first outflow pipes 13, 213, 313 have a higher back pressure in the direction opposite to the flow direction of the fluid F than the second outflow pipes 14, 214, 314, and the cross-sectional area ratio between the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314 is set so that the ratio of the value of the first outflow pipes 13, 213, 313 to the value of the second outflow pipes 14, 214, 314 is larger than the target distribution ratio of the fluid F between the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314.

[0099] This makes it easier for the fluid F to flow into the first outflow pipes 13, 213, 313, which have a large back pressure. Therefore, the fluid F can be distributed to the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314 at a distribution ratio close to the target distribution ratio.

[0100] (2) The second embodiment of refrigerant distribution is the refrigerant distribution pipe 10, 210, 310 of (1), in which the first outflow pipe 13, 213, 313 is a curved pipe having a first curved portion 19 on the downstream side, and the second outflow pipe 14, 214, 314 may be a straight pipe extending in a straight line.

[0101] This increases the options for the shape of the first outflow pipes 13, 213, 313. Here, the first curved portion 19 increases the back pressure that the fluid F receives in the first outflow pipes 13, 213, 313, making it difficult for the fluid F to flow into the first outflow pipes 13, 213, 313. However, as described above, the cross-sectional area ratio between the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314 is set so that the ratio of the value of the first outflow pipes 13, 213, 313 is large, so the fluid F easily flows into the first outflow pipes 13, 213, 313, which have a large back pressure. Therefore, while increasing the options for the shape of the first outflow pipes 13, 213, 313, it is possible to distribute the fluid F to the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314 at a distribution ratio close to a target distribution ratio.

[0102] (3) The refrigerant distribution pipe 10, 210, 310 of the third aspect is the refrigerant distribution pipe 10, 210, 310 of (1), wherein the first outflow pipe 13, 213, 313 is a curved pipe having a first curved portion 19 on the downstream side, and the second outflow pipe 14, 214, 314 is a curved pipe having a second curved portion 42 on the downstream side, and the curvature of the first curved portion 19 may be greater than the curvature of the second curved portion 42.

[0103] This further increases the options for the shapes of the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314. Note that because the curvature of the first curved portion 19 is greater than that of the second curved portion 42, the back pressure that the fluid F receives in the first outflow pipes 13, 213, 313 is greater than that in the second outflow pipes 14, 214, 314. This makes it difficult for the fluid F to flow into the first outflow pipes 13, 213, 313, but as described above, the cross-sectional area ratio between the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314 is set so that the ratio of the value for the first outflow pipes 13, 213, 313 is greater, so the fluid F also easily flows into the first outflow pipes 13, 213, 313, which have a greater back pressure. Therefore, while increasing the options for the shapes of the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314, it is possible to distribute the fluid F to the first outflow pipes 13, 213, 313 and the second outflow pipes 14, 214, 314 at a distribution ratio close to the target distribution ratio.

[0104] (4) The air conditioning apparatus 100 of the fourth aspect comprises the refrigerant pipe 3 having the refrigerant distribution pipe 10, 210, 310 described in any one of (1) to (3), a plurality of the outdoor units 2, and the indoor unit 1. [Explanation of symbols]

[0105] 1...indoor unit, 2...outdoor unit, 2a...compressor, 3...refrigerant pipe, 3a...gas pipe, 3b...liquid pipe, 4...control unit, 5...indoor gas pipe, 6...main pipe, 7...outdoor branch pipe, 7a...first outdoor branch pipe, 7b...second outdoor branch pipe, 10...refrigerant distribution pipe, 10a...first refrigerant distribution pipe, 10b...second refrigerant distribution pipe, 100...air conditioner, 11...inlet pipe, 11a1...end, 12...connection section, 12a...inlet section, 12b...tapered section, 12c...branch section, 13...first outflow pipe, 14...second outflow pipe, 15...inflow opening, 15a...center, 16...first outflow opening, 16a...center, 17...second outflow opening, 18...first straight pipe section, 19...first curved section, 20...second straight pipe section , 41...third straight pipe section, 42...second curved section, 43...fourth straight pipe section, De...extension direction, D1...first direction, D2...second direction, F...fluid, 41...third straight pipe section, 42...second curved section, 43...fourth straight pipe section, 210...refrigerant distribution pipe, 210a...first refrigerant distribution pipe, 210b...second refrigerant distribution pipe, 11a...outer wall surface, 21...center, 213...first outflow pipe, 214...second outflow pipe, 222...center, 223...center, 310...refrigerant distribution pipe, 310a...first refrigerant distribution pipe, 310b...second refrigerant distribution pipe, 313...first outflow pipe, 314...second outflow pipe, 322...center, 323...center, L1a...dimension, L2a...dimension, L1b...dimension, L2b...dimension

Claims

1. A refrigerant distribution pipe is used in a refrigerant pipe connecting a plurality of outdoor units having compressors to indoor units, and distributes a fluid containing an air-conditioning refrigerant and a refrigerating machine oil for lubricating the compressors to the plurality of outdoor units, an inlet pipe into which the fluid flows; a first outflow pipe through which the fluid flows to the outdoor unit; a second outlet pipe that causes the fluid to flow out to an outdoor unit different from the outdoor unit that is the destination of the fluid from the first outlet pipe; Equipped with The first outflow pipe has a larger back pressure in the opposite direction to the flow direction of the fluid than the second outflow pipe, a cross-sectional area ratio between the first outflow pipe and the second outflow pipe is set so that the ratio of the value of the first outflow pipe to the value of the second outflow pipe is larger than a target distribution ratio of the fluid between the first outflow pipe and the second outflow pipe.

2. 2. The refrigerant distribution pipe according to claim 1, wherein the first outlet pipe is a curved pipe having a first curved portion on a downstream side, and the second outlet pipe is a straight pipe extending linearly.

3. the first outflow pipe is a curved pipe having a first curved portion on a downstream side, the second outflow pipe is a curved pipe having a second curved portion on the downstream side, The refrigerant distribution pipe according to claim 1 , wherein the curvature of the first curved portion is greater than the curvature of the second curved portion.

4. The refrigerant pipe is provided with the refrigerant distribution pipe according to claim 1 or 2; A plurality of the outdoor units; The indoor unit; An air conditioning device comprising:

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