Rainwater drainage system

Abstract

To provide a rainwater drainage system that maintains high drainage performance through a siphon phenomenon and allows for easy maintenance of drainage pipes.SOLUTION: A rainwater drainage system 1 comprises: a drainage pipe 10 draining rainwater; a drain provided in the drainage pipe 10; and a drainage member 12 provided in the drainage pipe 10 downstream of the drain. The drainage member 12 includes: a cleaning port 25 branching off from the drainage pipe 10 in a horizontal direction or diagonally upward relative to the horizontal; and a lid 26 screwed to the cleaning port 25. A distance from an outer surface of the drainage pipe 10 to an end face of the lid 26 is 150 mm or less.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a stormwater drainage system. [Background technology]

[0002] Among known stormwater drainage systems, a siphon inducer is provided in the drainage pipe, and a drainage member is provided downstream of the siphon inducer. By providing a siphon inducer in the drainage pipe, a siphon phenomenon can be generated in the drainage pipe, allowing a large amount of rainwater to flow into the drainage pipe. The drainage member also has a cleaning port. A lid is attached to the cleaning port. Here, the cleaning port is provided in the elbow of the drainage member. Therefore, the lid must be positioned and attached so that the inner shape of the lid matches the inner shape of the elbow.

[0003] For this reason, the lid is detachably attached to the cleaning port using a so-called bayonet structure. That is, the insertion portion of the lid is inserted into the inside of the cleaning port, and the lid is rotated to insert the protrusion of the insertion portion into the engagement groove of the cleaning port. In this way, the lid is detachably attached to the cleaning port. According to the rainwater drainage system, by removing the lid from the cleaning port, debris and the like that has become clogged in the drainage pipe can be cleaned through the cleaning port. That is, maintenance of the drainage pipe can be easily performed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-77075 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional rainwater drainage systems require the lid to be attached to the cleaning port using a bayonet structure, which means the lid's bonding strength to the cleaning port is weak, making it difficult to ensure watertightness. In order to generate a siphoning effect using a siphon inducer installed in the drainage pipe, the cleaning port must be watertight and air must be prevented from accumulating. In other words, if the cleaning port is not watertight, it is difficult to generate negative pressure downstream of the siphon inducer. Furthermore, air entering and accumulating in the cleaning port makes it difficult to maintain negative pressure downstream of the siphon inducer. This makes it difficult to sustain the siphoning effect using the siphon inducer.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a rainwater drainage system that maintains high drainage performance through the siphon effect and also allows for easy maintenance of the drainage pipes. [Means for solving the problem]

[0007] A stormwater drainage system according to one embodiment of the present invention comprises a drainage pipeline for draining rainwater, a siphon induction section provided in the drainage pipeline, and a drainage member provided in the drainage pipeline downstream of the siphon induction section, wherein the drainage member comprises a cleaning port branching off from the drainage pipeline horizontally or diagonally upward from the horizontal, and a lid screwed to the cleaning port, and the distance from the outer surface of the drainage pipeline to the end face of the lid is 150 mm or less. [Effects of the Invention]

[0008] According to the present invention, high drainage performance can be maintained by utilizing the siphon effect, and further, maintenance of the drainage pipeline can be easily performed. [Brief explanation of the drawings]

[0009] [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 an exploded side view showing a drainage member provided in the stormwater drainage system of FIG. 1. FIG. [Figure 4]FIG. 4 is a perspective view showing the drainage member of FIG. 3. [Figure 5] FIG. 6 is a side view showing a drainage member of a stormwater drainage system according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a perspective view showing a drainage member provided in the stormwater drainage system of FIG. 5. [Figure 7] FIG. 10 is a cross-sectional view showing a drainage member of a stormwater drainage system according to a third embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing a finned joint of a stormwater drainage system according to a fourth embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view showing a finned joint of a stormwater drainage system according to a fifth embodiment of the present invention. [Figure 10] FIG. 10 is a perspective view showing a cross section of a finned joint of a stormwater drainage system according to a sixth embodiment of the present invention. [Figure 11] FIG. 13 is a cross-sectional view showing an example of joining a drainage member of a stormwater drainage system according to a seventh embodiment of the present invention to a drainage pipe line by an electric fusion joint. [Figure 12] FIG. 13 is a side view showing an example of joining a drainage member of a stormwater drainage system according to an eighth embodiment of the present invention to a drainage pipe with a flange. [Figure 13] FIG. 13 is a side view showing an example of joining a drainage member of a stormwater drainage system according to a ninth embodiment of the present invention to a drainage pipe line with a joining member. [Figure 14] 14 is a side view of the joining member of FIG. 13 cut along line AA. FIG. [Figure 15] FIG. 23 is a side view showing an example of joining a drainage member of a stormwater drainage system according to a tenth embodiment of the present invention to a drainage pipe line with a joining member. DETAILED DESCRIPTION OF THE INVENTION

[0010] (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.

[0011] 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.

[0012] The rainwater drainage system 1 includes a drainage pipeline 10, a drain (siphon inducer) 11, and a drainage member 12. The drainage pipeline 10 is a pipeline that drains rainwater. The drainage pipeline 10 includes multiple inlets 51, multiple vertical pipe sections 52, one or more horizontal pipe sections 53, and a vertical pipe section 54. The inlet 51 of the drainage pipeline 10 is disposed on a rooftop 105, and rainwater that has fallen on the rooftop 105 flows into the inlet 51. The inlet 51 guides the rainwater that has fallen on the rooftop 105 to a drain 11 (described later). In the first embodiment, an example in which the drainage pipeline 10 includes multiple inlets 51 will be described, but the drainage pipeline 10 may also include only one inlet 51. Furthermore, the drainage pipeline 10 has the vertical piping section 52, the horizontal piping section 53, and the vertical piping section 54 arranged indoors. In the first embodiment, an example is described in which the vertical piping section 52, the horizontal piping section 53, and the vertical piping section 54 are arranged indoors, but they may also be arranged outdoors. Furthermore, the drainage pipeline 10 may be composed of at least one of the vertical piping section 52, the horizontal piping section 53, and the vertical piping section 54.

[0013] As shown in Figures 1 and 2, a drain 11 is provided in the drainage pipeline 10 on the upstream side of the vertical piping section 52. The drain 11 is provided on the roof 105 of the building 100. The drain 11 drains, for example, water (e.g., rainwater) from the roof. The drain 11 is arranged on the roof slab S. The roof slab S has a through hole S1 formed therein. 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.

[0014] The drain 11 is capable of inducing a siphoning effect. The drain 11 includes a base plate 14, a tube 15, a lid 16, and ribs 17. The base plate 14 is annular. The base plate 14 is arranged coaxially with the through-hole S1. The tube 15 extends downward from the inner peripheral edge of the base plate 14. The lid 16 covers the inner peripheral edge of the base plate 14 and the tube 15 from above. The ribs 17 extend upward from the base plate 14. The ribs 17 connect the base plate 14 and the lid 16. A plurality of ribs 17 are arranged at intervals around the circumferential direction of the base plate 14. An opening 18 is provided between adjacent ribs 17 in the circumferential direction. In the illustrated example, the lid 16 and the ribs 17 are integrally molded. The lid 16 and the ribs 17 form an air baffle.

[0015] 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.

[0016] 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 14 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 ribs 17 do not necessarily connect the base plate 14 and the lid 16. For example, the ribs 17 may be molded integrally with the lid 16, and the ribs 17 may simply be placed on the base plate 14, with the lid 16 and base plate 14 being connected with bolts or the like. In this way, the base plate 14, the lid 16, and the ribs 17 are separate parts, which makes it easier to waterproof the roof, even in the case of indoor piping, for example. Furthermore, since the ribs 17 are molded integrally with the lid 16, there is no need to connect the lid 16 and the ribs 17 during construction; it is sufficient to simply place the lid 16 on the base plate 14, 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.

[0017] In the first embodiment, an example will be described in which a drain 11 is provided as a siphon induction part on the upstream side of the vertical piping part 52, but the siphon induction part is not limited to the drain 11 shown in this embodiment. Any drain that is provided on the upstream side of the piping part 52 can be used as the siphon induction part, regardless of whether it has an action or effect such as ease of inducing a siphon phenomenon.

[0018] The vertical pipe section 52 is arranged downward from each of the multiple inlets 51. The vertical pipe section 52 is 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 11 (vertical pipe section 52) and the horizontal pipe section 53 can be adjusted by the other horizontal pipe section.

[0019] 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.

[0020] The vertical pipe section 54 is arranged along the vertical direction. The vertical pipe section 54 may be offset at intermediate floors and include a horizontal section. The upper end of the vertical pipe section 54 is connected to the horizontal pipe section 53. Rainwater that passes through the vertical pipe section 54 is discharged to the outside of the building 100 by a drainage section (not shown). The rainwater discharged to the outside of 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.

[0021] 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.

[0022] 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.

[0023] 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. In particular, when the drainage pipeline 10 is a fire-resistant double-layer pipe, the inner pipe is a rigid polyvinyl chloride pipe, and if the drainage member 12 described below is made of rigid polyvinyl chloride resin, the drainage pipeline 10 and the drainage member 12 can be joined with adhesive, making installation easy. In this case, it is preferable that the outer surface of the drainage member 12 is also covered with a fiber mortar layer.

[0024] 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.

[0025] As shown in Figures 3 and 4, a drainage member 12 is provided in the drainage pipeline 10 downstream of the drain 11 (see Figure 2). The drainage member 12 is provided in any one of the vertical piping section 52, the horizontal piping section 53, or the vertical piping section 54 that make up the drainage pipeline 10. Hereinafter, when the drainage member 12 is provided in the drainage pipeline 10, the pipeline upstream of the drainage member 12 may be referred to as the "first drainage pipeline 21," and the pipeline downstream of the drainage member 12 may be referred to as the "second drainage pipeline 22." In other words, the drainage member 12 is joined between the first drainage pipeline 21 and the second drainage pipeline 22.

[0026] The drainage member 12 is, for example, a molded product made of stainless steel (Stainless Used Steel "SUS"), but may also be an injection-molded product made of resin. The drainage member 12 includes a main pipe 24, a cleaning port (cleaning section) 25, and a lid 26. In this embodiment, the drainage member 12 includes the cleaning port 25. For example, the drainage member 12 allows an operator to enter the interior of the drainage member 12 from the outside through the cleaning port 25 with their hands or tools. Therefore, the drainage member 12 may be provided, for example, near a location within the drainage pipeline 10 where debris tends to accumulate. For example, the drainage member 12 may be provided in a peripheral position (upstream or downstream) of an elbow or a confluence. For example, even if the drainage pipeline 10 includes a switching valve, a slide gate, or the like, the drainage member 12 may be provided in a peripheral position of the switching valve, the slide gate, or the like. The main pipe 24 constitutes a pipeline that is part of the drainage pipeline 10. The main pipe 24 is so-called flange-jointed coaxially between the first drainage pipeline 21 and the second drainage pipeline 22. The main pipe 24 has a pipe portion 31, a first flange 32, and a second flange 33.

[0027] The pipe section 31 has, for example, substantially the same inner and outer diameters over its entire length as the first drainage pipeline 21 and the second drainage pipeline 22. However, the inner and outer diameters of the pipe section 31 do not have to be the same over its entire length. The first flange 32 is integrally formed on the upstream end of the pipe section 31. The first flange 32 protrudes radially outward from the upstream end. The second flange 33 is integrally formed on the downstream end of the pipe section 31. The second flange 33 protrudes radially outward from the downstream end.

[0028] The first drainage pipeline 21 is a portion of the drainage pipeline 10 that is connected to the upstream side of the main pipe 24. The first drainage pipeline 21 includes a first main pipe 35, a first processed pipe 36, a third flange 37, and a first gasket 38. The first main pipe 35 is a so-called extrusion molded product. The first processed pipe 36 is a so-called injection molded product. At least one of the inner diameter and the outer diameter of the first main pipe 35 and the first processed pipe 36 is not equal over substantially the entire length. The first main pipe 35 and the first processed pipe 36 are butt-welded. A bead (not shown) is formed by butt welding at the fusion joint between the first main pipe 35 and the first processed pipe 36. The first processed pipe 36 is integrally provided with a first flange 39 at the end on the main pipe 24 side. Note that, for example, the first main pipe 35 and the first processed pipe 36 may be integrally molded by extrusion molding, and the first flange 39 may be post-molded on the integrally molded first main pipe 35 and first processed pipe 36.

[0029] A third flange 37 is provided separately from the first processed pipe 36. The third flange 37 is formed of, for example, SUS304. The third flange 37 is located on the opposite side of the first flange 39 from the main pipe 24. The third flange 37 is a loose flange that is movable relative to the first processed pipe 36. Note that the third flange 37 does not have to be separate from the first processed pipe 36, but may be integral with the first processed pipe 36, or the third flange 37 may be immovable relative to the first processed pipe 36. In this case, for example, the first flange 39 may function as the third flange 37. A packing groove (not shown) is provided at the end of the first processing pipe 36 on the main pipe 24 side. A first packing 38 is disposed in the packing groove. The first packing 38 may be an elastic material (e.g., rubber) or may not be an elastic material. The first packing 38 is annular. However, the packing groove may be omitted.

[0030] The first flange 32 of the main pipe 24 of the drainage member 12 is threadedly joined to the third flange 37 with bolts 41 and nuts 42. Therefore, the main pipe 24 and the first drainage pipeline 21 are joined via the first flange 32 and the third flange 37. In this state, the first gasket 38 comes into contact with the first gasket joint (not shown) of the main pipe 24. Therefore, the first gasket 38 seals water between the main pipe 24 and the first drainage pipeline 21. Note that the water may be sealed between the main pipe 24 and the first drainage pipeline 21 by utilizing the surface pressure of the first gasket 38, or the first gasket 38 may seal water by itself.

[0031] The second drainage pipeline 22 is a portion of the drainage pipeline 10 that is connected to the downstream side of the main pipe 24. The second drainage pipeline 22 comprises a second main pipe 43, a second processed pipe 44, a fourth flange 45, and a second gasket 46. The second main pipe 43 is a so-called extrusion molded product. The second processed pipe 44 is a so-called injection molded product. At least one of the inner diameter and the outer diameter of the second main pipe 43 and the second processed pipe 44 is not equal over substantially the entire length. The second main pipe 43 and the second processed pipe 44 are butt-welded. A bead (not shown) is formed by butt welding at the fusion joint between the second main pipe 43 and the second processed pipe 44. The second processed pipe 44 is integrally provided with a second flange 47 at its end on the main pipe 24 side. Note that, for example, the second main pipe 43 and the second processed pipe 44 may be integrally molded by extrusion molding, and the second flange 47 may be post-molded on the integrally molded second main pipe 43 and second processed pipe 44.

[0032] A fourth flange 45 is provided separately from the second processed pipe 44. The fourth flange 45 is formed of, for example, SUS304. The fourth flange 45 is located on the opposite side of the main pipe 24 from the second flange 47. The fourth flange 45 is a loose flange that is movable relative to the second processed pipe 44. The fourth flange 45 does not have to be separate from the second processed pipe 44, but may be integral with the second processed pipe 44, or the fourth flange 45 may be immovable relative to the second processed pipe 44. In this case, for example, the second flange 47 may function as the fourth flange 45. A packing groove (not shown) is provided at the end of the second processing pipe 44 on the main pipe 24 side. A second packing 46 is disposed in the packing groove. The second packing 46 may be an elastic material (e.g., rubber) or may not be an elastic material. The second packing 46 is annular. However, the packing groove does not have to be provided.

[0033] The second flange 33 of the main pipe 24 of the drainage member 12 is threadedly joined to the fourth flange 45 with bolts 48 and nuts 49. Therefore, the main pipe 24 and the second drainage pipeline 22 are joined via the second flange 33 and the fourth flange 45. In this state, the second gasket 46 comes into contact with the second gasket joint (not shown) of the main pipe 24. Therefore, the second gasket 46 seals water between the main pipe 24 and the second drainage pipeline 22. Note that the water may be sealed between the main pipe 24 and the second drainage pipeline 22 by utilizing the surface pressure of the second gasket 46, or the second gasket 46 may seal water by itself.

[0034] The cleaning port 25 branches off from the main pipe 24 in a horizontal direction. In the first embodiment, an example in which the cleaning port 25 branches off from the main pipe 24 in a horizontal direction is described; however, the cleaning port 25 may branch off from the main pipe 24 in a diagonally upward direction relative to the horizontal. The angle at which the cleaning port 25 branches off diagonally upward, i.e., the angle of inclination of the axis of the cleaning port 25 relative to the horizontal direction (the direction perpendicular to the axis of the main pipe 24), is preferably 45° or less, and more preferably 30° or less. If the angle of inclination is greater than 45°, there is a risk that the cleaning port 25 and the main pipe 24 will interfere with each other unless the length of the cleaning port 25 is increased. To avoid this interference, the cleaning port 25 needs to be made larger, which makes the system less compact. Furthermore, the relationship between the passage area Ar1 of the main pipe 24 and the passage area Ar2 of the cleaning port 25 is preferably Ar1 ≧ Ar2. Furthermore, when the main pipe 24 and the cleaning port 25 are pipes, the relationship between the pipe diameter D1 of the main pipe 24 and the pipe diameter D2 of the cleaning port 25 is preferably D1 ≧ D2. By making the passage area and pipe diameter of the cleaning port 25 smaller than those of the main pipe 24, it is possible to prevent the cleaning port 25 from obstructing the flow of rainwater flowing into the main pipe 24.

[0035] The lid 26 is screwed to the cleaning port 25. Specifically, a fifth flange 61 is integrally formed at the tip of the cleaning port 25. The fifth flange 61 protrudes outward from the tip of the cleaning port 25 in a brim-like shape. The lid 26 is screwed to the fifth flange 61 with bolts 63 and nuts 64. Therefore, the lid 26 is screwed to the cleaning port 25 with the bolts 63 and nuts 64. Note that instead of joining the lid 26 to the cleaning port 25 with the bolts 63 and nuts 64, a female thread may be provided on one of the lid 26 and the cleaning port 25 and a male thread may be provided on the other, and the lid 26 and the cleaning port 25 may be directly screwed together. A third packing 66 is interposed between the lid 26 and the fifth flange 61. The gap between the lid 26 and the fifth flange 61 is sealed by the third packing 66. The gap between the lid 26 and the fifth flange 61 may be sealed by utilizing the surface pressure of the third packing 66, or may be sealed by the third packing 66 itself.

[0036] The lid 26 is provided with, for example, an insertion portion 68. The insertion portion 68 is formed to be the same as the cross section of a passage (not shown) inside the cleaning port 25 so that it can be inserted along the passage. The tip of the insertion portion 68 may be formed flat. Alternatively, the tip of the insertion portion 68 may be formed curved to correspond to the inner wall of the main pipe 24. In the first embodiment, an example in which the insertion portion 68 is provided on the lid 26 will be described, but the insertion portion 68 does not necessarily have to be provided on the lid 26.

[0037] Furthermore, the lid 26 is joined to the cleaning port 25 with bolts 63 and nuts 64. Therefore, the lid 26 can be joined to the cleaning port 25 without rotating with respect to the cleaning port 25. This allows, for example, the passage of the cleaning port 25 to be formed with a rectangular cross section. Note that the passage of the cleaning port 25 may also be formed with a circular cross section.

[0038] Here, in the drainage member 12, the distance from the outer surface 31a of the pipe portion 31 in the main pipe 24 to the end face 26a of the lid 26 is 150 mm or less. The outer surface 31a of the pipe portion 31 is the surface that faces the lid 26 in the radial direction of the pipe portion 31, which is formed to have a circular cross section. The end face 26a of the lid 26 is the surface that faces the outer surface 31a of the pipe portion 31 in the radial direction of the pipe portion 31. For example, if the lid 26 is provided with an insertion portion 68, the end face of the insertion portion 68 is the end face 26a of the lid 26.

[0039] The main pipe 24 constitutes a pipeline that is part of the drainage pipeline 10. The pipe section 31 of the main pipe 24 is a pipe material whose inner and outer diameters are substantially equal to those of the first drainage pipeline 21 and the second drainage pipeline 22. Therefore, the distance from the outer surface of the drainage pipeline 10 (i.e., the outer surface 31a of the pipe section 31) to the end face 26a of the lid 26 of the drainage member 12 is 150 mm or less.

[0040] According to the rainwater drainage system 1 of the first embodiment described above, as shown in FIGS. 1 to 4 , a drain 11 is provided in the drainage pipeline 10 as a siphon inducer. This allows a siphon phenomenon to occur in the drainage pipeline 10. This allows a large amount of rainwater to flow into the drainage pipeline 10, improving the drainage capacity (drainage performance) of the drainage pipeline 10. In addition, a drainage member 12 is provided downstream of the drain 11. A lid 26 is screw-connected to the cleaning port 25 of the drainage member 12 with bolts 63 and nuts 64. This ensures that the lid 26 is watertight with respect to the cleaning port 25. This prevents rainwater from leaking to the outside through the cleaning port 25 and prevents air from entering the inside through the cleaning port 25.

[0041] 2 to 4, by preventing rainwater from leaking through the cleaning port 25, the drainage pipe 10 can be filled with rainwater, generating negative pressure downstream of the drain 11. This allows the siphoning effect to be induced by the drain 11. When it is not raining, the drainage pipe 10 can be maintained at atmospheric pressure. Furthermore, by preventing air from entering through the cleaning port 25, negative pressure can be maintained downstream of the roof drain 11. This allows the siphoning effect to be induced reliably by the drain 11.

[0042] Furthermore, by screwing the lid 26 onto the cleaning port 25 with bolts 63 and nuts 64, the lid 26 can be easily attached and detached from the cleaning port 25 by operating the bolts 63 and nuts 64. Therefore, for example, cleaning tools or the like can be inserted into the drainage pipe 10 through the cleaning port 25, making it easy to clean out debris that has clogged the drainage pipe 10 downstream of the drain 11. This makes it easy to perform maintenance on the drainage pipe 10.

[0043] Here, for example, if the cleaning port 25 is arranged facing upward, air is likely to accumulate in the cleaning port 25. Also, if the cleaning port 25 is arranged facing downward, rainwater will flow into the cleaning port and debris will likely accumulate. Therefore, the cleaning port 25 is arranged facing horizontally or diagonally upward from the horizontal. This makes it possible to prevent air from accumulating in the cleaning port 25. Also, rainwater that flows into the cleaning port 25 can be diverted downstream, preventing debris from accumulating in the cleaning port 25. This makes it possible to prevent interference with the siphoning effect of the cleaning port 25.

[0044] In addition, the distance from the outer surface of the drainage pipe 10 (the outer surface 31a of the pipe portion 31) to the end surface 26a of the lid 26 is set to 150 mm or less. As a result, the volume of the cleaning port 25, which serves as a branch pipe, can be reduced. Therefore, for example, it is possible to minimize the amount of air remaining in the cleaning port 25, thereby suppressing air entrainment during drainage. This makes it possible to avoid interfering with the siphoning phenomenon caused by the siphon inducer. It is also possible to suppress the retention of debris. Furthermore, by setting the distance from the outer surface of the drainage pipe 10 (outer surface 31a of the pipe section 31) to the end surface 26a of the cover 26 to 150 mm or less, the outer dimensions of the drainage member 12 can be kept small. This allows for a better fit during installation, particularly when the rainwater drainage system 1 is installed indoors. Also, even when the rainwater drainage system 1 is installed outdoors, its compact size allows for a good appearance (appearance).

[0045] In this way, in the rainwater drainage system 1, the drain member 12 is provided downstream of the drain 11, and the lid 26 is screwed to the cleaning port 25 of the drainage pipe 10. The cleaning port 25 is also arranged horizontally or obliquely upward relative to the horizontal. Furthermore, the distance from the outer surface of the drainage pipe 10 (outer surface 31a of the pipe section 31) to the end face 26a of the lid 26 is set to 150 mm or less. This allows the rainwater drainage system 1 to maintain high drainage performance by utilizing the siphon effect, and also makes maintenance of the drainage pipe 10 easy.

[0046] Furthermore, as shown in Figures 3 and 4, the main pipe 24 and the first drainage pipeline 21 in the drainage member 12 are joined via a first flange 32 and a third flange 37. In addition, the main pipe 24 and the second drainage pipeline 22 are joined via a second flange 33 and a fourth flange 45. This ensures watertightness of the main pipe 24 relative to the first drainage pipeline 21 and the second drainage pipeline 22. This makes it possible to prevent rainwater from leaking to the outside and air from entering the inside from the joint between the first drainage pipe 21 and the main pipe 24 and the joint between the second drainage pipe 22 and the main pipe 24. Therefore, the siphon phenomenon by the drain 11 can be reliably induced.

[0047] In addition, a first packing 38 is used to seal off water between the main pipe 24 and the first drainage pipeline 21. Furthermore, a second packing 46 is used to seal off water between the main pipe 24 and the second drainage pipeline 22. This improves the watertightness of the drainage member 12 relative to the drainage pipeline 10. This ensures that the siphon phenomenon caused by the drain 11 is induced.

[0048] In addition, the lid 26 is screwed to the cleaning port 25 with the bolts 63 and nuts 64. This ensures that the lid 26 is watertight with respect to the cleaning port 25. This ensures that the siphoning phenomenon caused by the drain 11 can be induced reliably.

[0049] Next, rainwater drainage systems according to second to tenth embodiments will be described with reference to Figures 5 to 15. In the rainwater drainage systems according to the second to tenth 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.

[0050] First, second and third embodiments of the drainage member 12 in the first embodiment will be described with reference to FIGS. (Second embodiment) As shown in Figures 5 and 6, the rainwater drainage system 1A of the second embodiment includes a drainage member 12A instead of the drainage member 12 of the first embodiment. The drainage member 12A is provided in the drainage pipeline 10. The drainage pipeline 10 has an opening (not shown) at a position corresponding to the drainage member 12A. The drainage member 12A includes a saddle portion 71, a cleaning port 72, and a lid 73. The saddle portion 71 is a portion that is fixed to the outer surface of the drainage pipeline 10 at the opening of the drainage member 12A. The saddle portion 71 is fixed to the outer surface of the drainage pipeline 10, for example, by fusion. The saddle portion 71 may be electrically fused. In this case, the saddle portion 71 may be provided with a terminal for electrical fusion (not shown). The surface of the saddle portion 71 that contacts the drainage pipeline 10 has a shape that follows the outer peripheral surface of the drainage pipeline 10. The surface of the saddle portion 71 that contacts the drainage pipeline 10 has a curved surface with a curvature equal to the curvature of the outer peripheral surface of the main pipe, for example. A branch hole (not shown) is formed in the saddle portion 71. The branch hole communicates with a through hole (not shown) that radially penetrates the drainage pipeline 10.

[0051] The cleaning port 72 protrudes (branches) horizontally from the saddle portion 71 (i.e., the drainage pipe 10) at a branch hole (not shown). In the second embodiment, an example in which the cleaning port 72 protrudes horizontally from the saddle portion 71 will be described, but the cleaning port 72 may also protrude obliquely upward from the saddle portion 71 relative to the horizontal. The angle of inclination at which the cleaning port 72 faces obliquely upward is preferably 45° or less, and more preferably 30° or less. Furthermore, the relationship between the pipe diameter D3 of the drainage pipeline 10 and the pipe diameter D4 of the cleaning port 72 is preferably D3 ≧ D4. By making the pipe diameter of the cleaning port 72 smaller than that of the drainage pipeline 10, the cleaning port 72 can be prevented from obstructing the flow of rainwater into the drainage pipeline 10.

[0052] The lid 73 is screwed to the cleaning port 72. Specifically, a male thread (not shown) is provided on the outer peripheral surface at the tip of the cleaning port 72. A female thread (not shown) that screws into a male thread (not shown) is provided on the inner peripheral surface of the lid 73. The lid 73 is screwed to the cleaning port 72 with the male and female threads. A gasket (not shown) is interposed between the lid 73 and the cleaning port 72. The gasket (not shown) seals water between the lid 73 and the cleaning port 72. Note that the seal between the lid 73 and the cleaning port 72 may be sealed by utilizing the surface pressure of the third gasket 66, or the third gasket 66 may seal water.

[0053] Here, the distance from the outer surface of the drainage pipe 10 to the end face of the lid 73 of the drainage member 12A is 150 mm or less. The outer surface of the drainage pipe 10 is the surface that faces the lid 73 in the radial direction of the drainage pipe 10, which has a circular cross section. The end face of the lid 73 is the surface that faces the outer surface of the drainage pipe 10 in the radial direction of the drainage pipe 10.

[0054] According to the rainwater drainage system 1A 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.

[0055] Furthermore, the saddle portion 71 of the drainage member 12A is fixed to the outer surface of the drainage pipeline 10. This ensures that the saddle portion 71 is watertight with respect to the drainage pipeline 10. This prevents rainwater from leaking to the outside and air from entering the inside from the joint between the drainage pipeline 10 and the saddle portion 71. This ensures that the siphoning effect caused by the drain 11 (see Figure 2) is induced.

[0056] In addition, the lid 73 is screwed to the cleaning port 72 by the male thread of the cleaning port 72 and the female thread of the lid 73. This ensures watertightness of the lid 73 relative to the cleaning port 72. This ensures that the siphoning phenomenon caused by the drain 11 (see FIG. 2) is induced.

[0057] (Third embodiment) As shown in FIG. 7 , the rainwater drainage system 1B of the third embodiment includes a drainage member 12B instead of the drainage member 12 of the first embodiment. The drainage member 12B is provided in the drainage pipeline 10. The drainage pipeline 10 has an opening 10op at a location corresponding to the drainage member 12B. In the illustrated example, a protrusion protruding toward the central axis of the opening 10op is provided on the inner circumferential surface of the opening 10op, but this protrusion is not necessary. This protrusion can prevent rainwater (drainage) from flowing from the drainage pipeline 10 into the branch pipe 81. On the other hand, this protrusion prevents rainwater (drainage) that has flowed into the branch pipe 81 from flowing out into the drainage pipeline 10. Therefore, the presence of the protrusion may cause rainwater to remain in the branch pipe 81. In this case, the accumulated rainwater may be discharged from the branch pipe 81 when the lid 85 is removed. The drainage member 12B includes a branch pipe 81, a cap nut 82, a cleaning port 83, a gasket 84, and a lid 85. The drainage member 12B is, for example, a so-called tee (T-pipe). The branch pipe 81 is a pipe made of resin. The branch pipe 81 protrudes (branches) from the drainage pipe 10 at an opening 10op of the drainage pipe 10 (main pipe). A flange 87 is provided at the tip of the branch pipe 81. The flange 87 protrudes radially outward from the tip of the branch pipe 81 in a flange-like shape.

[0058] The cap nut 82 is formed in an annular shape and is rotatably fitted into the branch pipe 81. The cap nut 82 is arranged on the drainage pipeline 10 side with respect to the flange portion 87. A male thread 88 is formed on the outer peripheral surface of the cap nut 82. In addition, a protrusion 89 is provided on the outer peripheral surface of the cap nut 82 at the end on the drainage pipeline 10 side. The protrusion 89 protrudes radially outward from the male thread 88 in the form of a flange. The outer shape of the protrusion 89 is, for example, a hexagonal polygon. Note that the outer shape of the protrusion 89 is not limited to a hexagonal polygon, and may be a dodecagonal polygon, etc.

[0059] The cleaning port 83 is formed from a cylindrical metal member (gunmetal). The cleaning port 83 has a cylindrical portion 91 and a connecting portion 92. An internal thread 93 is formed on the inner peripheral surface of the cylindrical portion 91. The outer shape of the cylindrical portion is a hexagonal polygon. Note that the outer shape of the cylindrical portion is not limited to a hexagonal polygonal shape, and may be a dodecagonal polygonal shape, etc. The male threads 88 of the cap nut 82 are threadedly coupled to the female threads 93 of the cylindrical portion 91. By rotating the protruding portion 89 of the cap nut 82 with a known tool, the cap nut 82 can be screwed into or removed from the cylindrical portion 91 of the cleaning port 83.

[0060] Cleaning port 83 is provided at the tip of branch pipe 81 by screwing in cap nut 82. In this state, gasket 84 is placed in groove 95 of tubular portion 91. Gasket 84 seals off water between the tip of branch pipe 81 and tubular portion 91. Gasket 84 may or may not be an elastic material (e.g., rubber). Gasket 84 is annular.

[0061] The cleaning port 83 protrudes (branches) horizontally from the drainage pipeline 10 via a branch pipe 81. In the third embodiment, an example is described in which the cleaning port 83 protrudes horizontally from the drainage pipeline 10, but the cleaning port 83 may also protrude diagonally upward from the drainage pipeline 10. The angle of inclination at which the cleaning port 72 faces diagonally upward is preferably 45° or less, and more preferably 30° or less. Furthermore, it is preferable that the relationship between the pipe diameter D5 of the drainage pipeline 10 and the pipe diameter D6 of the cleaning port 83 be D5 ≧ D6. By making the pipe diameter of the cleaning port 83 smaller than that of the drainage pipeline 10, the flow of rainwater flowing into the drainage pipeline 10 can be prevented from being obstructed by the cleaning port 83.

[0062] A connecting portion 92 is coaxially provided on the cylindrical portion 91 of the cleaning port 83. The connecting portion 92 protrudes from the cylindrical portion 91 to the opposite side of the drainage pipe 10. A male thread 96 is formed on the outer peripheral surface of the connecting portion 92. The lid 85 is threadedly connected to the connecting portion 92 of the cleaning port 83. Specifically, a female thread 97 is formed on the inner peripheral surface of the lid 85, which threadably mates with the male thread 96 of the connecting portion 92. The lid 85 is threadedly connected to the male thread 96 and female thread 97 of the connecting portion 92 of the cleaning port 83. A gasket (not shown) is interposed between the lid 85 and the connecting portion 92. The gasket (not shown) seals the gap between the lid 85 and the connecting portion 92. Note that the lid 85 and the connecting portion 92 may be connected without using a gasket. For example, the male thread 96 and the female thread 97 may be fastened together with a sealing material (not shown) wrapped around the male thread 96, and the sealing material may self-seal to seal the gap. It is also possible to eliminate the cylindrical portion 91. In this case, for example, the connecting portion 92 and the cap nut 82 may be threadedly fitted together with sealing tape or the like to prevent water leakage.

[0063] Here, the distance from the outer surface of the drainage pipe 10 to the end face 85a of the lid 85 of the drainage member 12 is 150 mm or less. The outer surface of the drainage pipe 10 is the surface that faces the lid 85 in the radial direction of the drainage pipe 10, which has a circular cross section. The end face of the lid 85 is the surface that faces the outer surface of the drainage pipe 10 in the radial direction of the drainage pipe 10.

[0064] According to the rainwater drainage system 1B of the third 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.

[0065] Furthermore, the drainage member 12B is provided with a resin branch pipe 81. The branch pipe 81 protrudes from the drainage pipeline 10. A metal member provided at the tip of the branch pipe 81 serves as a cleaning port 83. A lid 85 is screwed to the cleaning port 83 of the metal member. This ensures that the lid 85 is watertight with respect to the cleaning port 83. This ensures that the siphoning effect caused by the drain 11 (see Figure 2) can be induced reliably.

[0066] In addition, the lid 85 is screw-connected to the cleaning port 83 by means of the male thread 96 on the cleaning port 83 side and the female thread 97 on the lid 85. This ensures watertightness of the lid 85 relative to the cleaning port 83. This ensures that the siphoning effect caused by the drain 11 (see Figure 2) can be induced.

[0067] Next, fourth to sixth embodiments of the roof drain (i.e., siphon induction portion) 11 in the first embodiment will be described with reference to Figures 8 to 10. The siphon induction portion in the fourth to sixth embodiments is provided upstream of the drainage member in the drainage pipeline 10. For convenience, the following describes an example in which the siphon induction portion of the fourth to sixth embodiments is joined between the first drainage pipeline 10A and the second drainage pipeline 10B in the drainage pipeline 10.

[0068] (Fourth embodiment) As shown in Figure 8, a rainwater drainage system 1C of the fourth embodiment includes a finned joint (siphon inducer) 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.

[0069] 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 fourth 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.

[0070] The straight pipe section 123 is a cylindrical pipe located between the inlet joint section 124 and the outlet joint section 125 and coaxial with the inlet joint section 124 and the outlet joint section 125. The nominal 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 is also equal to the inner diameters of the first drainage pipe 10A and the second drainage pipe 10B. Therefore, the flow paths extending vertically through the first drainage pipe 10A, the finned joint 11A, and the second drainage pipe 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 through the finned joint 11A to the second drainage pipeline 10B is connected smoothly without any steps at either the connection point between the first drainage pipeline 10A and the finned joint 11A or the connection point between the finned joint 11A and the second drainage pipeline 10B.

[0071] 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 fourth 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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 into inlet 51 from baffle 128, making it possible to reliably induce the siphon effect. Moreover, because the rainwater has already been rectified by left side surface 121d and right side surface 121e after passing through each fin 121, it is drained smoothly without swirling.

[0078] 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 fourth 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 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.

[0079] According to the rainwater drainage system 1C of the fourth 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.

[0080] (Fifth embodiment) 9, a rainwater drainage system 1D of the fifth embodiment includes a finned joint (siphon inducer) 11B instead of the finned joint 11A of the fourth embodiment. The finned joint 11B includes 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.

[0081] 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.

[0082] Furthermore, rainwater that attempts to pass through while swirling can be straightened by each fin 132. 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.

[0083] 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. 8), making it possible to reliably induce the siphon effect.

[0084] According to the rainwater drainage system 1D of the fifth embodiment described above, similar to the fourth embodiment, high drainage performance can be maintained by the siphon effect, and further, maintenance of the drainage pipeline 10 (see Figure 8) can be easily performed.

[0085] (Sixth embodiment) 10, a rainwater drainage system 1E of the sixth embodiment includes a finned joint (siphon inducer) 11C instead of the finned joint 11A of the fourth embodiment. The finned joint 11C includes a joint body 140, a plurality of fins 141, and a finned ring 142. 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.

[0086] 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. 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] Finned joint 11C allows rainwater with a reduced flow rate to temporarily accumulate in the flow path between the upper side of each fin 141 and inlet 51 (see FIG. 8). This makes it difficult for air to get into the rainwater flowing from baffle 128 (see FIG. 8) into inlet 51, making it possible to reliably induce the siphon effect. Moreover, because the rainwater has already been rectified after passing through each fin 141, it is drained smoothly without swirling. 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.

[0092] According to the rainwater drainage system 1E of the sixth embodiment described above, similar to the fourth embodiment, high drainage performance can be maintained by the siphon effect, and further, maintenance of the drainage pipeline 10 (see Figure 8) can be easily performed. In the fourth to sixth 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.

[0093] Next, seventh to tenth embodiments will be described with reference to Figures 11 to 15 as examples of joining a drainage member to the drainage pipeline 10 provided in the first embodiment. The drainage member is joined between the first drainage pipeline 21 and the second drainage pipeline 22 (both see Figure 3) of the drainage pipeline 10. Below, in the seventh to tenth embodiments, the drainage member is referred to as a "drainage member 160," and an example will be described in which a main pipe 161 of the drainage member 160 is joined to the lower end of the first drainage pipeline 21. The main pipe 161 is a pipe that becomes part of the drainage pipeline 10.

[0094] Seventh embodiment As shown in FIG. 11 , in the rainwater drainage system 1F of the seventh embodiment, a main pipe 161 of a drainage member 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 main pipe 161 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 pipeline 21 and the main pipe 161, thereby achieving electric fusion joining.

[0095] 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.

[0096] In addition, a drain 11 (see FIG. 2) capable of inducing a siphon effect 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 achieve even higher drainage performance.

[0097] (Eighth embodiment) As shown in FIG. 12, in the rainwater drainage system 1G of the eighth embodiment, instead of the electrofusion joining using the electrofusion joint 165 of the seventh embodiment, a drainage member 160 is flange-joined to a first drainage pipeline 21. The first drainage pipeline 21 includes a first main pipe 35 and a first processed pipe 36. The main pipe 161 of the drainage member 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.

[0098] 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.

[0099] 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.

[0100] 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").

[0101] Furthermore, the first drainage pipeline 21 and the drainage member 160 are flange-joined radially outward from the outer circumferential surfaces of the first drainage pipeline 21 and the drainage member 160. A bolt joint using flanges 174, 175 is used to flange-join the first drainage pipeline 21 and the drainage member 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 drainage member 160. As a result, the first drainage pipeline 21 and the drainage member 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 drainage member 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. This allows the first drainage pipeline 21 and the drainage member 160 to be bolted together.

[0102] Here, the rainwater drainage system 1G includes a packing 179 (gasket). The first drainage pipeline 21 and the drainage member 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 drainage member 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 a bolt 177 and a nut 178. The packing contact portions 21b, 161b are provided on the end faces of the first drainage pipeline 21 and the drainage member 160. This makes it possible to improve the sealing performance at the joint between the first drainage pipeline 21 and the drainage member 160. This ensures that the drain member 160 is watertight with respect to the first drain pipe 21. This ensures that the siphon phenomenon caused by the drain 11 (see FIG. 2) is induced.

[0103] In the eighth embodiment, processed pipes 36, 172 are provided at the ends of the first drainage pipeline 21 and the drainage member 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 bolts 177 and nuts 178. For example, when washers are used, the washers may be arranged only on the bolt 177 side, only on the nut 178 side, or on both sides.

[0104] (Ninth embodiment) As shown in Figures 13 and 14, the rainwater drainage system 1H of the ninth embodiment includes a connecting member 180. That is, in the rainwater drainage system 1H, instead of the flange connection of the eighth embodiment, the connecting member 180 is used to connect the drainage member 160 to the first drainage pipeline 21. The first drainage pipeline 21 is the portion of the drainage member 160 that continues to the main pipe 161. The connecting member 180 connects the main pipe 161 and the first drainage pipeline 21.

[0105] 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 pipe 21 and the drainage member 160. The protrusions 182 protrude outward in the circumferential direction relative to the drainage member 160 and the first drainage pipe 21. The two divided bodies 181 are joined by bolts 184 and nuts (not shown) at the respective protrusions 182.

[0106] 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 drainage member 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 drainage member 160.

[0107] For example, the bolt 184 may penetrate the protruding piece of the joining 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 joining member 180 grips the first drainage pipeline 21 and the drainage member 160 is increased by tightening the bolt 184.

[0108] 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 drainage member 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 drainage member 160 is provided with the second groove 172a of the grooves 36a, 172a. Both axial ends of the connecting member 180 are fitted into each groove 36a, 172a, respectively. This strengthens the connection between the first drainage pipeline 21 and the drainage member 160 by the connecting member 180.

[0109] In addition, a packing 186 is fitted to the first drainage pipeline 21 and the drainage member 160 from the radial 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 drainage member 160. The packing 186 is covered from the radial outside by the joining member 180. The packing 186 is located between the upper end and the lower end of the joining member 180.

[0110] Gasket contact portions 186a are provided on the outer peripheral surfaces of the first drainage pipeline 21 and the drainage member 160. The gasket contact portion 186a of the first drainage pipeline 21 is a portion of the outer peripheral 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 drainage member 160 is a portion of the outer peripheral surface of the drainage member 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 peripheral surfaces rather than on the end faces of the first drainage pipeline 21 and the drainage member 160, the end faces of the first drainage pipeline 21 and the drainage member 160 butt against each other.

[0111] According to the rainwater drainage system 1H of the ninth embodiment, the main pipe 161 of the drainage member 160 is joined to the first drainage pipeline 21 by the joining member 180. This ensures watertightness of the drainage member 160 to the first drainage pipeline 21. This ensures that the siphoning phenomenon caused by the drain 11 (see FIG. 2) can be induced.

[0112] In the ninth embodiment, processed pipes 36, 172 are provided at the ends of the first drainage pipeline 21 and the drainage member 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.

[0113] (Tenth embodiment) 15, a rainwater drainage system 1I of the tenth embodiment includes a joint member 190. That is, in the rainwater drainage system 1H, instead of the joint member 180 of the ninth embodiment, the joint member 190 is used to join the drainage member 160 to the first drainage pipeline 21. The rainwater drainage system 1I includes a receiving port 191 on one of the first drainage pipeline 21 and the drainage member 160, and a spigot 192 on the other. In the tenth embodiment, the receiving port 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 drainage member 160. However, the spigot 192 may be provided in the first processed pipe 36 and the receiving port 191 may be provided in the second processed pipe 172.

[0114] 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.

[0115] 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.

[0116] 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 surface of the first drainage pipe 21 and the outer circumferential surface of the drainage member 160.

[0117] In addition, a gasket 201 is provided between the socket 191 and the spigot 192. In the tenth 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.

[0118] 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.

[0119] 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.

[0120] Therefore, the drainage member 160 can be joined to the first drainage pipeline 21 using the joining member 190. This ensures watertightness of the drainage member 160 to the first drainage pipeline 21. Therefore, the siphon phenomenon caused by the drain 11 (see FIG. 2) can be reliably induced.

[0121] 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 stormwater drainage system may have only a drain 11 as a siphon inducer, or may have only a finned joint 11A (or a finned joint 11B or a finned joint 11C), or may have both a drain 11 and a finned joint 11A.

[0122] (Addendum) The rainwater drainage system according to the embodiment can be understood, for example, as follows.

[0123] <1> A stormwater drainage system according to one embodiment of the present invention comprises a drainage pipeline for draining rainwater, a siphon induction section provided in the drainage pipeline, and a drainage member provided in the drainage pipeline downstream of the siphon induction section, wherein the drainage member comprises a cleaning port branching off from the drainage pipeline horizontally or diagonally upward from the horizontal, and a lid screwed to the cleaning port, and the distance from the outer surface of the drainage pipeline to the end face of the lid is 150 mm or less.

[0124] According to the rainwater drainage system, a siphon inducer is provided in the drainage pipe. This allows a siphon phenomenon to occur in the drainage pipe. This allows a large amount of rainwater to flow into the drainage pipe, improving the drainage capacity (drainage performance) of the drainage pipe. In addition, a drainage member is provided downstream of the siphon inducer. A lid is screwed to the cleaning port of the drainage member. This ensures that the lid is watertight with respect to the cleaning port. This prevents rainwater from leaking to the outside through the cleaning port and air from entering the inside through the cleaning port.

[0125] By preventing rainwater from leaking through the cleaning port, the drain pipe can be filled with rainwater, generating negative pressure downstream of the siphon inducer. This allows the siphon inducer to induce the siphoning phenomenon. When it is not raining, the drain pipe can be maintained at atmospheric pressure. Furthermore, by preventing air from entering through the cleaning port, negative pressure can be maintained downstream of the siphon inducer. This ensures that the siphoning phenomenon is induced by the siphon inducer.

[0126] Furthermore, by screwing the lid onto the cleaning port, the lid can be easily attached and detached from the cleaning port by operating the screws. Therefore, for example, cleaning tools can be inserted into the drainage pipe through the cleaning port, making it easy to clean out debris stuck in the drainage pipe downstream of the siphon inducer. This makes it easy to maintain the drainage pipe.

[0127] Here, for example, if the cleaning port is positioned facing upward, air is likely to accumulate in the cleaning port. Furthermore, if the cleaning port is positioned facing downward, rainwater will flow into the cleaning port and debris will likely accumulate. Therefore, the cleaning port is positioned horizontally or diagonally upward from the horizontal. This prevents air from accumulating in the cleaning port. Furthermore, rainwater that flows into the cleaning port can be directed downstream, preventing debris from accumulating in the cleaning port. This prevents the siphoning phenomenon caused by the siphon inducer from being impeded.

[0128] In addition, the distance from the outer surface of the drain pipe to the end face of the cover is set to 150 mm or less. As a result, the volume of the cleaning port, which serves as a branch pipe, can be reduced. This, for example, can minimize the amount of air stagnating in the cleaning port, suppressing air entrainment during drainage. This prevents interference with the siphoning phenomenon caused by the siphon inducer. It also suppresses the accumulation of debris. Furthermore, by setting the distance from the outer surface of the drainage pipe to the end face of the cover to 150 mm or less, the external dimensions of the drainage member can be kept small. This allows for a more compact installation, especially when installing a rainwater drainage system indoors. Even when installing a rainwater drainage system outdoors, its compact size allows for a more attractive appearance.

[0129] In this way, in the rainwater drainage system, a drainage member is provided downstream of the siphon inducer, and a lid is screwed onto the cleaning port of the drainage pipe. The cleaning port is also positioned horizontally or diagonally upward from the horizontal. Furthermore, the distance from the outer surface of the drainage pipe to the end face of the lid is set to 150 mm or less. This allows the rainwater drainage system to maintain high drainage performance through the siphon phenomenon, and also makes it easy to maintain the drainage pipe.

[0130] <2> the above <1> In the stormwater drainage system according to the present invention, the drainage member may comprise a main pipe that is part of the drainage pipeline, the cleaning port may branch off from the main pipe, the main pipe may be provided with a flange, and the main pipe and the part of the drainage pipeline that is connected to the main pipe may be joined via the flange.

[0131] According to the rainwater drainage system, the main pipe of the drainage member and the section of the drainage pipeline that connects to the main pipe are joined via a flange. This ensures the watertightness of the main pipe relative to the section that connects to the main pipe. This prevents rainwater from leaking to the outside and air from entering the joint between the section that connects to the main pipe and the main pipe. This ensures that the siphoning phenomenon can be reliably induced by the siphon inducer.

[0132] <3> the above <1> In the rainwater drainage system according to the present invention, the drainage member may include a main pipe that is part of the drainage pipeline, the cleaning port may branch off from the main pipe, and the rainwater drainage system may include a connecting member that connects the main pipe to a portion of the drainage pipeline that is connected to the main pipe.

[0133] According to the rainwater drainage system, the main pipe of the drainage member is connected to the section of the drainage pipeline that connects to the main pipe with a connecting member, thereby ensuring watertightness of the drainage member relative to the drainage pipeline, and thereby ensuring that the siphon inducer can reliably induce the siphon phenomenon.

[0134] <4> the above <1> In the rainwater drainage system according to the present invention, the drainage member may include a main pipe that is part of the drainage pipeline, the cleaning port may branch off from the main pipe, and the rainwater drainage system may include a gasket that seals off water between the main pipe and the portion of the drainage pipeline that is connected to the main pipe.

[0135] In this rainwater drainage system, a gasket is used to seal off water between the main pipe and the section of the drainage pipe that connects to the main pipe. This improves the watertightness of the drainage member relative to the drainage pipe. This ensures that the siphon inducer can induce the siphon phenomenon.

[0136] <5> the above <1> In the stormwater drainage system according to the above, the drainage member may include a saddle portion fixed to the outer surface of the drainage pipeline, and the cleaning port may protrude from the saddle portion.

[0137] According to the rainwater drainage system, the saddle portion of the drainage member is fixed to the outer surface of the drainage pipe. This ensures the watertightness of the saddle portion relative to the drainage pipe. This prevents rainwater from leaking to the outside and air from entering the inside through the joint between the drainage pipe and the saddle portion. This ensures that the siphoning phenomenon can be reliably induced by the siphon inducer.

[0138] <6> the above <1> In the rainwater drainage system according to the present invention, the drainage member may include a branch pipe made of resin protruding from the drainage pipeline, and the cleaning port may be a metal member provided at the tip of the branch pipe.

[0139] According to the rainwater drainage system, the drainage member is provided with a branch pipe made of resin. The branch pipe protrudes from the drainage pipeline. A metal member provided at the tip of the branch pipe serves as a cleaning port. A lid is screwed onto the cleaning port of the metal member. This ensures that the lid is watertight with respect to the cleaning port. This ensures that the siphoning phenomenon can be reliably induced by the siphon inducer.

[0140] <7> the above <1> In the rainwater drainage system according to the above, the lid may be screw-connected to the cleaning port with bolts.

[0141] According to the rainwater drainage system, the cover is connected to the cleaning port with bolts. This ensures that the cover is watertight with respect to the cleaning port. This ensures that the siphon inducer can reliably induce the siphon phenomenon.

[0142] <8> the above <1> In the rainwater drainage system according to the present invention, a male thread may be provided on the outer peripheral surface of the cleaning port, and a female thread may be provided on the inner peripheral surface of the lid, and the lid may be screwed to the cleaning port using the male thread and the female thread.

[0143] According to the rainwater drainage system, the lid is screwed to the cleaning port using the male thread on the cleaning port and the female thread on the lid. This ensures that the lid is watertight with respect to the cleaning port. This ensures that the siphon inducer can reliably induce the siphon phenomenon. [Explanation of symbols]

[0144] 1, 1A~1I...Rainwater drainage system 10...Drainage pipe line 11...Drain (siphon inducer) 11A~11C...Finned joint (siphon inducer) 12, 12A, 12B, 160...Drainage members 21…1st drainage pipe line 22…Second drainage pipe line 24, 161 mains 25, 72, 83...Cleaning port 26, 73, 85…lid 31...Pipe section 31a...Outer surface of the pipe (outer surface of the drainage pipe) 26a, 85a...End surface of the lid 32...First flange (flange) 33, 175...Second flange (flange) 38, 202...First packing (packing) 46, 203...Second packing (packing) 63...Bolt 71...Saddle 81...Resin branch pipe 96...Male thread 97...Female thread 179, 186, 201...Packing 180, 190... Joint members

Claims

1. A drainage pipe for draining rainwater; A siphon inducer provided in the drainage pipeline; a drainage member provided in the drainage pipeline downstream of the siphon inducer, The drainage member is A cleaning port branched from the drainage pipe in a horizontal direction or diagonally upward relative to the horizontal direction; a lid that is screwed to the cleaning port, A rainwater drainage system in which the distance from the outer surface of the drainage pipe to the end face of the cover is 150 mm or less.

2. The drainage member includes a main pipe that forms part of the drainage pipeline, The cleaning port is branched from the main pipe, The main pipe is provided with a flange; The storm water drainage system according to claim 1 , wherein the main pipe and the portion of the drainage pipeline that is connected to the main pipe are joined via the flange.

3. The drainage member includes a main pipe that forms part of the drainage pipeline, The cleaning port is branched from the main pipe, The storm water drainage system includes a joint member, The storm water drainage system according to claim 1 , wherein the connecting member connects the main pipe and a portion of the drainage pipeline that is connected to the main pipe.

4. The drainage member includes a main pipe that forms part of the drainage pipeline, The cleaning port is branched from the main pipe, The stormwater drainage system according to claim 1, further comprising a gasket that seals off water between the main pipe and a portion of the drainage pipeline that is connected to the main pipe.

5. The drainage member includes a saddle portion fixed to an outer surface of the drainage pipeline, The stormwater drainage system of claim 1 , wherein the cleanout port projects from the saddle portion.

6. The drainage member includes a branch pipe made of resin protruding from the drainage pipe, The rainwater drainage system according to claim 1 , wherein the cleaning port is a metal member provided at the tip of the branch pipe.

7. The storm water drainage system of claim 1 , wherein the cover is bolted to the cleanout opening.

8. A male screw is provided on the outer peripheral surface of the cleaning port, and a female screw is provided on the inner peripheral surface of the lid, The storm water drainage system according to claim 1 , wherein the lid is threadedly connected to the cleaning port by the male threads and the female threads.

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