Branch joint

Abstract

The present invention provides a branching joint that reduces pressure loss of branched water and eliminates the need to break down walls that partition the interior or exterior of a building to create large openings. [Solution] The branch joint 12 comprises a main pipe inlet 32 ​​having a main pipe inlet 31 into which pressurized water flows, a branch pipe section 36 having a branch pipe outlet 35 into which a portion of the pressurized water flows out, and a main pipe outlet 34 having a main pipe outlet 33 into which the remaining pressurized water flows out, and is made of a resin material. The main pipe outlet 34 is offset so as to overlap a portion of the main pipe inlet 32. The branch pipe section 36 is offset so as to overlap another portion of the main pipe inlet 32. The main pipe outlet 34 and the branch pipe section 36 extend in parallel to each other.

Description

Technical Field

[0001] The present invention relates to a branch joint connected to a water supply and hot water supply pipe and a fire fighting pipe.

Background Art

[0002] As a sprinkler pipe structure installed in the ceiling space of a building, for example, the one described in Japanese Patent Application Laid-Open No. 2018-075185 (Patent Document 1) is known. The structure described in Patent Document 1 is such that a water pipe is branched in the middle by interposing a T-shaped joint or a Y-shaped joint in the middle of the water pipe, and a sprinkler head is connected to the branched pipe.

[0003] According to the regulations of fire fighting equipment, the water discharge pressure per sprinkler head is required to be 0.1 MPa or more and 1 MPa or less, and the water discharge volume is required to be 50 L / min or more or 80 L / min or more.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional piping structure as described above, problems as described below occur. That is, in a T-shaped joint that branches at 90°, the pressure loss of the water pressure is large in the branched pipe, the water jet from the sprinkler head is weakened, and the fire extinguishing ability is reduced.

[0006] In terms of reducing pressure loss, Y-type fittings are more advantageous than T-type fittings. Figure 7 is a longitudinal cross-sectional view showing piping using Y-type fittings. The upstream main pipe 201 and the downstream main pipe 203 are connected by a Y-type fitting 202. A branch pipe 204 is further connected to the Y-type fitting 202. The branching angle β between the branch pipe 204 and the downstream main pipe 203 is set to an acute angle (for example, β = 45°). The downstream end of the branch pipe 204 is connected to a sprinkler head (not shown).

[0007] In the case of a Y-shaped joint that branches at a 45° angle, a pre-prepared set of piping is brought to the building construction site and installed, regardless of the interior wall layout of the building. As a result, as shown in Figure 7, the branch pipe 204 and the downstream main pipe 203 may have to penetrate walls 205 or beams that separate rooms within the building, maintaining a certain distance from each other.

[0008] In this case, a large opening 206 must be drilled through the wall 205, and the drilling and backfilling work in the wall 205 would be uneconomical in terms of man-hours, materials, and working time. Furthermore, while backfilling is unnecessary when drilling a large opening through a beam, there is a concern that drilling a large opening in a beam may reduce the beam's strength.

[0009] Furthermore, when injection molding joints using resin materials, there are issues such as the insertion direction of the core into the cavity mold and core abutment, requiring insert molding of cylindrical passage members, which leaves room for improvement in terms of material costs and manufacturing efficiency.

[0010] In view of the above circumstances, the present invention aims to provide an improved branch joint that is less prone to water pressure loss and does not require large openings in walls or beams. [Means for solving the problem]

[0011] For this purpose, the branch joint according to the present invention comprises a main pipe inlet having a main pipe inlet into which pressurized water flows, a branch pipe section having a branch pipe outlet from which a portion of the pressurized water flows out, and a main pipe outlet section having a main pipe outlet from which the remaining portion of the pressurized water flows out, and is formed of a resin member, wherein the main pipe outlet section is offset so as to overlap a portion of the main pipe inlet section, and the branch pipe section is offset so as to overlap another portion of the main pipe inlet section, and the main pipe outlet section and the branch pipe section extend in parallel to each other.

[0012] According to this invention, since the main pipe outlet and the branch pipe section extend in parallel to each other, the branching angle between them becomes zero or slight, and the pressure loss in the branch pipe section can be suppressed compared to conventional T-type joints. Furthermore, the branch pipe connected to the branch pipe outlet and the downstream main pipe connected to the main pipe outlet can be arranged parallel to each other, eliminating the need to form large openings through walls or beams compared to conventional Y-type joints. In addition, since the main pipe outlet and a part of the main pipe inlet are offset to overlap, and the branch pipe section and another part of the main pipe inlet are offset to overlap, it becomes possible to injection mold the branch joint using a cavity mold and core, improving manufacturing efficiency compared to conventional insert molding using passage members.

[0013] In one aspect of the present invention, the main pipe outlet and the branch pipe section extend parallel to each other. According to this aspect, the pressure loss in the branch pipe section can be further reduced. In another aspect, the main pipe outlet and the branch pipe section may extend substantially parallel to each other, gradually separating as they move downstream. In yet another aspect of the present invention, the branching angle of the main pipe outlet and the branch pipe section is a predetermined value that falls within the range of greater than 0° and less than 9°.

[0014] The shape of the bottom surface at the downstream end of the main pipe inlet is not particularly limited, but a preferred aspect of the present invention is that the bottom surface of the main pipe inlet is a flat surface facing the main pipe inlet. With this aspect, the pressurized water flowing in from the main pipe inlet and hitting the bottom surface can be directed not only to the main pipe outlet but also to the branch pipe section. Therefore, the difference between the flow rate of pressurized water flowing through the main pipe outlet and the flow rate of pressurized water flowing through the branch pipe section can be reduced compared to conventional T-type joints. In another aspect, the bottom surface of the main pipe inlet may be an inclined surface that is tilted with respect to the axis of the main pipe inlet. With this aspect, the pressurized water can flow smoothly from the main pipe inlet to the main pipe outlet or branch pipe section.

[0015] The shape of the bottom surface at the upstream end of the main pipe outlet is not particularly limited. The shape of the bottom surface at the upstream end of the branch pipe section is not particularly limited. For example, the bottom surface of the branch pipe section is approximately perpendicular to the axis of the branch pipe section and points toward the branch outlet. Alternatively, as one aspect of the present invention, the bottom surface of the branch pipe section is an inclined surface that intersects the axis of the branch pipe section at an angle. With such an aspect, the bottom surface of the branch pipe section faces the inner circumferential surface of the branch pipe section, narrowing the passage cross-sectional area and allowing a constriction to be created. Therefore, the flow rate of pressurized water flowing through the branch pipe section can be regulated.

[0016] The inner diameter of the branch pipe may be the same as the inner diameter of the main pipe inlet or outlet. However, in one aspect of the present invention, the inner diameter φ1 of the main pipe inlet, the inner diameter φ2 of the main pipe outlet, and the inner diameter φ3 of the branch pipe satisfy the relationship φ1≧φ2>φ3. In this aspect, the required amount of pressurized water can be allocated proportionally to the branch pipe. [Effects of the Invention]

[0017] Thus, according to the present invention, not only is the pressure loss of the branch joint reduced, but it is also only necessary to form an opening through the wall or beam equal to the width of the branch joint, significantly reducing the workload of forming the opening. Furthermore, the branch joint can be injection molded using a cavity mold and core, which is cost-effective. [Brief explanation of the drawing]

[0018] [Figure 1] It is a plan view showing a sprinkler pipe for fire extinguishing. [Figure 2] It is a longitudinal sectional view showing a branch joint according to the first embodiment of the present invention. [Figure 3] It is a longitudinal sectional view showing the state during the manufacture of the first embodiment. [Figure 4] It is a longitudinal sectional view showing a branch joint according to the second embodiment of the present invention. [Figure 5] It is a longitudinal sectional view showing a branch joint according to the third embodiment of the present invention. [Figure 6] It is a longitudinal sectional view showing a branch joint according to the fourth embodiment of the present invention. [Figure 7] It is a longitudinal sectional view showing a pipe using a Y-shaped joint.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a plan view showing a sprinkler pipe for fire extinguishing. FIG. 2 is a longitudinal sectional view showing a branch joint according to the first embodiment of the present invention. First, an example of the sprinkler pipe will be described. Regarding a large building such as a building, in the ceiling space inside the building, a pressure water supply port 10 and a loop pipe 11 are installed. Since the loop pipe 11 is connected to the pressure water supply port 10 at both ends 11d and 11f, these both ends 11d and 11f are connected to each other, and the loop pipe 11 is made endless. The pressure water supplied from the pressure water supply port 10 flows into both ends 11d and 11f of the loop pipe 11. As a result, the loop pipe 11 is filled with pressure water.

[0020] Inside the building, a wall 20 is provided. The wall 20 and the wall 21 partition rooms on the building floor. Openings 22 and 23 are formed in the wall 20. The loop pipe 11 extends through a plurality of openings 22 and 23 and is installed in the ceiling spaces 24 to 27 of each room.

[0021] Sprinkler heads 28 are installed on the ceiling of each room. The loop piping 11 has the same number of branch fittings 12, 12... as the number of sprinkler heads 28 installed at intervals. The branch fittings 12 and sprinkler heads 28 are connected by branch piping 13.

[0022] The upstream end of the branch pipe 13 extends along the loop pipe 11 and, together with the loop pipe 11, passes through an opening 22 drilled in the wall 20. The inner diameter of the opening 22 is sufficient to be approximately the same as the width dimension of the branch joint 12. Downstream of the opening 22, the branch pipe 13 extends gradually away from the loop pipe 11 and reaches the sprinkler head 28. In this embodiment, two walls 20 extending in a single row in the vertical direction and two walls 20 extending in a single row in the horizontal direction are arranged in a cross shape, and an opening 22 or opening 23 is formed in each of these four walls 20. In a modified example not shown, the walls 20 may be arranged in multiple rows in the vertical direction or in multiple rows in the horizontal direction, and many openings 22 and 23 may be provided in these multiple walls 20, and the loop pipe 11 may pass through many openings 22, 23. For example, the walls 20 may be arranged in a grid pattern.

[0023] The sprinkler piping in this embodiment is a dry sprinkler system. However, the sprinkler piping in this embodiment may also be a wet sprinkler system. In other words, the branch pipe 13 in this embodiment is applicable to both dry and wet sprinkler systems. When a fire is detected in a room in the building, pressurized water flows from the pressurized water supply port 10 to one end 11d and the other end 11f of the loop pipe 11. As the pressurized water flows from both ends 11d and 11f of the loop pipe towards the central part 11e of the loop pipe 11, a portion of the pressurized water is diverted at the branch joint 12, flows through the branch pipe 13, and is ejected into the room from the sprinkler head 28 located at the downstream end of the branch pipe 13.

[0024] Figure 2 is a vertical cross-sectional view showing a branch joint 12 according to the first embodiment of the present invention, representing a cross-section obtained by cutting the branch joint 12 with a plane containing axes X1, X2, and X3, which will be described later. The branch joint 12 is a single resin member. From the perspective of the branch joint 12, the loop piping 11 is comprised of an upstream pipe 11b and a downstream pipe 11c. The branch joint 12 includes a main pipe inlet 32 ​​having a main pipe inlet 31, a main pipe outlet 34 having a main pipe outlet 33, and a branch pipe section 36 having a branch pipe outlet 35, and branches downstream. The main pipe inlet 32, the main pipe outlet 34, and the branch pipe section 36 are pipe-shaped passages.

[0025] The main pipe inlet 31 opens to one side, to which the upstream pipe 11b is connected. The main pipe outlet 33 and the branch pipe outlet 35 open to the other side, approximately 180° opposite to the main pipe inlet 31, to which the downstream pipe 11c and the branch pipe 13 are connected, respectively. The part of the main pipe inlet 32 ​​opposite to the main pipe inlet 31 (downstream side) is called the inner part of the main pipe inlet 32, the part of the main pipe outlet 34 opposite to the main pipe outlet 33 (upstream side) is called the inner part of the main pipe outlet 34, and the part of the branch pipe section 36 opposite to the branch pipe outlet 35 (upstream side) is called the inner part of the branch pipe section 36. The inner part of the main pipe inlet 32 ​​and the inner part of the main pipe outlet 34 are connected to each other. Also, the inner part of the main pipe inlet 32 ​​and the inner part of the branch pipe section 36 are connected to each other.

[0026] Pressurized water flowing along the upstream pipe 11b flows from the main pipe inlet 31 into the branch joint 12, flows out from the main pipe outlet 33 or branch pipe outlet 35 without significantly changing direction, and flows along the downstream pipe 11c or branch pipe 13.

[0027] It should be added that the axis X1 of the main pipe inlet 32 ​​and the axis X2 of the main pipe outlet 34 do not coincide, and these axes X1 and X2 are offset from each other. This offset distance D1 satisfies the following relationship with the minimum inner diameter φ1 of the main pipe inlet 32 ​​and the minimum inner diameter φ2 of the main pipe outlet 34. (Formula 1) D1≦φ1 / 2+φ2 / 2

[0028] In other words, a portion of the main pipe inlet 32 ​​and a portion of the main pipe outlet 34 are connected so as to overlap each other. In this embodiment, the main pipe inlet 32 ​​and the main pipe outlet 34 are offset from each other and arranged in a substantially straight line. In this embodiment, the axes X1 and X2 are arranged parallel or substantially parallel. Here, substantially parallel refers to a predetermined value that is greater than 0° and within the range of 9° or less.

[0029] Similarly, the axis X1 of the main pipe inlet 32 ​​and the axis X3 of the branch pipe section 36 do not coincide, and these axes X1 and X3 are offset from each other. This offset distance D2 satisfies the following relationship with the minimum inner diameter φ1 of the main pipe inlet 32 ​​and the minimum inner diameter φ3 of the branch pipe section 36. (Formula 2)D2≦φ1 / 2+φ3 / 2

[0030] In other words, a portion of the main pipe inlet 32 ​​and a portion of the branch pipe section 36 are connected so that they overlap each other. In this embodiment, the main pipe inlet 32 ​​and the branch pipe section 36 are offset from each other and arranged in a substantially straight line.

[0031] The main pipe outlet section 34 and the branch pipe section 36 extend in parallel to each other, with no overlapping spacing between them. In this embodiment, axes X2 and X3 are arranged in parallel. Alternatively, in a modified example not shown, axes X2 and X3 are arranged approximately parallel to each other, and the distance between axes X2 and X3 gradually increases as you move downstream, that is, as you move away from the branch joint 12.

[0032] The inner bottom surface 41 of the main pipe inlet 32 ​​is a flat surface. The inner bottom surface 41 faces the main pipe inlet 31. In this embodiment, the inner bottom surface 41 is perpendicular to the axis X1. The angle between the inner bottom surface 41 and the inner circumferential surface of the main pipe outlet 34 is approximately a right angle. The angle between the inner bottom surface 41 and the inner circumferential surface of the branch pipe section 36 is also approximately a right angle. Here, "approximately a right angle" refers to the angle on the wall thickness side of the branch joint 12 (the same applies hereafter).

[0033] The inner bottom surface 45 of the main pipe outlet section 34 is located upstream of the inner bottom surface 41. The inner bottom surface 45 and the inner circumferential surface of the main pipe inlet section 32 are connected at approximately a right angle. The inner bottom surface 46 of the branch pipe section 36 is also located upstream of the inner bottom surface 41. The inner bottom surface 46 and the inner circumferential surface of the main pipe inlet section 32 are also connected at approximately a right angle.

[0034] The minimum inner diameters φ1, φ2, and φ3 of this embodiment satisfy the following relationship. (Formula 3)φ1≧φ2>φ3

[0035] The inner diameter of the main pipe inlet 32 ​​is wider on the main pipe inlet 31 side (upstream side) than on the far side (downstream side), and the end of the upstream pipe 11b is inserted into the main pipe inlet 31. The inner diameter of the main pipe outlet 34 is wider on the main pipe outlet 33 side (downstream side) than on the far side (upstream side), and the end of the downstream pipe 11c is inserted into the main pipe outlet 33. The inner diameter of the branch pipe section 36 is wider on the branch pipe outlet 35 side (downstream side) than on the far side (upstream side), and the end of the branch pipe 13 is inserted into the branch pipe outlet 35.

[0036] An electrofusion heating wire 37 is embedded in the main pipe inlet 32 ​​on the main pipe inlet 31 side. The electrofusion heating wire 37 extends spirally around the axis X1 of the main pipe inlet 31. On the outer surface of the main pipe inlet 32, a pair of terminal pins 38, 38 are erected at intervals in the direction of extension of the axis X1. One terminal pin 38 is connected to one end of the electrofusion heating wire 37. The other terminal pin 38 is connected to the other end of the electrofusion heating wire 37. By passing a predetermined current through the terminal pins 38, 38, the inner surface of the main pipe inlet 32 ​​is welded to the outer surface of the upstream pipe 11b, becoming one unit, and the main pipe inlet 32 ​​and the upstream pipe 11b are connected without any gaps.

[0037] Similarly, the electrofusion heating wire 37 and terminal pin 38 are embedded on the main pipe outlet 33 side of the main pipe outflow section 34 and on the branch pipe outlet 35 side of the branch pipe section 36. This ensures that the downstream piping inserted into the main pipe outflow section 34 and the main pipe outlet 33 is joined without any gaps. In addition, the branch pipes 13 inserted into the branch pipe section 36 and the branch pipe outlet 35 are joined without any gaps.

[0038] In this embodiment of the branch joint 12, the main pipe outlet section 34 is offset so as to overlap a part of the main pipe inlet section 32, and the branch pipe section 36 is offset so as to overlap another part of the main pipe inlet section 32, with the main pipe outlet section 34 and the branch pipe section 36 extending in parallel to each other. Compared to conventional T-type joints, this eliminates the pressure loss of the pressurized water flowing through the branch pipe section 36 when the water branches and flows through the main pipe outlet section 34 and the branch pipe section 36.

[0039] Furthermore, according to the branch joint 12 of this embodiment, as shown in Figure 7, it is no longer necessary to drill a relatively large opening 206 in the wall 205 or beam through which the conventional Y-type joint 202, downstream main pipe 203, and branch pipe 204 can pass. In other words, it is sufficient to drill a relatively small opening 22 in the wall 20 or beam through which the branch joint 12 can pass. As a result, the opening dimensions of the opening 22 shown in Figure 1 can be reduced compared to the conventional Y-type joint 202. Therefore, the amount of work required, such as drilling a wide opening in the wall 20 or beam in the ceiling space for the installation of the branch pipe 13, is reduced, which is advantageous in terms of construction.

[0040] Furthermore, according to the branch joint 12 of this embodiment, since the inner bottom surface 41 of the main pipe inlet 32 ​​is a flat surface substantially perpendicular to the axis X1, the pressurized water that flows in from the main pipe inlet 31 and hits the inner bottom surface 41 can be directed not only to the main pipe outlet 34 but also to the branch pipe section 36. Therefore, compared to conventional T-type joints, the difference between the flow rate of pressurized water flowing through the main pipe outlet 34 and the flow rate of pressurized water flowing through the branch pipe section 36 can be reduced.

[0041] Furthermore, with the branch joint 12 of this embodiment, the upstream pipe 11b and the downstream pipe 11c are arranged in a substantially straight line via the branch joint 12. As a result, pressurized water passes through the branch joint 12 without obstruction and flows down the loop pipe 11.

[0042] Furthermore, in this embodiment, the main pipe inlet 32, the main pipe outlet 34, and the branch pipe section 36 are integrally connected, and the branch joint 12 is a single resin component. This makes the branch joint 12 in this embodiment advantageous in terms of manufacturing cost.

[0043] Next, the manufacturing method of the branch joint 12 will be explained.

[0044] The branch joint 12 is insert-molded by injecting resin material into the internal space 101 of the cavity mold 100. The internal space 101 is pre-installed with an electrofusion heating wire 37 and terminal pins 38, and cores 102, 104, and 106. The cavity mold 100 can be divided into two or more parts. Core 102 corresponds to the inner diameter surface of the main pipe inlet 32, core 104 corresponds to the inner circumferential surface of the main pipe outlet 34, and core 106 corresponds to the inner circumferential surface of the branch pipe section 36. These cores 102, 104, and 106 extend straight into the interior of the mold 100. One side surface 102b of the tip of core 102 is in contact with the side surface of the tip of core 104. The other side surface 102c of the tip of core 102 is in contact with the side surface of the tip of core 106.

[0045] The internal space 101 is filled with molten resin material. After filling, once the resin material hardens, the cores 102, 104, and 106 are withdrawn from the mold 100 along the axes X1, X2, and X3, respectively, as shown by arrows F1, F2, and F3. The mold 100 is then divided, and the branched joint molded in the internal space 101 is removed.

[0046] According to the manufacturing method of this embodiment, the branch joint 12 shown in Figure 2 can be molded from a resin material, resulting in fewer manufacturing steps and cost advantages.

[0047] Next, a second embodiment of the present invention will be described. Figure 4 is a vertical cross-sectional view showing the branch joint 40 of the second embodiment, representing the cross-section obtained by cutting the branch joint 40 in a plane containing axes X1, X2, and X3. Components of the branch joint 40 that are common with the branch joint 12 described above are denoted by the same reference numerals and their description is omitted. The branch joint 40 is a modified example of the branch joint 12 described above, and its basic configuration is the same as that of the branch joint 12. As a configuration that differs from the branch joint 12, the inner bottom surfaces 42 and 43 of the main pipe inlet 32 ​​are inclined so that they approach axes X2 and X3 as they move downstream. The inner bottom surface 42 is connected to the inner circumferential surface of the main pipe outlet 34 at an obtuse angle α1. The inner bottom surface 43 is connected to the inner circumferential surface of the branch pipe section 36 at an obtuse angle α2. The obtuse angles α1 and α2 are the angles on the wall thickness side of the branch joint 40 (the same applies hereinafter).

[0048] The connection point 44 between the inner bottom surfaces 42 and 43 is located between axis X1 and axis X3 and protrudes toward the main pipe inlet 31. In other words, the inner bottom surface of the main pipe inlet 32 ​​includes the inner bottom surface 42 on the main pipe outlet 34 side and the inner bottom surface 43 on the branch pipe 36 side. The inner bottom surface 42 intersects the axis X1 of the main pipe inlet 32 ​​at an angle, but the inner bottom surface 43 does not intersect the axis X1.

[0049] According to the branch joint 40 of the second embodiment, since an inclined inner bottom surface 42 is provided, pressurized water can flow smoothly from the main pipe inlet 32 ​​to the main pipe outlet 34. Furthermore, since an inclined inner bottom surface 43 is provided, pressurized water can flow smoothly from the main pipe inlet 32 ​​to the branch pipe section 36.

[0050] Furthermore, since the connection point 44, which forms the boundary between the inner bottom surfaces 42 and 43, is positioned closer to axis X3 than to axis X2, the flow rate of pressurized water flowing through the main pipe outlet section 34 centered on axis X2 can be increased. The angles of the obtuse angles α1 and α2 are not particularly limited; α1 = α2, α1 < α2, or α1 > α2. By making the angles of the obtuse angles α1 and α2 different, the flow rate of pressurized water flowing through the main pipe outlet section 34 and the flow rate of pressurized water flowing through the branch pipe section 36 can be adjusted.

[0051] Next, a third embodiment of the present invention will be described. Figure 5 is a longitudinal cross-sectional view showing a branch joint 50 of the third embodiment. In the branch joint 50, components common to the branch joints 12 and 40 described above are denoted by the same reference numerals and their descriptions are omitted. The basic configuration of the branch joint 50 is the same as that of the branch joints 12 and 40 described above. As a configuration that differs from the branch joint 40, the inner bottom surface 51 of the branch pipe section 36 is an inclined surface that intersects diagonally with the axis X3 of the branch pipe section 36, and connects with the inner circumferential surface of the branch pipe section 36 at an angle α4 greater than 180° on the downstream side, and connects with the inner circumferential surface of the main pipe inlet section 32 at an obtuse angle α3 on the upstream side. The inner bottom surface 51 is closest to the connection point 52 between the inner bottom surface 43 of the main pipe inlet section 32 and the inner circumferential surface of the branch pipe section 36. For this reason, the passage cross-sectional area of ​​the branch pipe section 36 is smallest between the connection point 52 and the inner bottom surface 51.

[0052] According to the branch joint 50 of the third embodiment, since the inner bottom surface 51 intersects the axis X3 at an angle, the distance between the inner bottom surface 51 and the connection point 52 is narrowed, and a constriction is provided so that the passage cross-sectional area of ​​the branch pipe section 36 is narrowed. Therefore, the flow rate from the main pipe inlet 32 ​​to the branch pipe section 36 can be restricted.

[0053] Next, a fourth embodiment of the present invention will be described. Figure 6 is a longitudinal cross-sectional view showing a branch joint 60 of the fourth embodiment. In the branch joint 60, components common to the branch joints 12 and 40 described above are denoted by the same reference numerals and their descriptions are omitted. The branch joint 60 is a modified version of the branch joint 50 described above, and instead of the rear bottom surface 51 described above, it has rear bottom surfaces 61 and 62.

[0054] The inner bottom surface 61 of the branch pipe section 36 is an inclined surface that intersects the axis X3 of the branch pipe section 36 at an angle α4 greater than 180° on the downstream side, and connects to the inner circumferential surface of the branch pipe section 36 at an angle α5 greater than 180° on the upstream side.

[0055] The inner bottom surface 62 of the branch pipe section 36 is located at the innermost (upstream) end of the branch pipe section 36 and is positioned closer to axis X1 when viewed from axis X3. The inner bottom surface 62 and the inner circumferential surface of the main pipe inlet section 32 are connected at approximately a right angle.

[0056] In the branch joint 60 of the fourth embodiment, since the inner bottom surface 61 intersects with the axis X3, a constriction is provided between the inner bottom surface 61 and the connection point 52 so that the passage cross-sectional area of ​​the branch pipe section 36 is narrowed. Therefore, the flow rate from the main pipe inlet 32 ​​to the branch pipe section 36 can be reduced. In addition, since the inner bottom surface 62 is provided, the flow rate restriction due to the constriction (inner bottom surface 61) can be relaxed compared to the inner bottom surface 51 described above.

[0057] Although embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as the present invention, or within an equivalent scope. For example, some components may be extracted from one embodiment described above, and other components may be extracted from other embodiments described above, and these extracted components may be combined. The axes X1, X2, and X3 of the embodiments described above are arranged parallel to each other. Alternatively, as a modified example not shown, axis X1 may be inclined with respect to axis X2 or X3. The axes X1, X2, and X3 of the embodiments described above are arranged on a common virtual plane. Alternatively, axes X1 and X2 are arranged on a first virtual plane, and axes X1 and X3 are arranged on a different second virtual plane. In this embodiment, fire extinguishing piping was described as an example, but the branch joint 12 of this embodiment can also be used for water supply piping and hot water supply piping that are not for fire extinguishing activities. [Industrial applicability]

[0058] This invention is advantageously applicable to building piping. [Explanation of symbols]

[0059] 12 Branch joint, 31 Main pipe inlet, 32 Main pipe inlet, 33 Main pipe outlet, 34 Main pipe outflow section, 35 Branch pipe outlet, 36 Branch pipe section, 41-43 Deep bottom surface of main pipe inlet section, 51, 61, 62 The bottom surface of the branched pipe section.

Claims

1. A branch joint comprising a main pipe inlet having a main pipe inlet into which pressurized water flows, a branch pipe section having a branch pipe outlet from which a portion of the pressurized water flows out, and a main pipe outlet section having a main pipe outlet from which the remaining pressurized water flows out, and formed of a resin material, The main pipe outlet section is offset so as to overlap with a part of the main pipe inlet section. The branch pipe section is offset so as to overlap with another part of the main pipe inlet section. The main pipe outlet and the branch pipe section extend in parallel to each other, forming a branch joint.

2. The branch joint according to claim 1, wherein the main pipe outlet and the branch pipe section extend parallel to each other.

3. The branch joint according to claim 1, wherein the bottom surface of the main pipe inlet is a flat surface facing the main pipe entrance, or an inclined surface that is inclined with respect to the axis of the main pipe inlet.

4. The branch joint according to claim 1, wherein the bottom surface of the branch pipe section is an inclined surface that intersects the axis of the branch pipe section at an oblique angle.

5. A branch joint according to any one of claims 1 to 4, wherein the inner diameter φ1 of the main pipe inlet, the inner diameter φ2 of the main pipe outlet, and the inner diameter φ3 of the branch pipe satisfy the relationship φ1 ≥ φ2 > φ3.

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