Rainwater drainage system and building

Abstract

To provide a rainwater drainage system in which vibration caused by drainage is suppressed when draining water by using a siphon phenomenon.SOLUTION: A rainwater drainage system has: a siphon induction part 11; a vertical pipe 57 constituted on a downstream side of the siphon induction part 11; a horizontal pipe 58 connected to the vertical pipe 57; and a joint 14 connecting the vertical pipe 57 and the horizontal pipe 58, wherein an expansion pipe 160 is connected to the joint 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to stormwater drainage systems and buildings. [Background technology]

[0002] BACKGROUND ART A rain gutter system (rainwater drainage system) described in Patent Document 1 below has been known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-007220 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional rainwater drainage system, when draining rainwater using the siphon effect, there is a risk that the vibrations caused by the drainage may damage the pipes, and the vibration noise may cause discomfort to people inside the building.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a rainwater drainage system in which vibrations caused by drainage are suppressed when draining using the siphon effect. [Means for solving the problem]

[0006] A stormwater drainage system according to one aspect of the present invention comprises a siphon induction section, a vertical pipe configured downstream of the siphon induction section, a horizontal pipe connected to the vertical pipe, and a joint connecting the vertical pipe and the horizontal pipe, and an expansion pipe is connected to the joint. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a rainwater drainage system in which vibrations caused by drainage are suppressed when draining water using the siphon effect. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic perspective view showing a stormwater drainage system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a drain provided in the storm water drainage system of FIG. [Figure 3] 2 is a half cross-sectional view showing an example of an expansion pipe provided in the stormwater drainage system of FIG. 1. [Figure 4] FIG. 2 is a schematic diagram showing an example of a support form in the stormwater drainage system of FIG. 1. [Figure 5] 2A and 2B are schematic diagrams showing an example of a modified form of the stormwater drainage system of FIG. 1, in which (a) shows the state before deformation and (b) shows the state after deformation. [Figure 6] FIG. 6 is a cross-sectional view showing a finned joint of a stormwater drainage system according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a perspective view showing a finned joint of a stormwater drainage system according to a third embodiment of the present invention. [Figure 8] FIG. 10 is a perspective view showing a cross section of a finned joint of a stormwater drainage system according to a fourth embodiment of the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing an example of joining an expansion pipe of a stormwater drainage system according to a fifth embodiment of the present invention to a drainage pipeline by an electric fusion joint. [Figure 10] FIG. 10 is a side view showing an example of joining an expansion pipe of a stormwater drainage system according to a sixth embodiment of the present invention to a drainage pipeline with a flange. [Figure 11] FIG. 13 is a side view showing an example of joining an expansion pipe of a stormwater drainage system according to a seventh embodiment of the present invention to a drainage pipeline using a joining member. [Figure 12] 12 is a side view of the joining member of FIG. 11 cut along the line AA. FIG. [Figure 13] FIG. 13 is a side view showing an example of joining an expansion pipe of a stormwater drainage system according to an eighth embodiment of the present invention to a drainage pipeline using a joining member. [Figure 14]FIG. 13 is a side view showing an example of joining an expansion pipe of a stormwater drainage system according to a ninth embodiment of the present invention to a drainage pipeline using a mechanical joint member. [Figure 15] FIG. 2 is a cross-sectional view showing an example of an elbow pipe provided in the stormwater drainage system of FIG. [Figure 16] FIG. 2 is a cross-sectional view showing an example of an elbow pipe provided in the stormwater drainage system of FIG. [Figure 17] 2 is a bottom view showing an example of an elbow pipe provided in the storm water drainage system of FIG. 1. FIG. [Figure 18] FIG. 2 is a cross-sectional view showing an example of an elbow pipe provided in the stormwater drainage system of FIG. [Figure 19] FIG. 2 is a schematic diagram showing an example of an expansion pipe in the stormwater drainage system of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) Hereinafter, a stormwater drainage system according to a first embodiment of the present invention will be described with reference to FIGS. The stormwater drainage system 1 of this embodiment is installed in a building 100 as shown in FIG.

[0010] The stormwater drainage system 1 moves rainwater that falls on the roof 105 of the building 100 to near the ground and drains it into a sewer pipe. The building 100 may have one stormwater drainage system 1 or two or more stormwater drainage systems 1. When two stormwater drainage systems 1 are provided, the two stormwater drainage systems 1 may be arranged near opposite sides of the building 100.

[0011] The stormwater drainage system 1 includes a drainage pipe 10, a drain (siphon inducer) (first joint) 11, and a pipe support part 12. The drainage pipeline 10 is a pipeline that drains rainwater. The drainage pipeline 10 drains rainwater from each of a plurality of inlets 51 provided on the rooftop 105. The inlets 51 of the drainage pipeline 10 are arranged on the rooftop 105, and rainwater that has fallen on the rooftop 105 flows into the drainage pipeline 10. In the first embodiment, an example in which a plurality of inlets 51 are provided will be described, but only one inlet 51 may be provided.

[0012] The drainage pipeline 10 comprises a plurality of pipes 13 and a plurality of joints 14. The pipes 13 are straight pipes. The joints 14 connect the plurality of pipes 13 (for example, two pipes 13 or three pipes 13). The joints 14 are, for example, elbows or tee joints. The direction of the drainage water flow changes between the upstream and downstream sides of the joints 14.

[0013] As shown in FIG. 15, a protruding member 230 may be provided on the pipe 13 around the joint 14 (e.g., an elbow), or may be provided downstream of the joint 14. The protruding member 230 can reduce the cross-sectional area and flow resistance of the flow path of the joint 14 and the pipe 13. The protruding member 230 is provided on the pipe 13. It is preferable that the protruding member 230 is provided on the spigot of the pipe 13 that is inserted into the socket of the joint 14. The protruding member 230 may be installed on either a horizontal pipe or a vertical pipe (horizontal piping section or vertical piping section), and may be provided downstream of the elbow return, which will be described later. Furthermore, multiple protruding members 230 may be provided. The protruding member 230 of the tube 13 may have a length in the range of 0.1L≦L1≦0.5L, where L is the distance between the first end (upper end) and the second end (lower end) in the direction of the central axis of the tube 13, and L1 is the distance between the first end (upper end) and the apex 230a of the protruding member 230 in the direction of the central axis of the tube 13. Furthermore, where L2 is the distance between the apex 230a of the protruding member 230 and the second end (lower end) in the direction of the central axis of the tube 13, it is preferable that L2 > L1. Here, the apex 230a of the protruding member 230 may be the portion of the protruding member 230 that protrudes closest to the central axis of the tube 13. 15 may be integrally formed, and there are no limitations on the materials of the joint 14, pipe 13, and protrusion member 230. For example, the joint 14, pipe 13, and protrusion member 230 may be integrally formed by injection molding or blow molding. In addition, for example, the tube 13 and the protrusion member 230 may be formed integrally, and the tube 13 and the protrusion member 230 formed integrally may be connected to the fitting 14 by adhesive bonding, joining, fusion, etc.

[0014] The rainwater drainage system 1 includes the protruding member 230, which allows rainwater to flow along the inner surface of the joint 14 (elbow) due to the Coanda effect, allowing the rainwater to flow smoothly down. In addition, as the rainwater flows along the inner surface of the joint 14, it may take in surrounding rainwater, making the flow stronger, allowing the rainwater to flow down more smoothly.

[0015] In the stormwater drainage system 1, when drainage water from another pipe (for example, a branch pipe) is joined to the pipe 13 provided with the protruding member 230, it is preferable that the joining be made at a position that is 3 m or more downstream from the protruding member 230 installed on the pipe 13. In the case of the above positional relationship, the drainage water joining from the other pipe is less likely to obstruct the flow of rainwater flowing in the pipe 13, and the rainwater can flow down smoothly.

[0016] 16 and 17, the pipe 13 and the joint 14 may be made of PVC or a fire-resistant double-walled pipe. In this case, another joint 231 (for example, a double-ended socket) provided downstream of the pipe 13 may also be made of PVC. In the case of the PVC pipe 13 and joints 14, 231, the respective components may be joined by, for example, adhesive bonding.

[0017] As shown in Fig. 18, when pipe 13 is made of an olefin-based resin (for example, a polyethylene pipe (PE pipe)), the joint may be an electrofusion joint, as shown in Fig. 18. For example, the elbow (joint) on the upstream side of pipe 13 may be an electrofusion elbow 314, and the socket (joint) on the downstream side may be an electrofusion socket 313. Each of electrofusion elbow 314 and electrofusion socket 313 is provided with a terminal 300 for electrofusion. The position of terminal 300 is not limited to the position shown in Fig. 18. For example, in the pipe 13 of Figure 18, the terminals 300 may all be formed on the right side of the page, all on the left side of the page, all on the front side of the page, or all on the rear side of the page. When installing in a small space, installing the terminals 300 on the same side makes installation easier. Also, the pipe 13 equipped with the terminals 300 can be prevented from interfering with buildings or other pipes, improving installation efficiency. Furthermore, the pipe 13 may be joined to the joint 14 (elbow) by butt welding, or may be joined to the joint 14 by a mechanical joint. When the pipe 13 is a metal pipe, it may also be joined by a mechanical joint.

[0018] Pipe 13 includes, in this order from upstream to downstream, a plurality of vertical pipe sections 52, one or more horizontal pipe sections 53, a vertical pipe section 54, a horizontal pipe section 55, and a vertical pipe section 56. Vertical pipe sections 52, 54, and 56 are vertical pipes 57 extending up and down (vertically). Horizontal pipe sections 53 and 55 are horizontal pipes 58 extending horizontally.

[0019] Furthermore, the drainage pipeline 10 has vertical piping section 52, horizontal piping section 53, vertical piping section 54, horizontal piping section 55, and vertical piping section 56 arranged indoors. In the first embodiment, an example is described in which vertical piping section 52, horizontal piping section 53, vertical piping section 54, horizontal piping section 55, and vertical piping section 56 are arranged indoors, but they may also be arranged outdoors. Also, for example, horizontal piping section 55 and vertical piping section 56 may not be present.

[0020] The vertical pipe sections 52 are arranged downward from each of the multiple inlets 51. The vertical pipe sections 52 are arranged along a substantially vertical direction (which can also be referred to as an up-down direction). The upper end of the vertical pipe section 52 is connected to, for example, the inlet 51. The lower end of the vertical pipe section 52 is connected to the horizontal pipe section 53. The lower end of the vertical pipe section 52 is located in a pipe space. The lower end of the vertical pipe section 52 is located above the panel (ceiling panel). The lower end of the vertical pipe section 52 is connected to the horizontal pipe section 53 via, for example, an elbow or a tee. Note that another horizontal pipe section having a different orientation from the horizontal pipe section 53 may be further arranged between the vertical pipe section 52 and the horizontal pipe section 53. In this case, the position of the drain (first joint) 11 (vertical pipe section 52) and the horizontal pipe section 53 can be adjusted by the other horizontal pipe section.

[0021] The horizontal piping section 53 is arranged in the horizontal direction and is connected to the lower ends of each of the multiple vertical piping sections 52. The horizontal piping section 53 is located in a pipe space. The horizontal piping section 53 is connected to the upper end of the vertical piping section 54, which will be described later. The horizontal piping section 53 is arranged so that the end on the vertical piping section 54 side is horizontal with or lower than the opposite end.

[0022] In this embodiment, the horizontal piping section 53 is made up of a plurality of horizontal pipes 58. The horizontal piping section 53 includes a first horizontal pipe 53a and a second horizontal pipe 53b. The upstream end of the first horizontal pipe 53a is connected to the downstream end of the vertical piping section 52. The downstream end of the second horizontal pipe 53b is connected to the upstream end of the vertical piping section 54. The downstream end of the first horizontal pipe 53a is connected to the second horizontal pipe 53b. The first horizontal pipe 53a and the second horizontal pipe 53b extend in different directions.

[0023] The vertical pipe section 54 is arranged in the vertical direction. The upper end of the vertical pipe section 54 is connected to the horizontal pipe section 53. The vertical pipe section 54 may be offset at an intermediate floor and include a horizontal section, as in the example shown. The horizontal pipe section 55 is the horizontal section. The vertical pipe section 56 is offset from the vertical pipe section 54. The vertical pipe section 56 discharges wastewater from the horizontal pipe section 55 downward. Rainwater that passes through the vertical pipe section 56 is discharged outside the building 100 by a drainage section not shown. The rainwater discharged outside the building 100 is discharged into a sewer pipe via a rainwater manhole not shown. A rainwater storage tank not shown may be connected to the drainage section.

[0024] The joint 14 includes a first joint 61, a second joint 62, a third joint 63, a fourth joint 64, and a fifth joint 65. The first joint 61 connects the plurality of vertical pipe sections 52 to the first horizontal pipe 53a. The second joint 62 connects the first horizontal pipe 53a to the second horizontal pipe 53b. The third joint 63 connects the second horizontal pipe 53b to the vertical pipe section 54. The fourth joint 64 connects the vertical pipe section 54 to the horizontal pipe section 55. The fifth joint 65 connects the horizontal pipe section 55 to the vertical pipe section 56.

[0025] The drainage pipe 10 is made of a polyolefin resin, such as polyethylene or polypropylene. The polyolefin resin is not particularly limited. Examples thereof include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer. From the viewpoint of improving the strength of the molded article and the elongation percentage of the molded article at high temperatures, polyethylene or polypropylene is preferred, and polyethylene is more preferred.

[0026] Furthermore, examples of polyethylene (PE) include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE). Examples of polypropylene (PP) include homo-PP, block PP, and random PP. Examples of polybutene include polybutene-1. The ethylene-α-olefin copolymer is preferably a copolymer in which ethylene is copolymerized with an α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, or 1-octene at a ratio of about several mol %. These polyolefin resins may be used alone or in combination of two or more. The polyolefin resin may contain glass fiber, and may be a multi-layer pipe.

[0027] However, the drainage pipeline 10 is not limited to being made of polyolefin resin. The drainage pipeline 10 may be made of, for example, rigid polyvinyl chloride resin. For example, the drainage pipeline 10 may be a fire-resistant double-layer pipe in which an inner pipe of rigid polyvinyl chloride is covered with an outer pipe of fiber mortar. Furthermore, for example, the drainage pipeline 10 may be made of metal (for example, SGP (carbon steel pipe for piping) or SUS (stainless steel)).

[0028] In particular, when the drainage pipeline 10 is a double-walled fireproof pipe, a space is provided between the outer surface of the inner pipe, which is made of rigid polyvinyl chloride, and the inner surface of the outer pipe, which is made of fiber mortar. Therefore, when the inner pipe vibrates violently due to rainwater drainage using the siphon effect, the inner pipe and the outer pipe may come into contact, generating noise or causing damage to either the inner pipe or the outer pipe. However, by using the expansion pipe 160 described below, noise and damage to the double-walled fireproof pipe can be prevented. To prevent contact between the inner and outer pipes, a sheet or ring-shaped spacer may be provided between the outer surface of the inner pipe made of hard vinyl chloride and the inner surface of the outer pipe made of fiber mortar, or the space between the inner and outer pipes may be filled with the spacer. Examples of the material for the spacer include any one of the following (1) to (4), or a combination of two or more of (1) to (4). (1) Elastic materials such as synthetic rubber and acrylic rubber (2) Synthetic resins such as polyethylene and polypropylene (3) Foamed plastics such as polystyrene, polypropylene, polyethylene, polyurethane, etc., and porous synthetic resins (4) Inorganic or organic fiber materials such as glass wool, rock wool, polyester felt, and paper.

[0029] There are no particular limitations on the SDR value of the drainage pipeline 10. The SDR value is the ratio of the outer diameter D to the wall thickness T, and SDR value=outer diameter D / wall thickness T. The outer diameter of the drainage pipeline 10 may be, for example, 60.0 mm to 216.0 mm. In particular, the outer diameter of the drainage pipeline 10 is preferably, for example, 76.0 mm to 216.0 mm, especially in the downstream region where the flow rate is high. Furthermore, the drainage pipelines 10 in the vertical piping section 52, the horizontal piping section 53, and the vertical piping section 54 may have the same inner diameter, or may have different inner diameters. For example, the inner diameter of the drainage pipeline 10 may be smaller or larger from the upstream side to the downstream side in the drainage direction. For example, in the vertical piping section 54, the inner diameter of the drainage pipeline 10 may be smaller from the upstream side to the downstream side in the drainage direction. Furthermore, for example, in the horizontal piping section 53, the inner diameter of the drainage pipeline 10 may be larger from the upstream side to the downstream side in the drainage direction.

[0030] The drainage pipe 10 may be wrapped in a heat insulating material (such as glass wool or rock wool) or sound insulating material. These heat insulating and sound insulating materials prevent people inside the building 100 from hearing the drainage noise when the pipe is in use.

[0031] In this embodiment, a part of the drainage pipeline 10 is an expandable pipe 160. The expandable pipe 160 is more expandable than the part of the drainage pipeline 10 other than the expandable pipe 160. In this embodiment, the part of the drainage pipeline 10 around the joint 14 is the expandable pipe 160. The expandable pipe 160 may be the pipe 13 or the joint 14.

[0032] When the expansion pipe 160 is the pipe 13, it is preferable that the expansion pipe 160 is connected to the joint 14. Here, the expansion pipe 160 being connected to the joint 14 may mean, for example, that the expansion pipe 160 and the joint 14 are fixed in a butt-together state, or that the expansion pipe 160 and the joint 14 are fixed in a state in which a spigot provided on one of the expansion pipe 160 and the joint 14 is inserted into a socket provided on the other. The expansion pipe 160 may be configured on the upstream side of the joint 14, or may be configured on the downstream side of the joint 14. The expansion pipe 160 may be provided only on the upstream side or the downstream side of the joint 14, or may be provided on both sides of the joint 14. Here, the expansion pipe 160 may be at least one of the vertical piping section 52, the horizontal piping section 53, the vertical piping section 54, the horizontal piping section 55, and the vertical piping section 56. The expansion pipe 160 may be a part of any one of the vertical piping section 52, the horizontal piping section 53, the vertical piping section 54, the horizontal piping section 55, and the vertical piping section 56, or may be the entirety of any one of the vertical piping section 52, the horizontal piping section 53, the vertical piping section 54, the horizontal piping section 55, and the vertical piping section 56. The joint 14 to which the expansion pipe 160 is connected may be any one of the first joint 61, the second joint 62, the third joint 63, the fourth joint 64, and the fifth joint 65.

[0033] When the expansion pipe 160 is the joint 14, the expansion pipe 160 may be at least one of the first joint 61, the second joint 62, the third joint 63, the fourth joint 64, and the fifth joint 65. The expansion pipe 160 may be a part of any one of the first joint 61, the second joint 62, the third joint 63, the fourth joint 64, and the fifth joint 65. The expansion pipe 160 may be the entirety of any one of the first joint 61, the second joint 62, the third joint 63, the fourth joint 64, and the fifth joint 65.

[0034] As shown in FIG. 3, the inner surface of the telescopic tube 160 is preferably smooth. In the illustrated example, the telescopic tube 160 is a double tube. The telescopic tube 160 includes an outer tube 161 and an inner tube 162. The outer tube 161 is a bellows tube. The outer tube 161 expands and contracts, for example, by changing the shape of the bellows. The inner tube 162 is a straight tube. The inner tube 162 expands and contracts, for example, by changing the wall thickness. When the telescopic tube 160 is a double tube, the inner surface of the telescopic tube 160 being flat may mean that the inner circumferential surface of the inner tube 162 is smoother than the inner circumferential surface of the outer tube 161 in the tube axial direction, or that the difference in inner diameter of the inner tube 162 is smaller than the difference in inner diameter of the outer tube 161.

[0035] When the inner surface of the telescopic pipe 160 is smooth, the volume of the telescopic pipe 160 can be reduced and turbulence can be prevented from occurring inside the telescopic pipe 160, compared to when the inner surface of the telescopic pipe 160 is bellows, for example. Therefore, the siphon effect can be easily maintained inside the telescopic pipe 160. There are no limitations on the material of the telescopic tube 160. For example, the telescopic tube 160 may be made of resin, metal, rubber, etc. When the telescopic tube 160 is a double tube, the inner tube may be made of, for example, rubber, resin, etc.

[0036] As shown in Figures 1 and 2, a drain (first joint) 11 is provided at an inlet 51 at the upstream end of a drainage pipe 10. The drain 11 is provided on the roof 105 of a building 100. The drain 11 drains, for example, water (e.g., rainwater) from the roof. The drain 11 is arranged on a roof slab S. A through hole S1 is provided in the roof slab S. The through hole S1 passes through the roof slab S in the vertical direction. The drain 11 is arranged on the through hole S1. A pipe space is provided below the roof slab S. The pipe space is covered from below, for example, by a panel (ceiling panel) or the like.

[0037] The drain 11 is capable of inducing a siphoning effect. The drain 11 includes a base plate 14A, a tube 15, a lid 16, and a rib 17. The base plate 14A is annular. The base plate 14A is arranged coaxially with the through-hole S1. The tube 15 extends downward from the inner peripheral edge of the base plate 14A. The lid 16 covers the inner peripheral edge of the base plate 14A and the tube 15 from above. The rib 17 extends upward from the base plate 14A. The rib 17 connects the base plate 14A and the lid 16. A plurality of ribs 17 are arranged at intervals around the circumferential direction of the base plate 14A. An opening 18 is provided between adjacent ribs 17 in the circumferential direction. In the illustrated example, the lid 16 and the rib 17 are integrally molded. The lid 16 and the rib 17 form an air baffle.

[0038] Rainwater on the roof is rectified by the ribs 17 as it passes through the opening 18. As a result, air is less likely to be mixed into the water flowing into the drain 11. At this time, for example, if the water level on the roof 105 is below the height of the lid 16, air is even less likely to be mixed into the water flowing into the drain 11. As a result, the siphoning phenomenon is more likely to occur in the rainwater drainage system 1. The water that has passed through the opening 18 further passes through a downspout provided in the upper end of the tube 15 and flows downward.

[0039] Note that either the lid 16 or the rib 17 may be omitted. Even in this case, the drain 11 can induce the siphoning phenomenon. The drain 11 may be capable of inducing the siphoning phenomenon only by the lid 16, or only by the rib 17. Furthermore, both the lid 16 and the rib 17 may be omitted. The drain 11 does not have to be capable of inducing the siphoning phenomenon. Furthermore, the configuration of the drain 11 is not limited to the above configuration. For example, another member such as a clamp ring may be present between the base plate 14A and the air baffle. The clamp ring may function, for example, as a waterproof layer holder. Furthermore, the lid 16 may cover the entire tube 15 (drop opening), or the lid 16 may cover only a portion of the tube 15 from above. Furthermore, the rib 17 does not have to connect the base plate 14A and the lid 16. For example, the rib 17 may be molded integrally with the lid 16, and the rib 17 may simply be placed on the base plate 14A, with the lid 16 and the base plate 14A being connected with bolts or the like. In this way, the base plate 14A, the lid 16, and the rib 17 are separate parts, which makes it easier to waterproof the rooftop, even in the case of indoor piping, for example. Furthermore, since the rib 17 is molded integrally with the lid 16, there is no need to connect the lid 16 and the rib 17 during construction; it can simply be placed on the base plate 14A, which improves construction ease. In the illustrated example, the radially inner ends of circumferentially adjacent ribs 17 are connected to each other. However, the ends do not have to be connected to each other. For example, of the multiple ribs 17, circumferentially adjacent ribs 17 do not have to be connected to each other.

[0040] In the first embodiment, an example will be described in which a drain 11 is provided at the inlet 51 as the siphon induction part, but the siphon induction part is not limited to the drain 11 shown in this embodiment. Any drain that is installed at the inlet 51 can be used as the siphon induction part, regardless of whether it has an effect or function such as ease of inducing a siphon phenomenon.

[0041] As shown in Fig. 4, the pipe support part 12 supports the drainage pipe 10. The pipe support part 12 includes a first support part 12a and a second support part 12b. The outline arrow F shown in Fig. 4 (and Fig. 5) indicates the direction of the drainage flow.

[0042] The first support portion 12a supports, for example, the drainage pipeline 10 in a suspended manner. The first support portion 12a includes, for example, a suspension bolt (not shown) and a suspension band (not shown). The suspension bolt is suspended, for example, from a roof slab S or a floor slab (slab, etc.). The suspension band is fixed, for example, to the lower end of the suspension bolt. The suspension band is wrapped around the drainage pipeline 10. Note that the first support portion 12a may be provided with vibration-damping rubber. The vibration-damping rubber may be provided, for example, on the suspension bolt. In this case, the suspension bolt may be separated into two parts, an upper part and an lower part, and the vibration-damping rubber may be placed between these two bolts (cut bolts). The vibration-damping rubber may be integrated, for example, into the suspension band.

[0043] The second support portion 12b has a stronger support force for the drainage pipeline 10 than the first support portion 12a. The second support portion 12b supports the drainage pipeline 10, for example, by preventing vibration. The second support portion 12b includes, for example, a shaped steel. Examples of the shaped steel include an L-shaped angle bar. The second support portion 12b may include a plurality of shaped steels. The second support portion 12b may include, for example, a first shaped steel and a second shaped steel. In this case, the plurality of first shaped steels may be suspended from, for example, the slab S. The second shaped steel may connect the lower ends of the plurality of first shaped steels together, for example. The second shaped steel may support the drainage pipeline 10 from below, for example. The drainage pipeline 10 may be fixed to the second shaped steel by a band, for example.

[0044] The first support portions 12a and the second support portions 12b may be arranged alternately in the pipeline direction of the drainage pipeline 10. However, the first support portions 12a and the second support portions 12b may also be arranged consecutively in the pipeline direction. The drainage pipeline 10 may be supported within 0.5 m from the end of the expandable pipe 160. In other words, the pipeline support part 12 may be provided within 0.5 m from the end of the expandable pipe 160. This, for example, prevents the expandable pipe 160 from deforming due to its own weight. As a result, for example, it is possible to prevent the expansion pipe 160 from deforming to cause an unexpected reverse gradient.

[0045] In this embodiment, when the joint 14 connects the upright pipe 57 and the horizontal pipe 58, for example, the flow of drainage water changes, and large vibrations tend to occur around the joint 14. Similarly, when the joint 14 connects the first horizontal pipe 53a and the second horizontal pipe 53b, large vibrations tend to occur around the joint 14. This type of vibration becomes significantly larger when the siphoning phenomenon is induced by the drain 11 (siphon inducer). Therefore, for example, when an expansion pipe 160 is connected to the joint 14 or when the joint 14 is the expansion pipe 160, if large vibrations such as those described above occur, the vibrations can be absorbed and suppressed by the expansion and contraction of the expansion pipe 160, as shown in Figures 5(a) and (b).

[0046] Next, rainwater drainage systems according to second to eighth embodiments will be described with reference to Figures 6 to 13. In the rainwater drainage systems according to second to eighth embodiments, the same or similar components as those in the rainwater drainage system 1 according to the first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0047] First, second to fourth embodiments of the drain (i.e., siphon inducer) 11 in the first embodiment will be described with reference to Figures 6 to 8. The siphon inducer in the second to fourth embodiments is provided upstream of the expandable pipe 160 in the drainage pipeline 10. For convenience, an example in which the siphon inducer in the second to fourth embodiments is joined between the first drainage pipeline 10A and the second drainage pipeline 10B in the drainage pipeline 10 will be described below.

[0048] (Second embodiment) As shown in Figure 6, the rainwater drainage system 1C of the second embodiment includes a finned joint (siphon inducer, second joint) 11A instead of the drain 11 of the first embodiment. The finned joint 11A is a reducer provided in the drainage pipeline 10. The finned joint 11A has a joint body 120 and a plurality of fins 121. The joint body 120 is a cylindrical pipe having a central axis along the vertical direction, and has an inlet-side joint 124 formed at the upper end, an outlet-side joint 125 formed at the lower end, and a straight pipe section 123 formed therebetween.

[0049] The inlet-side fitting 124 has a ring shape and is fixed by being fitted coaxially onto the lower end of the first drainage pipeline 10 A. The inner peripheral surface of the inlet-side fitting 124 is slightly larger than the outer diameter of the lower end of the first drainage pipeline 10 A, and is watertightly connected to the lower end of the first drainage pipeline 10 A via a sealing material (not shown). The outlet-side fitting 125 also has a ring shape and is fixed by being fitted coaxially to the upper end of the second drainage pipe 10B. The inner peripheral surface of the outlet-side fitting 125 is slightly larger than the outer diameter of the upper end of the second drainage pipe 10B, and is watertightly connected to the upper end of the second drainage pipe 10B via a sealing material (not shown). Although the second embodiment illustrates an example of an external fitting, it is not limited to an external fitting, and an internal fitting may also be used. If an internal fitting is used, the outer diameter at this connection position can be designed to have an external shape that does not change in the pipe axis direction (no steps), thereby resulting in a stormwater drainage system 1C with excellent aesthetics. The fact that an internal fitting may be used also applies to each of the embodiments and modified examples described below.

[0050] The straight pipe section 123 is a cylindrical pipe located between the inlet-side joint 124 and the outlet-side joint 125 and coaxial with the inlet-side joint 124 and the outlet-side joint 125. The outer diameters of the first drainage pipe 10A, the finned joint 11A, and the second drainage pipe 10B may be the same. In this case, the external appearance is unified, resulting in an aesthetically pleasing stormwater drainage system 1C. The inner diameter of the straight pipe section 123 may also be the same as the inner diameters of the first drainage pipe 10A and the second drainage pipe 10B. The inner diameter of the straight pipe section 123 may also be the same as the inner diameters of the first drainage pipe 10A and the second drainage pipe 10B. The outer diameter of the straight pipe section 123 may also be the same as the outer diameters of the first drainage pipe 10A and the second drainage pipe 10B. Therefore, the flow paths extending vertically through the first drainage pipeline 10A, the finned joint 11A, and the second drainage pipeline 10B form cylindrical internal spaces with the same inner diameter at each vertical position, except for the portions where the fins 121 described below are arranged. In other words, the flow path from the first drainage pipeline 10A to the second drainage pipeline 10B via the finned joint 11A is connected smoothly without any steps at both the connection point between the first drainage pipeline 10A and the finned joint 11A and the connection point between the finned joint 11A and the second drainage pipeline 10B.

[0051] The fins 121 are a plurality of blades formed integrally with the inner wall surface 123a of the straight pipe portion 123 of the finned joint 11A. However, the fins 121 may be separate from the straight pipe portion 123. In the second embodiment, four fins 121 are arranged at equal angular intervals (90° intervals) in the circumferential direction around the central axis of the straight pipe portion 123. The number of fins 121 is not limited to four, and may be two, three, five or more, or even ten or more. Each fin 121 has the same shape and dimensions, and is also positioned in the same position along the pipe axis direction. That is, all of the fins 121 are isosceles triangles in longitudinal cross section or side view, and their bases are connected to the inner wall surface 123a of the straight pipe section 123 so as to be integral with each other. Therefore, each fin 121 is formed so as to protrude from the inner wall surface 123a toward the pipe axis (central axis). One of the equal sides of the isosceles triangle that forms these fins 121 is a straight upper side 121a, which is located on the upstream side (vertically upper side) of the flow path, and the other straight lower side 121b is located on the downstream side (vertically lower side) of the flow path. The upper side 121a and the lower side 121b are connected at a connection point 121c.

[0052] Each fin 121 is arranged so as to face another fin 121 at a circumferential position on the opposite side across the tube axis. In the present embodiment, as described above, four fins 121 are arranged at equal angular intervals when viewed along the tube axis, so two pairs of fins 121 are arranged, each pair facing each other across the tube axis. The upper edges 121a of each of these fins 121 form thin, inclined surfaces that protrude into the flow path. These inclined surfaces connect to inner wall surface 123a at the uppermost positions of the upper edges 121a, and the height at which they protrude from inner wall surface 123a gradually increases from this uppermost position toward the downstream side, until they reach their highest point at connection point 121c. The thin inclined surfaces formed by the upper edges 121a arranged in this manner face rainwater flowing down from the upstream side, and as this rainwater hits the inclined surfaces, they impart flow path resistance.

[0053] Each lower edge 121b of each fin 121 also forms a thin inclined surface that protrudes into the flow path. These inclined surfaces connect to inner wall surface 123a at the lowest end of lower edge 121b, and the protrusion height from inner wall surface 123a gradually increases from this lowest end position toward the upstream side, until it reaches its highest protrusion height from inner wall surface 123a at connection point 121c. In other words, the inclined surfaces formed on each upper edge 121a and the inclined surfaces formed on each lower edge 121b have the same shape and dimensions, but their inclination directions are opposite in the vertical direction, with connection point 121c as the boundary.

[0054] The left side surface 121d and the right side surface 121e of each fin 121 are flat surfaces with an isosceles triangle shape and are parallel to each other. Therefore, each fin 121 has a constant thickness from its upper end to its lower end. Because the left side surface 121d and the right side surface 121e extend into the flow path, rainwater passing through each fin 121 is subjected to viscous resistance due to contact with the left side surface 121d and the right side surface 121e. Therefore, rainwater is subjected to both resistance due to contact with the inclined surface formed by the upper side 121a and viscous resistance due to contact with the left side surface 121d and the right side surface 121e. Hereinafter, these two resistances may be collectively referred to as the flow path resistance of the fin 121.

[0055] A baffle 128 is provided at the inlet 51. The baffle 128 prevents debris and other contaminants from flowing into the first drainage pipe 10A. After debris and other contaminants have been removed by the baffle 128, the rainwater flows from the inlet 51 through the first drainage pipe 10A into the finned joint 11A.

[0056] Rainwater flowing into the finned joint 11A begins to encounter flow resistance when it hits each fin 121. This flow resistance creates a braking effect that slows the flow rate of the flowing rainwater. Meanwhile, downstream of the connection point 121c, the direction of the slope formed by the lower side 121b is opposite to that of the upper side 121a, and the protruding height from the inner wall surface 123a gradually decreases, preventing excessive flow resistance from being applied to the rainwater. Additionally, the left side 121d and right side 121e of each fin 121 can straighten the rainwater that attempts to pass through while swirling. Therefore, each fin 121 provides appropriate flow resistance to the rainwater, slowing its flow rate while simultaneously straightening the rainwater.

[0057] Finned joint 11A allows rainwater, whose flow rate has been reduced, to temporarily accumulate in the flow path between upper side 121a of each fin 121 and inlet 51. This makes it difficult for air to enter the rainwater flowing from baffle 128 into inlet 51, making it possible to reliably induce the siphon effect. Moreover, the rainwater after passing through each fin 121 is rectified by left side surface 121d and right side surface 121e, which prevents vortexes from occurring and allows the rainwater to be drained smoothly (without difficulty).

[0058] The length and shape of the fins 121 are not particularly limited. For example, the shape of the fins 121 is not limited to the isosceles triangle shape of the second embodiment, but may be, for example, a right-angled triangle shape or a trapezoid shape. Also, a throttled pipe section may be provided instead of the straight pipe section 123 of the finned joint (second joint) 11A, and fins may be provided on the throttled pipe section. Any known reducer may be used as long as the shape of the fins 121 is such that drained rainwater induces a pressure loss.

[0059] According to the rainwater drainage system 1C of the second embodiment described above, similarly to the first embodiment, high drainage performance can be maintained by the siphon effect, and further, maintenance of the drainage pipeline 10 can be easily performed.

[0060] (Third embodiment) 7, the rainwater drainage system 1D of the third embodiment includes a finned joint (siphon inducer) (third joint) 11B instead of the finned joint 11A of the second embodiment. The finned joint 11B has a joint body 120, an inner pipe 131, and a plurality of fins 132. The inner pipe 131 is arranged coaxially inside the joint body 120. The inner pipe 131 is configured in an inverted truncated cone shape that tapers from the upstream side to the downstream side along the pipe axis. The inner pipe 131 has an inner wall surface 131a and an outer wall surface 131b that taper downward. A circular inlet opening is formed at the upper end of the inner pipe 131, and a circular outlet opening with a smaller diameter than the upper end is formed at the lower end of the inner pipe 131. The outer wall surface 131b of the inner pipe 131 is fixed by a pair of fins 132 in a state where it is spaced apart from the inner wall surface 123a of the straight pipe section 123.

[0061] As a result, two flow paths are formed within the finned joint 11B: a first flow path formed between the inner wall surface 123a and the outer wall surface 131b, and a second flow path formed within the inner wall surface 131a. Therefore, rainwater flowing into this finned joint 11B branches into two paths: one that flows through the first flow path and one that flows through the second flow path. Of these, the rainwater flowing through the first flow path slows down due to flow path resistance caused by the reduced flow path area. Meanwhile, the rainwater flowing through the second flow path slows down due to flow path resistance caused by hitting the pair of fins 132.

[0062] Furthermore, the fins 132 straighten the rainwater, suppress the generation of vortexes, and allow the rainwater to be drained smoothly. Therefore, the finned joint 11B can impart appropriate flow resistance to the rainwater to reduce the flow rate, while also straightening the rainwater at the same time.

[0063] As a result, according to the configuration of finned joint 11B, rainwater with its flow velocity reduced temporarily accumulates in the flow paths between the first flow path and the second flow path and the inlet 51. Therefore, air is less likely to enter the rainwater flowing into the inlet 51 from the baffle 128 (see FIG. 6), making it possible to reliably induce the siphon effect.

[0064] According to the rainwater drainage system 1D of the third embodiment described above, similar to the second embodiment, high drainage performance can be maintained by the siphon effect, and further, maintenance of the drainage pipeline 10 (see Figure 6) can be easily performed.

[0065] (Fourth embodiment) As shown in Fig. 8, a rainwater drainage system 1E of the fourth embodiment includes a finned joint (siphon inducer, fourth joint) 11C instead of the finned joint 11A of the second embodiment. The finned joint 11C has a joint body 140, a plurality of fins 141, and a finned ring 142. In the finned joint 11C, the joint body 140, the plurality of fins 141, and the finned ring 142 may be integrally formed or may be separate bodies. For example, the finned joint 11C may be formed by injection molding. The fitting body 140 has a straight pipe section 123 which is a cylindrical pipe having a pipe axis along the vertical direction, an inlet side joint section 124 formed integrally with the upper end of the straight pipe section 123, and an outlet side joint section 144 connected coaxially to the lower end of the straight pipe section 123.

[0066] A finned ring 142 having fins 141 on its inner circumferential surface is integrally connected to the outlet-side joint 144 via a connecting portion 144a. For example, the outlet-side joint 144 is not limited to the case where the finned ring 142 having fins 141 on its inner circumferential surface is integrally connected to the connecting portion 144a with an adhesive or the like, and the outlet-side joint 144 may be integrally formed by injection molding. The finned ring 142 has an upstream edge 142a located relatively upstream, a downstream edge 142b located relatively downstream, a contraction section 142c connecting the upstream edge 142a and the downstream edge 142b, and a plurality of fins 141 arranged at equal angular intervals circumferentially around the pipe axis on the inner surface of the contraction section 142c.

[0067] The upstream edge 142a and the downstream edge 142b are both annular flange portions with outer diameters close to the inner diameter of the inner circumferential surface of the straight pipe section 123. Therefore, the upstream edge 142a and the downstream edge 142b can contact the inner wall surface 123a of the straight pipe section 123 without any gaps. When viewed in a cross section including the pipe axis, the inner circumferential surface of the upstream edge 142a gradually becomes thicker from the upstream side to the downstream side. Therefore, although the upstream edge 142a is inserted into the straight pipe section 123, it does not create an excessively large step with respect to the inner wall surface 123a, allowing rainwater passing through it to pass smoothly without disruption. The downstream edge 142b is smoothly connected to the upper end of the connecting portion 144a without creating an excessively large step. Therefore, the downstream edge 142b allows the flow of rainwater passing through it to pass smoothly without being disturbed. In addition, the downstream edge 142b forms an annular gap with the inner peripheral surface of the outlet-side fitting portion 144, and the lower end of the straight pipe portion 123 is fitted watertight into this annular gap.

[0068] The contracted section 142c has an arch-like shape in a cross section including the tube axis, with the upper half from the upstream side to the midpoint in the tube axis direction forming a contracted flow path, and the lower half from the midpoint toward the downstream side in the tube axis direction forming an expanded flow path. That is, in the upper half, the inner diameter of the circular opening as viewed along the tube axis gradually decreases from the upstream side to the downstream side, reaching a minimum inner diameter at the boundary with the lower half. Then, in the following lower half, the inner diameter of the circular opening as viewed along the tube axis gradually increases from the minimum inner diameter as viewed from the upstream side to the downstream side, and finally becomes equal to the inner diameter of the connecting section 144a at the boundary with the connecting section 144a.

[0069] Each fin 141 is a substantially linear protrusion having an upper end 141a located at the most upstream side in the tube axis direction and a lower end 141b located at the most downstream side in the tube axis direction. When viewed along the tube axis direction, the lower end 141b of each fin 141 is located at a position slightly shifted laterally from directly below the upper end 141a. Therefore, each fin 141 is arranged at an incline so that a line connecting these upper ends 141a and lower ends 141b intersects with the tube axis when superimposed. Furthermore, an inclined flow path is formed between adjacent fins 141 in a direction that intersects with the tube axis when superimposed.

[0070] When viewed in a cross section perpendicular to a line connecting the upper end 141a and the lower end 141b, each fin 141 has a substantially triangular cross-sectional shape at each position on the line. The height of this triangular cross-section gradually increases from the upper end 141a to the center of the line, and then gradually decreases from the center of the line to the lower end 141b. When these fins 141 are viewed face-to-face, the width gradually increases from the upper end 141a to the center of the line, and then gradually narrows from the center of the line to the lower end 141b. In other words, each fin 141 is thickest at the center in the tube axis direction and gradually becomes thinner from this center toward the upper end 141a. Similarly, each fin 141 gradually becomes thinner from the center toward the lower end 141b. Furthermore, when each fin 141 is viewed in a cross section that includes a straight line connecting the upper end 141a and the lower end 141b and is along the thickness direction of the wall of the contraction section 142c, it forms a convex arch shape that follows the inner surface of the contraction section 142c. Each fin 141 can apply a flow resistance to rainwater that gradually increases along the pipe axis direction.

[0071] Finned joint 11C allows rainwater, whose flow rate has been reduced, to temporarily accumulate in the flow path between the upper side of each fin 141 and inlet 51 (see FIG. 6). This makes it difficult for air to get into the rainwater flowing from baffle 128 (see FIG. 6) into inlet 51, making it possible to reliably induce the siphon effect. Moreover, the rainwater is rectified after passing through each fin 141, preventing the occurrence of vortexes and allowing the rainwater to be drained smoothly (without turbulence). In addition, a finned ring 142 on which each fin 141 is formed is integrated with the outlet-side fitting portion 144, and a socket-type structure is adopted in which it is coaxially fitted into the lower end of the straight pipe portion 123. This makes it easy to install and replace each fin 141, as well as to perform maintenance such as cleaning.

[0072] According to the rainwater drainage system 1E of the fourth embodiment described above, similar to the second embodiment, high drainage performance can be maintained by the siphon effect, and further, maintenance of the drainage pipeline 10 (see Figure 6) can be easily performed. In the second to fourth embodiments, the flow path cross-sectional area is reduced by the fins 121, 132, and 141, but instead, the flow path cross-sectional area may be reduced by reducing the inner diameter, for example, as in a so-called reducer.

[0073] Next, fifth to eighth embodiments will be described with reference to Figures 9 to 13 as examples of joining an expandable pipe 160 to the drainage pipeline 10 provided in the first embodiment. The expandable pipe 160 is joined between the first drainage pipeline 21 and the second drainage pipeline 22 (both see Figure 5) of the drainage pipeline 10. Below, in the fifth to eighth embodiments, examples of joining the expandable pipe 160 to the lower end of the first drainage pipeline 21 will be described.

[0074] (Fifth embodiment) As shown in FIG. 9 , in the stormwater drainage system 1F of the fifth embodiment, an expansion pipe 160 is joined to a first drainage pipeline 21 by an electrofusion joint 165. The electrofusion joint 165 includes a main body 166, a heating wire 167, and a terminal 168. The main body 166 is a pipe (straight pipe) made of polyolefin resin. Ends of the first drainage pipeline 21 and the expansion pipe 160 are fitted into the main body 166. The heating wire 167 is embedded in the main body 166. The heating wire 167 forms a spiral in the circumferential direction of the main body 166. A voltage is applied to the heating wire 167 through the terminal 168. Two terminals 168 are provided on the main body 166. The two terminals 168 are connected to the positive and negative poles of a power supply (not shown). The power supply connected to the terminal 168 applies a voltage to the heating wire 167. The heating wire 167 generates heat, and the main body 166 melts together with the first drainage pipe 21 and the expansion pipe 160, thereby achieving electric fusion welding.

[0075] Here, as described above, the SDR value of the drainage pipe 10 of the stormwater drainage system 1F is greater than 23. Therefore, the wall thickness of the drainage pipe 10 is smaller than the outer diameter of the drainage pipe 10, and as a result, the inner diameter of the drainage pipe 10 is larger. This allows for improved drainage performance even with a drainage pipe 10 having a small outer diameter. As a result, for example, it is possible to reduce the piping space and increase the degree of freedom in design, etc. Also, for example, interference with piping other than the drainage pipe 10 indoors (for example, other drainage pipes (drainage pipes for domestic wastewater), piping for air conditioning, and piping for water supply) is less likely to occur.

[0076] In addition, a drain (first joint) 11 (see FIG. 2) capable of inducing a siphon phenomenon is provided upstream of the first drainage pipeline 21. This further improves the drainage capacity of the drainage pipeline 10, and even a drainage pipeline 10 with a small outer diameter can have a further improved drainage performance.

[0077] (Sixth embodiment) As shown in Fig. 10, in the rainwater drainage system 1G of the sixth embodiment, instead of the electrofusion joining using the electrofusion joint 165 of the fifth embodiment, an expansion pipe 160 is flange-joined to the first drainage pipeline 21. The first drainage pipeline 21 includes a first main pipe 35 and a first processed pipe 36. The expansion pipe 160 includes a second main pipe 171 and a second processed pipe 172. The main pipes 35, 171 are pipe materials whose inner and outer diameters are substantially the same over their entire lengths. The main pipes 35, 171 are so-called extrusion-molded products.

[0078] The processed pipes 36, 172 are butt-welded to the main pipes 35, 171. The beads 21a, 161a between the processed pipes 36, 172 and the main pipes 35, 171 are generated when the processed pipes 36, 172 and the main pipes 35, 171 are butt-welded. The processed pipes 36, 172 are so-called injection-molded products. In the processed pipes 36, 172, at least one of the inner diameter and the outer diameter is not uniform over substantially the entire length.

[0079] The processed pipes 36 and 172 are provided with flanges 174 and 175. The first processed pipe 36 is provided with a first flange 174 of the flanges 174 and 175. The second processed pipe 172 is provided with a second flange 175 of the flanges 174 and 175. Each flange 174 and 175 is integral with the first processed pipe 36 or the second processed pipe 172, for example. Instead of butt welding the main pipes 35, 171 and the processed pipes 36, 172, flanges 174, 175 may be directly post-processed onto the main pipes 35, 171.

[0080] However, the flanges 174, 175 may be separate from the first processed pipe 36 and the second processed pipe 172. The flanges 174, 175 may be movable vertically relative to the first processed pipe 36 and the second processed pipe 172. In other words, the flanges 174, 175 may be so-called loose flanges. For example, the first flange 174 may be a loose flange, and the second flange 175 may be a flange integral with the second processed pipe 172. The second flange 175 may be a loose flange, and the first flange 174 may be a flange integral with the first processed pipe 36. Both the first flange 174 and the second flange 175 may be loose flanges. Furthermore, the flanges 174, 175 may be coupling members including flanges independent of the first processed pipe 36 and the second processed pipe 172 (for example, flexible couplings for steel drainage pipes specified in the Japan Metal Joints Association standard "JPF MDJ-002").

[0081] Furthermore, the first drainage pipeline 21 and the expansion pipe 160 are flange-joined radially outward from the outer circumferential surfaces of the first drainage pipeline 21 and the expansion pipe 160. A bolt joint using flanges 174, 175 is employed for flange-joining the first drainage pipeline 21 and the expansion pipe 160. The bolt 177 and the nut 178 are arranged radially outward from the outer circumferential surfaces of the first drainage pipeline 21 and the expansion pipe 160. As a result, the first drainage pipeline 21 and the expansion pipe 160 are joined by the bolt 177 and the nut 178 radially outward from the outer circumferential surfaces of the first drainage pipeline 21 and the expansion pipe 160. The bolt 177 passes through the first flange 174 and the second flange 175 in the vertical direction. The head of the bolt 177 and the nut 178 sandwich the first flange 174 and the second flange 175 in the vertical direction. In this way, the first drainage pipeline 21 and the expansion pipe 160 are bolted together.

[0082] Here, the rainwater drainage system 1G includes a packing 179 (gasket). The first drainage pipeline 21 and the telescopic pipe 160 are provided with packing contact portions 21b, 161b. The packing contact portions 21b, 161b are portions with which the packing 179 comes into contact. The packing 179 seals the gap between the first drainage pipeline 21 and the telescopic pipe 160. The packing 179 may be an elastic material (e.g., rubber), or may not be an elastic material. The packing 179 is annular. The packing 179 is disposed, for example, between the first flange 174 and the second flange 175. The packing 179, together with the first flange 174 and the second flange 175, is sandwiched in the vertical direction by bolts 177 and nuts 178. The packing contact portions 21b, 161b are provided on the end faces of the first drainage pipeline 21 and the telescopic pipe 160. This makes it possible to improve the sealing performance at the joint between the first drainage pipeline 21 and the expansion pipe 160. This ensures watertightness of the expansion pipe 160 relative to the first drainage pipeline 21. This ensures that the siphon phenomenon caused by the drain (first joint) 11 (see FIG. 2) can be induced.

[0083] In the sixth embodiment, processed pipes 36, 172 are provided at the ends of the first drainage pipeline 21 and the expansion pipe 160, but the processed pipes 36, 172 may not be required. For example, flanges 174, 175 may be provided directly at the ends of the main pipes 35, 171. In this case, the flanges 174, 175 can be formed integrally with the main pipes 35, 171 by processing the ends of the main pipes 35, 171 manufactured by extrusion molding. In this case, the beads 21a, 161a may not be required. Furthermore, to prevent loosening of the screws due to vibration, spring washers, U-nuts, double nuts, etc. may be used for fixing the bolt 177 and nut 178. For example, when a washer is used, the washer may be arranged only on the bolt 177 side, only on the nut 178 side, or on both sides.

[0084] (Seventh embodiment) As shown in Figures 11 and 12, the rainwater drainage system 1H of the seventh embodiment includes a connecting member 180. That is, in the rainwater drainage system 1H, instead of the flange connection of the sixth embodiment, the connecting member 180 is used to connect the expansion pipe 160 to the first drainage pipeline 21. The first drainage pipeline 21 is a portion that continues to the expansion pipe 160. The connecting member 180 connects the expansion pipe 160 and the first drainage pipeline 21.

[0085] The joining member 180 is divided into two parts in the circumferential direction. The joining member 180 comprises two divided bodies 181 as joints. Each divided body 181 has protrusions 182 protruding from both ends of its semicircular arc shape. The semicircular arc-shaped portions of each divided body 181 are overlapped and arranged along the outer periphery of the first drainage pipeline 21 and the expansion pipe 160. The protrusions 182 protrude outward in the circumferential direction relative to the expansion pipe 160 and the first drainage pipeline 21. The two divided bodies 181 are joined by each protrusion 182 with a bolt 184 and a nut (not shown).

[0086] The bolt 184 passes horizontally through each of the protrusions 182 of the two overlapping segments 181. The head and nut of the bolt 184 horizontally sandwich the overlapping segments 182 together. This causes the two segments 181 to join the first drainage pipeline 21 and the telescopic pipe 160 by sandwiching them horizontally. Tightening the bolt 184 increases the strength with which the two segments 181 (i.e., the joining member 180) grip the first drainage pipeline 21 and the telescopic pipe 160.

[0087] For example, the bolt 184 may penetrate the protruding piece of the connecting member 180 in the vertical direction instead of the horizontal direction. Even in this case, a configuration can be adopted in which the strength with which the connecting member 180 grips the first drainage pipeline 21 and the expansion pipe 160 is increased by tightening the bolt 184.

[0088] Here, grooves 36a, 172a are provided in the first processed pipe 36 of the first drainage pipeline 21 and the second processed pipe 172 of the telescopic pipe 160. The grooves 36a, 172a are grooves extending in the circumferential direction. The grooves 36a, 172a extend continuously around the entire circumference in the circumferential direction. The first processed pipe 36 of the first drainage pipeline 21 is provided with the first groove 36a of the grooves 36a, 172a. The second processed pipe 172 of the telescopic pipe 160 is provided with the second groove 172a of the grooves 36a, 172a. Both axial ends of a connecting member 180 are fitted into each groove 36a, 172a, respectively. This strengthens the connection between the first drainage pipeline 21 and the telescopic pipe 160 by the connecting member 180.

[0089] In addition, packings 186 are fitted to the first drainage pipeline 21 and the telescopic pipe 160 from the radially outside. One packing 186 is fitted across the first processed pipe 36 of the first drainage pipeline 21 and the second processed pipe 172 of the telescopic pipe 160. The packing 186 is covered from the radially outside by the joining member 180. The packing 186 is located between the upper end and lower end of the joining member 180.

[0090] Gasket contact portions 186a are provided on the outer circumferential surfaces of the first drainage pipeline 21 and the telescopic pipe 160. The gasket contact portion 186a of the first drainage pipeline 21 is a portion of the outer circumferential surface of the first drainage pipeline 21 that is located on the opposite side of the first main pipe 35 from the first groove 36a. The gasket contact portion 186a of the telescopic pipe 160 is a portion of the outer circumferential surface of the telescopic pipe 160 that is located on the opposite side of the second main pipe 171 from the second groove 172a. In this way, because the gasket contact portions 186a are on the outer circumferential surfaces rather than on the end faces of the first drainage pipeline 21 and the telescopic pipe 160, the end faces of the first drainage pipeline 21 and the telescopic pipe 160 butt against each other.

[0091] According to the rainwater drainage system 1H of the seventh embodiment, the expansion pipe 160 is joined to the first drainage pipeline 21 by the joining member 180. This ensures watertightness of the expansion pipe 160 to the first drainage pipeline 21. This ensures that the siphoning effect caused by the drain (first joint) 11 (see FIG. 2) is induced.

[0092] In the seventh embodiment, processed pipes 36, 172 are provided at the ends of the first drainage pipeline 21 and the expansion pipe 160, but the processed pipes 36, 172 may not be provided. For example, grooves 36a, 172a may be provided directly at the ends of the main pipes 35, 171. In this case, the grooves 36a, 172a can be formed in the main pipes 35, 171 by, for example, cutting the ends of the main pipes 35, 171 manufactured by extrusion molding. In this case, the beads 21a, 161a may not be required. Furthermore, to prevent loosening of the screws due to vibration, spring washers, U-nuts, double nuts, etc. may be used for fastening the bolt 184 and nut. For example, when a washer is used, the washer may be disposed only on the bolt 184 side, only on the nut side, or on both sides.

[0093] (Eighth embodiment) 13, a rainwater drainage system 1I of the eighth embodiment includes a joint member 190. That is, in the rainwater drainage system 1I, the joint member 190 is used instead of the joint member 180 of the seventh embodiment to join the expansion pipe 160 to the first drainage pipeline 21. The rainwater drainage system 1I includes a socket 191 on one of the first drainage pipeline 21 and the expansion pipe 160, and a spigot 192 on the other. In the eighth embodiment, the inlet 191 is provided in the first processed pipe 36 of the first drainage pipeline 21. The spigot 192 is provided in the second processed pipe 172 of the telescopic pipe 160. However, the spigot 192 may be provided in the first processed pipe 36 and the inlet 191 may be provided in the second processed pipe 172.

[0094] A slit 194 is provided in the socket 191. The slit 194 extends in the circumferential direction. The slit 194 extends along the circumferential direction of the socket 191 for at least half the circumference but less than the entire circumference. The slit 194 penetrates the socket 191 in the radial direction. A recess 195 is provided in the spigot 192. The recess 195 is annular. The recess 195 is provided on the outer peripheral surface of the spigot 192. The recess 195 is at the same position as the slit 194 in the up-down direction.

[0095] Joint member 190 includes ring 197 and stopper 198. Ring 197 is provided in socket 191. Ring 197 is disposed within slit 194. Ring 197 is exposed radially outward from slit 194. Ring 197 is C-shaped in a plan view from the top and bottom. Ring 197 is elastically deformable. For example, ring 197 is elastically deformable so that peripheral ends of ring 197 move apart in the circumferential direction. In this case, ring 197 expands in diameter. Ring 197 is elastically deformable so that peripheral ends of ring 197 move closer to each other in the circumferential direction. In this case, ring 197 contracts in diameter. Ring 197 is fitted into recess 195. This prevents spigot 192 from slipping out of socket 191.

[0096] The stopper 198 is provided in the receiving port 191. The stopper 198 prevents the ring 197 fitted in the recess 195 from coming out of the recess 195. The stopper 198 is annular. The stopper 198 extends continuously around the entire circumference. The stopper 198 is arranged on the outer circumferential surface of the receiving port 191. The stopper 198 covers the ring 197 from the outside in the radial direction. As a result, the stopper 198 prevents the ring 197 from elastically deforming so that its diameter expands radially outward. The stopper 198 is provided in the receiving port 191 so as to be able to slide. The stopper 198 is located radially outward of the outer circumferential surfaces of the first drainage pipe 21 and the telescopic pipe 160.

[0097] In addition, a gasket 201 is provided between the socket 191 and the spigot 192. In the eighth embodiment, two gaskets 201 are provided. The gaskets 201 include a first gasket 202 and a second gasket 203. The first gasket 202 is provided between the base end of the socket 191 and the tip of the spigot 192. In the first drainage pipe 21, the socket 191 has a larger diameter than other portions. A step is provided on the inner circumferential surface of the first drainage pipe 21 at the base end of the socket 191. The first gasket 202 is disposed between this step and the tip of the spigot 192. The second gasket 203 is disposed between the inner circumferential surface of the socket 191 and the outer circumferential surface of the spigot 192.

[0098] Furthermore, two sets of packing contact portions 201a are provided between socket 191 and spigot 192. The first set of packing contact portions 201a is provided on the inner peripheral surface of socket 191 and the tip surface of spigot 192. The second set of packing contact portions 201a is provided on the inner peripheral surface of socket 191 and the outer peripheral surface of spigot 192.

[0099] According to stormwater drainage system 1I, before socket 191 and spigot 192 are joined, stopper 198 is vertically offset relative to ring 197. When spigot 192 is inserted into socket 191 in this state, the portion of spigot 192 located above recess 195 forcibly elastically deforms ring 197, expanding its diameter. When spigot 192 rises sufficiently relative to socket 191 and the vertical position of recess 195 coincides with the vertical position of ring 197, the forced elastic deformation of ring 197 is released, and ring 197 undergoes restoration and contracts in diameter. This causes ring 197 to fit into recess 195. Then, stopper 198 is slid vertically, so that stopper 198 covers ring 197 from the radially outer side.

[0100] Therefore, the expansion pipe 160 can be joined to the first drainage pipeline 21 using the joining member 190. This ensures watertightness of the expansion pipe 160 to the first drainage pipeline 21. Therefore, the siphon phenomenon can be reliably induced by the drain (first joint) 11 (see FIG. 2).

[0101] (Ninth embodiment) 14, a rainwater drainage system 1J of the ninth embodiment includes a mechanical joint member 210. That is, in the rainwater drainage system 1J, for example, instead of the joining member 190 of the eighth embodiment, a mechanical joint member 210 (joint member) is used to join the expansion pipe 160 to the first drainage pipeline 21. The rainwater drainage system 1J includes a socket 211 on one of the first drainage pipeline 21 and the expansion pipe 160, and a spigot 212 on the other. The mechanical joint member 210 connected to the expansion pipe 160 is a joint in which a rubber ring 213 is provided on the inner surface side of the socket 211. The mechanical coupling member 210 comprises a coupling body 214 having a socket 211 formed at the end of a tubular body, a rubber ring 213 disposed in the socket 211 of the coupling body 214, and a pressure ring 215 that cooperates with the coupling body 214 to compress the rubber ring 213. The coupling body 214 is provided at one end of the first drainage pipeline 21 and the expansion pipe 160. Furthermore, a bolt hole 217 through which a tightening bolt 216 passes is formed on the outer periphery of the joint body 214. A tapered pressure contact surface 218, which tapers in diameter toward the back, is formed on the inner periphery of the joint body 214 on the opening side (near the end). A tapered pressing surface 219, which tapers in diameter from the joint body 214 side toward the back, is formed on the pressure ring 215 that compresses the rubber ring 213. A bolt hole 220 is formed on the outer periphery of the pressure ring 215 at a position opposite the bolt hole 217 of the joint body 214 described above. By fitting a bolt 216 into the bolt holes 217, 220 and fitting a nut 221 onto the end of the bolt 216, the joint body 214 and the pressure ring 215 are sandwiched between the head of the bolt 216 and the nut 221. This compresses the rubber ring 213 in the axial and radial directions, and the spigot 212 is fixed to the socket 211. It should be noted that a plurality of bolts 216 and nuts 221 may be provided.

[0102] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the components in the present embodiments can be replaced with well-known components as appropriate. For example, the pipe 13 may be a horizontal main pipe (not shown) connected to the downstream side of the vertical piping section 56, and the joint 14 may be a leg joint connecting the vertical piping section 56 and the horizontal main pipe. In this case, the expansion pipe 160 may be connected to the leg joint, or the leg joint may be the expansion pipe 160. For example, the rainwater drainage system may have only a drain (first joint) 11 as a siphon inducer, or may have only a finned joint (second joint) 11A (or a finned joint (third joint) 11B or a finned joint (fourth joint) 11C), or may have both a drain (first joint) 11 and a finned joint (second joint) 11A.

[0103] For example, as shown in FIG. 16 , the shape of the expansion pipe 160 may be a so-called elbow bend. Furthermore, instead of an elbow bend, a so-called U-bend, a loop bend, or a bellows-type expansion joint may be used. Examples of elbow bends include a combination of four so-called large 90-degree elbows or eight 45-degree elbows, forming a U-shape overall. In this case, the overall combined shape has improved flexibility compared to a single, unassembled state of multiple components. Furthermore, it is preferable that the elbow bend be a large 90-degree elbow with a curvature radius. In a rainwater drainage system, a large 90-degree elbow is less likely to cause pressure loss and allows rainwater to flow smoothly. Furthermore, fewer 90-degree elbows can be configured than 45-degree elbows, making installation easier. In the rainwater drainage system, by making the expansion pipe 160 into an elbow return, U-bend, or loop bend, water leakage can be suppressed and expansion is also possible, even in the case of an indoor piping rainwater siphon. When the expansion pipe 160 is configured as an elbow return, the elbow return can be provided on either the vertical pipe or the horizontal pipe of the storm water drainage system piping 13. When the expansion pipe 160 is configured as an elbow return, any shape is acceptable as long as it is an elbow, not just a large 90-degree bend. By configuring the expansion pipe 160 as an elbow return, it is possible to relieve expansion and contraction by sandwiching the elbow between straight pipes. Furthermore, an elbow return requires less space and is easier to install than a U-bend or loop bend. When the telescopic pipe 160 is made into an elbow return, it is preferable to provide the pipe 13 with a pipe support 12 at least 10 cm away from the end of the elbow. In this case, it is desirable for the pipe support 12 to loosely support the pipe 13. Loosely supporting the pipe 13 means supporting the pipe 13 so that it can move in the pipe axial direction. Furthermore, when the expansion pipe 160 is configured as a U-bend, it can be provided on either a vertical pipe or a horizontal pipe. For example, the U-bend may be a so-called double-eccentric U-bend. Furthermore, the upstream opening and the downstream opening of the U-bend may be formed so that any two of the X, Y, and Z axes defined in a Cartesian coordinate system are offset. In this case, the expansion pipe 160 can be easily expanded or expanded, and installation in a narrow space can be facilitated. When the expansion pipe 160 is configured as a loop bend, it is desirable to use it on a horizontal pipe. When a loop bend is used on a vertical pipe, rainwater tends to accumulate inside the loop bend. Therefore, using a loop bend on a horizontal pipe can prevent rainwater from becoming trapped inside the loop bend.

[0104] (Addendum) The rainwater drainage system according to the embodiment can be understood, for example, as follows.

[0105] <1> A stormwater drainage system according to one aspect of the present invention comprises a siphon induction section, a vertical pipe configured downstream of the siphon induction section, a horizontal pipe connected to the vertical pipe, and a joint connecting the vertical pipe and the horizontal pipe, and an expansion pipe is connected to the joint. <2> the above <1> In the stormwater drainage system according to the above, a configuration may be adopted in which the expansion pipe is configured upstream of the joint. <3> the above <1> In the rainwater drainage system according to the above, a configuration may be adopted in which the expansion pipe is configured downstream of the joint. <4> A stormwater drainage system according to one embodiment of the present invention comprises a siphon induction section, a vertical pipe configured downstream of the siphon induction section, a horizontal pipe connected to the vertical pipe, and a joint connecting the vertical pipe and the horizontal pipe, the joint being an expandable pipe. <5> A stormwater drainage system according to one embodiment of the present invention comprises a siphon induction section, a first horizontal pipe arranged downstream of the siphon induction section, a second horizontal pipe connected to the first horizontal pipe and extending in a direction intersecting the first horizontal pipe, and a joint connecting the first horizontal pipe and the second horizontal pipe, and an expansion pipe connected to the joint. <6> A stormwater drainage system according to one embodiment of the present invention comprises a siphon induction section, a first horizontal pipe arranged downstream of the siphon induction section, a second horizontal pipe connected to the first horizontal pipe and extending in a direction intersecting the first horizontal pipe, and a joint connecting the first horizontal pipe and the second horizontal pipe, wherein the joint is an expandable pipe.

[0106] When a joint connects a vertical pipe and a horizontal pipe, for example, large vibrations are likely to occur around the joint due to changes in the flow of drainage. Similarly, when a joint connects a first horizontal pipe and a second horizontal pipe, large vibrations are likely to occur around the joint. This type of vibration becomes significantly larger when the siphoning phenomenon is induced by the siphon inducer. Therefore, for example, if an expansion pipe is connected to the joint or the joint is an expansion pipe, when large vibrations such as those described above occur, the vibrations can be absorbed and suppressed by the expansion and contraction of the expansion pipe.

[0107] <7> the above <1> from <6> In the storm water drainage system according to any one of the above aspects, the expandable pipe may have a smooth inner surface.

[0108] The inner surface of the expansion pipe is smooth. This reduces the volume of the expansion pipe and suppresses the occurrence of turbulence inside the expansion pipe, compared to when the inner surface of the expansion pipe is bellows. This makes it easier to maintain the siphon effect inside the expansion pipe.

[0109] <8> the above <1> from <4> In the rainwater drainage system according to any one of the above embodiments, at least one of the vertical pipe, the horizontal pipe and the joint may be configured to be supported within 0.5 m of the end of the expansion pipe. <9> the above <5> or <6> In the rainwater drainage system according to the above, at least one of the first horizontal pipe, the second horizontal pipe and the joint may be configured to be supported within 0.5 m of the end of the expansion pipe.

[0110] The vertical pipe, horizontal pipe, first horizontal pipe, second horizontal pipe, and joints are supported within 0.5 m of the end of the expansion pipe. This prevents the expansion pipe from deforming under its own weight, for example. As a result, it prevents unexpected reverse slopes due to deformation of the expansion pipe. [Explanation of symbols]

[0111] 1. Stormwater drainage system 1C Stormwater drainage system 1D Stormwater Drainage System 1E Stormwater drainage system 1F Rainwater drainage system 1G Stormwater drainage system 1H Stormwater drainage system 1I Stormwater drainage system 11 Siphon induction section 13 tube 14 Joints 53a 1st horizontal pipe 53b 2nd horizontal pipe 57 Vertical pipe 58 Horizontal pipe 160 Telescopic tube

Claims

1. A siphon inducer; A vertical pipe configured downstream of the siphon inducer; a horizontal pipe connected to the vertical pipe; a joint that connects the vertical pipe and the horizontal pipe, An expansion pipe is connected to the joint. Stormwater drainage system.

2. The expansion pipe is configured on the upstream side of the joint. The stormwater drainage system of claim 1.

3. The expansion pipe is configured downstream of the joint. The stormwater drainage system of claim 1.

4. A siphon inducer; A vertical pipe configured downstream of the siphon inducer; a horizontal pipe connected to the vertical pipe; a joint that connects the vertical pipe and the horizontal pipe, The joint is an expansion pipe. Stormwater drainage system.

5. A siphon inducer; A first horizontal pipe configured downstream of the siphon inducer; a second horizontal pipe connected to the first horizontal pipe and extending in a direction intersecting the first horizontal pipe; and a joint connecting the first horizontal pipe and the second horizontal pipe, An expansion pipe is connected to the joint. Stormwater drainage system.

6. A siphon inducer; A first horizontal pipe configured downstream of the siphon inducer; a second horizontal pipe connected to the first horizontal pipe and extending in a direction intersecting the first horizontal pipe; and a joint connecting the first horizontal pipe and the second horizontal pipe, The joint is an expansion pipe. Stormwater drainage system.

7. The inner surface of the telescopic tube is smooth. A stormwater drainage system according to any one of claims 1 to 6.

8. At least one of the vertical pipe, the horizontal pipe, and the joint is supported within 0.5 m from the end of the expansion pipe. A stormwater drainage system according to any one of claims 1 to 4.

9. At least one of the first horizontal pipe, the second horizontal pipe, and the joint is supported within 0.5 m from the end of the expansion pipe. A stormwater drainage system according to claim 5 or 6.

10. A building in which a storm water drainage system according to any one of claims 1 to 6 is arranged.

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