Branch pipes and refrigeration equipment

Abstract

A stainless steel branch pipe can be obtained with simple processing. [Solution] In the branch pipe 10, the branch pipe body 20 includes a sealing portion 28 that seals the first gap Z1 between the outer surface 31c of the first pipe joint 31 and the first opening 26a, the second gap Z2 between the outer surface 32c of the second pipe joint 32 and the second opening 26b, and the third gap Z3 between the outer surface 33c of the third pipe joint 33 and the third opening 26c. The sealing portion 28 includes a brazing material layer S that connects the branch pipe body 20 to the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33.

Description

Technical Field

[0001] The present disclosure relates to a branch pipe and a refrigeration device. This application claims domestic priority based on Japanese Patent Application No. 2025-013882 filed on January 30, 2025, and incorporates by reference all the descriptions set forth in the above application.

Background Art

[0002] Conventionally, a plate-type refrigerant pipe formed by bonding stainless steel plates and connecting a joint pipe perpendicularly to the plate surface is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When forming a connection portion for connecting a joint pipe in the plate-type refrigerant pipe, it is necessary to perform a burring process, so the processing difficulty is high. Therefore, it is difficult to manufacture a branch pipe for branching the refrigerant flow in the plate-type refrigerant pipe.

[0005] An object of the present disclosure is to obtain a stainless steel branch pipe with simple processing.

Means for Solving the Problems

[0006] (1) The branch pipe of the present disclosure is a branch pipe that connects a first pipe, a second pipe, and a third pipe, and branches the fluid flowing through the first pipe to the second pipe and the third pipe, comprising: a branch pipe body comprising a first plate-shaped member made of stainless steel having a first surface and a second plate-shaped member made of stainless steel having a second surface positioned opposite to the first surface; a first pipe joint having a first joint portion connectable to the first pipe at one end in the axial direction; a second pipe joint having a second joint portion connectable to the second pipe at one end in the axial direction; and a third pipe joint having a third joint portion connectable to the third pipe at one end in the axial direction. The branch pipe body includes a joint that joins the first plate-shaped member and the second plate-shaped member, a flow path formed between the first surface and the second surface, and a first opening, a second opening, and a third opening formed by the first plate-shaped member and the second plate-shaped member at the ends of the flow path in the direction of fluid flow, which communicate with the first pipe, the second pipe, and the third pipe, respectively. The other end of the first pipe joint in the axial direction is connected to the first opening, the other end of the second pipe joint in the axial direction is connected to the second opening, and the other end of the third pipe joint in the axial direction is connected to the third opening. The branch pipe body includes a sealing portion that seals the first gap between the outer circumferential surface of the first pipe joint and the first opening, the second gap between the outer circumferential surface of the second pipe joint and the second opening, and the third gap between the outer circumferential surface of the third pipe joint and the third opening. The sealing portion includes a brazing layer connecting the branch pipe body with the first pipe joint, the second pipe joint, and the third pipe joint.

[0007] The branch pipe of this disclosure can be obtained by applying simple processing to a stainless steel plate.

[0008] (2) In the branch pipe of (1) of the present disclosure, the distance between the first plate-shaped member and the second plate-shaped member preferably increases in the portion where the first plate-shaped member and the second plate-shaped member form the first gap, the second gap, and the third gap, as the distance progresses from the end of the joint opposite to the first pipe joint, the second pipe joint, and the third pipe joint toward the central axis of the first pipe joint, the second pipe joint, and the third pipe joint.

[0009] (3) In the branch pipe of (1) or (2) of the present disclosure, the first plate-like member preferably has a volume-reducing portion that reduces the internal volume of at least one of the first gap, the second gap, and the third gap.

[0010] The branch pipe with the above configuration can reduce the gaps between the first, second, and third openings and each pipe joint by providing a volume reduction section, thereby reducing the amount of brazing material used to seal the gaps.

[0011] (4) In the branch pipe according to the embodiment of (3) of the present disclosure, the volume reduction portion preferably includes a first thickness portion in which the thickness of the first plate-like member is a first thickness, and a second thickness portion in which the thickness of the first plate-like member is a second thickness that is smaller than the first thickness.

[0012] In the branch pipe with the above configuration, a volume reduction section can be easily provided by providing a first plate-shaped member with a first plate thickness section and a second plate thickness section with different plate thicknesses.

[0013] (5) In the branch pipe according to the embodiment of (4) of the present disclosure, the first plate-like member preferably comprises a straight plate portion and a curved plate portion, wherein the straight plate portion is the second plate thickness portion.

[0014] In the branch pipe with the above configuration, a volume reduction section can be easily provided by making the second plate thickness section a straight plate section.

[0015] (6) In the branch pipe according to the embodiment of (4) of the present disclosure, the first plate-like member preferably comprises a straight plate portion and a curved plate portion, wherein the curved plate portion has the second plate thickness portion.

[0016] In the branch pipe with the above configuration, a volume reduction section can be easily provided by providing the second plate thickness section in the curved plate section.

[0017] (7) In the branch pipe according to the embodiment of (4) of the present disclosure, the first plate-like member preferably has the first plate thickness portion in the portion that forms at least one of the first gap, the second gap, and the third gap.

[0018] In the branch pipe of this disclosure, a volume reduction portion can be easily provided by providing a first plate thickness portion in the portion that forms the gap in the first plate-shaped member.

[0019] (8) In the branch pipe according to the embodiment of (3) of the present disclosure, the volume reduction portion is preferably composed of a projection that protrudes from the first plate-like member toward at least one of the first gap, the second gap, and the third gap.

[0020] In the branch pipe of this disclosure, a volume reduction portion can be easily provided by providing a protrusion in the portion that forms a gap in the first plate-shaped member.

[0021] (9) In the branch pipe according to the embodiment of (8) of the present disclosure, the first plate-like member preferably has a back surface which is the surface opposite to the first surface, and a recess formed on the back surface which is located on the back side of the position of the protrusion.

[0022] The branch pipe of this disclosure allows for the easy provision of a protrusion in the portion of the first plate-shaped member that forms a gap, by pressing the back surface of the first plate-shaped member and creating a recess on the back surface. This makes it easy to provide a volume reduction portion.

[0023] (10) In a branch pipe according to any embodiment of (1) to (9) of the present disclosure, the branch pipe body has a first end having the first opening and a second end having the second opening and the third opening, the joint includes a branch section formed between the second opening and the third opening, the branch section has a flow divider located on the first end side of the branch section that divides the fluid flowing in from the first opening to the second opening side and the third opening side, and a flow straightening section extending from the end of the flow divider on the second end side in a first direction parallel to the axial directions of the second opening and the third opening. Preferably the length of the flow straightening section in the first direction is greater than the insertion allowance of the second pipe fitting at the second opening and the insertion allowance of the third pipe fitting at the third opening.

[0024] The branch pipe of this disclosure can reliably straighten the fluid flowing out from the second and third openings by the flow straightening section.

[0025] (11) In the branch pipe according to the embodiment of (10) of the present disclosure, the flow path includes a first flow path formed by the diversion section, the first plate-shaped member, and the second plate-shaped member, and a second flow path formed by the straightening section, the first plate-shaped member, and the second plate-shaped member, wherein the flow cross-sectional area of ​​the first flow path is preferably equal to or greater than the flow cross-sectional area of ​​the second flow path.

[0026] The branch pipe of this disclosure can suppress the resistance that the fluid receives from the diversion section in the first flow path.

[0027] (12) In a branch pipe according to the embodiment of (10) or (11) of the present disclosure, the rectifier portion has a first portion on the first end side and a second portion on the second end side, and is parallel to the mating surface between the first plate-like member and the second plate-like member in the branch portion, and preferably the width of the second portion in a second direction perpendicular to the first direction is smaller than the width of the first portion in the second direction.

[0028] The manifold of the present disclosure can easily position the second pipe joint and the third pipe joint at the second opening and the third opening.

[0029] (13) In the manifold according to any one of the aspects (1) to (12) of the present disclosure, the joint portion includes a branch portion formed between the second opening and the third opening, and it is preferable that a first distance between the second pipe joint and the third pipe joint is larger than a thickness of the branch portion.

[0030] The manifold of the present disclosure can ensure the joining strength between the first plate-like member and the second plate-like member in the branch portion by securing a separation distance between the second pipe joint and the third pipe joint.

[0031] (14) In the manifold according to any one of the aspects (1) to (13) of the present disclosure, the first plate-like member includes a first bent portion with a concave first surface side and a second bent portion with a convex first surface side. When a bending radius of the first surface in the second bent portion is defined as a plate bending outer diameter (r so ), an outer diameter of the first pipe joint, the second pipe joint, and the third pipe joint is defined as a joint outer diameter (r t ), a distance between the second pipe joint and the third pipe joint is defined as a first distance (W1), and a plate thickness of the first plate-like member is defined as a plate thickness (t), it is preferable that the first distance (W1) satisfies the following formula 1, and the plate bending outer diameter (r so ) satisfies the following formula 2. Formula 1: W1 ≧ 2√((r t + r so ) 2 - r so 2 ) - 2r t (Here, W1: first distance, r so : plate bending outer diameter, r t : joint outer diameter) Formula 2: r so ≧ 2t (Here, t: plate thickness of the first plate-like member)

[0032] The branch pipe of this disclosure facilitates the bending of the first plate-shaped member and the second plate-shaped member, which are made of stainless steel, by ensuring a separation distance that satisfies Equations 1 and 2.

[0033] (15) In a branch pipe according to the embodiment of (14) of the present disclosure, the first plate-like member comprises a straight plate portion and a curved plate portion, the joint portion includes a branch portion formed between the second opening and the third opening, the branch portion has the straight plate portion, and is parallel to the mating surface between the first plate-like member and the second plate-like member in the branch portion, and in a second direction perpendicular to a first direction parallel to the axial direction of the second opening and the third opening, the width of the straight plate portion in the branch portion is defined as the first width (α), The first distance (W1) preferably satisfies the following equation 3. Formula 3: W1 ≥ 2√((r t +r so ) 2 -r so 2 )-2r t +α (Here, W1: first distance, α: first width)

[0034] The branch pipe of this disclosure can have its strength improved by ensuring a separation distance that satisfies Equation 3.

[0035] (16) In a branch pipe according to any embodiment of (1) to (15) of the present disclosure, the first plate-shaped member comprises a straight plate portion and a curved plate portion, including a first curved portion having a concave first surface and a second curved portion having a convex first surface, the joint portion includes a branch portion formed between the second opening and the third opening and an outer edge joint portion other than the branch portion, and the bending radius of the first surface in the second curved portion is the outer diameter of the plate bending (r so ) and the outer diameters of the first pipe fitting, the second pipe fitting, and the third pipe fitting are set to the outer diameter of the fitting (r t) and the thickness of the first plate-like member is defined as plate thickness (t), and the width of the straight plate portion at the outer edge joint is defined as the second width (β) in a second direction that is parallel to the joint surface between the first plate-like member and the second plate-like member at the branching portion and perpendicular to the first direction that is parallel to the axial direction of the second opening and the third opening, The second width (β) satisfies the following equation 4, and When the distance from the first pipe joint, the second pipe joint, and the third pipe joint to the end of the outer edge joint is defined as the second distance (W2), The second distance (W2) preferably satisfies the following equation 5. Formula 4: t ≤ β ≤ 20t (Here, r so : outer diameter of the bent plate, r t (: outer diameter of the joint, β: width of the second member, t: thickness of the first plate-like member) Formula 5: W2≧√((r t +r so ) 2 -r so 2 )-r t +β (Here, W2: the second distance)

[0036] The branch pipe of this disclosure can have its strength improved by ensuring a distance from the pipe joint to the end of the outer edge joint that satisfies equations 4 and 5.

[0037] (17) In any of the embodiments of (1) to (16) of the present disclosure, the first pipe, the second pipe, and the third pipe are preferably refrigerant pipes through which a single refrigerant consisting of carbon dioxide or a mixed refrigerant containing carbon dioxide flows.

[0038] The branch pipe of this disclosure can be used in refrigerant piping for a single refrigerant consisting of carbon dioxide, which is at a higher pressure than conventional refrigerants, or for a mixed refrigerant containing carbon dioxide.

[0039] (18) The refrigeration apparatus of the present disclosure comprises the branch pipe in any of the embodiments of (1) to (17) above.

[0040] The refrigeration apparatus of this disclosure uses branch pipes obtained by simple processing of stainless steel plates, and allows for the simple construction of a refrigeration apparatus including a refrigerant circuit that operates at a higher pressure than conventional systems. [Brief explanation of the drawing]

[0041] [Figure 1] Figure 1 is a schematic diagram showing a refrigeration apparatus according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic perspective view showing a branch pipe according to one embodiment of the present disclosure. [Figure 3] Figure 3 is a schematic cross-sectional view showing a branch pipe according to one embodiment of the present disclosure. [Figure 4] Figure 4 is an explanatory diagram of a branch pipe according to the first embodiment. [Figure 5] Figure 5 is an explanatory diagram of a branch pipe according to the second embodiment. [Figure 6] Figure 6 is an explanatory diagram of a branch pipe according to the third embodiment. [Figure 7A] Figure 7A is an explanatory diagram of a branch pipe according to the fourth embodiment. [Figure 7B] Figure 7B is an explanatory diagram of a branch pipe according to the fourth embodiment. [Figure 8A] Figure 8A is an explanatory diagram of a branch pipe according to the fifth embodiment. [Figure 8B] Figure 8B is an explanatory diagram of a branch pipe according to the fifth embodiment. [Figure 9] Figure 9 is an explanatory diagram of a branch pipe according to the fifth embodiment. [Figure 10] Figure 10 is an explanatory diagram of a modified example of the branch pipe according to the fifth embodiment. [Figure 11A] Figure 11A is an explanatory diagram of a branch pipe according to the sixth embodiment. [Figure 11B] Figure 11B is an explanatory diagram of a modified example of the branch pipe according to the sixth embodiment. [Figure 12] Figure 12 is a schematic diagram of the branch pipe as seen from the first opening side. [Figure 13]Figure 13 is a schematic diagram of the branch pipe as seen from the second and third openings. [Figure 14] Figure 14 is an explanatory diagram of the outer diameter of the bent plate and the outer diameter of the joint in a branch pipe. [Figure 15] Figure 15 is an explanatory diagram illustrating a modified example of a branching section in a branched pipe. [Figure 16] Figure 16 is an explanatory diagram of the flow path of the branch pipes in the diversion and straightening sections.

[0042] The branch pipe and refrigeration apparatus having said branch pipe described herein will be described in detail below with reference to the attached drawings. However, this disclosure is not limited to these examples, and all modifications within the meaning and scope of the claims are intended to be included.

[0043] [Overall configuration of the refrigeration system] Figure 1 is a schematic diagram showing a refrigeration system according to one embodiment of the present disclosure. The refrigeration system 100 shown in this embodiment is an air conditioning system that adjusts the temperature and humidity of a room to be air-conditioned by a vapor compression type refrigeration cycle. The refrigeration system 100 comprises a plurality of indoor units 101 (two in this embodiment) installed inside the room and an outdoor unit 102 installed outside the room. The indoor units 101 and the outdoor unit 102 are connected to each other by refrigerant piping 110. The indoor units 101 include a first indoor unit 101 (hereinafter also referred to as the first indoor unit 101A) and a second indoor unit 101 (hereinafter also referred to as the second indoor unit 101B). Although this embodiment illustrates a refrigeration system 100 with two indoor units 101, the refrigeration system 100 of the present disclosure may be configured to have three or more indoor units 101.

[0044] The refrigeration system 100 includes a refrigerant circuit 103 that performs a vapor compression type refrigeration cycle. The refrigerant circuit 103 includes a plurality of component parts and refrigerant piping 110 that connects the plurality of component parts. The refrigerant piping 110 includes the branch pipe 10 of this disclosure. The configuration of the branch pipe 10 will be described in detail later.

[0045] The refrigerant circuit 103 includes multiple components such as a compressor 104 that compresses the refrigerant to produce high-temperature, high-pressure gaseous refrigerant, multiple indoor heat exchangers 105, an expansion valve 106 that reduces the pressure of the refrigerant, an outdoor heat exchanger 107, an accumulator 108, and a four-way switching valve 109, all of which are connected by refrigerant piping 110.

[0046] The refrigeration system 100 of this disclosure uses a single refrigerant consisting of carbon dioxide or a mixed refrigerant containing carbon dioxide (a so-called natural refrigerant) as the refrigerant. The refrigerant flowing through the refrigerant circuit 103 is at a pressure of 4.0 MPa or higher (for example, about 8 to 14 MPa). Therefore, the refrigerant piping 110 and branch pipes 10 used in the refrigeration system 100 have strength capable of withstanding a pressure of 4.0 MPa or higher. The refrigerant piping 110 and branch pipes 10 used in the refrigeration system 100 are made of stainless steel and have higher pressure resistance strength compared to, for example, refrigerant piping and branch pipes used in refrigerant circuits using conventional refrigerants (for example, R32, R410A, etc.).

[0047] The compressor 104 compresses low-pressure gaseous refrigerant and discharges high-pressure gaseous refrigerant. The compressor 104 has an inlet or suction section 104a and a discharge port or discharge section 104b. Low-pressure gaseous refrigerant is drawn in from the suction section 104a. High-pressure gaseous refrigerant is discharged from the discharge section 104b in the direction of arrow A. Various types of compressors, such as a scroll compressor, can be used as the compressor 104. The compressor 104 is housed in the casing 102a of the outdoor unit 102. The accumulator 108 is provided in the refrigerant piping 110 on the suction side of the compressor 104.

[0048] The indoor heat exchanger 105 is installed in the indoor unit 101 and performs heat exchange between the refrigerant and the indoor air. For example, the indoor heat exchanger 105 can be a cross-fin type fin-and-tube heat exchanger or a microchannel type heat exchanger. The indoor fan 121 is installed near the indoor heat exchanger 105. The indoor fan 121 blows indoor air to the indoor heat exchanger 105 and sends conditioned air into the room.

[0049] The expansion valve 106 is installed in the refrigerant piping 110 between the outdoor heat exchanger 107 and the indoor heat exchanger 105. The expansion valve 106 expands the refrigerant passing through it and reduces the pressure to a predetermined level. The expansion valve 106 in this embodiment is an electronic expansion valve.

[0050] The outdoor heat exchanger 107 performs heat exchange between the refrigerant and the outdoor air. The outdoor heat exchanger 107 can be, for example, a cross-fin type fin-and-tube heat exchanger or a microchannel type heat exchanger. The outdoor fan 122 is installed near the outdoor heat exchanger 107. The outdoor fan 122 blows outdoor air to the outdoor heat exchanger 107.

[0051] The refrigerant piping 110 is equipped with a four-way switching valve 109, a gas shut-off valve 123, and a liquid shut-off valve 124 for switching the refrigerant flow path. The refrigeration system 100 can switch between cooling and heating operation by reversing the flow of refrigerant by switching the four-way switching valve 109, and supplying the refrigerant discharged from the compressor 104 to the outdoor heat exchanger 107 and the indoor heat exchanger 105.

[0052] The gas shut-off valve 123 and the liquid shut-off valve 124 open or close the refrigerant path. Opening and closing are performed, for example, manually. The gas shut-off valve 123 and the liquid shut-off valve 124 are closed, for example, when the refrigeration system 100 is installed, to prevent the refrigerant sealed in the outdoor unit 102 from leaking to the outside. On the other hand, the gas shut-off valve 123 and the liquid shut-off valve 124 are open when the refrigeration system 100 is in use.

[0053] During heating operation of the refrigeration unit 100, the four-way switching valve 109 is switched as shown by the solid line, causing the refrigerant to flow in the direction indicated by the solid arrow. As a result, the high-pressure gaseous refrigerant discharged from the compressor 104 in the direction of arrow A passes through the four-way switching valve 109, then through the open gas shut-off valve 123, and enters the indoor heat exchanger 105. The high-pressure gaseous refrigerant dissipates heat in the indoor heat exchanger 105 as it becomes high-pressure liquid refrigerant. The high-pressure liquid refrigerant reaches the expansion valve 106 via the open liquid shut-off valve 124, where it is depressurized. The depressurized refrigerant reaches the outdoor heat exchanger 107, where it absorbs heat and becomes low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant is drawn into the compressor 104 via the four-way switching valve 109 and the accumulator 108. During heating operation, the indoor heat exchanger 105 functions as a heat radiator, and the outdoor heat exchanger 107 functions as a heat absorber.

[0054] On the other hand, during cooling operation, the flow of the refrigerant is reversed by switching the four-way switching valve 109 as shown by the dotted line, causing the refrigerant to flow in the direction indicated by the dotted arrow. As a result, the high-pressure gaseous refrigerant discharged from the compressor 104 in the direction of arrow A passes through the four-way switching valve 109 and enters the outdoor heat exchanger 107. The high-pressure gaseous refrigerant dissipates heat in the process of becoming high-pressure liquid refrigerant in the outdoor heat exchanger 107. The high-pressure liquid refrigerant reaches the expansion valve 106, where it is depressurized. The depressurized refrigerant reaches the indoor heat exchanger 105 via the open liquid shut-off valve 124, where it absorbs heat and becomes low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant is drawn into the compressor 104 via the open gas shut-off valve 123, the four-way switching valve 109, and the accumulator 108. During cooling operation, the indoor heat exchanger 105 functions as a heat absorber, and the outdoor heat exchanger 107 functions as a heat radiator.

[0055] [Regarding refrigerant piping] As shown in Figure 1, in the refrigeration system 100 of this disclosure, the refrigerant piping 110 includes a first pipe 111, a second pipe 112, and a third pipe 113. The refrigerant piping 110 further includes a branch pipe 10 connecting the first pipe 111, the second pipe 112, and the third pipe 113. The first pipe 111, the second pipe 112, the third pipe 113, and the branch pipe 10 constitute a part of the refrigerant circuit 103. The first pipe 111, the second pipe 112, and the third pipe 113 are made of copper, and the branch pipe 10 is made of stainless steel. In the refrigerant piping 110 of this disclosure, the first pipe 111, the second pipe 112, and the third pipe 113 may be made of stainless steel, for example, and are not limited to being made of copper.

[0056] The first piping 111 includes a refrigerant piping 110 located inside the outdoor unit 102 and a refrigerant piping 110 connecting the outdoor unit 102 to the branch pipe 10. The first piping 111 includes a first liquid refrigerant piping 111L and a first gaseous refrigerant piping 111G. Liquid refrigerant flows through the first liquid refrigerant piping 111L, and gaseous refrigerant flows through the first gaseous refrigerant piping 111G.

[0057] The second piping 112 is a refrigerant piping 110 that connects the first indoor unit 101A and the branch pipe 10. The second piping 112 includes a second liquid refrigerant piping 112L and a second gaseous refrigerant piping 112G. Liquid refrigerant flows through the second liquid refrigerant piping 112L, and gaseous refrigerant flows through the second gaseous refrigerant piping 112G.

[0058] The third piping 113 is a refrigerant piping 110 that connects the second indoor unit 101B and the branch pipe 10. The third piping 113 includes a third liquid refrigerant piping 113L and a third gaseous refrigerant piping 113G. Liquid refrigerant flows through the third liquid refrigerant piping 113L, and gaseous refrigerant flows through the third gaseous refrigerant piping 113G.

[0059] [Regarding branch pipes] As shown in Figure 1, the refrigeration system 100 of this disclosure includes two branch pipes 10 (referred to as the first branch pipe 10X and the second branch pipe 10Y). The refrigeration system 100 of this disclosure may also be configured to include three or more branch pipes 10 depending on the number of indoor units 101. In this embodiment, the branch pipes 10 are used to connect the indoor unit 101 and the outdoor unit 102, but the use of the branch pipes 10 of this disclosure is not limited to this, and they may also be used, for example, in the branch portions of the internal piping of the outdoor unit 102. In this embodiment, the branch pipes 10 are used to carry a refrigerant, which is an example of a fluid, but they may also be used to carry fluids other than refrigerants (water, nitrogen gas, etc.).

[0060] The first branch pipe 10X connects the first liquid refrigerant piping 111L to the second liquid refrigerant piping 112L and the third liquid refrigerant piping 113L. The first branch pipe 10X branches the liquid refrigerant flowing in from the first liquid refrigerant piping 111L and allows it to flow out to the second liquid refrigerant piping 112L and the third liquid refrigerant piping 113L. The first branch pipe 10X also merges the liquid refrigerants flowing in from the second liquid refrigerant piping 112L and the third liquid refrigerant piping 113L and allows them to flow out to the first liquid refrigerant piping 111L.

[0061] The second branch pipe 10Y connects the first gas refrigerant piping 111G to the second gas refrigerant piping 112G and the third gas refrigerant piping 113G. The second branch pipe 10Y branches the gas refrigerant flowing in from the first gas refrigerant piping 111G and allows it to flow out to the second gas refrigerant piping 112G and the third gas refrigerant piping 113G. The second branch pipe 10Y also merges the gas refrigerants flowing in from the second gas refrigerant piping 112G and the third gas refrigerant piping 113G and allows them to flow out to the first gas refrigerant piping 111G.

[0062] Figure 2 is a schematic perspective view showing a branch pipe according to one embodiment of the present disclosure. Figure 3 is a schematic cross-sectional view showing a branch pipe according to one embodiment of the present disclosure. As shown in Figures 2 and 3, the branch pipe 10 comprises a branch pipe body 20, a first pipe joint 31, a second pipe joint 32, and a third pipe joint 33. Note that in Figure 2, for the sake of explanation, some parts (such as the sealing part 28, the first joint part 34, the second joint part 35, and the third joint part 36, which will be explained later) are not shown.

[0063] As shown in Figure 2, the branch pipe body 20 is composed of a first plate-shaped member 21 and a second plate-shaped member 22. The first plate-shaped member 21 and the second plate-shaped member 22 are members manufactured into a predetermined shape by press-forming stainless steel plates. The material of the first plate-shaped member 21 and the second plate-shaped member 22 is, for example, SUS304L. As will be explained later, the first plate-shaped member 21 and the second plate-shaped member 22 may be subjected to further machining other than press-forming (for example, grinding, polishing, etc.) (see Figures 8A and 8B).

[0064] The first plate-shaped member 21 has a first surface 21a. The first surface 21a is the surface that faces inward towards the branch pipe body 20 when the first plate-shaped member 21 is assembled as the branch pipe body 20. The second plate-shaped member 22 has a second surface 22a. The second surface 22a is the surface that faces inward towards the branch pipe body 20 when the second plate-shaped member 22 is assembled as the branch pipe body 20. The first plate-shaped member 21 and the second plate-shaped member 22 are arranged with their first surface 21a and second surface 22a facing each other.

[0065] The branch pipe body 20 is further composed of a joint 24. The branch pipe body 20 is composed of a joint 24 which joins a first plate-shaped member 21 and a second plate-shaped member 22. In this embodiment, the joint 24 is composed of a layer of brazing material (sheet brazing) formed between the first surface 21a and the second surface 22a. In the branch pipe body 20 of this embodiment, the joint 24 is the portion where the first surface 21a and the second surface 22a are brazed together, but it may also be a portion (bead) where the outer surface (end face) of the first plate-shaped member 21 perpendicular to the first surface 21a and the outer surface (end face) of the second plate-shaped member 22 perpendicular to the second surface 22a are welded (TIG welding, laser welding, etc.).

[0066] The branch pipe body 20 further comprises a flow path 25 formed between a first surface 21a and a second surface 22a. The flow path 25 is a flow path (space) through which a fluid (in this embodiment, a refrigerant (liquid refrigerant or gaseous refrigerant)) flows. The branch pipe body 20 has a plurality of openings 26. The plurality of openings 26 include a first opening 26a, a second opening 26b, and a third opening 26c formed by the first plate-shaped member 21 and the second plate-shaped member 22 at the ends of the flow path 25 in the direction of refrigerant flow. The first opening 26a, the second opening 26b, and the third opening 26c are opened in directions that do not intersect with the first surface 21a and the second surface 22a. The branch pipe 10 of this embodiment has three openings 26 (first opening 26a, second opening 26b, and third opening 26c). The first opening 26a, the second opening 26b, and the third opening 26c are each formed inside the cylindrical portion formed by the first plate-like member 21 and the second plate-like member 22. In the branch pipe 10 of this disclosure, there may be three or more openings 26, for example, four.

[0067] As described above, the branch pipe 10 of this disclosure can be easily manufactured by joining a first plate-shaped member 21 and a second plate-shaped member 22, which are made by press-forming (bending) stainless steel plates. In other words, the branch pipe 10 can be manufactured by simple processing such as press-forming (bending) and welding.

[0068] The branch pipe body 20 further includes a branch section 27. The branch section 27 is the part that branches the refrigerant flowing into the flow path 25 from the first opening 26a to the second opening 26b side and the third opening 26c side. The branch section 27 is also the part (merging section) that merges the refrigerant flowing into the flow path 25 from the second opening 26b and the third opening 26c and flows it to the first opening 26a side. In the branch pipe 10 of this embodiment, there is one branch section 27, but two or more may be provided depending on the number of openings 26.

[0069] The first pipe joint 31 has one end 31a inserted into the first opening 26a. The second pipe joint 32 has one end 32a inserted into the second opening 26b. The third pipe joint 33 has one end 33a inserted into the third opening 26c. The first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 are brazed in a furnace to the branch pipe body 20.

[0070] In the branch pipe 10, leakage of refrigerant from the gaps (hereinafter referred to as gap Z) between the outer circumferential surface 31c on one end 31a of the first pipe joint 31 and the first opening 26a, between the outer circumferential surface 32c on one end 32a of the second pipe joint 32 and the second opening 26b, and between the outer circumferential surface 33c on one end 33a of the third pipe joint 33 and the third opening 26c is a problem. For this reason, the branch pipe 10 is further provided with a sealing part 28 that seals the gap Z. The form of the sealing part 28 will be described in detail later.

[0071] The branch pipe 10 further comprises a first joint section 34 provided at the other end 31b of the first pipe joint 31, a second joint section 35 provided at the other end 32b of the second pipe joint 32, and a third joint section 36 provided at the other end 33b of the third pipe joint 33. The first joint section 34, the second joint section 35, and the third joint section 36 are made of copper fittings. The copper first joint section 34, the second joint section 35, and the third joint section 36 can be connected to the first pipe 111, the second pipe 112, and the third pipe 113 by brazing at the site. In the branch pipe 10 of this disclosure, the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 may be made of materials other than copper and are not limited to being made of copper.

[0072] The branch pipe 10 forms part of the refrigerant piping 110 by connecting the first joint 34 to the first pipe 111, the second joint 35 to the second pipe 112, and the third joint 36 to the third pipe 113.

[0073] [Regarding the setting of dimensions for each part of the branch pipe] As shown in Figures 2 and 3, the branch pipe 10 of this embodiment includes a branch section 27 formed between the second opening 26b and the third opening 26c. As shown in Figure 3, in the branch pipe 10 of this embodiment, the axial length L1 of the branch section 27 formed between the second opening 26b and the third opening 26c is set to be greater than the insertion allowance L2 of the second pipe fitting 32 at the second opening 26b and the insertion allowance L3 of the third pipe fitting 33 at the third opening 26c (L1>L2, L1>L3).

[0074] By having this configuration, the branch pipe 10 of this embodiment can ensure pressure resistance that can withstand the use of high-pressure refrigerants, and can also reliably straighten the flow of refrigerant from the first pipe 111 to the second pipe 112 and the third pipe 113.

[0075] As shown in Figures 2 and 3, in the branch pipe 10 of this embodiment, the separation distance W between the second opening 26b and the third opening 26c is set to a distance greater than the thickness D of the branch section 27 (W > D). The thickness D of the branch section 27 is the sum of the thicknesses of the first plate-like member 21, the second plate-like member 22, and the joint 24.

[0076] In this embodiment, the branch pipe 10 can be configured in such a way that it can secure an insertion allowance L2 for the second pipe joint 32 at the second opening 26b, and an insertion allowance L3 for the third pipe joint 33 at the third opening 26c. As a result, the branch pipe 10 in this embodiment can be configured to withstand the pressure required for the use of high-pressure natural refrigerants.

[0077] [Regarding the sealing part] In the branch pipe 10 of this disclosure, the brazing layer S connecting the first to third pipe joints 31 to 33 and the branch pipe body 20 can be used as a sealing part 28. The brazing layer S is a layer made of brazing material. However, when using the brazing layer S as a sealing part 28, it is necessary to supply an appropriate amount of brazing material to the gap Z, and if the amount of brazing material is not appropriate, shrinkage cavities may occur in the brazing layer S. Since shrinkage cavities are areas where refrigerant may leak, it is preferable that the branch pipe 10 of this disclosure adopts a configuration that suppresses refrigerant leakage from shrinkage cavities in the brazing layer S. For this reason, the branch pipe 10 of this disclosure is configured based on one of the following ideas: 1) sealing the gap Z using a material other than brazing material while allowing the occurrence of shrinkage cavities in the brazing layer S, or 2) reducing the gap Z and suppressing the occurrence of shrinkage cavities by suppressing the amount of brazing material used in the brazing layer S.

[0078] [Branch pipe according to the first embodiment] Figure 4 is an explanatory diagram of a branch pipe according to the first embodiment. Figure 4 shows a first embodiment of the branch pipe 10 of the present disclosure. In this description, the branch pipe 10 according to the first embodiment will also be referred to as branch pipe 10A. As shown in Figure 4, the branch pipe 10A according to the first embodiment is characterized by having an end plate 51. The upper part of Figure 4 shows the branch pipe body 20 before the end plate 51 is installed, with the first opening 26a and the first pipe joint 31 viewed from the axial direction. The lower part of Figure 4 shows the branch pipe body 20 after the end plate 51 is installed, with the first opening 26a and the first pipe joint 31 viewed from the axial direction. As shown in Figure 4, the branch pipe 10A has an end plate 51 that seals the gap Z between the first opening 26a and the first pipe joint 31. The end plate 51 is part of the sealing portion 28. The branch pipe 10A suppresses leakage of fluid (refrigerant) from the gap Z by sealing the gap Z with the end plate 51. Furthermore, branch pipe 10A allows for the occurrence of shrinkage cavities in the brazing material. Therefore, in branch pipe 10A, the gap Z does not need to be completely filled with brazing material. Furthermore, in branch pipe 10A, the gap Z may be completely filled with brazing material.

[0079] As shown in Figure 4, the end plate 51 is positioned at the axial end of the first opening 26a of the branch pipe body 20. The end plate 51 is made of stainless steel. The end plate 51 is furnace brazed to the axial end of the first opening 26a of the branch pipe body 20 and to the first pipe joint 31.

[0080] Figure 4 illustrates only the end plate 51 located at the first opening 26a, and the end plates 51 located at the second opening 26b and the third opening 26c are not shown. In the branch pipe 10A, the end plates 51 are similarly located at the axial end of the second opening 26b of the branch pipe body 20 and at the axial end of the third opening 26c of the branch pipe body 20.

[0081] In the branch pipe 10A, the end plate 51 does not have to be placed in all of the first opening 26a, the second opening 26b, and the third opening 26c, but may be placed in one or more of the first opening 26a, the second opening 26b, and the third opening 26c. In other words, the branch pipe 10A includes an end plate 51 placed in at least one of the axial ends of the first opening 26a, the axial end of the second opening 26b, and the axial end of the third opening 26c.

[0082] In the branch pipe 10, if the gaps Z between each opening 26a to 26c and each pipe joint 31 to 33 are all filled with brazing material, the amount of brazing material required will increase, and the brazing process will become more laborious (i.e., brazing will take longer). In the branch pipe 10A according to the first embodiment, the gaps Z are sealed by the end plate 51, so there is no need to fill the gaps Z with brazing material. Therefore, the branch pipe 10A having the end plate 51 can reduce the amount of brazing material used in the sealing portion 28 and reduce the labor required for brazing. In addition, by reducing sink marks in the brazing material layer S, leakage of refrigerant from the gaps Z can be suppressed.

[0083] [Branch pipe according to the second embodiment] Figure 5 is an explanatory diagram of a branch pipe according to the second embodiment. Figure 5 shows a second embodiment of the branch pipe 10 of the present disclosure. In this description, the branch pipe 10 according to the second embodiment will also be referred to as branch pipe 10B. As shown in Figure 5, the branch pipe 10B according to the second embodiment is characterized by having an inclusion 52. Figure 5 shows the first opening 26a and the first pipe joint 31 of the branch pipe 10B as viewed from the axial direction. As shown in Figure 5, the branch pipe 10B has a sealing portion 28 that fills the gap Z between the first opening 26a and the first pipe joint 31. In the branch pipe 10B, the sealing portion 28 includes a brazing material that fills the gap Z and an inclusion 52. The inclusion 52 is part of the sealing portion 28. The branch pipe 10B can reduce the gap Z by the inclusion 52 and suppress the amount of brazing material used, thereby reducing shrinkage cavities in the brazing material layer S, and thereby suppressing refrigerant leakage from the gap Z. In this embodiment, the intervening material 52 is a stainless steel wire. However, the intervening material 52 constituting the branch pipe 10B in this embodiment is not limited to a stainless steel wire.

[0084] Figure 5 illustrates only the inclusion 52 placed in the first opening 26a, and the inclusions 52 placed in the second opening 26b and the third opening 26c are not shown. In the branch pipe 10B of this embodiment, the inclusions 52 are similarly placed in the second opening 26b and the third opening 26c. In the branch pipe 10B, the inclusions 52 do not have to be placed in all of the first opening 26a, the second opening 26b, and the third opening 26c, and may be placed in one or more of the first opening 26a, the second opening 26b, and the third opening 26c. In other words, the branch pipe 10B includes an inclusion 52 placed in at least one of the first opening 26a, the second opening 26b, and the third opening 26c.

[0085] The first plate-shaped member 21 and the second plate-shaped member 22 are brazed in a furnace with an inclusion 52 placed in the region (gap Z) surrounded by the first plate-shaped member 21, the second plate-shaped member 22, and each pipe joint 31-33. In the branch pipe 10B according to the second embodiment, a portion of the gap Z is filled with the inclusion 52, and the remaining gap Z is filled with brazing material. In the branch pipe 10B with this configuration, the amount of brazing material required to fill the gap Z can be reduced by the volume of the inclusion 52. As a result, the branch pipe 10B can reduce the amount of brazing material used in the sealing portion 28 and reduce the effort required for brazing. In addition, shrinkage cavities in the brazing material layer S can be reduced, thereby suppressing refrigerant leakage from the gap Z.

[0086] In the branch pipe 10B of this embodiment, it is preferable that the inclusion 52 placed in the first opening 26a is connected to one of the inclusions 52 placed in the second opening 26b and one of the inclusions 52 placed in the third opening 26c. Furthermore, in the branch pipe 10B of this embodiment, it is preferable that the other inclusion 52 placed in the second opening 26b is connected to the other inclusion 52 placed in the third opening 26c. By using inclusions 52 with such a configuration, the number of inclusions 52 can be reduced, thereby reducing the brazing effort. The amount of shrinkage voids in the brazing material layer S can be reduced, thereby suppressing the leakage of refrigerant from the gap Z.

[0087] [Branch pipe according to the third embodiment] Figure 6 is an explanatory diagram of a branch pipe according to the third embodiment. Figure 6 shows a third embodiment of the branch pipe 10 of the present disclosure. In this description, the branch pipe 10 according to the third embodiment will also be referred to as branch pipe 10C. As shown in Figure 6, the branch pipe 10C according to the third embodiment is characterized in that the pipe joint has a bulging portion. Figure 6 shows the first opening 26a and the first pipe joint 31 of the branch pipe 10C as viewed from the axial direction. As shown in Figure 6, the branch pipe 10C has a sealing portion 28 that fills the gap Z between the first opening 26a and the first pipe joint 31.

[0088] In the branch pipe 10C, the first pipe joint 31 has a bulge portion 53. The bulge portion 53 is the part of the first pipe joint 31 that bulges outwards toward the gap Z. The bulge portion 53 bulges radially outward from a virtual circle C (see Figure 6) which is assumed to be a perfect circle when the cross-sectional shape of the first pipe joint 31 perpendicular to the axial direction is assumed to be a perfect circle. In other words, the first pipe joint 31 having the bulge portion 53 does not have a perfect circle when the cross-sectional shape of the cross-sectional shape perpendicular to the axial direction is not a perfect circle. By reducing the gap Z with the bulge portion 53 in the branch pipe 10C and suppressing the amount of brazing material used, shrinkage cavities in the brazing material layer S can be reduced, thereby suppressing refrigerant leakage from the gap Z.

[0089] Figure 6 illustrates only the bulge 53 of the first pipe joint 31, and the bulges 53 provided on the second pipe joint 32 and the third pipe joint 33 are not shown. In the branch pipe 10C, the second pipe joint 32 and the third pipe joint 33 have bulges 53 similar to those of the first pipe joint 31. The branch pipe 10C does not need to have bulges 53 in all of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33; it may be configured so that one or more of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 have bulges 53. In other words, the branch pipe 10C includes a bulge 53 located in at least one of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33.

[0090] In the third embodiment, the branch pipe 10C reduces the internal volume of the gap Z by providing a bulge 53. As a result, the branch pipe 10C can reduce the amount of brazing material used in the sealing portion 28 and reduce the effort required for brazing. In addition, it can reduce sink marks in the brazing material layer S, thereby suppressing refrigerant leakage from the gap Z.

[0091] [Branch pipe according to the fourth embodiment] Figures 7A and 7B are explanatory diagrams of a branch pipe according to the fourth embodiment. Figure 7A shows the fourth embodiment of the branch pipe 10 of the present disclosure. In this description, the branch pipe 10 according to the fourth embodiment will also be referred to as branch pipe 10D. As shown in Figure 7A, the branch pipe 10D according to the fourth embodiment is characterized in that the branch pipe body 20 is composed of a third plate-shaped member 23. Figure 7A shows the first opening 26a and the first pipe joint 31 of the branch pipe 10D as viewed from the axial direction. As shown in Figure 7A, the branch pipe 10D has a sealing portion 28 that fills the gap Z between the first opening 26a and the first pipe joint 31.

[0092] In the branch pipe 10D, the branch pipe body 20 has a third plate-shaped member 23. The third plate-shaped member 23 is a stainless steel plate (flat plate). The third plate-shaped member 23 has a third surface 23a facing the first surface 21a of the first plate-shaped member 21, and a fourth surface 23b facing the second surface 22a of the second plate-shaped member 22. The third surface 23a is joined to the first surface 21a by a joint 24. The fourth surface 23b is joined to the second surface 22a by a joint 24. In the branch pipe 10D, the first plate-shaped member 21 and the second plate-shaped member 22 are joined via the third plate-shaped member 23 by a joint 24.

[0093] In the branch pipe 10D, the third plate-shaped member 23 is provided with an overhang portion 54 that protrudes from the joint portion 24 into the first opening 26a. By reducing the gap Z with the overhang portion 54, the branch pipe 10D can reduce the amount of brazing material used, thereby reducing shrinkage cavities in the brazing material layer S, and thereby suppressing refrigerant leakage from the gap Z.

[0094] Figure 7A illustrates only the protruding portion 54 located in the first opening 26a, and the protruding portions 54 located in the second opening 26b and the third opening 26c are not shown. In the branch pipe 10D, the third plate-shaped member 23 has a protruding portion 54 that protrudes from the joint 24 to the second opening 26b, and a protruding portion 54 that protrudes from the joint 24 to the third opening 26c. In the branch pipe 10D, the protruding portion 54 does not have to be located in all of the first opening 26a, the second opening 26b, and the third opening 26c, and may be located in one or more of the first opening 26a, the second opening 26b, and the third opening 26c. In other words, the branch pipe 10D includes a protruding portion 54 located in at least one of the first opening 26a, the second opening 26b, and the third opening 26c.

[0095] In the fourth embodiment, the branch pipe 10D reduces the internal volume of the gap Z by providing an overhang portion 54. As a result, the branch pipe 10D can reduce the amount of brazing material used in the sealing portion 28 and reduce the effort required for brazing. In addition, it can reduce sink marks in the brazing material layer S, thereby suppressing refrigerant leakage from the gap Z.

[0096] The branch pipe 10D may also have the configuration shown in Figure 7B. Figure 7B shows a modified example of the branch pipe 10D according to the fourth embodiment. As shown in Figure 7B, the modified example of the branch pipe 10D according to the fourth embodiment is characterized in that the branch pipe body 20 is composed of a plurality (two in this embodiment) third plate-shaped members 23 (third plate-shaped members 23X, 23Y).

[0097] As shown in Figure 7B, in a modified example of the branch pipe 10D, the branch pipe body 20 has two third plate-shaped members 23. The third surface 23a of one of the third plate-shaped members 23X is joined to the first surface 21a by a joint 24. The fourth surface 23b of one of the third plate-shaped members 23X is joined to the third surface 23a of the other third plate-shaped member 23Y by a joint 24. The fourth surface 23b of the other third plate-shaped member 23Y is joined to the second surface 22a by a joint 24. In a modified example of the branch pipe 10D, the first plate-shaped member 21 and the second plate-shaped member 22 are joined via two third plate-shaped members 23X and 23Y by a joint 24.

[0098] A modified branch pipe 10D according to the fourth embodiment has two third plate-shaped members 23, which allows the proportion of the volume of the protruding portion 54 to the internal volume of the gap Z to be increased, thereby reducing the internal volume of the gap Z more significantly compared to the branch pipe 10D shown in Figure 7A. Therefore, with this modified branch pipe 10D, the amount of brazing material used in the sealing portion 28 can be reduced, and the effort required for brazing can be reduced. In addition, shrinkage cavities in the brazing material layer S can be reduced, thereby suppressing refrigerant leakage from the gap Z. The number of third plate-shaped members 23 constituting the modified branch pipe 10D may be three or more.

[0099] [Branch pipe according to the fifth embodiment] Figures 8A and 8B are explanatory diagrams of a branch pipe according to the fifth embodiment. Figure 8A shows the fifth embodiment of the branch pipe 10 of the present disclosure. In this description, the branch pipe 10 according to the fifth embodiment will also be referred to as the branch pipe 10E. As shown in Figure 8A, the branch pipe 10E according to the fifth embodiment is characterized in that the branch pipe body 20 has a machined portion 55. Figure 8A shows the first opening 26a and the first pipe joint 31 of the branch pipe 10E as viewed from the axial direction. As shown in Figure 8A, the branch pipe 10E has a sealing portion 28 that fills the gap Z between the first opening 26a and the first pipe joint 31.

[0100] In the branch pipe 10E, the first plate-shaped member 21 and the second plate-shaped member 22 have machined portions 55. In the branch pipe body 20 shown in Figure 8A, the machined portions 55 are formed on the flat portions of the first plate-shaped member 21 and the second plate-shaped member 22.

[0101] The machined portion 55 is a part of the first plate-shaped member 21 and the second plate-shaped member 22, which are formed by press-forming or the like from stainless steel plates (flat plates), that has been further machined (cutting in this embodiment) to change the shape of a part of the first surface 21a and the second surface 22a. In this embodiment, the machined portion 55 is a part of the first plate-shaped member 21 and the second plate-shaped member 22 that has been cut and a part of it removed to change the shape of the first surface 21a and the second surface 22a. Note that the machined portion 55 may also be a part that has been partially removed by machining other than cutting (for example, grinding, polishing, etc.).

[0102] In the branch pipe 10E, when the first opening 26a is viewed from the axial direction, the machined portion 55 becomes a new first surface 21a of the first plate-shaped member 21 and a new second surface 22a of the second plate-shaped member 22. In the branch pipe 10E, the branch pipe body 20 is constructed by joining the first surface 21a (machined portion 55) and the second surface 22a (machined portion 55) by a joint portion 24.

[0103] In the absence of the machined portion 55 (for example, see the upper diagram in Figure 4), the shape of the first opening 26a when viewed from the axial direction is a shape in which the tangential direction change is continuous (first shape). On the other hand, as shown in Figure 8A, in a branch pipe 10E having a machined portion 55, the shape of the first opening 26a (machined portion 55) when viewed from the axial direction is a shape with an inflection point P1 in which the tangential direction change is discontinuous (second shape). A branch pipe 10E including this (second shape) can reduce the internal volume of the gap Z compared to a branch pipe 10 including the (first shape). By reducing the gap Z with the machined portion 55 and suppressing the amount of brazing material used, the branch pipe 10E can reduce sink marks in the brazing material layer S, thereby suppressing refrigerant leakage from the gap Z.

[0104] Figure 8A illustrates only the machined portion 55 provided around the first opening 26a, and the machined portions 55 provided around the second opening 26b and the third opening 26c are not shown. The branch pipe 10E also has machined portions 55 around the second opening 26b and the third opening 26c, similar to those around the first opening 26a. In the branch pipe 10E, the machined portions 55 do not have to be provided in all of the first opening 26a, the second opening 26b, and the third opening 26c, and the configuration may be such that the machined portions 55 are provided in one or more of the first opening 26a, the second opening 26b, and the third opening 26c. In other words, the branch pipe 10E includes a machined portion 55 provided in at least one of the first opening 26a, the second opening 26b, and the third opening 26c.

[0105] In the fifth embodiment, the branch pipe 10E reduces the internal volume of the gap Z by providing a machined portion 55. As a result, the branch pipe 10E can reduce the amount of brazing material used in the sealing portion 28 and reduce the effort required for brazing. In addition, it can reduce sink marks in the brazing material layer S, thereby suppressing refrigerant leakage from the gap Z.

[0106] The branch pipe 10E may also have the configuration shown in Figure 8B. Figure 8B shows a modified example of the branch pipe 10E according to the fifth embodiment. As shown in Figure 8B, the modified example of the branch pipe 10E according to the fifth embodiment is characterized in that the machined portion 55 is formed on the arc (curved) portion of the first plate-shaped member 21 and the second plate-shaped member 22.

[0107] As shown in Figure 8B, in a modified example of the branch pipe 10E according to the fifth embodiment, the machined portion 55 is formed in an arc (curved) portion. In the modified branch pipe 10E, the machined portion 55 is a part of the first surface 21a of the first plate-like member 21 and a part of the second surface 22a of the second plate-like member 22.

[0108] In the modified branch pipe 10E, the machined portion 55 when the first opening 26a is viewed from the axial direction has a shape (third shape) having an inflection point P2 where the tangential change is discontinuous. Compared to the branch pipe 10 containing the (first shape), the internal volume of the gap Z can be reduced. Therefore, the modified branch pipe 10E can reduce the amount of brazing material used in the sealing portion 28 and reduce the effort required for brazing. In addition, shrinkage cavities in the brazing material layer S can be reduced, thereby suppressing refrigerant leakage from the gap Z.

[0109] [Explanation of the branch pipe according to the fifth embodiment from a different perspective] Figure 9 is an explanatory diagram of a branch pipe according to the fifth embodiment. Figure 9 shows the branch pipe 10E according to the fifth embodiment. Here, the branch pipe 10E according to the fifth embodiment will be further explained from a different perspective. In the branch pipe 10E shown in Figure 9, the second plate-shaped member 22 has the same shape as the first plate-shaped member 21. Therefore, in the following explanation of the branch pipe 10E, the shape of the first plate-shaped member 21 will be mainly explained, and the explanation of the shape of the second plate-shaped member 22 will be omitted as appropriate.

[0110] Figure 9 shows the first opening 26a and the first pipe joint 31 in the branch pipe 10E as viewed from the axial direction. As shown in Figure 9, the branch pipe 10E has a first gap Z1 formed between the first opening 26a and the first pipe joint 31.

[0111] In the branch pipe 10E shown in Figure 9, the first plate-shaped member 21 comprises a straight plate portion 21X and a curved plate portion 21Y. The straight plate portion 21X is the part of the first plate-shaped member 21 that is flat. The curved plate portion 21Y is the part of the first plate-shaped member 21 that is curved due to bending. The second plate-shaped member 22 comprises a straight plate portion 22X and a curved plate portion 22Y. The straight plate portion 22X is the part of the second plate-shaped member 22 that is flat. The curved plate portion 22Y is the part of the second plate-shaped member 22 that is curved due to bending.

[0112] In the branch pipe 10E, the first plate-shaped member 21 and the second plate-shaped member 22 have a volume-reducing portion 60. The volume-reducing portion 60 is a part that plays a role in reducing the internal volume of the gap Z. In the branch pipe 10E, the volume-reducing portion 60 includes a first plate thickness portion 61 and a second plate thickness portion 62. In the branch pipe 10E, the plate thickness t of the first plate thickness portion 61 is defined as the first plate thickness t1, and the plate thickness t of the second plate thickness portion 62 is defined as the second plate thickness t2. In the branch pipe 10E, the second plate thickness t2 of the second plate thickness portion 62 is smaller than the first plate thickness t1 of the first plate thickness portion 61 (t1 > t2).

[0113] In the branch pipe 10E shown in Figure 9, the first plate thickness portion 61 is a curved plate portion 21Y, and the second plate thickness portion 62 is a straight plate portion 21X. In the branch pipe 10E shown in Figure 9, the second plate thickness portion 62 is a portion of the straight plate portion 21X of the first plate-shaped member 21 that has been machined (e.g., cut) to change the shape of a part of the first surface 21a. In other words, in the branch pipe 10E of this embodiment, the straight plate portion 21X includes the machined portion 55. The second plate thickness portion 62 may also be a portion of the straight plate portion 21X that has been removed by a process other than cutting (e.g., grinding, polishing, etc.).

[0114] The branch pipe 10E can reduce the first gap Z1 by providing a volume reduction section 60 composed of a first thickness section 61 and a second thickness section 62, each having a different plate thickness t. By reducing the first gap Z1, the branch pipe 10E can suppress the amount of brazing material used and reduce shrinkage cavities in the brazing material layer S, thereby suppressing refrigerant leakage from the first gap Z1.

[0115] Although detailed explanations are omitted in this description, in the branch pipe 10E shown in Figure 9, the volume reduction section 60, which includes the first plate thickness section 61 and the second plate thickness section 62, is also provided in the straight plate section 21X and curved plate section 21Y on the second opening 26b and third opening 26c sides. In this case, the volume reduction section 60 (not shown) provided on the second opening 26b and third opening 26c sides can reduce the second gap Z2 and the third gap Z3 (see Figure 13, which will be explained later). In the branch pipe 10E shown in Figure 9, the volume reduction section 60 only needs to reduce the internal volume of at least one of the first gap Z1, the second gap Z2, and the third gap Z3.

[0116] Figure 10 is an explanatory diagram of a modified branch pipe according to the fifth embodiment. Figure 10 shows a modified branch pipe 10E according to the fifth embodiment. The branch pipe 10E may have the configuration shown in Figure 10. As shown in Figure 10, the modified branch pipe 10E differs from the branch pipe 10E shown in Figure 9 in that the curved plate portion 21Y of the first plate-shaped member 21 has a second plate thickness portion 62.

[0117] In the branch pipe 10E shown in Figure 10, the second thickness t2 of the second plate thickness section 62 is smaller than the first thickness t1 of the first plate thickness section 61 (t1 > t2). In the branch pipe 10E shown in Figure 10, the straight plate section 21X is the first plate thickness section 61, and the curved plate section 21Y has the second plate thickness section 62.

[0118] In the branch pipe 10E shown in Figure 10, the curved portion 21Y of the first plate-shaped member 21, which is formed by press-forming a stainless steel plate (flat plate), is further machined (cutting in this embodiment) to modify the shape of a part of the first surface 21a. The second plate thickness portion 62 in this embodiment is a part of the first surface 21a whose shape has been modified by cutting the curved portion 21Y of the first plate-shaped member 21 and removing a part of it. In other words, in the branch pipe 10E of this embodiment, the curved portion 21Y includes the machined portion 55. The second plate thickness portion 62 may also be a part of the curved portion 21Y that has been partially removed by processing other than cutting (for example, grinding, polishing, etc.).

[0119] The branch pipe 10E is provided with a volume reduction section 60 which includes a first plate thickness section 61 and a second plate thickness section 62, each with different plate thicknesses. By reducing the first gap Z1 and suppressing the amount of brazing material used, shrinkage cavities in the brazing material layer S can be reduced, thereby suppressing refrigerant leakage from the first gap Z1.

[0120] Although detailed explanations are omitted in this description, in the modified example of the branch pipe 10E shown in Figure 10, the volume-reducing section 60, which includes the first plate thickness section 61 and the second plate thickness section 62, is also provided in the straight plate section 21X and curved plate section 21Y on the second opening 26b and third opening 26c sides. In this case, the volume-reducing section 60 (not shown) provided on the second opening 26b and third opening 26c sides can reduce the second gap Z2 and the third gap Z3 (see Figure 13, which will be explained later). In the modified example of the branch pipe 10E shown in Figure 10, the volume-reducing section 60 only needs to reduce the internal volume of at least one of the first gap Z1, the second gap Z2, and the third gap Z3.

[0121] As described above, the branch pipe 10E of this embodiment shown in Figures 9 and 10 can reduce the internal volume of at least one of the first gap Z1, the second gap Z2, and the third gap Z3 by combining the first plate thickness portion 61 and the second plate thickness portion 62. For this reason, the branch pipe 10E of this embodiment can be easily provided with a volume reduction portion 60.

[0122] [Branch pipe according to the sixth embodiment] Figure 11A is an explanatory diagram of a branch pipe according to the sixth embodiment. Figure 11A shows a branch pipe 10F, which is the branch pipe 10 according to the sixth embodiment. Figure 11A shows the first opening 26a and the first pipe joint 31 of the branch pipe 10F as viewed from the axial direction. In the branch pipe 10F shown in Figure 11A, the second plate-shaped member 22 has the same shape as the first plate-shaped member 21. Therefore, in the following description of the branch pipe 10F, the shape of the first plate-shaped member 21 will be described, and the description of the shape of the second plate-shaped member 22 will be omitted.

[0123] In the following description, the joint 24 is defined as a portion composed of a first plate-like member 21, a second plate-like member 22, and a layer of brazing material (sheet brazing) formed between the first surface 21a and the second surface 22a.

[0124] As shown in Figure 11A, the branch pipe 10F is provided with a volume reduction section 60. In the branch pipe 10F, the volume reduction section 60 is composed of a protruding section 63. The protruding section 63 reduces the internal volume of the first gap Z1.

[0125] As shown in Figure 11A, the protrusion 63 is formed on the first surface 21a of the first plate-shaped member 21 in the portion that forms the first gap Z1 between it and the first pipe joint 31. The protrusion 63 is a modified portion of the first surface 21a and protrudes from the first surface 21a toward the first gap Z1.

[0126] The first gap Z1 in the branch pipe 10F increases in the distance between the first surface 21a of the first plate-like member 21 and the second surface 22a of the second plate-like member 22 (inter-surface distance SD, which will be explained later; see Figure 12) as you move from the joint 24 toward the axial center of the first pipe joint 31. However, in the portion where the protrusion 63 is formed, the increase in the distance between the first plate-like member 21 and the second plate-like member 22 is smaller.

[0127] The protrusion 63 shown in Figure 11A is formed, for example, by welding a convex member to the first surface 21a of the first plate-shaped member 21. The protrusion 63 may be formed continuously parallel to the axial direction of the first pipe joint 31, or it may be formed intermittently at predetermined intervals while being parallel to the axial direction of the first pipe joint 31. In this embodiment, the case in which the protrusion 63 is formed by welding is illustrated, but the method of forming the protrusion 63 is not limited to this, and it may be formed by methods other than welding.

[0128] Although detailed explanations are omitted in this description, in the branch pipe 10F shown in Figure 11A, the volume-reducing section 60 including the protruding portion 63 is provided on both the second opening 26b and the third opening 26c side. In this case, the volume-reducing section 60 (not shown) provided on the second opening 26b and the third opening 26c side protrudes from the first surface 21a toward the second gap Z2 and the third gap Z3. In the branch pipe 10F shown in Figure 11A, the volume-reducing section 60 including the protruding portion 63 only needs to reduce the internal volume of at least one of the first gap Z1, the second gap Z2, and the third gap Z3.

[0129] [Modified example of the branch pipe according to the sixth embodiment] Figure 11B is an explanatory diagram of a modified branch pipe according to the sixth embodiment. Figure 11B shows a modified branch pipe 10F, which is branch pipe 10 according to the sixth embodiment. Figure 11B shows the first opening 26a and the first pipe joint 31 of the branch pipe 10F as viewed from the axial direction. In the modified branch pipe 10F shown in Figure 11B, the second plate-shaped member 22 has the same shape as the first plate-shaped member 21. Therefore, in the following description of the modified branch pipe 10F, the shape of the first plate-shaped member 21 will be described, and the description of the shape of the second plate-shaped member 22 will be omitted.

[0130] As shown in Figure 11B, a modified version of the branch pipe 10F includes a protrusion 63 and a recess 64. In the modified version of the branch pipe 10F, the protrusion 63 is formed, for example, by punching the back surface 21b at the location where the protrusion 63 is formed. In other words, in the modified version of the branch pipe 10F, the recess 64 is formed by striking the back surface 21b, thereby forming a protrusion 63 that protrudes from the first surface 21a. In this case, the first plate-like member 21 has a pair of protrusions 63 and recesses 64 on its front and back surfaces.

[0131] As shown in Figure 11B, the protrusion 63 is formed on the first surface 21a of the first plate-shaped member 21 in the portion that forms the first gap Z1 between it and the first pipe joint 31. The protrusion 63 projects from the first surface 21a toward the first gap Z1. The protrusion 63 is a portion of the first surface 21a with a modified shape. The protrusion 63 and recess 64 may be formed continuously parallel to the axial direction of the first pipe joint 31, or they may be formed intermittently at predetermined intervals while being parallel to the axial direction of the first pipe joint 31.

[0132] Although detailed explanations are omitted in this description, in the modified example of the branch pipe 10F shown in Figure 11B, the volume-reducing portion 60 including the protruding portion 63 is also provided on the side of the second opening 26b and the third opening 26c. In this case, the volume-reducing portion 60 (not shown) provided on the side of the second opening 26b and the third opening 26c protrudes from the first surface 21a toward the second gap Z2 and the third gap Z3. In the modified example of the branch pipe 10F shown in Figure 11B, the volume-reducing portion 60 including the protruding portion 63 only needs to reduce the internal volume of at least one of the first gap Z1, the second gap Z2, and the third gap Z3.

[0133] [Regarding the branch pipe itself] In the branch pipe 10 according to the first to sixth embodiments described above, the branch pipe body 20 includes a sealing portion 28 that seals the first gap Z1 between the outer circumferential surface 31c of the first pipe joint 31 and the first opening 26a, the second gap Z2 between the outer circumferential surface 32c of the second pipe joint 32 and the second opening 26b, and the third gap Z3 between the outer circumferential surface 33c of the third pipe joint 33 and the third opening 26c. The sealing portion 28 includes a brazing material layer S that connects the branch pipe body 20 to the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 (see Figure 3). With a branch pipe 10 having such a configuration, a stainless steel branch pipe can be obtained by performing simple processing on a stainless steel plate.

[0134] [Regarding the dimensional relationships of each part in a branch pipe] Figure 12 is a schematic diagram of the branch pipe as seen from the first opening. Figure 13 is a schematic diagram of the branch pipe as seen from the second and third openings. Figure 14 is an explanatory diagram of the outer diameter of the bent plate and the outer diameter of the joint in the branch pipe. Here, using Figures 12, 13, and 14, the dimensional relationships of each part of the branch pipe 10 of this disclosure will be explained in detail. The dimensional relationships of each part explained here are common to the branch pipe 10 (brazing pipe 10A to branch pipe 10F) of each embodiment shown in this description. Note that in Figures 12, 13, and 14, for the sake of explanation, the sealing part 28 (brazing material layer S) that fills the gap Z is not shown.

[0135] As shown in Figures 12 and 13, in the branch pipe 10 of this disclosure, the first plate-shaped member 21 has a straight plate portion 21X and a curved plate portion 21Y, and the second plate-shaped member 22 has a straight plate portion 22X and a curved plate portion 22Y. As shown in Figure 12, the branch pipe 10 has a gap Z (hereinafter also referred to as the first gap Z1) formed between the first pipe joint 31 and the curved plate portion 21Y of the first plate-shaped member 21 and the curved plate portion 22Y of the second plate-shaped member 22 at the point where they face each other. As shown in Figure 13, the branch pipe 10 has a gap Z (hereinafter also referred to as the second gap Z2) formed between the second pipe joint 32 and the curved plate portion 21Y of the first plate-shaped member 21 and the curved plate portion 22Y of the second plate-shaped member 22 at the point where they face each other. The branch pipe 10 has a gap Z (hereinafter also referred to as the third gap Z3) formed between the third pipe joint 33 and the curved portion 21Y of the first plate-shaped member 21 and the curved portion 22Y of the second plate-shaped member 22 at the point where they face each other.

[0136] In the following description, the direction in the branch pipe 10 is defined as follows: The direction parallel to the axial direction of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 is defined as the first direction D1 (see Figure 3). Note that the first direction D1 includes not only the direction strictly parallel to the axial direction of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33, but also the direction parallel to the axial direction of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33. At the positions where the straight plate sections 21X and 22X exist, the direction that is perpendicular to the thickness direction of the first plate-like member 21 and the second plate-like member 22, and perpendicular to the first direction D1, is defined as the second direction D2 (see Figure 3).

[0137] As shown in Figures 12 and 13, the branch pipe 10 includes a joint 24 where a first plate-shaped member 21 and a second plate-shaped member 22 are joined. The joint 24 in this embodiment is composed of a first plate-shaped member 21, a second plate-shaped member 22, and a layer made of brazing material (sheet brazing) formed between the first surface 21a and the second surface 22a. The joint 24 includes a branch portion 27 formed between a second gap Z2 and a third gap Z3, and an outer edge joint portion 29 which is a joint 24 other than the branch portion 27.

[0138] As shown in Figure 12, the first gap Z1 in the branch pipe 10 is formed between the curved plate portion 21Y and the first pipe joint 31. The distance SD between the faces of the first plate-like member 21 and the second plate-like member 22 increases as you move from the end of the joint 24 opposite to the first pipe joint 31 toward the axial position (central axis G) of the first pipe joint 31. In other words, in the first gap Z1, the distance SD between the faces increases as you move from the end of the joint 24 on the first pipe joint 31 side toward the axial position (central axis G) of the first pipe joint 31. The first gap Z1 is a three-dimensional space that extends in the first direction D1 (the axial direction of the first pipe joint 31).

[0139] As shown in Figure 13, the second gap Z2 in the branch pipe 10 is formed between the curved plate portion 21Y and the second pipe joint 32. The distance SD between the faces of the first plate-like member 21 and the second plate-like member 22 increases as you move from the end of the joint 24 opposite to the second pipe joint 32 toward the axial position (central axis G) of the second pipe joint 32. In other words, in the second gap Z2, the distance SD between the faces increases as you move from the end of the joint 24 on the second pipe joint 32 side toward the axial position (central axis G) of the second pipe joint 32. The second gap Z2 is a three-dimensional space that extends in the first direction D1 (the axial direction of the second pipe joint 32).

[0140] As shown in Figure 13, the third gap Z3 in the branch pipe 10 is formed between the curved plate portion 21Y and the third pipe joint 33. The distance SD between the faces of the first plate-like member 21 and the second plate-like member 22 increases as the distance in the third gap Z3 progresses from the end of the joint 24 opposite to the third pipe joint 33 toward the axial position (central axis G) of the third pipe joint 33. In other words, in the third gap Z3, the distance SD between the faces increases as the distance progresses from the end of the joint 24 on the third pipe joint 33 side toward the axial position (central axis G) of the third pipe joint 33. The third gap Z3 is a three-dimensional space that extends in the first direction D1 (the axial direction of the third pipe joint 33).

[0141] As shown in Figure 13, in this explanation, for the straight plate portion 21X in the branching portion 27, the width of the straight plate portion 21X in the second direction D2 is defined as the first width α.

[0142] As shown in Figures 12 and 13, in this explanation, for the straight plate portion 21X in the outer edge joint 29, the width of the straight plate portion 21X in the second direction D2 is defined as the second width β.

[0143] As shown in Figure 13, in this explanation, the distance from one end of the second pipe joint 32 in the second direction D2 to the other end of the third pipe joint 33 in the second direction D2 is defined as the first distance W1. In the branch pipe 10, the first distance W1 is greater than the thickness D of the branch section 27.

[0144] As shown in Figure 12, in this explanation, the distance from one end of the first pipe joint 31 in the second direction D2 to one end of the joint 24 (outer edge joint 29) located on that side, and the distance from the other end of the first pipe joint 31 in the second direction D2 to the other end of the joint 24 (outer edge joint 29) located on that side, are defined as the second distance W2. Similarly, as shown in Figure 13, the distance from the other end of the second pipe joint 32 in the second direction D2 to the other end of the joint 24 (outer edge joint 29) located on that side, and the distance from one end of the third pipe joint 33 in the second direction D2 to one end of the joint 24 (outer edge joint 29) located on that side, are also defined as the second distance W2.

[0145] As shown in Figures 12, 13, and 14, in this explanation, the outer diameters of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 constituting the branch pipe 10 are referred to as the outer diameter r of the joint. t The outer diameter of the joint r is defined as follows. t This is the distance (radius) from the central axis G of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 to the outer surfaces 31c, 32c, and 33c, respectively. t r is the outer diameter of the portion of the first pipe joint 31, second pipe joint 32, and third pipe joint 33 that is inserted into the branch pipe body 20. t These may be different from each other.

[0146] As shown in Figure 14, the first plate-shaped member 21 constituting the branch pipe 10 includes a first bend portion 21c that is concave on the first surface 21a side and a second bend portion 21d that is convex on the first surface 21a side. In this description, the bending radius of the first surface 21a at the second bend portion 21d is defined as the outer diameter of the plate bend r so It is stipulated as follows.

[0147] The branch pipe 10 of this disclosure has a first distance W1 that satisfies the following formula 1, and the outer diameter of the bent plate r so It is preferable that the following equation 2 is satisfied.

[0148] Formula 1: W1 ≥ 2√((r t +r so ) 2 -r so 2 )-2r t (Here, W1: first distance, r so : outer diameter of the bent plate, r t (Outer diameter of the fitting)

[0149] Formula 2: r so ≥2t (Here, t: thickness of the first plate-like member)

[0150] Stainless steel sheets are more difficult to bend than steel sheets. The branch pipe 10, configured to satisfy the above equations 1 and 2, makes it easier to bend the first plate-shaped member 21 and the second plate-shaped member 22, which are made of stainless steel. This makes it easier to manufacture the branch pipe body 20.

[0151] Furthermore, it is more preferable that the branch pipe 10 of this disclosure satisfies the following formula 3 for the first distance W1.

[0152] Formula 3: W1 ≥ 2√((r t +r so ) 2 -r so 2 )-2r t +α (Here, W1: first distance, α: first width)

[0153] A branch pipe 10 configured to satisfy the above equation 3 can improve its strength by ensuring a first distance W1 that includes a first width α. For this reason, a branch pipe 10 configured to satisfy the above equation 3 is suitable for use as a branch pipe for a single refrigerant consisting of carbon dioxide, which is at a higher pressure than conventional refrigerants, or for a mixed refrigerant containing carbon dioxide.

[0154] Furthermore, it is preferable that the branch pipe 10 of this disclosure has a second width β that satisfies the following formula 4, and a second distance W2 that satisfies the following formula 5.

[0155] Formula 4: t ≤ β ≤ 20t (Here, β: second width, t: thickness of the first plate-like member)

[0156] Formula 5: W2≧√((r t +r so ) 2 -r so 2 )-r t +β (Here, W2: second distance, r so : outer diameter of the bent plate, r t : Outer diameter of the joint, β: Second width)

[0157] The branch pipe 10 of this disclosure can have its strength improved by setting the second width β and the second distance W2 to satisfy the above equations 4 and 5. Increasing the second width β can improve the strength of the branch pipe body 20, but if the second width β is increased too much, there is a high possibility that a local gap will occur between the first plate-shaped member 21 and the second plate-shaped member 22. If brazing material flows into this gap, it will lead to a decrease in the strength of the branch pipe 10. In addition, increasing the second width β increases the amount of brazing material used. The branch pipe 10 of this disclosure can achieve both improved strength and reduced brazing material usage by setting the second width β and the second distance W2 to satisfy the above equations 4 and 5.

[0158] [Regarding variations in branching points] Figure 15 is an explanatory diagram of a modified branch section in a branch pipe. Figure 15 shows a modified branch pipe 10. In the branch pipe 10 shown in Figure 15, the configuration of the branch section 27 of the joint 24 differs from the branch section 27 described above (see Figure 3). In the branch pipe 10 shown in Figure 15, the branch section 27 includes a flow division section 27a and a flow straightening section 27b.

[0159] The flow divider 27a divides the fluid that has flowed into the flow path 25 within the branch pipe body 20 through the first pipe joint 31 into the second pipe joint 32 side and the third pipe joint 33 side. Note that the width of the flow divider 27a in the second direction D2 is not constant with respect to the first direction D1.

[0160] The flow straightening section 27b straightens the flow of fluid that has been separated by the flow dividing section 27a. The flow straightening section 27b includes a first portion 27b1 located on the first end 20a side of the branch pipe body 20 and a second portion 27b2 located on the second end 20b side of the branch pipe body 20. The width w2 of the first portion 27b1 in the second direction D2 is constant with respect to the first direction D1. The width w2 of the second portion 27b2 in the second direction D2 is also constant with respect to the first direction D1.

[0161] In the modified branch section 27, the width w1 of the first portion 27b1 in the second direction D2 is larger than the width w2 of the second portion 27b2 in the second direction D2. For this reason, the rectifying section 27b includes a stepped portion 27c formed at the end of the first portion 27b1 on the end side of the first end 20a. It is preferable that the thickened portions of the second pipe joint 32 and the third pipe joint 33 coincide with the position of the side surface of the rectifying section 27b (first portion 27b1) when viewed from the first direction D1. It is more preferable that the width w1 of the first portion 27b1 is set to a width such that the inner circumferential surfaces of the second pipe joint 32 and the third pipe joint 33 in contact with the stepped portion 27c are flush with the side surface of the rectifying section 27b (first portion 27b1) in the second direction D2.

[0162] In the modified branch pipe 10, the branch section 27 (flow straightening section 27b) is equipped with a stepped section 27c, which allows the second pipe fitting 32 inserted into the second opening 26b and the third pipe fitting 33 inserted into the third opening 26c to be positioned axially. With this configuration, the branch pipe 10 allows for easy positioning of the second pipe fitting 32 and the third pipe fitting 33 at the second opening 26b and the third opening 26c. Furthermore, with this configuration, the step difference between the flow straightening section 27b and the second pipe fitting 32 and the third pipe fitting 33 can be reduced, thereby suppressing the resistance that the fluid experiences when flowing out of the second opening 26b and the third opening 26c.

[0163] In this embodiment, a stepped portion 27c is provided at the branching portion 27, but in the modified branching pipe 10, a stepped portion (not shown) may be provided at the outer edge joint portion 29. In the modified branching pipe 10, a stepped portion 27c may be provided at the branching portion 27, and a stepped portion (not shown) may also be provided at the outer edge joint portion 29.

[0164] In the modified branch pipe 10, the formation length L4 of the flow straightening section 27b in the first direction D1 is larger than the insertion depth L2 of the second opening 26b and the insertion depth L3 of the third opening 26c (L4>L2, L4>L3). The formation length L4 is the distance between the end of the flow straightening section 27b on the first end 20a side and the end of the flow straightening section 27b on the second end 20b side. In a branch pipe 10 with this configuration, by ensuring the formation length L4 of the flow straightening section 27b, the fluid flowing out from the second opening 26b and the third opening 26c can be reliably straightened by the flow straightening section 27b.

[0165] Figure 16 is an explanatory diagram of the flow path of the branch pipe in the diversion section and the straightening section. As shown in Figure 16, in the modified branch pipe 10, the flow path 25 includes a first flow path 25a and a second flow path 25b. The first flow path 25a is a flow path 25 surrounded by the diversion section 27a, the first plate-shaped member 21, and the second plate-shaped member 22. The second flow path 25b is a flow path 25 surrounded by the straightening section 27b (first portion 27b1), the first plate-shaped member 21, and the second plate-shaped member 22. In the modified branch pipe 10, the first flow path cross-sectional area A1 of the first flow path 25a has an area greater than or equal to the second flow path cross-sectional area A2 of the second flow path 25b (A1 ≥ A2). In this explanation, "first flow path cross-sectional area A1" refers to the minimum cross-sectional area that appears when the first flow path 25a is cut by a plane perpendicular to the flow direction (velocity vector) of the fluid flowing through the first flow path 25a, and "second flow path cross-sectional area A2" refers to the maximum cross-sectional area that appears when the second flow path 25b is cut by a plane perpendicular to the flow direction (velocity vector) of the fluid flowing through the second flow path 25b. In other words, in the modified branch pipe 10, the flow path 25 connecting the first pipe joint 31 to the second pipe joint 32, and the flow path 25 connecting the first pipe joint 31 to the third pipe joint 33, are not narrowed midway through the flow path 25 by the first flow path 25a. With a branch pipe 10 configured in this way, the resistance that the fluid receives from the diversion section 27a in the first flow path 25a can be suppressed.

[0166] Furthermore, in the modified branch pipe 10, it is preferable that the length L1 of the branch section 27 (see Figure 15) is set so that there are no portions in the flow path 25 where the flow path cross-sectional area is smaller than the first flow path cross-sectional area A1 and the second flow path cross-sectional area A2.

[0167] [Effects of the Embodiment] (1) The branch pipe 10 of the above embodiment is a branch pipe 10 that connects a first pipe 111, a second pipe 112, and a third pipe 113, and branches the fluid flowing through the first pipe 111 to the second pipe 112 and the third pipe 113, and comprises a branch pipe body 20 which includes a first plate-shaped member 21 made of stainless steel having a first surface 21a and a second plate-shaped member 22 made of stainless steel having a second surface 22a which is arranged opposite to the first surface 21a, a first pipe joint 31 which has a first joint portion 34 which can be connected to the first pipe 111 at one end 31a in the axial direction, a second pipe joint 32 which has a second joint portion 35 which can be connected to the second pipe 112 at one end 32a in the axial direction, and a third pipe joint 33 which has a third joint portion 36 which can be connected to the third pipe 113 at one end 33a in the axial direction. The branch pipe body 20 includes a joint 24 that joins a first plate-shaped member 21 and a second plate-shaped member 22, a flow path 25 formed between a first surface 21a and a second surface 22a, and a first opening 26a, a second opening 26b, and a third opening 26c formed by the first plate-shaped member 21 and the second plate-shaped member 22 at the ends of the flow path 25 in the direction of fluid flow, which communicate with the first pipe 111, the second pipe 112, and the third pipe 113, respectively. The other end 31b of the first pipe joint 31 is connected to the first opening 26a in the axial direction, the other end 32b of the second pipe joint 32 is connected to the second opening 26b, and the other end 33b of the third pipe joint 33 is connected to the third opening 26c in the axial direction. The branch pipe body 20 includes a sealing portion 28 that seals the first gap Z1 between the outer surface 31c of the first pipe joint 31 and the first opening 26a, the second gap Z2 between the outer surface 32c of the second pipe joint 32 and the second opening 26b, and the third gap Z3 between the outer surface 33c of the third pipe joint 33 and the third opening 26c. The sealing portion 28 includes a brazing material layer S that connects the branch pipe body 20 to the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33.

[0168] According to the branch pipe 10 of the above embodiment, a stainless steel branch pipe can be obtained by performing simple processing on a stainless steel plate.

[0169] (2) In the branch pipe 10 of the above embodiment, the inter-face distance SD, which is the distance between the first plate-shaped member 21 and the second plate-shaped member 22, increases in the portion where the first plate-shaped member 21 and the second plate-shaped member 22 form the first gap Z1, the second gap Z2, and the third gap Z3, as it proceeds from the end of the joint 24 opposite to the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 toward the central axis G of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33.

[0170] (3) In the branch pipe 10E shown in Figures 9 and 10 and the branch pipe 10F shown in Figures 11A and 11B, the first plate-shaped member 21 has a volume-reducing portion 60 that reduces the internal volume of at least one of the first gap Z1, the second gap Z2, and the third gap Z3.

[0171] In the above embodiment, the branch pipes 10E and 10F are provided with a volume reduction section 60, which reduces the gaps Z1, Z2, and Z3 between the first, second, and third openings 26a, 26b, and 26c and the pipe joints 31, 32, and 33. This reduces the amount of brazing material used to seal the gaps Z1, Z2, and Z3, and also suppresses fluid leakage from the gaps Z1, Z2, and Z3 between the branch pipe body 20 and the pipe joints 31, 32, and 33.

[0172] (4) In the branch pipe 10E shown in Figures 9 and 10, the volume reduction section 60 includes a first plate thickness section 61 in which the plate thickness t of the first plate-like member 21 is a first plate thickness t1, and a second plate thickness section 62 in which the plate thickness t of the first plate-like member 21 is a second plate thickness t2 which is smaller than the first plate thickness t1.

[0173] According to the branch pipe 10E of the above embodiment, the volume reduction section 60 can be easily provided in the first plate-shaped member 21 by providing a first plate thickness section 61 and a second plate thickness section 62 with different plate thicknesses t.

[0174] (5) In the branch pipe 10E shown in Figure 9, the first plate-shaped member 21 comprises a straight plate portion 21X and a curved plate portion 21Y, and the straight plate portion 21X is the second plate thickness portion 62.

[0175] According to the branch pipe 10E of the above embodiment, the volume reduction section 60 can be easily provided by configuring the second plate thickness section 62 with a straight plate section 21X.

[0176] (6) In the branch pipe 10E shown in Figure 10, the first plate-shaped member 21 comprises a straight plate portion 21X and a curved plate portion 21Y, and the curved plate portion 21Y has a second plate thickness portion 62.

[0177] According to the branch pipe 10E of the above embodiment, the volume reduction section 60 can be easily provided by providing the second plate thickness section 62 in the curved plate section 21Y.

[0178] (7) In the branch pipe 10E shown in Figure 9, the first plate-shaped member 21 has a first plate thickness portion 61 in the portion that forms at least one of the first gap Z1, the second gap Z2, and the third gap Z3.

[0179] According to the branch pipe 10E of the above embodiment, the volume reduction portion 60 can be easily provided by providing a first plate thickness portion 61 in the portion that forms the gap Z in the first plate-shaped member 21.

[0180] (8) In the branch pipe 10F shown in Figures 11A and 11B, the volume reduction section 60 is composed of a projection 63 that protrudes from the first plate-shaped member 21 toward at least one of the first gap Z1, the second gap Z2, and the third gap Z3.

[0181] According to the branch pipe 10F of the above embodiment, the volume reduction portion 60 can be easily provided by providing a protrusion 63 in the portion of the first plate-shaped member 21 that forms the gap Z.

[0182] (9) In the branch pipe 10F shown in Figure 11B, the first plate-shaped member 21 has a back surface 21b which is the surface opposite to the first surface 21a, and a recess 64 formed on the back surface 21b which is located on the back side of the position of the protruding portion 63.

[0183] According to the branch pipe 10F of the above embodiment, by pressing the back surface 21b of the first plate-shaped member 21 and creating a recess 64 on the back surface 21b, a protrusion 63 can be easily provided in the portion of the first plate-shaped member 21 that forms a gap Z. This makes it easy to provide a volume reduction portion 60.

[0184] (10) In the branch pipe 10 shown in Figure 15, the branch pipe body 20 has a first end 20a having a first opening 26a, and a second end 20b having a second opening 26b and a third opening 26c. The joint 24 includes a branch section 27 formed between the second opening 26b and the third opening 26c. The branch section 27 has a flow divider 27a located on the first end 20a side of the branch section 27 which divides the fluid flowing in from the first opening 26a to the second opening 26b side and the third opening 26c side, and a flow straightening section 27b extending from the end of the flow divider 27a on the second end 20b side in a first direction D1 parallel to the axial direction of the second opening 26b and the third opening 26c. In the branch pipe 10 of the above embodiment, the length L4 of the rectifier section 27b for the first direction D1 is greater than the insertion depth L2 of the second pipe joint 32 at the second opening 26b and the insertion depth L3 of the third pipe joint 33 at the third opening 26c.

[0185] According to the branch pipe 10 of the above embodiment, the fluid flowing out from the second opening 26b and the third opening 26c can be reliably straightened by the flow straightening section 27b.

[0186] (11) In the branch pipe 10 shown in Figure 16, the flow path 25 includes a first flow path 25a formed by a diversion section 27a, a first plate-shaped member 21, and a second plate-shaped member 22, and a second flow path 25b formed by a straightening section 27b, a first plate-shaped member 21, and a second plate-shaped member 22, wherein the first flow path cross-sectional area A1 of the first flow path 25a is greater than or equal to the second flow path cross-sectional area A2 of the second flow path 25b.

[0187] According to the branch pipe 10 of the above embodiment, the resistance that the fluid receives from the diversion section 27a in the first flow path 25a can be suppressed.

[0188] (12) In the branch pipe 10 shown in Figure 15, the rectifier section 27b has a first portion 27b1 on the first end 20a side and a second portion 27b2 on the second end 20b side, and is parallel to the mating surface of the first plate-shaped member 21 and the second plate-shaped member 22 in the branch section 27, and the width w2 of the second portion 27b2 in the second direction D2 which is perpendicular to the first direction D1 is smaller than the width w1 of the first portion 27b1 in the second direction D2.

[0189] According to the branch pipe 10 of the above embodiment, the second pipe joint 32 and the third pipe joint 33 can be easily positioned at the second opening 26b and the third opening 26c.

[0190] (13) In the branch pipe 10 of the above embodiment, the joint 24 includes a branch section 27 formed between the second opening 26b and the third opening 26c, and the first distance W1 between the second pipe joint 32 and the third pipe joint 33 is greater than the thickness D of the branch section 27.

[0191] According to the branch pipe 10 of the above embodiment, by securing a first distance (separation distance) W1 between the second pipe joint 32 and the third pipe joint 33, the joint strength between the first plate-shaped member 21 and the second plate-shaped member 22 at the branch section 27 can be secured.

[0192] (14) In the branch pipe 10 of the above embodiment, the first plate-shaped member 21 includes a first bend portion 21c on the side of the first surface 21a being concave, and a second bend portion 21d on the side of the first surface 21a being convex, wherein the bending radius of the first surface 21a in the second bend portion 21d is the outer diameter of the plate bending r so The outer diameters of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 are set to the outer diameter r of the joint. t Assuming that the distance between the second pipe joint 32 and the third pipe joint 33 is the first distance W1, and the thickness of the first plate-like member 21 is the plate thickness t, then the first distance W1 satisfies the following equation 1, and the outer diameter of the plate bending r so This satisfies equation 2 below. Formula 1: W1 ≥ 2√((r t +r so ) 2 -rso 2 )-2r t (Here, W1: first distance, r so : outer diameter of the bent plate, r t (Outer diameter of the fitting) Formula 2: r so ≥2t (Here, t: thickness of the first plate-like member)

[0193] According to the branch pipe 10 of the above embodiment, by securing a first distance (separation distance) W1 that satisfies equations 1 and 2, the bending of the first plate-shaped member 21 and the second plate-shaped member 22, which are made of stainless steel, becomes easier.

[0194] (15) In the branch pipe 10 of the above embodiment, the first plate-shaped member 21 comprises a straight plate portion 21X and a curved plate portion 21Y, and the joint portion 24 includes a branch portion 27 formed between the second opening 26b and the third opening 26c, the branch portion 27 has a straight plate portion 21X, and the first distance W1 satisfies the following formula 3 when the width of the straight plate portion 21X in the branch portion 27 is a first width α in a second direction D2 that is parallel to the mating surface of the first plate-shaped member 21 and the second plate-shaped member 22 and is perpendicular to the first direction D1 which is parallel to the axial direction of the second opening 26b and the third opening 26c. Formula 3: W1 ≥ 2√((r t +r so ) 2 -r so 2 )-2r t +α (Here, W1: first distance, α: first width)

[0195] According to the branch pipe 10 of the above embodiment, the strength of the branch pipe 10 can be improved by ensuring a first distance (separation distance) W1 that satisfies equation 3.

[0196] (16) In the branch pipe 10 of the above embodiment, the first plate-shaped member 21 comprises a straight plate portion 21X and a curved plate portion 21Y, and includes a first curved portion 21c on the side of the first surface 21a being concave, and a second curved portion 21d on the side of the first surface 21a being convex, and the joint portion 24 includes a branch portion 27 formed between the second opening 26b and the third opening 26c, and an outer edge joint portion 29 other than the branch portion 27, and the bending radius of the first surface 21a in the second curved portion 21d is the outer diameter of the plate bending r so The outer diameters of the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 are set to the outer diameter r of the joint. t Assuming the plate thickness (thickness) of the first plate-like member 21 is plate thickness t, and the width of the straight plate portion 21X at the outer edge joint 29 is defined as the second width β in the second direction D2 which is perpendicular to the first direction D1 which is parallel to the joint surface of the first plate-like member 21 and the second plate-like member 22 at the branching portion 27 and parallel to the axial direction of the second opening 26b and the third opening 26c, then the second width β satisfies the following formula 4, and the distance from the first pipe joint 31, the second pipe joint 32, and the third pipe joint 33 to the end of the outer edge joint 29 is defined as the second distance W2, then the second distance W2 satisfies the following formula 5. Formula 4: t ≤ β ≤ 20t (Here, r so : outer diameter of the bent plate, r t (: outer diameter of the joint, β: width of the second member, t: thickness of the first plate-like member) Formula 5: W2≧√((r t +r so ) 2 -r so 2 )-r t +β (Here, W2: the second distance)

[0197] According to the branch pipe 10 of the above embodiment, the strength of the branch pipe 10 can be improved by ensuring a second distance W2 from each pipe joint 31, 32, 33 to the end of the outer edge joint 29 so as to satisfy equations 4 and 5.

[0198] (17) In the branch pipe 10 of the above embodiment, the first pipe 111, the second pipe 112, and the third pipe 113 are refrigerant pipes 110 through which a single refrigerant consisting of carbon dioxide or a mixed refrigerant containing carbon dioxide flows.

[0199] The branch pipe 10 with the above configuration can be used in refrigerant piping 110 for a single refrigerant consisting of carbon dioxide, which is at a higher pressure than conventional refrigerants, or for a mixed refrigerant containing carbon dioxide.

[0200] (18) The refrigeration apparatus 100 of the present disclosure includes a branch pipe 10.

[0201] According to the refrigeration device 100 of this embodiment, a refrigeration device 100 including a refrigerant circuit 103 that operates at a higher pressure than conventional devices can be easily constructed by using a branch pipe 10 obtained by simply processing a stainless steel plate.

[0202] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. [Explanation of symbols]

[0203] 10: Branch pipe 10E: Branch pipe 20: Branch pipe body 20a: First end 20b: Second end 21: First plate-shaped member 21a: 1st page 21b: Back side 21X: Straight plate part 21Y: Curved plate part 22: Second plate-shaped member 22a: 2nd side 24: Joint 25: Flow path 25a: First channel 25b: Second channel 26a: 1st opening 26b: 2nd opening 26c: 3rd opening 27: Branching point 27a: Diversion section 27b: Rectifier 27b1: Part 1 27b2:Second part 28: Sealing section 29: Outer edge joint 31: First pipe joint 31a: One end 31b: Other end 31c: Outer surface 32: Second pipe joint 32a: One end 32b: Other end 32c: Outer surface 33: Third pipe joint 33a: One end 33b: Other end 33c: Outer surface 34: First joint section 35: Second joint section 36: Third joint section 60: Volume reduction section 61: 1st plate thickness section 62: 2nd plate thickness section 63: Protrusion 64: Recess 100: Refrigeration equipment 110: Refrigerant piping 111: First piping 112: Second piping 113: Third pipe S: Brazing layer Z: Gap G: Central axis L2: Insertion margin (in the second opening) L3: Insertion margin (at the third opening) L4: Formation length (of the rectifier section) W1: First distance W2: Second distance w1: width (of the first part) w2: width (of the second part) A1: Cross-sectional area of ​​the (first channel) A2: Cross-sectional area of ​​the (second channel) α: First width β: Second width D: Thickness (of the branching point) t: thickness of the (first plate-like member) SD: Distance between the faces (of the first plate-shaped member and the second plate-shaped member)

Claims

1. A branch pipe (10) that connects a first pipe (111), a second pipe (112), and a third pipe (113), and branches the fluid flowing through the first pipe (111) to the second pipe (112) and the third pipe (113), A branch pipe body (20) comprising a first plate-shaped member (21) made of stainless steel having a first surface (21a), and a second plate-shaped member (22) made of stainless steel having a second surface (22a) positioned opposite the first surface (21a), A first pipe joint (31) having a first joint portion (34) that can be connected to the first pipe (111) at one end (31a) in the axial direction, A second pipe joint (32) having a second joint portion (35) that can be connected to the second pipe (112) at one end (32a) in the axial direction, A third pipe joint (33) having a third joint portion (36) that can be connected to the third pipe (113) at one end (33a) in the axial direction, Equipped with, The branch pipe body (20) is A joint portion (24) that joins the first plate-shaped member (21) and the second plate-shaped member (22), A flow path (25) is formed between the first surface (21a) and the second surface (22a), At the end of the fluid flow path (25) in the direction of fluid flow, there are first openings (26a), second openings (26b), and third openings (26c) formed by the first plate-shaped member (21) and the second plate-shaped member (22), which communicate with the first pipe (111), the second pipe (112), and the third pipe (113), respectively. The first pipe joint (31) has its other end (31b) in the axial direction connected to the first opening (26a), The second pipe joint (32) has its other end (32b) in the axial direction connected to the second opening (26b), The third pipe joint (33) has its other end (33b) in the axial direction connected to the third opening (26c), The branch pipe body (20) is The pipe fitting (33) is provided with a sealing portion (28) that seals the first gap (Z1) between the outer circumferential surface (31c) of the first pipe fitting (31) and the first opening (26a), the second gap (Z2) between the outer circumferential surface (32c) of the second pipe fitting (32) and the second opening (26b), and the third gap (Z3) between the outer circumferential surface (33c) of the third pipe fitting (33) and the third opening (26c), The sealing portion (28) is The branch pipe body (20) includes a brazing layer (S) connecting the first pipe joint (31), the second pipe joint (32), and the third pipe joint (33), The first plate-shaped member (21) is It has a volume-reducing section (60) that reduces the internal volume of at least one of the first gap (Z1), the second gap (Z2), and the third gap (Z3), The volume reduction portion (60) includes a first thickness portion (61) in which the thickness (t) of the first plate-like member (21) is a first thickness (t1), and a second thickness portion (62) in which the thickness (t) of the first plate-like member (21) is a second thickness (t2) which is smaller than the first thickness (t1), and is a branch pipe (10E).

2. The branch pipe (10E) according to claim 1, wherein the distance (SD) between the first plate-shaped member (21) and the second plate-shaped member (22) increases in the portion where the first plate-shaped member (21) and the second plate-shaped member (22) form the first gap (Z1), the second gap (Z2), and the third gap (Z3), as the distance increases from the end of the joint (24) opposite to the first pipe joint (31), the second pipe joint (32), and the third pipe joint (33) toward the central axis (G) of the first pipe joint (31), the second pipe joint (32), and the third pipe joint (33).

3. The first plate-shaped member (21) comprises a straight plate portion (21X) and a curved plate portion (21Y), The branch pipe (10E) according to claim 1 or claim 2, wherein the straight plate portion (21X) is the second plate thickness portion (62).

4. The first plate-shaped member (21) comprises a straight plate portion (21X) and a curved plate portion (21Y), The curved plate portion (21Y) has the second plate thickness portion (62), as described in claim 1 or claim 2, for the branch pipe (10E).

5. The branch pipe (10E) according to claim 1 or 2, wherein the first plate-shaped member (21) has the first plate thickness portion (61) in the portion that forms at least one of the first gap (Z1), the second gap (Z2), and the third gap (Z3).

6. A branch pipe (10) that connects a first pipe (111), a second pipe (112), and a third pipe (113), and branches the fluid flowing through the first pipe (111) to the second pipe (112) and the third pipe (113), A branch pipe body (20) comprising a first plate-shaped member (21) made of stainless steel having a first surface (21a), and a second plate-shaped member (22) made of stainless steel having a second surface (22a) positioned opposite the first surface (21a), A first pipe joint (31) having a first joint portion (34) that can be connected to the first pipe (111) at one end (31a) in the axial direction, A second pipe joint (32) having a second joint portion (35) that can be connected to the second pipe (112) at one end (32a) in the axial direction, A third pipe joint (33) having a third joint portion (36) that can be connected to the third pipe (113) at one end (33a) in the axial direction, Equipped with, The branch pipe body (20) is A joint portion (24) that joins the first plate-shaped member (21) and the second plate-shaped member (22), A flow path (25) is formed between the first surface (21a) and the second surface (22a), At the end of the fluid flow path (25) in the direction of fluid flow, there are first openings (26a), second openings (26b), and third openings (26c) formed by the first plate-shaped member (21) and the second plate-shaped member (22), which communicate with the first pipe (111), the second pipe (112), and the third pipe (113), respectively. The first pipe joint (31) has its other end (31b) in the axial direction connected to the first opening (26a), The second pipe joint (32) has its other end (32b) in the axial direction connected to the second opening (26b), The third pipe joint (33) has its other end (33b) in the axial direction connected to the third opening (26c), The branch pipe body (20) is The pipe fitting (33) is provided with a sealing portion (28) that seals the first gap (Z1) between the outer circumferential surface (31c) of the first pipe fitting (31) and the first opening (26a), the second gap (Z2) between the outer circumferential surface (32c) of the second pipe fitting (32) and the second opening (26b), and the third gap (Z3) between the outer circumferential surface (33c) of the third pipe fitting (33) and the third opening (26c), The sealing portion (28) is The branch pipe body (20) includes a brazing layer (S) connecting the first pipe joint (31), the second pipe joint (32), and the third pipe joint (33), The first plate-shaped member (21) is It has a volume-reducing section (60) that reduces the internal volume of at least one of the first gap (Z1), the second gap (Z2), and the third gap (Z3), The volume reduction section (60) is A branch pipe (10F) is formed by a projection (63) that protrudes from the first plate-shaped member (21) toward at least one of the first gap (Z1), the second gap (Z2), and the third gap (Z3).

7. The first plate-shaped member (21) is The back surface (21b) is the surface opposite to the first surface (21a), The branch pipe (10F) according to claim 6, having a recess (64) formed on the back surface (21b) located on the back side of the position of the protruding portion (63).

8. The branch pipe body (20) has a first end (20a) having the first opening (26a), and a second end (20b) having the second opening (26b) and the third opening (26c), The joint portion (24) includes a branch portion (27) formed between the second opening (26b) and the third opening (26c), The branching section (27) includes a flow divider (27a) located on the first end (20a) side of the branching section (27) that divides the fluid flowing in from the first opening (26a) to the second opening (26b) side and the third opening (26c) side, and a flow straightening section (27b) extending from the end of the flow divider (27a) on the second end (20b) side in a first direction (D1) parallel to the axial direction of the second opening (26b) and the third opening (26c), The length (L4) of the rectifier portion (27b) in the first direction (D1) is: The branch pipe according to claim 1 or claim 6, wherein the insertion depth (L2) of the second pipe fitting (32) at the second opening (26b) and the insertion depth (L3) of the third pipe fitting (33) at the third opening (26c) are greater than the insertion depth (L3) of the third pipe fitting (33) at the third opening (26c).

9. The flow path (25) includes a first flow path (25a) formed by the flow division section (27a), the first plate-shaped member (21), and the second plate-shaped member (22), and a second flow path (25b) formed by the flow straightening section (27b), the first plate-shaped member (21), and the second plate-shaped member (22). The branch pipe according to claim 8, wherein the cross-sectional area (A1) of the first flow path (25a) is greater than or equal to the cross-sectional area (A2) of the second flow path (25b).

10. The rectifier section (27b) is It has a first portion (27b1) on the first end (20a) side and a second portion (27b2) on the second end (20b) side, The branch pipe (10) according to claim 8, wherein the width (w2) of the second portion (27b2) in the branch portion (27) is parallel to the mating surface between the first plate-like member (21) and the second plate-like member (22), and the width (w2) of the second portion (27b2) in the second direction (D2) perpendicular to the first direction (D1) is smaller than the width (w1) of the first portion (27b1) in the second direction (D2).

11. The joint portion (24) includes a branch portion (27) formed between the second opening (26b) and the third opening (26c), The branch pipe (10) according to claim 1 or claim 6, wherein the first distance (W1) between the second pipe joint (32) and the third pipe joint (33) is greater than the thickness (D) of the branch section (27).

12. The first plate-shaped member (21) is It includes a first curved portion (21c) on the first surface (21a) side which is concave, and a second curved portion (21d) on the first surface (21a) side which is convex, The bending radius of the first surface (21a) in the second curved portion (21d) is the outer diameter of the plate bending (r ｓｏ )year, The outer diameters of the first pipe fitting (31), the second pipe fitting (32), and the third pipe fitting (33) are set to the outer diameter of the fitting (r ｔ )year, The distance between the second pipe joint (32) and the third pipe joint (33) is defined as the first distance (W1). When the thickness of the first plate-like member (21) is defined as plate thickness (t), The first distance (W1) satisfies the following equation 1, The outer diameter of the bent plate (r ｓｏ The branch pipe (10) according to claim 1 or claim 6 satisfies the following formula 2. Equation 1: W1≧2√((r ｔ +r ｓｏ ) ２ -r ｓｏ ２ )-2r ｔ (Here, W1: first distance, r ｓｏ : outer diameter of the bent plate, r ｔ (Outer diameter of the joint) Formula 2: r ｓｏ ≥2t (Here, t: thickness of the first plate-like member)

13. The first plate-shaped member (21) comprises a straight plate portion (21X) and a curved plate portion (21Y), The joint portion (24) includes a branch portion (27) formed between the second opening (26b) and the third opening (26c), The branch portion (27) has the straight plate portion (21X), When the width of the straight plate portion (21X) in the branch portion (27) is defined as the first width (α) in a second direction (D2) that is parallel to the mating surface between the first plate-like member (21) and the second plate-like member (22) in the branch portion (27) and perpendicular to the first direction (D1) that is parallel to the axial direction of the second opening (26b) and the third opening (26c), The branch pipe (10) according to claim 12, wherein the first distance (W1) satisfies the following formula 3. Equation 3: W1≧2√((r ｔ +r ｓｏ ) ２ -r ｓｏ ２ )-2r ｔ +α (Here, W1: first distance, α: first width)

14. The first plate-shaped member (21) comprises a straight plate portion (21X) and a curved plate portion (21Y), It includes a first curved portion (21c) on the first surface (21a) side which is concave, and a second curved portion (21d) on the first surface (21a) side which is convex, The joint portion (24) includes a branch portion (27) formed between the second opening (26b) and the third opening (26c), and an outer edge joint portion (29) other than the branch portion (27), The bending radius of the first surface (21a) in the second curved portion (21d) is the outer diameter of the plate bending (r ｓｏ )year, The outer diameters of the first pipe fitting (31), the second pipe fitting (32), and the third pipe fitting (33) are set to the outer diameter of the fitting (r ｔ )year, Let the thickness of the first plate-shaped member (21) be denoted as plate thickness (t). When the width of the straight plate portion (21X) in the outer edge joint portion (29) is defined as the second width (β) in a second direction (D2) that is parallel to the joint surface between the first plate-like member (21) and the second plate-like member (22) in the branch portion (27) and perpendicular to the first direction (D1) that is parallel to the axial direction of the second opening (26b) and the third opening (26c), The second width (β) satisfies the following formula 4, When the distance from the first pipe joint (31), the second pipe joint (32), and the third pipe joint (33) to the end of the outer edge joint (29) is defined as the second distance (W2), The second distance (W2) is the branch pipe (10) according to claim 1 or claim 6, which satisfies the following formula 5. Formula 4: t ≤ β ≤ 20t (Here, β: second width, t: thickness of the first plate-like member) Equation 5: W2≧√((r ｔ +r ｓｏ ) ２ -r ｓｏ ２ ) -r ｔ +β (Here, W2: second distance, r) ｓｏ : outer diameter of the bent plate, r ｔ : Outer diameter of the joint, β: Second width)

15. The first pipe (111), the second pipe (112), and the third pipe (113) are, The branch pipe (10) according to claim 1 or claim 6, which is a refrigerant pipe (110) through which a single refrigerant consisting of carbon dioxide or a mixed refrigerant containing carbon dioxide flows.

16. A refrigeration apparatus (100) comprising the branch pipe (10) according to claim 1 or claim 6.

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