Reducing symmetry y-type bifurcations of concrete joint deformations

Abstract

The application provides a symmetrical Y-shaped bifurcated pipe for reducing deformation of a concrete joint, which comprises a pipe body, a plurality of branch pipes connected with the main pipe, and a plurality of reinforcing plate groups, wherein the plurality of reinforcing plate groups are arranged at the outer periphery of the main pipe and the plurality of branch pipes in a circumferential direction of the pipe body, and each reinforcing plate is provided with a reinforcing hole. The technical scheme provided by the application can solve the problem of the influence of the deformation of the bifurcated pipe on safety in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bifurcated pipe, in particular to a symmetrical Y-shaped bifurcated pipe for reducing deformation of the joint with concrete. BACKGROUND

[0002] The bifurcated pipe is an important part of a hydropower station, which is responsible for guiding water flow into two or more water turbine generator sets to save engineering investment. In recent years, with the development of conventional hydropower and pumped storage, bifurcated pipes are more and more applied in engineering. The bifurcated pipe is usually buried in a tunnel, and its shape is usually divided into three types: asymmetric Y-shaped, symmetrical Y-shaped and three-way. Among them, the safety of the bifurcated pipe is crucial to the safety of the hydropower engineering.

[0003] In engineering, more attention is paid to the hydraulic characteristics of the bifurcated pipe, such as flow pattern, water head loss, and erosion characteristics, while less attention is paid to its structural deformation. The deformation of the bifurcated pipe will affect the deformation of the joint with concrete, and then cause the vibration of the pipe system, affecting the safety of the unit. For high water head units, the deformation of the bifurcated pipe is more obvious, and it is extremely important to strictly control it. SUMMARY

[0004] The present application provides a symmetrical Y-shaped bifurcated pipe for reducing deformation of the joint with concrete to solve the problem of safety affected by the deformation of the bifurcated pipe in the related art.

[0005] The present application provides a symmetrical Y-shaped bifurcated pipe for reducing deformation of the joint with concrete, which comprises: a pipe body comprising a main pipe and a plurality of branch pipes connected to the main pipe; and a reinforcing plate group comprising a plurality of reinforcing plates, the plurality of reinforcing plates being arranged at the outer periphery of the main pipe and the plurality of branch pipes in a circumferential direction of the pipe body, and each of the reinforcing plates being provided with a reinforcing hole.

[0006] Further, the plurality of reinforcing plates comprises a plurality of main plate segments and a plurality of auxiliary plate segments, the plurality of main plate segments being arranged at the outer periphery of the main pipe in the circumferential direction of the main pipe, and the plurality of auxiliary plate segments being arranged at the outer periphery of the branch pipes in the circumferential direction of the branch pipes, and the reinforcing hole comprises a first hole segment arranged on the main plate segment and a second hole segment arranged on the auxiliary plate segment.

[0007] Further, the plurality of reinforcing plates further comprises a connecting plate segment, the connecting plate segment being connected to the outer periphery of two adjacent branch pipes, and the reinforcing hole comprises a third hole segment arranged on the connecting plate segment.

[0008] Further, the branch pipe comprises an inclined pipe segment and a straight pipe segment, two ends of the inclined pipe segment being connected to the main pipe and the straight pipe segment respectively, the auxiliary plate segment comprises an inclined plate segment and a straight plate segment, two ends of the inclined plate segment being connected to the main plate segment and the straight plate segment respectively, the inclined plate segment being connected to the outer periphery of the inclined pipe segment, the straight plate segment being connected to the outer periphery of the straight pipe segment, the second hole segment comprises a fourth hole segment arranged on the inclined plate segment and a fifth hole segment arranged on the straight plate segment, and the connecting plate segment is connected to the outer wall of the inclined pipe segment and the outer wall of the straight pipe segment.

[0009] Further, a ratio between the length of the first hole section and the length of the main plate section is greater than or equal to 0.6 and less than or equal to 0.7; a ratio between the length of the fourth hole section and the length of the inclined plate section is greater than or equal to 0.5 and less than or equal to 0.6; and a ratio between the length of the fifth hole section and the length of the straight plate section is greater than or equal to 0.55 and less than or equal to 0.65.

[0010] Further, the inclined pipe section and the straight pipe section are both two, the end of the two inclined pipe sections is connected with the main pipe, and the inclined plate section and the straight plate section are both four, the four inclined plate sections are connected with the corresponding main plate sections respectively.

[0011] Further, the connecting plate section comprises a connecting straight plate, a connecting inclined plate and a connecting horizontal plate, the outer wall of each inclined pipe section is connected with the connecting inclined plate, the outer wall of each straight pipe section is connected with the connecting straight plate, and the two ends of the connecting straight plate are connected with the connecting inclined plate and the connecting horizontal plate respectively, and the connecting straight plate, the connecting inclined plate and the connecting horizontal plate jointly enclose the third hole section.

[0012] Further, the main plate section, the inclined plate section and the straight plate section are all rectangular structures; and / or, the first hole section, the fourth hole section and the fifth hole section are all rectangular holes.

[0013] Further, the included angle between the two adjacent main plate sections is 90°; and / or, the included angle between the two adjacent auxiliary plate sections is 90°.

[0014] Further, the diameter of the main pipe is equal to the diameter of the branch pipe, and a ratio between the width of the reinforcing plate and the diameter of the main pipe is greater than or equal to 0.4 and less than or equal to 0.6.

[0015] By applying the technical scheme of the present application, the branch pipe comprises a pipe body and reinforcing plates, when pouring concrete, the branch pipe is embedded into the concrete, and the reinforcing plates can increase the contact area between the branch pipe and the concrete to increase the limiting effect on the branch pipe, meanwhile, the reinforcing holes arranged on the reinforcing plates can make the concrete flow through, so as to avoid the interaction force between the reinforcing plate and the pipe body due to the extrusion of the concrete, and further, the reinforcing plate can reduce the deformation of the branch pipe during the operation of the unit and reduce the deformation of the joint between the branch pipe and the concrete. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings constituting a part of the specification of the present application are used to provide further understanding of the present application, the schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application. In the drawings:

[0017] Figure 1 Fig. 1 shows the structure schematic diagram of the branch pipe provided by the embodiment of the present application;

[0018] Figure 2Fig. 3 shows another structural schematic diagram of the branch pipe according to the embodiment of the present application.

[0019] In the above drawings, the following reference signs are used:

[0020] 10, pipe body; 11, main pipe; 12, branch pipe; 121, inclined pipe section; 122, straight pipe section;

[0021] 20, reinforcing plate set; 21, main plate section; 211, first hole section; 22, auxiliary plate section; 221, inclined plate section; 2211, fourth hole section; 222, straight plate section; 2221, fifth hole section; 23, connecting plate section; 231, connecting straight plate; 232, connecting inclined plate; 233, connecting cross plate; 234, third hole section. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting on the application or its applications or uses. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0023] As shown in Figs. 1 and 2, the embodiment of the present application provides a symmetric Y-type branch pipe for reducing deformation of a concrete joint, which comprises a pipe body 10 and a reinforcing plate set 20. The pipe body 10 comprises a main pipe 11 and a plurality of branch pipes 12 connected to the main pipe 11. The reinforcing plate set 20 comprises a plurality of reinforcing plates, which are arranged at intervals along the circumference of the pipe body 10 outside the main pipe 11 and the plurality of branch pipes 12. Each reinforcing plate is provided with reinforcing holes. Figure 1 Figure 2 The technical solutions of the present application are applied to the symmetric Y-type branch pipe for reducing deformation of a concrete joint, which comprises a pipe body 10 and a reinforcing plate set 20. When pouring concrete, the branch pipe is embedded into the concrete, and the plurality of reinforcing plates can increase the contact area of the branch pipe with the concrete to increase the limiting effect on the branch pipe. Meanwhile, the reinforcing holes provided on the reinforcing plates can allow the concrete to flow through, so that the interaction force between the reinforcing plates and the pipe body 10 due to the extrusion of the concrete is reduced, and the deformation of the branch pipe during the operation of the unit is reduced, and the deformation of the branch pipe and the concrete joint is reduced.

[0024] The technical solutions of the present application are applied to the symmetric Y-type branch pipe for reducing deformation of a concrete joint, which comprises a pipe body 10 and a reinforcing plate set 20. When pouring concrete, the branch pipe is embedded into the concrete, and the plurality of reinforcing plates can increase the contact area of the branch pipe with the concrete to increase the limiting effect on the branch pipe. Meanwhile, the reinforcing holes provided on the reinforcing plates can allow the concrete to flow through, so that the interaction force between the reinforcing plates and the pipe body 10 due to the extrusion of the concrete is reduced, and the deformation of the branch pipe during the operation of the unit is reduced, and the deformation of the branch pipe and the concrete joint is reduced.

[0025] ​In the embodiment, since the reinforcing plates are arranged on the main pipe 11 and the branch pipes 12, the reinforcing plates can increase the contact area between the main pipe 11 and the concrete and the contact area between the branch pipes 12 and the concrete at the same time when the concrete is poured, so that the contact area between the pipe body 10 and the concrete is large.

[0026] The branch pipe can be any one of asymmetric Y-shaped, symmetric Y-shaped and three-way shaped.

[0027] It should be noted that, in order to further reduce the interaction force between the pipe body 10 and the reinforcing plates, the reinforcing plates cannot interfere with each other.

[0028] In addition, the reinforcing plates can increase the contact area with the concrete, ensure the sufficient and tight filling of the concrete during the pouring of the concrete, strengthen the restriction of the concrete on the branch pipe, and reduce the deformation of the branch pipe during the operation of the unit.

[0029] As shown in Figure 1 The reinforcing plates include a plurality of main plate segments 21 and a plurality of auxiliary plate segments 22, the plurality of main plate segments 21 are arranged on the outer periphery of the main pipe 11 in a circumferential direction of the main pipe 11, the plurality of auxiliary plate segments 22 are arranged on the outer periphery of the branch pipes 12 in a circumferential direction of the branch pipes 12, and the reinforcing holes include first hole segments 211 arranged on the main plate segments 21 and second hole segments arranged on the auxiliary plate segments 22. The reinforcing plates with the above structure can increase the contact area between the main pipe 11 and the concrete by using the main plate segments 21, increase the contact area between the branch pipes 12 and the concrete by using the auxiliary plate segments 22, and further increase the contact area between the pipe body 10 and the concrete.

[0030] The number of the main plate segments 21 and the number of the auxiliary plate segments 22 can be the same, or the number of the main plate segments 21 can be greater than the number of the auxiliary plate segments 22, or the number of the main plate segments 21 can be less than the number of the auxiliary plate segments 22, and the specific setting is determined according to the actual situation.

[0031] In addition, the main plate segments 21 and the auxiliary plate segments 22 can be arranged in a connected relationship or can be arranged separately.

[0032] As shown in Figure 1 The reinforcing plates further include a connecting plate segment 23, the connecting plate segment 23 is connected to the outer peripheries of two adjacent branch pipes 12, and the reinforcing holes include third hole segments 234 arranged on the connecting plate segment 23. The connecting plate segment 23 can not only increase the connection strength between the branch pipes 12, but also increase the contact area with the concrete, and reduce the deformation of the branch pipe during the operation of the unit.

[0033] When the number of the branch pipes is three, the connecting plate segment 23 can be arranged between two adjacent branch pipes 12.

[0034] As shown in Figure 1As shown, the branch pipe 12 comprises an inclined pipe section 121 and a straight pipe section 122, two ends of the inclined pipe section 121 are connected with the main pipe 11 and the straight pipe section 122 respectively, the auxiliary plate section 22 comprises an inclined plate section 221 and a straight plate section 222, two ends of the inclined plate section 221 are connected with the main plate section 21 and the straight plate section 222 respectively, the inclined plate section 221 is connected at the outer periphery of the inclined pipe section 121, the straight plate section 222 is connected at the outer periphery of the straight pipe section 122, the second hole section comprises a fourth hole section 2211 arranged on the inclined plate section 221 and a fifth hole section 2221 arranged on the straight plate section 222, the connecting plate section 23 is connected with the outer wall of the inclined pipe section 121 and the outer wall of the straight pipe section 122. With the above structure, the contact area of the inclined pipe section 121 with the concrete can be increased by the inclined plate section 221, the contact area of the straight pipe section 122 with the concrete can be increased by the straight plate section 222, and then the contact area of the whole branch pipe 12 with the concrete is large.

[0035] The ratio between the length of the first hole section 211 and the length of the main plate section 21 is greater than or equal to 0.6 and less than or equal to 0.7. With the above ratio range, the first hole section 211 can be arranged on the main plate section 21 under the condition of ensuring the structural strength of the main plate section 21, so that the concrete can flow through, the contact area of the main plate section 21 with the concrete is increased, and the force of the concrete on the main plate section 21 is reduced.

[0036] Specifically, the ratio between the length of the fourth hole section 2211 and the length of the inclined plate section 221 is greater than or equal to 0.5 and less than or equal to 0.6. With the above ratio range, the fourth hole section 2211 can be arranged on the inclined plate section 221 under the condition of ensuring the structural strength of the inclined plate section 221, so that the concrete can flow through, the contact area of the inclined plate section 221 with the concrete is increased, and the force of the concrete on the inclined plate section 221 is reduced.

[0037] The ratio between the length of the fifth hole section 2221 and the length of the straight plate section 222 is greater than or equal to 0.55 and less than or equal to 0.65. With the above ratio range, the fifth hole section 2221 can be arranged on the straight plate section 222 under the condition of ensuring the structural strength of the straight plate section 222, so that the concrete can flow through, the contact area of the straight plate section 222 with the concrete is increased, and the force of the concrete on the straight plate section 222 is reduced.

[0038] As shown in the drawings, Figure 1 The inclined pipe section 121 and the straight pipe section 122 are both two, the end of the two inclined pipe sections 121 is connected with the main pipe 11, the inclined plate section 221 and the straight plate section 222 are both four, the four inclined plate sections 221 are connected with the corresponding main plate sections 21 respectively. With the above structure, the shape of the inclined plate section 221 and the straight plate section 222 can be adapted to the shape of the branch pipe 12, and then the arrangement of the reinforcing plate is facilitated.

[0039] In the embodiment, the main plate segments 21 are four, and the four main plate segments 21 are uniformly distributed on the outer periphery of the main pipe 11. The secondary plate segments 22 are six, and three secondary plate segments 22 are arranged on the outer periphery of each branch pipe 12. Among them, the two secondary plate segments 22 on the upper side of the pipe body 10 and the two secondary plate segments 22 on the lower side of the pipe body 10 are connected with the corresponding main plate segments 21, respectively.

[0040] As shown in Figure 1 The connecting plate segment 23 includes a connecting straight plate 231, a connecting inclined plate 232, and a connecting horizontal plate 233. The outer wall of each inclined pipe segment 121 is connected with the connecting inclined plate 232, and the outer wall of each straight pipe segment 122 is connected with the connecting straight plate 231. The two ends of the connecting straight plate 231 are connected with the connecting inclined plate 232 and the connecting horizontal plate 233, respectively. The connecting straight plate 231, the connecting inclined plate 232, and the connecting horizontal plate 233 jointly enclose a third hole segment. The connecting plate segment 23 with the above structure can adapt to the shape of the branch pipe 12 and make full use of the space between the two branch pipes 12.

[0041] In the embodiment, the connecting straight plate 231 and the connecting inclined plate 232 are both two. The connecting horizontal plate 233 is connected between the two connecting straight plates 231.

[0042] As shown in Figure 1 The main plate segment 21, the inclined plate segment 221, and the straight plate segment 222 are all rectangular structures, and the first hole segment 211, the fourth hole segment 2211, and the fifth hole segment 2221 are all rectangular holes. The above structure has the advantages of simple structure and easy processing.

[0043] Among them, the included angle between the two adjacent main plate segments 21 is 90°, and the included angle between the two adjacent secondary plate segments 22 is 90°. The above range of included angles has the advantages of simple structure and easy setting.

[0044] As shown in Figure 1 The diameter of the main pipe 11 is equal to the diameter of the branch pipe 12, and the ratio between the width of the reinforcing plate and the diameter of the main pipe 11 is greater than or equal to 0.4 and less than or equal to 0.6. The above ratio range can increase the contact area with the concrete by using the reinforcing plate, and will not cause deformation on the outer side of the pipe body 10.

[0045] Among them, the ratio between the width of the reinforcing plate and the diameter of the main pipe 11 can be 0.4, 0.5, 0.6, and any value greater than or equal to 0.4 and less than or equal to 0.6.

[0046] It should be noted that the bifurcated pipe provided in the embodiment is symmetrical with the horizontal middle surface of the pipe body 10. The reinforcing plates above and below the pipe body 10 can increase the strength of the bifurcated pipe in the vertical direction, reduce the deformation of the bifurcated pipe in the vertical direction caused by the impact of unstable water flow in the pipeline, and further reduce the deformation of the joint between the bifurcated pipe and the concrete in the vertical direction through the constraint of the concrete on the bifurcated pipe. The reinforcing plates on both sides of the pipe body 10 can increase the strength of the bifurcated pipe in the horizontal direction, reduce the deformation of the bifurcated pipe in the horizontal direction caused by the impact of unstable water flow in the pipeline, and further reduce the deformation of the joint between the bifurcated pipe and the concrete in the horizontal direction through the constraint of the concrete on the bifurcated pipe. The connecting plate section 23 can further increase the strength of the bifurcated pipe, reduce the inward deformation of the bifurcated pipe caused by the impact of unstable water flow in the pipeline, and further reduce the deformation of the joint between the bifurcated pipe and the concrete through the constraint of the concrete on the bifurcated pipe.

[0047] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0048] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless otherwise specifically stated. It is to be understood that the drawings are not necessarily to scale as the dimensions of the parts shown are for the purpose of illustration and description only and not limiting of the scope of the application. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and apparatus should be considered as being within the scope of the application. In the examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation of the application. Thus, other examples of the exemplary embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the disclosure, and thus, once defined, do not need to be further discussed.

[0049] In the description of the application, it should be understood that the orientation words such as "front, back, upper, lower, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are generally based on the orientation or position relationship shown in the drawings, only for the convenience of describing the application and simplifying the description, without making the opposite statement, these orientation words do not indicate and imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the scope of protection of the application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0050] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used herein to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0051] In addition, it should be noted that the use of "first", "second" and the like to define parts only facilitates the differentiation of the corresponding parts, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as a limitation on the scope of protection of the application.

[0052] The above only describes the preferred embodiments of the application and is not intended to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the scope of protection of the application.

Claims

1. A reduced symmetry Y-pattern bifurcation for concrete joints for directing water flow into a hydroelectric generator set, characterized in that, The manifold comprises: a pipe body (10) comprising a main pipe (11) and a plurality of branch pipes (12) connected to the main pipe (11); a reinforcing plate set (20) comprising a plurality of reinforcing plates, the plurality of reinforcing plates being arranged at intervals along the circumference of the pipe body (10) on the outer circumferences of the main pipe (11) and the plurality of branch pipes (12), and each of the reinforcing plates being provided with reinforcing holes; the plurality of reinforcing plates comprising a plurality of main plate segments (21) arranged at intervals along the circumference of the main pipe (11) on the outer circumference of the main pipe (11) and a plurality of auxiliary plate segments (22) arranged at intervals along the circumference of the branch pipe (12) on the outer circumference of the branch pipe (12), and the reinforcing holes comprising first hole segments (211) provided on the main plate segments (21) and second hole segments provided on the auxiliary plate segments (22); the plurality of reinforcing plates further comprising a connecting plate segment (23) connected to the outer circumferences of two adjacent branch pipes (12), and the reinforcing holes comprising third hole segments (234) provided on the connecting plate segment (23); the branch pipe (12) comprising an inclined pipe segment (121) and a straight pipe segment (122), two ends of the inclined pipe segment (121) being connected to the main pipe (11) and the straight pipe segment (122) respectively, the auxiliary plate segment (22) comprising an inclined plate segment (221) and a straight plate segment (222), two ends of the inclined plate segment (221) being connected to the main plate segment (21) and the straight plate segment (222) respectively, the inclined plate segment (221) being connected to the outer circumference of the inclined pipe segment (121), the straight plate segment (222) being connected to the outer circumference of the straight pipe segment (122), the second hole segments comprising fourth hole segments (2211) provided on the inclined plate segment (221) and fifth hole segments (2221) provided on the straight plate segment (222), and the connecting plate segment (23) being connected to the outer walls of the inclined pipe segment (121) and the straight pipe segment (122); the connecting plate segment (23) comprising a connecting straight plate (231), a connecting inclined plate (232), and a connecting horizontal plate (233), the outer wall of each inclined pipe segment (121) being connected to the connecting inclined plate (232), the outer wall of each straight pipe segment (122) being connected to the connecting straight plate (231), two ends of the connecting straight plate (231) being connected to the connecting inclined plate (232) and the connecting horizontal plate (233) respectively, and the connecting straight plate (231), the connecting inclined plate (232), and the connecting horizontal plate (233) together forming the third hole segments.

2. The manifold according to claim 1, wherein: a ratio between the length of the first hole segment (211) and the length of the main plate segment (21) is greater than or equal to 0.6 and less than or equal to 0.7; a ratio between the length of the fourth hole segment (2211) and the length of the inclined plate segment (221) is greater than or equal to 0.5 and less than or equal to 0.

6. A ratio between a length of the fifth hole section (2221) and a length of the straight plate section (222) is greater than or equal to 0.55 and less than or equal to 0.

65.

3. The manifold of claim 1 wherein, The inclined pipe sections (121) and the straight pipe sections (122) are both two, the end portions of the two inclined pipe sections (121) are connected with the main pipe (11), and the inclined plate sections (221) and the straight plate sections (222) are both four, the four inclined plate sections (221) are connected with the corresponding main plate sections (21) respectively.

4. The manifold of claim 1 wherein, The main plate sections (21), the inclined plate sections (221) and the straight plate sections (222) are all rectangular structures; and / or, the first hole sections (211), the fourth hole sections (2211) and the fifth hole sections (2221) are all rectangular holes.

5. The manifold of claim 1 wherein, An included angle between two adjacent main plate sections (21) is 90°; and / or, an included angle between two adjacent auxiliary plate sections (22) is 90°.

6. The manifold of claim 1 wherein, The diameter of the main pipe (11) is equal to the diameter of the branch pipe (12), and a ratio between the width of the reinforcing plate and the diameter of the main pipe (11) is greater than or equal to 0.4 and less than or equal to 0.6.

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