WO2025197923A1 - Refrigerant distribution pipe and air conditioner - Google Patents

Abstract

A refrigerant distribution pipe according to the present disclosure comprises: an inflow pipe into which a fluid flows; a connection part which extends in one direction from an end of the inflow pipe, has an inflow opening communicating with the inflow pipe at the end on the inflow pipe side in the extension direction, and has a first outflow opening and second outflow opening provided side by side in a first direction orthogonal to the extension direction at the end on the side opposite the inflow pipe in the extension direction; a first outflow pipe which communicates with the connection part through the first outflow opening and through which the fluid flows out to an outdoor unit; and a second outflow pipe which communicates with the connection part through the second outflow opening and through which the fluid flows out to an outdoor unit different from the outdoor unit of the outflow destination from the first outflow pipe. The cross-sectional center of the first outflow opening and the cross-sectional center of the second outflow opening are positioned, relative to the cross-sectional center of the inflow opening, to one side in a second direction orthogonal to the extension direction and the first direction.

Description

Refrigerant distribution pipe and air conditioning device

The present disclosure relates to a refrigerant distribution pipe and an air conditioning apparatus.
This application claims priority to Japanese Patent Application No. 2024-042417 filed in Japan on March 18, 2024, and Japanese Patent Application No. 2024-042476 filed in Japan on March 18, 2024, the contents of which are incorporated herein by reference.

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 expansion section that expands 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 expansion section and branch off in two directions.

Japanese Patent Application Laid-Open No. 2008-2679

However, when using the distribution pipe disclosed in Patent Document 1 and other documents, depending on the installation orientation and shape of the distribution pipe, the actual flow rate of refrigeration oil distributed by the distribution pipe may deviate significantly from the target distribution flow rate (hereinafter referred to as the "target flow rate").

The present disclosure has been made to solve the above-mentioned problems, and aims to provide a refrigerant distribution pipe and an air conditioner that can prevent the actual distribution flow rate of refrigeration oil from deviating from the target flow rate.

In order to solve the above problem, the refrigerant distribution pipe of the present disclosure is used in a refrigerant pipe connecting multiple outdoor units and indoor units each having a compressor, and distributes a fluid containing an air-conditioning refrigerant and refrigeration oil for lubricating the compressor to the multiple outdoor units, and comprises an inlet pipe into which the fluid flows, and an inlet opening extending in one direction from the end of the inlet pipe, having an inlet opening communicating with the inlet pipe at the end on the inlet pipe side in the extension direction, and being arranged side by side in a first direction perpendicular to the extension direction at the end on the opposite side from the inlet pipe in the extension direction. a connecting portion having a first outlet opening and a second outlet opening, a first outlet pipe communicating with the connecting portion at the first outlet opening and discharging the fluid to the outdoor unit, and a second outlet pipe communicating with the connecting portion at the second outlet opening and discharging the fluid to an outdoor unit different from the outdoor unit to which the fluid is directed from the first outlet pipe, wherein the center of the cross section of the first outlet opening and the center of the cross section of the second outlet opening are located on one side of the center of the cross section of the inlet opening in a second direction perpendicular to the extension direction and the first direction.

The refrigerant distribution pipe according to the present disclosure is used in a refrigerant pipe connecting multiple outdoor units and indoor units each having a compressor, and distributes a fluid containing an air-conditioning refrigerant and refrigeration oil for lubricating the compressor to the multiple outdoor units. The refrigerant distribution pipe comprises an inlet pipe into which the fluid flows, and a refrigerant pipe extending in one direction from the end of the inlet pipe, having an inlet opening communicating with the inlet pipe at the end on the inlet pipe side in the extension direction, and a refrigerant pipe provided at the end opposite the inlet pipe in the extension direction, aligned in a first direction perpendicular to the extension direction. a connecting portion having a first outlet opening and a second outlet opening, a first outlet pipe that communicates with the connecting portion at the first outlet opening and allows the fluid to flow to the outdoor unit, and a second outlet pipe that communicates with the connecting portion at the second outlet opening and allows the fluid to flow from the first outlet pipe to an outdoor unit different from the outdoor unit to which it is directed; the cross sections of the first outlet pipe and the second outlet pipe are shaped like rectangles with one side extending in the extension direction and a second direction perpendicular to the first direction.

The air conditioning apparatus according to the present disclosure includes a refrigerant pipe having any one of the above-described refrigerant distribution pipes, a plurality of the outdoor units, and the indoor units.

The refrigerant distribution pipe according to the present disclosure is used in a refrigerant pipe connecting multiple outdoor units with compressors and indoor units, and distributes a fluid containing air-conditioning refrigerant and refrigeration oil for lubricating the compressors to the multiple outdoor units. The refrigerant distribution pipe comprises an inlet pipe into which the fluid flows, a first outlet pipe through which the fluid flows to the outdoor units, and a second outlet pipe through which the fluid flows from the first outlet pipe to an outdoor unit different from the destination outdoor unit. The first outlet pipe has a higher back pressure in the direction opposite to the flow direction of the fluid than the second outlet pipe, and the 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 the target distribution ratio of the fluid between the first outflow pipe and the second outflow pipe.

The air conditioning apparatus according to the present disclosure comprises the refrigerant pipe having the above-described refrigerant distribution pipe, a plurality of the outdoor units, and the indoor units.

The refrigerant distribution pipe and air conditioning system disclosed herein can prevent the actual distribution flow rate of refrigeration oil from deviating from the target flow rate.

1 is an overall configuration diagram of an air conditioning apparatus according to a first embodiment of the present disclosure. FIG. 2 is a plan view of a refrigerant distribution pipe according to the first embodiment of the present disclosure. FIG. 2 is a side view of the refrigerant distribution pipe according to the first embodiment of the present disclosure. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. FIG. 10 is a diagram illustrating a case where a refrigerant distribution pipe according to a comparative example to the first embodiment of the present disclosure is used. 4A to 4C are diagrams illustrating the effects of the refrigerant distribution pipe according to the first embodiment of the present disclosure. FIG. 4 is a cross-sectional view of a refrigerant distribution pipe according to a modified example of the first embodiment of the present disclosure. FIG. 10 is a cross-sectional view of a refrigerant distribution pipe according to a second embodiment of the present disclosure. FIG. 10 is a diagram illustrating a case where a refrigerant distribution pipe according to a comparative example to the second embodiment of the present disclosure is used. 10A and 10B are diagrams illustrating the effects of the refrigerant distribution pipe according to the second embodiment of the present disclosure. FIG. 10 is a cross-sectional view of a refrigerant distribution pipe according to a modified example of the second embodiment of the present disclosure. FIG. 10 is a plan view of a refrigerant distribution pipe according to a third embodiment of the present disclosure. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12. 14 is a cross-sectional view taken along line XIV-XIV in FIG. 12. FIG. 11 is a plan view of a refrigerant distribution pipe according to a modified example of the third embodiment of the present disclosure. FIG. 10 is a cross-sectional view of a refrigerant distribution pipe according to a fourth embodiment of the present disclosure. FIG. 13 is a diagram illustrating a case where a refrigerant distribution pipe according to a comparative example to the fourth embodiment of the present disclosure is used. 10A and 10B are diagrams illustrating the effects of the refrigerant distribution pipe according to the fourth embodiment of the present disclosure. FIG. 10 is a cross-sectional view of a refrigerant distribution pipe according to a fifth embodiment of the present disclosure. FIG. 13 is a diagram illustrating a case where a refrigerant distribution pipe according to a comparative example to the fifth embodiment of the present disclosure is used. 13A to 13C are diagrams illustrating the effects of the refrigerant distribution pipe according to the fifth embodiment of the present disclosure. FIG. 13 is a cross-sectional view of a refrigerant distribution pipe according to a modified example of the fifth embodiment of the present disclosure.

First Embodiment
(Configuration of air conditioning device)
Hereinafter, a refrigerant distribution pipe 10 and an air conditioning apparatus 100 according to a first embodiment of the present disclosure will be described with reference to Figs. 1 to 7 .
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, which is provided with multiple indoor units 1. 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.

Each indoor unit 1 is equipped with a cooling expansion valve (not shown) and an indoor heat exchanger (not shown). Each outdoor unit 2 is equipped with a compressor 2a, an outdoor heat exchanger (not shown), and a heating expansion valve (not shown).

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 described below is not performed.

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 the first refrigerant distribution pipe 10a, and the other is designated as the second refrigerant distribution pipe 10b.

The indoor gas pipe 5 connects multiple indoor units 1 to the main pipe 6, which in turn connects the indoor gas pipe 5 to the first refrigerant distribution pipe 10a. The main pipe 6 is a straight pipe, for example, with a length of 500 mm or more.

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, the first outdoor branch pipe 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.

The air conditioning apparatus 100 described above can perform a cooling operation to cool the indoor air and a 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.

During cooling operation, the 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 the outside 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 in the indoor heat exchanger and turned into gas flows into the outdoor unit 2 via gas pipe 3a and is sent to the compressor 2a.

During heating operation, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator. The refrigerant circuit is made up of the compressor 2a, indoor heat exchanger, heating expansion valve, and outdoor heat exchanger.

During heating operation, a four-way valve (not shown) installed in the outdoor unit 2 is switched to a different direction than 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 into the outdoor unit 2 through the liquid pipe 3b. 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 outside air. This gas refrigerant is then sent to the compressor 2a of the outdoor unit 2.

Furthermore, refrigeration oil is used in the compressor 2a of the outdoor unit 2 of the air conditioning system 100 to lubricate the sliding parts inside the compressor 2a. The refrigeration oil prevents burnout in the compressor 2a. Some of this refrigeration oil flows through the refrigerant circuits, including the indoor heat exchanger and outdoor heat exchanger, along with the refrigerant discharged from the compressor 2a, and is then recovered back into the compressor 2a.

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 device 100 of this embodiment, a so-called oil return operation is performed to periodically recover refrigeration oil to the compressor 2a side in order to recover refrigeration oil that has adhered and accumulated on the heat exchanger or the inner walls of the refrigerant pipes 3.

During oil return operation, the control unit 4 controls the refrigerant flow rate so that the compressors 2a in all outdoor units 2 draw in and discharge the same amount of refrigerant. This ensures that refrigeration oil is recovered evenly in all outdoor units 2.

The oil return operation will be described below.
During cooling operation, the control unit 4 starts a 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. 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.

On the other hand, during heating operation, the control unit 4 starts refrigeration oil recovery operation at a specified timing. During refrigeration oil recovery operation during heating, the fan in the indoor unit 1 is first stopped to stop 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 through the liquid pipe 3b to the indoor unit 1. The liquid refrigerant does not undergo heat exchange in the indoor heat exchanger, and is guided back to the outdoor unit 2 via the gas pipe 3a 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 refrigeration oil that has dispersed in the indoor heat exchanger and liquid pipe 3b to be returned to the compressor 2a.

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.

(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 refrigerating machine 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.

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 second refrigerant distribution pipe 10b as an example, and the description of the configuration of the first refrigerant distribution pipe 10a will be omitted as appropriate.

As shown in FIG. 2, the second refrigerant distribution pipe 10 b includes an inlet pipe 11 , a connection portion 12 , a first outlet pipe 13 , and a second outlet pipe 14 .
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, which 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.

The inlet pipe 11 opens on the indoor unit 1 side. During oil return operation, a fluid F containing refrigerant and lubricating refrigeration oil flows into the inlet pipe 11. The inlet pipe 11 of the second refrigerant distribution pipe 10b 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.

The connection 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.

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

The inlet portion 12a is provided at the end of the connection 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 is connected to the inlet pipe 11. Fluid F is supplied to the inlet opening 15 from the inlet pipe 11.

The tapered portion 12b extends from the inlet portion 12a in the extension direction De on the opposite side to the inlet pipe 11. When viewed from the second direction D2, the tapered portion 12b is formed in a tapered (trapezoidal) shape that gradually widens in the first direction D1 as it moves away from the inlet portion 12a in the extension direction De. Also, as shown in Figure 3, when viewed from the first direction D1, the tapered portion 12b gradually inclines to one side in the second direction D2 as it moves away from the inlet portion 12a in the extension direction De. The surface of the tapered portion 12b on the other side in the second direction D2 has a smaller inclination angle than the surface of the tapered portion 12b on one side in the second direction D2.

The branch portion 12c is provided at the end of the connecting portion 12 opposite the inlet pipe 11 side in the extension direction De. The branch portion 12c has a first branch pipe 12c1, a second branch pipe 12c2, and a connecting wall 12d. The first branch pipe 12c1 and the second branch pipe 12c2 are arranged side by side in the first direction D1. The first branch pipe 12c1 and the second branch pipe 12c2 both extend in the extension direction De and communicate with the tapered portion 12b. The connecting wall 12d is provided between the first branch pipe 12c1 and the second branch pipe 12c2 in the first direction D1. As shown in FIG. 4, the connecting wall 12d is curved so as to protrude toward the center 15a of the inlet opening 15 in the second direction D2 when viewed from the extension direction De.

The first branch pipe 12c1 has a first outlet opening 16 at its end opposite the tapered portion 12b in the extension direction De. The second branch pipe 12c2 has a second outlet opening 17 at its 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. As shown in FIG. 4, 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. 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 section of the first outlet opening 16 and the cross section of the second outlet opening 17 are formed in a circular shape.

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 when viewed from the extension direction De (radially inward from the outer wall surface 11a of the inlet pipe 11).

Fluid F that flows into the connection part 12 through the inlet opening 15 flows out of the connection part 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 located on the opposite side of the connection part 12 from the inlet pipe 11 in the extension direction De.

The first outlet pipe 13 communicates with the connection portion 12 via the 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. In this embodiment, the first outlet pipe 13 is a curved pipe that is L-shaped when viewed from the second direction D2. The first outlet pipe 13 is a curved pipe that has a first straight pipe section 18, a curved section 19, and a second straight pipe section 20.

The first straight pipe section 18 extends linearly from the connection section 12 in the extension direction De. The curved section 19 is provided at the end of the first straight pipe section 18 opposite the connection section 12 in the extension direction De. The curved section 19 curves in the first direction D1 as it moves away from the first straight pipe section 18 in the extension direction De. The second straight pipe section 20 extends linearly from the curved section 19 in the first direction D1.

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 in this embodiment is a straight pipe extending in the extension direction De.

In this embodiment, the first outflow pipe 13 and the second outflow pipe 14 are both circular pipes with circular cross sections.

The first refrigerant distribution pipe 10a has the same configuration as the second refrigerant distribution pipe 10b as described above. That is, the first refrigerant distribution pipe 10a includes an inlet pipe 11, a connection portion 12, a first outlet pipe 13, and a second outlet pipe 14.
However, the first refrigerant distribution pipe 10a and the second refrigerant distribution pipe 10b differ from each other in the following respects.

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. In the second refrigerant distribution pipe 10b, the first outflow pipe 13 and the second outflow pipe 14 are both connected to the first outdoor branch pipes 7a extending from each of the remaining two outdoor units 2.
In the first refrigerant distribution pipe 10a, the cross-sectional area of the second outflow pipe 14 is designed to be larger than the cross-sectional area of the first outflow pipe 13. On the other hand, in the second refrigerant distribution pipe 10b, the cross-sectional areas of the first outflow pipe 13 and the second outflow pipe 14 are designed to be approximately the same.

(Arrangement of inlet pipe, first outlet pipe, and second outlet pipe)
The arrangement of the inlet pipe 11, the first outlet pipe 13, and the second outlet pipe 14 will be described below using the second refrigerant distribution pipe 10b of the refrigerant distribution pipes 10 as an example.

As shown in FIG. 4, the center 21 of the cross section of the inlet pipe 11 is located on the other side of the second direction D2 relative to 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.

Furthermore, the center 22 of the cross section of the first outflow pipe 13 is located on one side of the center 15a of the cross section of the inflow opening 15 in the second direction D2 throughout the entire first outflow pipe 13. Furthermore, the center 23 of the cross section of the second outflow pipe 14 is located on one side of the center 15a of the cross section of the inflow opening 15 in the second direction D2 throughout the entire second outflow pipe 14. Here, the center 21 of the cross section of the inflow pipe 11 is the center of gravity of the cross section of the inflow pipe 11, the center 22 of the cross section of the first outflow pipe 13 is the center of gravity of the cross section 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 section of the second outflow pipe 14. In this embodiment, the entire first outflow pipe 13 and the entire second outflow pipe 14 are located on one side of the center 15a of the cross section of the inflow opening 15 in the second direction D2.

Furthermore, the first outflow pipe 13 and the second outflow pipe 14 are positioned closer to the inflow pipe 11 in the first direction D1. More specifically, near the connection portion 12, 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 closer to the center 21 of the inflow pipe 11 than the ends 11a1 on both sides of the outer wall surface 11a of the inflow pipe 11 in the first direction D1. In the illustrated example, near the connection portion 12, 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 closer to the center 21 of the inflow pipe 11 than the outer wall surface 11a of the inflow pipe 11 when viewed from the extension direction De (radially inward from the outer wall surface 11a of the inflow pipe 11).

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.

(Action and effect)
The refrigerant distribution pipe 10 having the above-described configuration can exhibit the following effects.

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 the indoor units 1, and distributes a fluid F containing air-conditioning refrigerant and refrigeration oil for lubricating the compressors 2a to the multiple outdoor units 2. The refrigerant distribution pipe 10 comprises an inlet pipe 11, a connection portion 12, a first outlet pipe 13, and a second outlet pipe 14. Fluid F flows into the inlet pipe 11. The connection portion 12 extends in one direction (extension direction De) from the end of the inlet pipe 11. The connection portion 12 has an inlet opening 15 communicating with the inlet pipe 11 at the end on the inlet pipe 11 side in the extension direction De, and a first outlet opening 16 and a second outlet opening 17 at the end opposite the inlet pipe 11 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. 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.

Here, as a comparative example, consider a conventional refrigerant distribution pipe 10R as shown in Figure 5. This refrigerant distribution pipe 10R has an inlet pipe 11R, a connection portion 12R, a first outlet pipe 13R, and a second outlet pipe 14R. 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 10R, 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 22R of the cross section of the first outlet pipe 13R overlap in the extension direction De, and the center 17aR of the second outlet opening 17R and the center 23R of the cross section of the second outlet pipe 14R overlap in the extension direction De. For this reason, the center 22R of the cross section of the first outflow pipe 13R and the center 23R of the cross section of the second outflow pipe 14R are located at the same position in the second direction D2 relative to the center 21R of the inflow pipe 11R. Such a refrigerant distribution pipe 10R is typically installed so that the inflow pipe 11R is aligned along a horizontal plane.

If the refrigerant distribution pipe 10R is not filled with fluid F, for example, if the refrigerant distribution pipe 10R 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 Figure 5. Also, if the downstream side of the first outflow pipe 13R 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, causing the liquid level S of the fluid F to be inclined with respect to the first direction D1.

When the liquid level S of the fluid F is inclined with respect to the first direction D1, the amount of fluid F distributed between the first outflow pipe 13R and the second outflow pipe 14R becomes significantly unbalanced. For this reason, in the conventional refrigerant distribution pipe 10R, the actual distributed flow rate of refrigeration oil significantly deviates from the target distributed flow rate (hereinafter referred to as the "target flow rate").
In addition, Figure 5 illustrates both the case where the liquid level S of the fluid F is a high liquid level HS and the case where it 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.

In contrast, according to this embodiment, when the refrigerant distribution pipe 10 is installed so that the inlet pipe 11 is aligned along a horizontal plane, both the first outlet pipe 13 and the second outlet pipe 14 can be positioned vertically below the inlet 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. 6, unevenness in the amount of fluid F distributed between the first outlet pipe 13 and the second outlet pipe 14 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 outlet pipe 13 and the second outlet pipe 14 is suppressed. This makes it possible to suppress unevenness in the amount of refrigeration oil supplied to each outdoor unit 2. This makes it possible to suppress deviations in the actual distributed flow rate of refrigeration oil from the target flow rate.

In this embodiment, the entire first outlet pipe 13 and the entire second outlet pipe 14 are located to one side of the center 15a of the cross section of the inlet opening 15 in the second direction D2.

This further reduces the bias in the amount of fluid F distributed between the first outflow pipe 13 and the second outflow pipe 14. This further reduces the bias in the amount of refrigeration oil supplied to each outdoor unit 2. This further reduces the deviation of the actual distributed flow rate of refrigeration oil from the target flow rate.

In this embodiment, at the connection portion 12, 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 21 of the cross section of the inlet pipe 11 in the first direction D1 than the ends 11a1 on both sides of the outer wall surface 11a of the inlet pipe 11.

This further reduces the bias in the amount of fluid F distributed between the first outflow pipe 13 and the second outflow pipe 14. This further reduces the bias in the amount of refrigeration oil supplied to each outdoor unit 2. This further reduces the deviation of the actual distributed flow rate of refrigeration oil from the target flow rate.

In the first embodiment described above, the entire first outlet pipe 13 and the entire second outlet pipe 14 are located on one side of the center 21 of the cross section of the inlet pipe 11 in the second direction D2, but this is not limited to this. For example, in a cross section perpendicular to the extension direction De, a portion of the first outlet pipe 13 and a portion of the second outlet pipe 14 may be located on the other side of the center 21 of the cross section of the inlet pipe 11 in the second direction D2.

Furthermore, in the first embodiment described above, 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 cross section of the inlet opening 15 than the outer wall surface 11a of the inlet pipe 11 when viewed from the extension direction De (radially inward in the inlet pipe 11), but this is not limited to this. For 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 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 when viewed from the extension direction De (radially outward from the outer wall surface 11a of the inlet pipe 11). Furthermore, as shown in FIG. 7, 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.

In addition, in the first embodiment described above, the cross sections of the inlet opening 15, the first outlet opening 16, and the second outlet opening 17 are circular, but this is not limited to this. The cross sections of the inlet opening 15, the first outlet opening 16, and the second outlet opening 17 may be polygonal, or may be irregularly shaped with a protruding or recessed portion. In this case as well, 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.

Furthermore, in the above 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 limited to this. 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 shaped like a polygon, or may be shaped like an irregular shape with a protruding or recessed portion. In this case as well, 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 22 of the first outlet pipe 13 is the center of gravity of the cross section of the first outlet pipe 13, and the center 23 of the cross section of the second outlet pipe 14 is the center of gravity of the cross section of the second outlet pipe 14.

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 8 to 11. Configurations similar to those in the first embodiment will be given the same names and reference numerals as in the first embodiment, and descriptions thereof will be omitted as appropriate.

As shown in FIG. 8, in the refrigerant distribution pipe 210 of this embodiment, the first outlet pipe 213 and the second outlet pipe 214 are rectangular pipes. The shapes of the first outlet pipe 213 and the second outlet pipe 214 will be explained using the first refrigerant distribution pipe 210a as an example, and explanations of the second refrigerant distribution pipe 210b will be omitted where appropriate.

When viewed in a cross section perpendicular to the extension direction De, the cross section of the first outflow pipe 213 and the cross section of the second outflow pipe 214 are shaped like a rectangle with one side extending in the second direction D2. Furthermore, the first outflow pipe 213 is shaped so that both ends of the first outflow pipe 213 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 214 is shaped so that both ends of the second direction D2 of the second outflow pipe 214 overlap with both ends of the inflow pipe 11 in the second direction D2 in the extension direction De.

Furthermore, in the first refrigerant distribution pipe 210a, the cross-sectional area of the second outflow pipe 214 is designed to be larger than the cross-sectional area of the first outflow pipe 213, as in the first embodiment. More specifically, while the dimensions L2a and L2b in the second direction D2 of both the first outflow pipe 213 and the second outflow pipe 214 are maintained, the dimension L1b in the first direction D1 of the second outflow pipe 214 is made larger than the dimension L1a in the first direction D1 of the first outflow pipe 213.

On the other hand, in the second refrigerant distribution pipe 210b, the cross-sectional areas of the first outflow pipe 213 and the second outflow pipe 214 are designed to be approximately the same, as in the first embodiment. More specifically, the dimensions L2a, L2b in the second direction D2 of both the first outflow pipe 213 and the second outflow pipe 214 are maintained, while the dimension L1a in the first direction D1 of the first outflow pipe 213 and the dimension L1b in the first direction D1 of the second outflow pipe 214 are designed to be approximately the same.

(Action and effect)
The refrigerant distribution pipe 210 having the above-described configuration can exhibit the following effects.

In this embodiment, the first outflow pipe 213 and the second outflow pipe 214 are rectangular pipes, and when viewed in a cross section perpendicular to the extension direction De, the cross section of the first outflow pipe 213 and the cross section of the second outflow pipe 214 are shaped like a rectangle along the first direction D1 and the second direction D2.

As a comparative example, consider a conventional refrigerant distribution pipe 210R as shown in Figure 9. In this refrigerant distribution pipe 210R, the cross sections of the first outflow pipe 213R and the second outflow pipe 214R are circular when viewed in a cross section perpendicular to the extension direction De. This type of refrigerant distribution pipe 210R is typically installed so that the inflow pipe 11R is aligned along a horizontal plane.

As shown in Figure 9, when the height of the liquid level S of the fluid F changes, the cross-sectional area ratio occupied by the fluid F in the first outflow pipe 213R and the second outflow pipe 214R changes. As a result, with the conventional refrigerant distribution pipe 210R, the actual distribution flow rate of the refrigeration oil deviates significantly from the target distribution flow rate (hereinafter referred to as the "target flow rate").

In contrast, according to this embodiment, by installing the refrigerant distribution pipe 210 so that the inlet pipe 11 is aligned along a horizontal plane, the first outlet pipe 213 and the second outlet pipe 214 can be arranged so that the rectangular cross section of the first outlet pipe 213 and the rectangular cross section of the second outlet pipe 214 extend vertically. As a result, even if the liquid level S of the fluid F changes as shown in FIG. 10, the cross-sectional area ratio occupied by the fluid F in the first outlet pipe 213 and the second outlet pipe 214 can be maintained constant. Therefore, it is possible to prevent the actual distribution flow rate of refrigeration oil from deviating from the target flow rate.

Furthermore, as shown in FIG. 11, the configuration of the second embodiment may be combined with the first embodiment. That is, the first outlet pipe 213 and the second outlet pipe 214 may be formed into a rectangular shape as described above, and 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 on one side of the center 15a of the cross section of the inlet opening 15 in the second direction D2. Furthermore, the entire first outlet pipe 213 and the entire second outlet pipe 214 may be located on one side of the center 15a of the cross section of the inlet 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 in the first direction D1 than the ends 11a1 on both sides of the outer wall surface 11a of the inlet pipe 11.

Third Embodiment
A refrigerant distribution pipe 10X and an air conditioning apparatus 100 according to a third embodiment of the present disclosure will be described below with reference to Figures 12 to 14. Configurations similar to those in the above embodiment will be designated by the same names and reference numerals as in the above embodiment, and descriptions thereof will be omitted as appropriate.

In this embodiment, the first refrigerant distribution pipe 10aX and the second refrigerant distribution pipe 10bX have the same configuration. Therefore, the configuration of the refrigerant distribution pipe 10X will be described using the first refrigerant distribution pipe 10aX as an example, and the description of the configuration of the second refrigerant distribution pipe 10bX will be omitted as appropriate.

As shown in FIG. 12, the first refrigerant distribution pipe 10aX includes an inlet pipe 11X, a connection portion 12X, a first outlet pipe 13X, and a second outlet pipe 14X.

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

The connection portion 12X extends in one direction (extension direction De) from the end of the inlet pipe 11X. In this embodiment, the connection portion 12X extends linearly in the same direction as the inlet pipe 11X. In other words, the inlet pipe 11X extends in the extension direction De.

The fluid F that has flowed into the inlet pipe 11X flows through the connection portion 12X. The connection portion 12X connects the inlet pipe 11X to the first outlet pipe 13X and the second outlet pipe 14X. The connection portion 12X has an inlet portion 12aX, a tapered portion 12bX, and a branch portion 12cX.

The inlet portion 12aX is provided at the end of the connection portion 12X on the inlet pipe 11X side in the extension direction De. The inlet portion 12aX has an inlet opening 15X connected to the inlet pipe 11X. The inlet opening 15X opens in the extension direction De and is connected to the inlet pipe 11X. Fluid F is supplied to the inlet opening 15X from the inlet pipe 11X.

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

The branch portion 12cX is provided at the end of the connecting portion 12X opposite the inlet pipe 11X side in the extension direction De. The branch portion 12cX has a first branch pipe 12c1X, a second branch pipe 12c2X, and a connecting wall 12dX. The first branch pipe 12c1X and the second branch pipe 12c2X are arranged side by side in the first direction D1. The first branch pipe 12c1X and the second branch pipe 12c2X both extend in the extension direction De and are connected to the tapered portion 12bX. The connecting wall 12dX is provided between the first branch pipe 12c1X and the second branch pipe 12c2X in the first direction D1.

The first branch pipe 12c1X has a first outlet opening 16X at the end opposite the tapered portion 12bX in the extension direction De. The second branch pipe 12c2X has a second outlet opening 17X at the end opposite the tapered portion 12bX in the extension direction De. The first outlet opening 16X and the second outlet opening 17X are arranged side by side in the first direction D1.

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

The first outlet pipe 13X communicates with the connection portion 12X via the first outlet opening 16X, and allows the fluid F that has flowed in from the inlet pipe 11X to flow out to the outdoor unit 2. In this embodiment, the first outlet pipe 13X is a curved pipe that is L-shaped when viewed from the second direction D2. The first outlet pipe 13X is a curved pipe that has a first straight pipe portion 18X, a first curved portion 19X, and a second straight pipe portion 20X.

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

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

In this embodiment, the first outflow pipe 13X and the second outflow pipe 14X are both circular pipes with circular cross sections. As shown in Fig. 13, a center 22X of the cross section of the first outflow pipe 13X and a center 23X of the cross section of the second outflow pipe 14X are located at the same position in the second direction D2 relative to a center 21X of the inflow pipe 11X. Here, the center 21X of the cross section of the inflow pipe 11X is the center of gravity of the cross section of the inflow pipe 11X, the center 22X of the first outflow pipe 13X is the center of gravity of the cross section of the first outflow pipe 13X, and the center 23X of the cross section of the second outflow pipe 14X is the center of gravity of the cross section of the second outflow pipe 14X.
In the first refrigerant distribution pipe 10aX, the first outflow pipe 13X is connected to the first outdoor branch pipe 7a extending from one outdoor unit 2, and the second outflow pipe 14X is connected to the second outdoor branch pipe 7b connecting the first refrigerant distribution pipe 10aX and the second refrigerant distribution pipe 10bX. Furthermore, the second refrigerant distribution pipe 10bX is connected to the remaining two outdoor units 2 via two first outdoor branch pipes 7a.

The second refrigerant distribution pipe 10bX has the same configuration as the first refrigerant distribution pipe 10aX as described above, that is, the second refrigerant distribution pipe 10bX includes an inlet pipe 11X, a connection portion 12X, a first outlet pipe 13X, and a second outlet pipe 14X.
However, the second refrigerant distribution pipe 10bX differs from the first refrigerant distribution pipe 10aX in the following points.

In the second refrigerant distribution pipe 10bX, the first outflow pipe 13X and the second outflow pipe 14X are both connected to the first outdoor branch pipes 7a extending from each of the remaining two outdoor units 2.

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

Here, the cross-sectional area of the first outflow pipe 13X is S1, and the cross-sectional area of the second outflow pipe 14X is S2. Furthermore, the target distribution amount of the fluid F to the first outflow pipe 13X is X1, and the target distribution amount of the fluid F to the second outflow pipe 14X is X1.
In each refrigerant distribution pipe 10X, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13X and the second outflow pipe 14X is set so that the ratio of the value of the first outflow pipe 13X to the value of the second outflow pipe 14X is larger than the target distribution ratio (X1:X2) of the fluid F between the first outflow pipe 13X and the second outflow pipe 14X, i.e., (S1/S2)>(X1/X2).

Below, specific values for the cross-sectional area ratio (S1:S2) between the first outflow pipe 13X and the second outflow pipe 14X for each of the first refrigerant distribution pipe 10aX and the second refrigerant distribution pipe 10bX are explained.

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

In contrast, in the first refrigerant distribution pipe 10aX, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13X and the second outflow pipe 14X is set to S1/S2 > 1/2. For example, as shown in Figures 12 and 13, it is set to S1:S2 = 1:1.

In the second refrigerant distribution pipe 10bX, the fluid F flowing through the first outflow pipe 13X is directed to one outdoor unit 2, and the fluid F flowing through the second outflow pipe 14X is directed to one outdoor unit 2. For this reason, in the second refrigerant distribution pipe 10bX, the target distribution ratio (X1:X2) of the fluid F between the first outflow pipe 13X and the second outflow pipe 14X is set to the same ratio as the number of destination outdoor units 2, for example, X1:X2 = 1:1. In other words, X1/X2 = 1/1.

In contrast, in the first refrigerant distribution pipe 10aX, the cross-sectional area ratio (S1:S2) between the first outflow pipe 13X and the second outflow pipe 14X is set so that S1/S2 > 1/1. For example, as shown in Figures 12 and 14, it is set to S1:S2 = 2:1.

(Action and effect)
The refrigerant distribution pipe 10X having the above-described configuration can exhibit the following effects.

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

This makes it easier for fluid F to flow into the first outflow pipe 13X, which has a high back pressure. Therefore, fluid F can be distributed to the first outflow pipe 13X and the second outflow pipe 14X 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").

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

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

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

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

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

This allows the distribution ratio of the fluid F between the first outflow pipe 13X and the second outflow pipe 14X to be close to 1:1.
The cross-sectional area ratio (S1:S2) between the first outflow pipe 13X and the second outflow pipe 14X 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 13X and the second outflow pipe 14X 1:1, it is preferable that the cross-sectional area ratio (S1:S2) between the first outflow pipe 13X and the second outflow pipe 14X be 2:1. However, for example, when the cross-sectional area S2 of the second outflow pipe 14X is 1, the cross-sectional area S1 of the first outflow pipe 13X may be 1.2 to 3.

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

As shown in Figure 15, in this modified example, the second outflow pipe 14X is a curved pipe having a third straight pipe section 41X, a second curved section 42X, and a fourth straight pipe section 43X.

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

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

(Action and effect)
The refrigerant distribution pipe 10X having the above-described configuration can exhibit the following effects.

In this modified example, the first outflow pipe 13X is a curved pipe having a first curved portion 19X on the downstream side, and the second outflow pipe 14X is a curved pipe having a second curved portion 42X on the downstream side. The curvature of the first curved portion 19X is greater than the curvature of the second curved portion 42X.

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

In the above third embodiment, examples where the back pressure of the first outflow pipe 13X is greater than the back pressure of the second outflow pipe 14X were described using examples where the first outflow pipe 13X is a curved pipe and the second outflow pipe 14X is a straight pipe, or where the curvature of the first curved portion 19X of the first outflow pipe 13X is greater than the curvature of the second curved portion 42X of the second outflow pipe 14X, but this is not limited to this. For example, even if both the first outflow pipe 13X and the second outflow pipe 14X are straight pipes, the back pressure of the first outflow pipe 13X will be greater than the back pressure of the second outflow pipe 14X even if there is a curved portion downstream of the first outflow pipe 13X and near the first outflow pipe 13X.

Furthermore, in the above third embodiment, the cross sections of the inlet pipe 11X, the first outlet pipe 13X, and the second outlet pipe 14X in the flow direction are circular, but this is not limited to this. The cross sections of the inlet pipe 11X, the first outlet pipe 13X, and the second outlet pipe 14X in the flow direction may be shaped like a polygon, or may be shaped like an irregular shape with a protruding or recessed portion.

Fourth Embodiment
A refrigerant distribution pipe 210X and an air conditioning apparatus 100 according to a fourth embodiment of the present disclosure will be described below with reference to Figures 16 to 18. Configurations similar to those in the above embodiments will be given the same names and reference numerals as in the above embodiments, and descriptions thereof will be omitted as appropriate.
In this embodiment, the first refrigerant distribution pipe 210aX and the second refrigerant distribution pipe 210bX have the same configuration. The configuration of this embodiment will be described below using the first refrigerant distribution pipe 210aX as an example.

As shown in FIG. 16, the center 16aX of the cross section of the first outlet opening 16X and the center 17aX of the cross section of the second outlet opening 17X are located on one side of the center 15aX of the cross section of the inlet opening 15X in the second direction D2. Here, the center 15aX of the cross section of the inlet opening 15X is the center of gravity of the cross section of the inlet opening 15X, the center 16aX of the cross section of the first outlet opening 16X is the center of gravity of the cross section of the first outlet opening 16X, and the center 17aX of the cross section of the second outlet opening 17X is the center of gravity of the cross section of the second outlet opening 17X. In this embodiment, the cross sections of the first outlet opening 16X and the second outlet opening 17X are formed in a circular shape.

Furthermore, the center 16aX of the cross section of the first outlet opening 16X and the center 17aX of the cross section of the second outlet opening 17X are located closer to the center 15aX of the inlet opening 15X in the first direction D1 than the ends 11aX1 on both sides of the outer wall surface 11aX of the inlet pipe 11X. In the illustrated example, the center 16aX of the cross section of the first outlet opening 16X and the center 17a of the cross section of the second outlet opening 17X are located closer to the center 15aX of the inlet opening 15X than the outer wall surface 11aX of the inlet pipe 11X when viewed from the extension direction De (radially inward from the outer wall surface 11aX of the inlet pipe 11X). The center 16aX of the cross section of the first outlet opening 16X and the center 17aX of the cross section of the second outlet opening 17X may be located farther from the center 15aX of the cross section of the inlet opening 15X than the outer wall surface 11aX of the inlet pipe 11X (radially outward from the outer wall surface 11aX of the inlet pipe 11X) when viewed from the extension direction De. Furthermore, in the first direction D1, the center 16aX of the cross section of the first outlet opening 16X and the center 17aX of the cross section of the second outlet opening 17X may be located outside the tangent to the outer wall surface 11aX at the end 11aX1 or on the tangent to the outer wall surface 11aX at the end 11aX1 when viewed from the extension direction De.

Furthermore, the center 21X of the cross section of the inlet pipe 11X is located on the other side of the second direction D2 relative to the center 16aX of the cross section of the first outlet opening 16X and the center 17aX of the cross section of the second outlet opening 17X throughout the entire inlet pipe 11X.

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

Furthermore, in this embodiment, at the branch portion 12cX of the connection portion 12X, the connection wall 12dX is curved so as to protrude toward the center 15aX of the inlet opening 15 in the second direction D2 when viewed from the extension direction De. Therefore, the first outlet pipe 13X and the second outlet pipe 14X are positioned closer to the inlet pipe 11X in the first direction D1. More specifically, near the connection portion 12X, the center 222X of the cross section of the first outlet pipe 213X and the center 223X of the cross section of the second outlet pipe 214X are located closer to the center 21X of the inlet pipe 11X in the first direction D1 than the ends 11aX1 on both sides of the outer wall surface 11aX of the inlet pipe 11X. In the illustrated example, near the connection portion 12X, the center 222X of the cross section of the first outflow pipe 213X and the center 223X of the cross section of the second outflow pipe 214X are located closer to the center 21X of the inflow pipe 11X than the outer wall surface 11aX of the inflow pipe 11X (radially inward from the outer wall surface 11aX of the inflow pipe 11X) when viewed from the extension direction De.

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

(Action and effect)
The refrigerant distribution pipe 210X having the above-described configuration can exhibit the following effects.

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

Here, as a comparative example, consider a conventional refrigerant distribution pipe 210RX as shown in Figure 17. This refrigerant distribution pipe 210RX has an inlet pipe 11RX, a connection portion 12RX, a first outlet pipe 213RX, and a second outlet pipe 214RX. The center 16aRX of the cross section of the first outlet opening 16RX and the center 17aRX of the cross section of the second outlet opening 17RX are located at the same position in the second direction D2 relative to the center 15aRX of the inlet opening 15X. In this refrigerant distribution pipe 210RX, at the connection portion 12RX, the cross-sectional center 15aRX of the inlet opening 15RX and the cross-sectional center 21RX of the inlet pipe 11RX overlap in the extension direction De; the cross-sectional center 16aRX of the first outlet opening 16RX and the cross-sectional center 222RX of the first outlet pipe 213RX overlap in the extension direction De; and the cross-sectional center 17aRX of the second outlet opening 17RX and the cross-sectional center 223RX of the second outlet pipe 14RX overlap in the extension direction De. Therefore, the cross-sectional center 222RX of the first outlet pipe 213RX and the cross-sectional center 223RX of the second outlet pipe 214RX are located at the same position in the second direction D2 as the center 21RX of the inlet pipe 211R. This type of refrigerant distribution pipe 210RX is typically installed so that the inlet pipe 11RX is aligned with a horizontal plane.

If the refrigerant distribution pipe 210RX is not filled with fluid F, for example, if the refrigerant distribution pipe 210RX is installed at an angle so that the first direction D1 intersects with a horizontal plane, the liquid level SX of the fluid F will be inclined relative to the first direction D1 as shown in Figure 17. Also, if the downstream side of the first outflow pipe 213RX 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, causing the liquid level SX of the fluid F to be inclined relative to the first direction D1.

When the liquid level SX 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 213RX and the second outflow pipe 214RX becomes significantly unbalanced. For this reason, in the conventional refrigerant distribution pipe 210RX, the actual distributed flow rate of the refrigerating machine oil significantly deviates from the target distributed flow rate.
In addition, Figure 17 illustrates both the case where the liquid level SX of the fluid F is a high liquid level HSX and the case where the liquid level SX is a low liquid level LSX, and in both cases, the amount of fluid F distributed between the first outflow pipe 13RX and the second outflow pipe 14RX is significantly biased.

In contrast, according to this embodiment, when the refrigerant distribution pipe 210X is installed so that the inlet pipe 11X is aligned along a horizontal plane, both the first outlet pipe 213X and the second outlet pipe 214X can be positioned vertically below the inlet pipe 11X. As a result, even if the liquid level SX of the fluid F is inclined with respect to the first direction D1 as shown in FIG. 18 , unevenness in the amount of fluid F distributed between the first outlet pipe 213X and the second outlet pipe 214X is suppressed. Whether the liquid level SX of the fluid F is high HSX or low LSX, unevenness in the amount of fluid F distributed between the first outlet pipe 213X and the second outlet pipe 214X is suppressed. This makes it possible to suppress unevenness in the amount of refrigeration oil supplied to each outdoor unit 2. This further prevents the actual distributed flow rate of refrigeration oil from deviating from the target flow rate.

In this embodiment, the entire first outlet pipe 213X and the entire second outlet pipe 214X are located to one side of the center 15aX of the cross section of the inlet opening 15X in the second direction D2.

This further reduces the bias in the amount of fluid F distributed between the first outflow pipe 213X and the second outflow pipe 214X. This further reduces the bias in the amount of refrigeration oil supplied to each outdoor unit 2. This further reduces the deviation of the actual distributed flow rate of refrigeration oil from the target flow rate.

In this embodiment, at the connection portion 12X, the center 222X of the cross section of the first outflow pipe 213X and the center 223X of the cross section of the second outflow pipe 214X are located closer to the center 21X of the cross section of the inflow pipe 11X in the first direction D1 than the ends 11aX1 on both sides of the outer wall surface 11aX of the inflow pipe 11X.

This further reduces the bias in the amount of fluid F distributed between the first outflow pipe 213X and the second outflow pipe 214X. This further reduces the bias in the amount of refrigeration oil supplied to each outdoor unit 2. This further reduces the deviation of the actual distributed flow rate of refrigeration oil from the target flow rate.

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

Fifth Embodiment
A refrigerant distribution pipe 310X and an air conditioning apparatus 100 according to a fifth embodiment of the present disclosure will be described below with reference to Figures 19 to 22. Configurations similar to those in the above embodiments will be given the same names and reference numerals as in the above embodiments, and descriptions thereof will be omitted as appropriate.

As shown in FIG. 19, in the refrigerant distribution pipe 310X of this embodiment, the first outlet pipe 313X and the second outlet pipe 314X are rectangular pipes. The shapes of the first outlet pipe 313X and the second outlet pipe 314X will be explained using the second refrigerant distribution pipe 310bX as an example, and explanations of the first refrigerant distribution pipe 310aX will be omitted as appropriate.

When viewed in a cross section perpendicular to the extension direction De, the cross section of the first outflow pipe 313X and the cross section of the second outflow pipe 314X are shaped like a rectangle with one side extending in the second direction D2. Furthermore, the first outflow pipe 313X is shaped so that both ends of the first outflow pipe 313X in the second direction D2 overlap with both ends of the inflow pipe 11X in the second direction D2 in the extension direction De. Similarly, the second outflow pipe 314X is shaped so that both ends of the second direction D2 of the second outflow pipe 314X overlap with both ends of the inflow pipe 11X in the second direction D2 in the extension direction De.

Furthermore, in the second refrigerant distribution pipe 310bX, the cross-sectional area S1 of the first outflow pipe 313X is designed to be larger than the cross-sectional area S2 of the second outflow pipe 314X, as in the third embodiment. More specifically, while the dimensions L2aX and L2bX in the second direction D2 of both the first outflow pipe 313X and the second outflow pipe 314X are maintained, the dimension L1aX in the first direction D1 of the first outflow pipe 313X is made larger than the dimension L1bX in the first direction D1 of the second outflow pipe 314X.

(Action and effect)
The refrigerant distribution pipe 310X having the above-described configuration can exhibit the following effects.

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

As a comparative example, consider a conventional refrigerant distribution pipe 310RX as shown in Figure 20. In this refrigerant distribution pipe 310RX, the cross sections of the first outflow pipe 313RX and the second outflow pipe 314RX are circular when viewed in a cross section perpendicular to the extension direction De. This type of refrigerant distribution pipe 310RX is typically installed so that the inflow pipe 11RX is aligned along a horizontal plane.

As shown in Figure 20, when the height of the liquid surface SX of fluid F changes, the cross-sectional area ratio occupied by fluid F between the first outflow pipe 313RX and the second outflow pipe 314RX changes. As a result, with the conventional refrigerant distribution pipe 310RX, the actual distribution flow rate of refrigeration oil deviates significantly from the target flow rate.

In contrast, according to this embodiment, by installing the refrigerant distribution pipe 310X so that the inlet pipe 11X is aligned along a horizontal plane, the first outlet pipe 313X and the second outlet pipe 314X can be arranged so that the rectangular cross section of the first outlet pipe 313X and the rectangular cross section of the second outlet pipe 314X extend vertically. As a result, even if the liquid level SX of the fluid F changes as shown in FIG. 21, the cross-sectional area ratio occupied by the fluid F in the first outlet pipe 313X and the second outlet pipe 314X can be maintained constant. This further prevents the actual distributed flow rate of refrigeration oil from deviating from the target flow rate.

22, the configuration of the fifth embodiment may be combined with not only the third embodiment but also the fourth embodiment. That is, the first outflow pipe 313X and the second outflow pipe 314X may be formed into a rectangular shape as described above, and in each refrigerant distribution pipe 10X, the cross-sectional area ratio (S1:S2) of the first outflow pipe 313X to the second outflow pipe 314X may be set so that the ratio of the value of the first outflow pipe 313X to the value of the second outflow pipe 314X is larger than the target distribution ratio (X1:X2) of fluid F between the first outflow pipe 313X and the second outflow pipe 314X. Furthermore, the center 16aX of the cross section of the first outflow opening 16X and the center 17aX of the cross section of the second outflow opening 17X may be located on one side of the center 15aX of the cross section of the inflow opening 15X in the second direction D2. Furthermore, the entire first outlet pipe 313X and the entire second outlet pipe 314X may be located to one side of the center 15aX of the cross section of the inlet opening 15X in the second direction D2. Furthermore, the center 16aX of the cross section of the first outlet opening 16X and the center 17aX of the cross section of the second outlet opening 17X may be located closer to the center 15aX of the cross section of the inlet opening 15X in the first direction D1 than the ends 11aX1 on both sides of the outer wall surface 11aX of the inlet pipe 11X.

(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 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, 10bX, 210bX, 310bX may be provided as the refrigerant distribution pipe 10, 210, 10X, 210X, 310X.

Furthermore, in the above embodiment, the first outflow pipe 13, 213 is a curved pipe and the second outflow pipe 14, 214 is a straight pipe, but this is not limited to this. The shapes of the first outflow pipe 13, 213 and the second outflow pipe 14, 214 can be changed as appropriate. For example, the first outflow pipe 13, 213 may be a straight pipe and the second outflow pipe 14, 214 may be a curved pipe. Furthermore, both the first outflow pipe 13, 213 and the second outflow pipe 14, 214 may be curved pipes or straight pipes. Furthermore, if the first outflow pipe 13, 213 and the second outflow pipe 14, 214 are curved pipes, the degree of curvature of the first outflow pipe 13, 213 and the second outflow pipe 14, 214 can also be changed as appropriate.

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

(1) The refrigerant distribution pipe 10, 210 according to the first aspect is used in a refrigerant pipe 3 connecting a plurality of outdoor units 2 having compressors 2a to indoor units 1, and distributes a fluid F containing an air-conditioning refrigerant and a refrigeration oil for lubricating the compressors 2a to the plurality of outdoor units 2. The refrigerant distribution pipe 10, 210 comprises an inlet pipe 11 into which the fluid F flows, an inlet opening 15 extending in one direction from the end of the inlet pipe 11 and communicating with the inlet pipe 11 at the end on the inlet pipe 11 side in the extension direction De, and a first outlet opening 16 arranged side by side in a first direction D1 perpendicular to the extension direction De at the end on the opposite side from the inlet pipe 11 in the extension direction De, and a connecting portion 12 having a first outlet opening 16 and a second outlet opening 17; a first outlet pipe 13, 213 that communicates with the connecting portion 12 at the first outlet opening 16 and allows the fluid F to flow to the outdoor unit 2; and a second outlet pipe 14, 214 that communicates with the connecting portion 12 at the second outlet opening 17 and allows the fluid F to flow to an outdoor unit 2 different from the outdoor unit 2 to which the fluid F is directed from the first outlet pipe 13, 213. 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 a second direction D2 that is perpendicular to the extension direction De and the first direction D1.

According to this aspect, when the refrigerant distribution pipes 10, 210 are installed so that the inlet pipe 11 is aligned along a horizontal plane, both the first outlet pipe 13, 213 and the second outlet pipe 14, 214 can be positioned vertically below the inlet pipe 11. This prevents uneven distribution of the fluid F between the first outlet pipe 13, 213 and the second outlet pipe 14, 214, even if the liquid level S of the fluid F is inclined with respect to the first direction D1. This prevents uneven distribution of the refrigeration oil supplied to each outdoor unit 2.

(2) The refrigerant distribution pipe 10, 210 of the second aspect may be the refrigerant distribution pipe 10, 210 of (1), in which the entire first outflow pipe 13, 213 and the entire second outflow pipe 14, 214 are located to one side of the center 15a of the cross section of the inflow opening 15 in the second direction D2.

This further reduces the uneven distribution of fluid F between the first outflow pipes 13, 213 and the second outflow pipes 14, 214. This further reduces the uneven distribution of refrigeration oil supplied to each outdoor unit 2.

(3) The refrigerant distribution pipe 10, 210 of the third aspect is the refrigerant distribution pipe 10, 210 of (1) or (2), wherein 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 in the first direction D1 than the ends 11a1 on both sides of the outer wall surface 11a of the inlet pipe 11.

This further reduces the uneven distribution of fluid F between the first outflow pipes 13, 213 and the second outflow pipes 14, 214. This further reduces the uneven distribution of refrigeration oil supplied to each outdoor unit 2.

(4) The refrigerant distribution pipe 10, 210 of the fourth aspect is the refrigerant distribution pipe 10, 210 of any one of (1) to (3), and the cross section of the first outflow pipe 13, 213 and the cross section of the second outflow pipe 14, 214 may be shaped like a rectangle having one side extending in the second direction D2.

In this embodiment, by installing the refrigerant distribution pipes 10, 210 so that the inlet pipe 11 is aligned along a horizontal plane, the first outlet pipe 13, 213 and the second outlet pipe 14, 214 can be arranged so that the rectangular cross section of the first outlet pipe 13, 213 and the rectangular cross section of the second outlet pipe 14, 214 extend vertically. As a result, even if the liquid level S of the fluid F changes, the cross-sectional area ratio occupied by the fluid F in the first outlet pipe 13, 213 and the second outlet pipe 14, 214 can be maintained constant.

(5) The refrigerant distribution pipe 10, 210 according to the fifth aspect is used in a refrigerant pipe 3 connecting a plurality of outdoor units 2 having compressors 2a to indoor units 1, and distributes a fluid F containing an air-conditioning refrigerant and a refrigerating machine oil for lubricating the compressors 2a to the plurality of outdoor units 2. The refrigerant distribution pipe 10, 210 includes an inlet pipe 11 into which the fluid F flows, an inlet opening 15 extending in one direction from the end of the inlet pipe 11, and communicating with the inlet pipe 11 at the end on the inlet pipe 11 side in the extension direction De, and a second opening 15 arranged side by side in a first direction D1 perpendicular to the extension direction De at the end on the opposite side from the inlet pipe 11 in the extension direction De. The device comprises a connecting portion 12 having a first outlet opening 16 and a second outlet opening 17, a first outlet pipe 13, 213 that communicates with the connecting portion 12 at the first outlet opening 16 and allows the fluid F to flow to the outdoor unit 2, and a second outlet pipe 14, 214 that communicates with the connecting portion 12 at the second outlet opening 17 and allows the fluid F to flow to an outdoor unit 2 different from the outdoor unit 2 to which the fluid F is directed from the first outlet pipe 13, 213. The cross sections of the first outlet pipe 13, 213 and the second outlet pipe 14, 214 are shaped like rectangles with one side extending in the extension direction De and in a second direction D2 perpendicular to the first direction D1.

(6) The air conditioning apparatus 100 of the sixth aspect comprises the refrigerant pipe 3 having any one of the refrigerant distribution pipes 10, 210 described in (1) to (5), a plurality of the outdoor units 2, and the indoor units 1.

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

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

(8) The eighth aspect of refrigerant distribution is the refrigerant distribution pipe 10X, 210X, 310X of (7), in which the first outflow pipe 13X, 213X, 313X is a curved pipe having a first curved portion 19X on the downstream side, and the second outflow pipe 14X, 214X, 314X may be a straight pipe extending linearly.

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

(9) The refrigerant distribution pipes 10X, 210X, and 310X of the ninth aspect are the refrigerant distribution pipes 10X, 210X, and 310X of (7), wherein the first outflow pipe 13X, 213X, and 313X are curved pipes having a first curved portion 19X on the downstream side, and the second outflow pipes 14X, 214X, and 314X are curved pipes having a second curved portion 42X on the downstream side, and the curvature of the first curved portion 19X may be greater than the curvature of the second curved portion 42X.

This further increases the options for the shapes of the first outflow pipes 13X, 213X, 313X and the second outflow pipes 14X, 214X, 314X. Furthermore, because the curvature of the first curved portion 19X is greater than the curvature of the second curved portion 42X, the back pressure experienced by the fluid F in the first outflow pipes 13X, 213X, 313X is greater than that in the second outflow pipes 14X, 214X, 314X. This makes it difficult for fluid F to flow through the first outflow pipes 13X, 213X, and 313X. However, as described above, the cross-sectional area ratio between the first outflow pipes 13X, 213X, and 313X and the second outflow pipes 14X, 214X, and 314X is set so that the ratio of the values of the first outflow pipes 13X, 213X, and 313X is large. This makes it easier for fluid F to flow into the first outflow pipes 13X, 213X, and 313X, which have high back pressure. This allows for an increased number of options for the shapes of the first outflow pipes 13X, 213X, and 313X and the second outflow pipes 14X, 214X, and 314X, while still allowing for distribution of fluid F to the first outflow pipes 13X, 213X, and 313X and the second outflow pipes 14X, 214X, and 314X at a distribution ratio close to the target distribution ratio.

(10) The air conditioning apparatus 100 of the tenth aspect includes the refrigerant pipe 3 having the refrigerant distribution pipe 10X, 210X, 310X described in any one of (7) to (9), a plurality of the outdoor units 2, and the indoor unit 1.

The refrigerant distribution pipe and air conditioning system disclosed herein can prevent the actual distribution flow rate of refrigeration oil from deviating from the target flow rate.

DESCRIPTION OF SYMBOLS 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 conditioning device, 11...inlet pipe, 11a...exterior wall surface, 11a1...end portion, 12...connection portion, 12a...inlet portion, 12b...tapered portion, 12c...branch portion, 12c1...first branch pipe, 12d...connection wall, 13...first outflow pipe, 14...second Outflow pipe, 15... Inflow opening, 15a... Center, 16... First outflow opening, 16a... Center, 17... Second outflow opening, 17a... Center, 18... First straight pipe part, 19... Curved part, 20... Second straight pipe part, 21... Center, 22... Center, 23... Center, De... Extension direction, D1... First Direction, D2...Second direction, F...Fluid, S...Liquid level, HS...High liquid level, LS...Low liquid level, 210...Refrigerant distribution pipe, 210a...First refrigerant distribution pipe, 210b...Second refrigerant distribution pipe, 213...First outflow pipe, 214...Second outflow pipe, 222...Center, 223...Center, L1a...Dimension Dimensions, L2a...dimension, L1b...dimension, L2b...dimension 10X...refrigerant distribution pipe, 10aX...first refrigerant distribution pipe, 10bX...second refrigerant distribution pipe, 11X...inlet pipe, 11a1X...end, 12X...connection portion, 12aX...inlet portion, 12bX...tapered portion, 12cX...branch portion, 13X...first outlet pipe, 14X...second outlet pipe, 15X...inlet opening, 15aX...center, 16X...first outlet opening, 16aX...center, 17X...second outlet opening, 18X...first straight pipe portion, 19X...first curved portion, 20X...second straight pipe portion, 41X...third straight pipe portion, 4 2X...second curved portion, 43X...fourth straight pipe portion, 210X...refrigerant distribution pipe, 210aX...first refrigerant distribution pipe, 210bX...second refrigerant distribution pipe, 11aX...outer wall surface, 21X...center, 213X...first outflow pipe, 214X...second outflow pipe, 222X...center, 223X...center, 310X...refrigerant distribution pipe, 310aX...first refrigerant distribution pipe, 310bX...second refrigerant distribution pipe, 313X...first outflow pipe, 314X...second outflow pipe, 322X...center, 323X...center, L1aX...dimension, L2aX...dimension, L1bX...dimension, L2bX...dimension

Claims (10)

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 connecting portion extending in one direction from an end of the inflow pipe, having an inflow opening communicating with the inflow pipe at an end on the inflow pipe side in the extension direction, and having a first outflow opening and a second outflow opening arranged side by side in a first direction perpendicular to the extension direction at an end on the opposite side from the inflow pipe in the extension direction;
a first outflow pipe that communicates with the connection portion at the first outflow opening and allows the fluid to flow out to the outdoor unit;
a second outlet pipe that communicates with the connection portion at the second outlet opening and causes the fluid to flow out to the outdoor unit different from the outdoor unit that is the destination of the fluid from the first outlet pipe;
Equipped with
a center of a cross section of the first outlet opening and a center of a cross section of the second outlet opening are located on one side of the center of the cross section of the inlet opening in a second direction perpendicular to the extension direction and the first direction. The refrigerant distribution pipe according to claim 1, wherein the entire first outlet pipe and the entire second outlet pipe are located to one side of the center of the cross section of the inlet opening in the second direction. A refrigerant distribution pipe as described in claim 1 or 2, wherein the center of the cross section of the first outlet opening and the center of the cross section of the second outlet opening are located closer to the center of the cross section of the inlet opening than the ends on either side of the outer wall surface of the inlet pipe in the first direction. The refrigerant distribution pipe according to claim 1 or 2, wherein the cross section of the first outflow pipe and the cross section of the second outflow pipe are shaped like a rectangle having one side extending in the second direction. 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 connecting portion extending in one direction from an end of the inflow pipe, having an inflow opening communicating with the inflow pipe at an end on the inflow pipe side in the extension direction, and having a first outflow opening and a second outflow opening arranged side by side in a first direction perpendicular to the extension direction at an end on the opposite side from the inflow pipe in the extension direction;
a first outflow pipe that communicates with the connection portion at the first outflow opening and allows the fluid to flow out to the outdoor unit;
a second outlet pipe that communicates with the connection portion at the second outlet opening and causes the fluid to flow out to the outdoor unit different from the outdoor unit that is the destination of the fluid from the first outlet pipe;
Equipped with
a cross section of the first outflow pipe and a cross section of the second outflow pipe each being shaped like a rectangle having one side extending in the extension direction and in a second direction perpendicular to the first direction; The refrigerant pipe is provided with the refrigerant distribution pipe according to claim 1 or 5;
A plurality of the outdoor units;
The indoor unit;
An air conditioning device comprising: 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 for causing the fluid to flow out 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. The refrigerant distribution pipe described in claim 7, wherein the first outflow pipe is a curved pipe having a first curved portion on the downstream side, and the second outflow pipe is a straight pipe extending linearly. 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 7 , wherein the curvature of the first curved portion is greater than the curvature of the second curved portion. The refrigerant pipe is provided with the refrigerant distribution pipe according to claim 7 or 8;
A plurality of the outdoor units;
The indoor unit;
An air conditioning device comprising: