drain

Abstract

This provides a drain that allows for improved flow rate while ensuring installation stability. [Solution] The drain 1 comprises a cylindrical portion 21 having a first opening 21a and a second opening 21b, and a flange 22 located at the end of the cylindrical portion 21 on the first opening 21a side and extending radially outward from the cylindrical portion 21. The inner circumferential surface of the cylindrical portion 21 includes a protruding portion 24 that protrudes toward the central axis C21 of the cylindrical portion 21 such that the flow path cross-sectional area of ​​the cylindrical portion 21 is smaller than the cross-sectional area of ​​the second opening 21b. The protruding portion 24 includes a top portion 24a where the flow path cross-sectional area is minimized. If r is the radius of the second opening 21b, h is the amount of protrusion at the top 24a of the protruding portion 24, L1 is the distance between the first opening 21a and the top 24a in the direction of the central axis C21, and L2 is the distance between the top 24a and the end 24b of the protruding portion 24 on the second opening 21b side in the direction of the central axis C2, then 0.05r ≤ h ≤ 0.30r, 0.1r ≤ L1 ≤ 0.7r, and L1 ≤ L2 ≤ 5L1.

Description

Technical Field

[0001] The present disclosure relates to a drain.

Background Art

[0002] Patent Document 1 discloses a drainage member (siphon drain member) attached to an eaves gutter. The drainage member includes a plate-shaped lid member disposed at the upper end, a mounting cylinder fitted to a downspout on the vertical gutter, and a plurality of vertical ribs connecting the lid member and the mounting cylinder and arranged at intervals in the circumferential direction. The mounting cylinder has a cylindrical portion forming a drop opening, and a plate-shaped flange portion extending radially outward from the upper end of the cylindrical portion. The cylindrical portion penetrates the through-hole of the eaves gutter from above, and the flange portion has a stepped portion formed by being thinly cut out over the entire circumference on the lower surface of the outer peripheral side, and this stepped portion is locked on the bottom wall (bottom surface) of the eaves gutter. In the mounting cylinder, the connection portion on the inner surface side where the cylindrical portion corresponding to the drop opening and the flange portion are continuously provided has a tapered surface or a bell mouth shape formed on a curved surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=:35]]In the drainage member disclosed in Patent Document 1, since the connection portion has a bell mouth shape, while an improvement in flow rate can be expected by reducing the inlet loss in the drainage member, the effective width available for locking with the bottom wall of the eaves gutter in the flange portion will decrease. The decrease in the effective width contributes to a reduction in the stability of attaching the drainage member to the eaves gutter.

[0005] In particular, a larger radius of curvature at the connection point increases the effect of reducing inlet losses, meaning an improvement in flow rate can be expected. However, this also raises concerns about reduced stability of the installation due to the decrease in effective width. Conversely, a smaller radius of curvature at the connection point reduces the effective width, which can improve installation stability. However, this also raises concerns about reduced inlet losses, meaning a decrease in flow rate.

[0006] In order to ensure sufficient effective width, one might consider increasing the outer diameter of the flange, but this could lead to another problem: the need for larger drainage components.

[0007] This disclosure provides a drain that enables improved flow rate while ensuring mounting stability. [Means for solving the problem]

[0008] A drain according to one aspect of the present disclosure comprises a cylindrical portion having a first opening and a second opening, and a flange at the end of the cylindrical portion on the first opening side extending radially outward from the cylindrical portion, wherein the inner circumferential surface of the cylindrical portion includes a protruding portion that projects toward the central axis of the cylindrical portion such that the flow path cross-sectional area of ​​the cylindrical portion is smaller than the cross-sectional area of ​​the second opening, the protruding portion includes a top where the flow path cross-sectional area is minimized, and if the radius of the second opening is r, the amount of protrusion at the top of the protruding portion is h, the distance between the first opening and the top in the direction of the central axis is L1, and the distance between the top and the end of the protruding portion on the second opening side in the direction of the central axis is L2, then 0.05r ≤ h ≤ 0.30r, 0.1r ≤ L1 ≤ 0.7r, and L1 ≤ L2 ≤ 5L1. [Effects of the Invention]

[0009] Aspects of this disclosure enable improved flow rates while ensuring mounting stability. [Brief explanation of the drawing]

[0010] [Figure 1] Schematic diagram of a gutter drainage structure including a drain according to an embodiment. [Figure 2] Cross-sectional view of a gutter drainage structure including a drain according to an embodiment. [Figure 3] Perspective view of the drain according to the embodiment [Figure 4] Plan view of the drain according to the embodiment [Figure 5] Bottom view of the drain according to the embodiment [Figure 6] Side view of the drain according to the embodiment [Figure 7] Cross-sectional view of the drain according to the embodiment [Figure 8] Enlarged view of the area indicated by P1 in Figure 7 [Figure 9] Schematic diagram of the gutter drainage structure according to modified example 1 [Figure 10] Schematic diagram of the gutter drainage structure according to modified example 2 [Figure 11] Schematic diagram of the gutter drainage structure according to modified example 3 [Modes for carrying out the invention]

[0011] [1. Embodiments] The embodiments of this disclosure will be described below, with reference to the drawings as appropriate. However, the embodiments described below are illustrative examples for illustrating this disclosure and are not intended to limit this disclosure to the following (for example, the shape, dimensions, arrangement, etc., of each component). Unless otherwise specified, positional relationships such as up, down, left, and right shall be based on the positional relationships shown in the drawings. The figures described in the embodiments below are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0012] In the following explanation, when it is necessary to distinguish between multiple components, prefixes such as "1st," "2nd," etc., will be added to the names of the components. However, if the components can be distinguished from each other by the symbols attached to them, prefixes such as "1st," "2nd," etc., may be omitted for the sake of readability.

[0013] In the following description, when it is necessary to distinguish between a plurality of components from each other, suffixes such as "-1" and "-2" are attached to the reference signs of the components. However, when it is not necessary to distinguish between a plurality of components, the suffixes such as "-1" and "-2" may be omitted in consideration of the readability of the text.

[0014] [1.1 Structure] FIG. 1 is a schematic view of a eaves gutter drainage structure 100 including a drain 1 according to an embodiment.

[0015] The eaves gutter drainage structure 100 is a piping system for conveying a fluid with a Reynolds number of 4000 or more. It can be said that a fluid with a Reynolds number of 4000 or more is a fluid in which the flow inside the cylinder becomes turbulent. Examples of the fluid include liquids (drinking water, heat source water, drainage, oil, etc.), gases (air, steam, etc.), and gas-liquid two-phase flows (mixture of liquid and gas). The eaves gutter drainage structure 100 constitutes a rain gutter system that receives rainwater from the roof 210 of the building 200 and flows it to the step part 310 on the ground 300. The rainwater collected in the step part 310 flows out from the step part 310 through the buried pipe 320 into the rainwater pipe. The building 200 is, for example, a building of a non-residential facility such as a store, an office, a factory, a building, a school, a welfare facility or a hospital, and a residential facility such as a detached house, an apartment house, or each household of a detached house or an apartment house. The non-residential facilities also include a theater, a cinema, a hall, a game arcade, a complex facility, a department store, a hotel, an inn, a kindergarten, a library, a museum, an art museum, an underground shopping street, a station, an airport, etc.

[0016] The eaves gutter drainage structure 100 includes a drain 1, an eaves gutter 10, a joint 11, a vertical pipe 12, and a socket 13.

[0017] The eaves gutter 10 receives rainwater from the roof 210 of the building 200. The eaves gutter 10 is installed under the roof 210 of the building 200. As an example, the eaves gutter 10 is arranged at the eaves edge of the roof 210. In particular, the eaves gutter 10 is arranged to extend along the eaves edge of the roof 210. The eaves gutter 10 is long and barrel-shaped. The eaves gutter 10 has a bottom wall 10a. An inlet 10b is formed in the bottom wall 10a. The inlet 10b is, for example, a circular opening. In a rain gutter system, the inlet 10b is also referred to as a water collection port, a drainage port, or a downspout. As an example, the eaves gutter 10 can be formed by extrusion molding of a resin material. The eaves gutter 10 may be provided with a core material for reinforcing the strength of the entire eaves gutter 10. The core material can be, for example, made of metal. As another example, the eaves gutter 10 may be formed of a metal plate, for example, a steel plate (also called a coil).

[0018] The drain 1 is arranged at the inlet 10b of the eaves gutter 10. The drain 1 is used to reduce the generation of vortices and the entrainment of air at the inlet 10b.

[0019] FIG. 2 is a cross-sectional view of the eaves gutter drainage structure 100 including the drain 1. In FIG. 2, the illustration of the vertical pipe 12 and the socket 13 is omitted. FIG. 3 is a perspective view of the drain 1. FIG. 4 is a plan view of the drain 1. FIG. 5 is a bottom view of the drain 1. FIG. 6 is a side view of the drain 1. FIG. 7 is a cross-sectional view of the drain 1. Here, FIG. 2 is a cross-sectional view taken along line A-A of FIG. 4, and FIG. 7 is a cross-sectional view taken along line B-B of FIG. 4. FIG. 8 is an enlarged view of the portion indicated by P1 in FIG. 7.

[0020] The drain 1 includes a drainage cylinder portion 2, a funnel portion 3, and one or more blades 4. In the present embodiment, the drain 1 includes five blades 4.

[0021] As shown in FIG. 2, the drainage cylinder portion 2 has an upstream end portion 2a and a downstream end portion 2b. The drainage cylinder portion 2 further has a downspout 2c. The downspout 2c is an internal space between the upstream end portion 2a and the downstream end portion 2b in the drainage cylinder portion 2.

[0022] As shown in Figures 2 and 3, the drain pipe section 2 comprises a cylindrical section 21 and a flange 22.

[0023] The cylindrical portion 21 is cylindrical with a central axis C21. The cylindrical portion 21 has a first opening 21a and a second opening 21b. The inner circumferential surface of the cylindrical portion 21 defines the wall surface of the flow path from the first opening 21a to the second opening 21b. It is preferable that the surface roughness of the inner circumferential surface of the cylindrical portion 21 be small. The center of the first opening 21a and the center of the second opening 21b lie on the central axis C21. In this embodiment, the radius R1 of the first opening 21a is greater than the radius r of the second opening 21b. The end of the cylindrical portion 21 on the first opening 21a side becomes the upstream end 2a of the drain pipe portion 2. The end of the cylindrical portion 21 on the second opening 21b side becomes the downstream end 2b of the drain pipe portion 2. Male threads 21c are formed on the outer circumferential surface of the cylindrical portion 21.

[0024] The radius r of the second opening 21b of the cylindrical portion 21 defines the inner diameter D of the cylindrical portion 21. In this embodiment, the inner diameter D of the cylindrical portion 21 is the diameter (=2r) of the second opening 21b of the cylindrical portion 21. The inner diameter D of the cylindrical portion 21 defines the inner diameter of the drain outlet 2c. The inner diameter D of the drain outlet 2c may be set appropriately according to the dimensions of the piping connected to the drain 1. The dimensions of the piping, for example, the outer diameter and thickness, may be set in accordance with the standard for rigid polyvinyl chloride pipes (general) of JIS K 6741 "Rigid polyvinyl chloride pipes".

[0025] Table 1 shows an example of nominal diameters for VP rigid polyvinyl chloride pipes in the JIS K 6741 standard for rigid polyvinyl chloride pipes (general). In Table 1, the units for outer diameter (standard dimension), thickness (minimum dimension), and approximate inner diameter are mm.

[0026] [Table 1]

[0027] Table 2 shows an example of nominal diameters for VU rigid polyvinyl chloride pipes in the JIS K 6741 standard for rigid polyvinyl chloride pipes (general). In Table 2, the units for outer diameter (standard dimension), thickness (minimum dimension), and approximate inner diameter are mm.

[0028] [Table 2]

[0029] The radius r of the second opening 21b of the cylindrical portion 21, and consequently the inner diameter D of the cylindrical portion 21, may be set based on an approximate inner diameter corresponding to the nominal diameter of the piping. In this embodiment, the inner diameter D of the cylindrical portion 21 may be set to correspond to a nominal diameter of 75 mm, 100 mm, or 125 mm.

[0030] The flange 22 is located at the end of the cylindrical portion 21 on the side of the first opening 21a and extends radially outward from the cylindrical portion 21. Therefore, in the drain pipe portion 2, the flange 22 also defines the upstream end 2a. In this embodiment, the flange 22 is annular with a central axis C22. The central axis C22 of the flange 22 and the central axis C21 of the cylindrical portion 21 coincide, and these define the central axis C2 of the drain pipe portion 2.

[0031] The flange 22 has a first surface 22a on the side of the first opening 21a and a second surface 22b on the side of the second opening 21b, in the direction of the central axis C21 of the cylindrical portion 21. In Figure 2, the first surface 22a is the upper surface of the flange 22, and the second surface 22b is the lower surface of the flange 22. In the direction of the central axis C21 of the cylindrical portion 21, the first surface 22a is on the same plane as the first opening 21a. Since the first surface 22a constitutes part of the surface that guides water to the first opening 21a, it is preferable that the surface roughness is small. The second surface 22b is the part of the flange 22 that contacts the upper surface of the bottom wall 10a of the gutter 10. As shown in Figures 2 and 5, the width of the second surface 22b is the width W of the flange 22, and therefore the effective width that can be used for locking the flange 22 with the bottom wall 10a of the gutter 10. In this embodiment, if the outer radius of the flange 22 is R2, the width W of the flange 22 may be R2 - R1.

[0032] As shown in Figure 2, in this embodiment, the cylindrical portion 21 includes a reduced diameter portion 23. The reduced diameter portion 23 is a portion of the cylindrical portion 21 on the first opening 21a side, where the inner radius decreases from the radius R1 of the first opening 21a to the radius r of the second opening 21b, moving from the first opening 21a to the second opening 21b. The reduced diameter portion 23 enables a reduction in inlet loss at the first opening 21a compared to the case where the angle between the first surface 22a of the flange 22 and the inner circumferential surface of the cylindrical portion 21 is 90°. In this embodiment, the reduced diameter portion 23 is also a portion of the cylindrical portion 21 on the first opening 21a side, where the outer radius decreases from the radius R1 of the first opening 21a to the radius r of the second opening 21b, moving from the first opening 21a to the second opening 21b.

[0033] In this embodiment, in a cross-section passing through the central axis C21 of the cylindrical portion 21, the inner circumferential surface 23a and the outer circumferential surface 23b at the reduced diameter portion 23 of the cylindrical portion 21 are curved. This configuration makes it possible to reduce inlet loss at the first opening 21a. In particular, in a cross-section passing through the central axis C21 of the cylindrical portion 21, the inner circumferential surface 23a and the outer circumferential surface 23b are smooth, arc-shaped curved surfaces.

[0034] In this embodiment, in a cross-section passing through the central axis C21 of the cylindrical portion 21, the radius of curvature of the inner circumferential surface 23a at the reduced diameter portion 23 of the cylindrical portion 21 is greater than the radius of curvature of the outer circumferential surface 23b at the reduced diameter portion 23 of the cylindrical portion 21. In other words, at the reduced diameter portion 23 of the cylindrical portion 21, the difference between the outer radius and the inner radius increases from the first opening 21a to the second opening 21b. This allows the radius of curvature of the outer circumferential surface 23b to be set to a value suitable for securing the width W of the flange 22, while the inner circumferential surface 23a can be set to a value that contributes to reducing inlet loss at the first opening 21a. Therefore, it is possible to reduce inlet loss at the first opening 21a while suppressing the reduction in the width W of the flange 22. This enables improved flow rate while ensuring mounting stability.

[0035] In this embodiment, as can be clearly seen from Figure 2, the cylindrical portion 21 has a reduced portion in which the cross-sectional area of ​​the flow path of the cylindrical portion 21 is smaller than the cross-sectional area of ​​the second opening 21b. More specifically, the inner circumferential surface of the cylindrical portion 21 includes a protruding portion 24 that protrudes toward the central axis C21 of the cylindrical portion 21 such that the cross-sectional area of ​​the flow path of the cylindrical portion 21 is smaller than the cross-sectional area of ​​the second opening 21b. As shown in Figure 5, the protruding portion 24 is a portion on the inner circumferential surface of the cylindrical portion 21 that protrudes toward the central axis C21 of the cylindrical portion 21 from a circle defined by the radius r of the second opening 21b when viewed from the direction of the central axis C21 of the cylindrical portion 21. In other words, it is a portion on the inner circumferential surface of the cylindrical portion 21 that is within a circle defined by the radius r of the second opening 21b.

[0036] In a cross-section passing through the central axis C21 of the cylindrical portion 21, the protruding portion 53 is bulging. The protruding portion 24 includes the top portion 24a where the flow path cross-sectional area is minimized.

[0037] The protruding portion 24 is located on the inner circumferential surface of the cylindrical portion 21, between the first opening 21a and the second opening 21b of the cylindrical portion 21. In particular, in this embodiment, the protruding portion 24 is located on the inner circumferential surface of the cylindrical portion 21, between the reduced diameter portion 23 of the cylindrical portion 21 and the second opening 21b.

[0038] In this embodiment, the end 24b of the protruding portion 24 on the side of the second opening 21b does not coincide with the second opening 21b in the direction of the central axis C21 of the cylindrical portion 21, and is located on the side of the first opening 21a relative to the second opening 21b. In the cylindrical portion 21, the inner radius and outer radius do not change in the direction of the central axis C21 of the cylindrical portion 21 in the portion 25 between the protruding portion 24 and the second opening 21b.

[0039] In a cross-section passing through the central axis C21 of the cylindrical portion 21, the inner circumferential surface 24c at the protruding portion 24 of the cylindrical portion 21 is curved. This configuration enables further improvement of flow rate.

[0040] On the inner circumferential surface of the cylindrical portion 21, the protruding portion 24 and the reduced-diameter portion 23 are continuously connected. Here, "X and Y are continuously connected" means that X and Y are connected in such a way that no steps or other obstacles that would hinder fluid movement occur between them. This reduces the pressure loss between the protruding portion 24 and the reduced-diameter portion 23, thereby improving the flow rate. Furthermore, on the inner circumferential surface of the cylindrical portion 21, the protruding portion 24 and portion 25 are continuously connected. This reduces the pressure loss between the protruding portion 24 and portion 25, thereby improving the flow rate.

[0041] Next, the function of the protruding portion 24 will be explained. As shown in Figure 1, the drain 1 connects the gutter 10 and the vertical pipe 12, allowing water to flow from the gutter 10 to the vertical pipe 12. In other words, the drain 1 changes the direction of water flow from the longitudinal direction of the gutter 10 to the direction of the central axis C21 of the cylindrical portion 21. When the direction of water flow changes significantly, pressure loss due to separation can be one of the causes of a decrease in drainage performance. In this case, the pressure loss is often large at the portion on the inner circumferential surface of the cylindrical portion 21 on the side of the first opening 21a. The existence of such a large pressure loss can be a major cause of a decrease in flow rate. The pressure loss at this portion is thought to be due to separation. This separation is caused by the water separating from the inner circumferential surface of the cylindrical portion 21. That is, the water flowing from the gutter 10 into the drain 1 initially flows along the first surface 22a of the flange 22, but beyond the first opening 21a, it may separate from the inner circumferential surface of the cylindrical portion 21. This type of separation is particularly noticeable when the water flow velocity is high. The higher the flow velocity, the wider the area over which pressure loss occurs.

[0042] In this embodiment, the inner circumferential surface of the cylindrical portion 21 has a protruding portion 24. The presence of the protruding portion 24 is expected to (1) allow water to flow more easily along the inner circumferential surface of the cylindrical portion 21 than if the protruding portion 24 were absent, and (2) reduce the number of areas where pressure loss may occur. Therefore, the protruding portion 24 can reduce the occurrence of pressure loss caused by separation downstream from the first opening 21a, thereby improving the flow rate. The protruding portion 24 does not require an increase in the outer radius of the cylindrical portion 21, thus enabling miniaturization. Therefore, the protruding portion 24 can improve the flow rate without affecting the width W of the flange 22.

[0043] Next, preferred dimensions for the protruding portion 24 will be described. As shown in Figure 2, if r is the radius of the second opening 21b, h is the amount of protrusion at the top 24a of the protruding portion 24, L1 is the distance between the first opening 21a and the top 24a in the direction of the central axis C21, and L2 is the distance between the top 24a and the end 24b of the protruding portion 24 on the second opening 21b side in the direction of the central axis C2, then it is preferable that the protruding portion 24 satisfies at least one of the following relationships expressed by equations (1) to (3). This makes it possible to improve the flow rate while ensuring mounting stability. Note that the amount of protrusion at the top 24a of the protruding portion 24 is the difference between the distance between the central axis C21 and the top 24a when viewed from the direction of the central axis C21, and the radius r of the second opening 21b.

[0044]

number

[0045] As shown in Figures 3 and 5, when viewed from the direction of the central axis C21 of the cylindrical portion 21, the protruding portion 24 extends across the entire inner surface of the cylindrical portion 21. This configuration allows for the improvement of flow rate due to the protruding portion 24 across the entire inner surface of the cylindrical portion 21.

[0046] From another perspective, the inner circumferential surface of the cylindrical portion 21 only needs to have a protruding portion 24 that projects toward the central axis C21 of the cylindrical portion 21 so as to create a Coanda effect between the first opening 21a and the second opening 21b. In other words, the protruding portion 24 only needs to have a shape that produces a Coanda effect. This makes it possible to improve the flow rate while ensuring mounting stability.

[0047] As shown in Figures 2 and 3, the funnel portion 3 is located on the side of the first opening 21a relative to the drain pipe portion 2. In other words, the funnel portion 3 is located at the upstream end 2a of the drain pipe portion 2. More specifically, the funnel portion 3 is positioned opposite the upstream end 2a of the drain pipe portion 2, such that the central axis C3 of the funnel portion 3 coincides with the central axis C2 of the drain pipe portion 2.

[0048] As shown in Figures 2 and 7, the funnel section 3 has a first opening 3a and a second opening 3b. The funnel section 3 directs the fluid flowing in through the first opening 3a to the outlet 2c of the drain pipe section 2 through the second opening 3b.

[0049] The funnel portion 3 has a reduced diameter portion 31, a small diameter cylindrical portion 32, and a flange 33.

[0050] As shown in Figure 7, the reduced diameter portion 31 is cylindrical in shape, with its outer and inner diameters decreasing as it approaches the drain pipe portion 2. The reduced diameter portion 31 can also be described as a hollow frustoconical shape with open ends. The reduced diameter portion 31 has a first surface 311 and a second surface 312. The first surface 311 is the inner circumferential surface of the reduced diameter portion 31. The first surface 311 defines the surface of the reduced diameter portion 31 opposite to the drain pipe portion 2. The second surface 312 is the outer circumferential surface of the reduced diameter portion 31. The second surface 312 defines the surface of the reduced diameter portion 31 facing the drain pipe portion 2. In this embodiment, the maximum outer diameter of the reduced diameter portion 31 is smaller than the inner diameter of the drain pipe portion 2 (the inner diameter of the cylindrical portion 21). In this embodiment, the inclination angle of the first surface 311 of the reduced diameter portion 31 in a cross-section passing through the central axis of the reduced diameter portion 31 is 40 degrees or more and 60 degrees or less.

[0051] The small-diameter cylindrical portion 32 extends from the end of the reduced-diameter portion 31 on the drain pipe portion 2 side (the lower end in Figure 2) towards the drain pipe portion 2. The small-diameter cylindrical portion 32 is cylindrical with less change in inner and outer diameter than the reduced-diameter portion 31. The interior of the small-diameter cylindrical portion 32 is connected to the interior of the reduced-diameter portion 31. The outer and inner circumferential surfaces of the small-diameter cylindrical portion 32 are substantially perpendicular to the central axis of the drain pipe portion 2, and are neither the surface on the drain pipe portion 2 side nor the surface on the opposite side of the drain pipe portion 2.

[0052] The flange 33 extends radially outward from the end of the reduced-diameter portion 31 opposite to the drain pipe portion 2 (the upper end in Figure 7). The flange 33 is plate-shaped and has a first surface 331 and a second surface 332. The first surface 331 is the upper surface of the flange 33. The first surface 331 defines the surface of the flange 33 opposite to the drain pipe portion 2. The second surface 332 is the lower surface of the flange 33. The second surface 332 defines the surface of the flange 33 facing the drain pipe portion 2. The flange 33 is annular. In this embodiment, the outer diameter of the flange 33 is smaller than the inner diameter of the drain pipe portion 2 (the inner diameter of the pipe portion 21).

[0053] As can be seen from Figures 4 and 5, in the funnel portion 3, the opening at the end of the reduced diameter portion 31 opposite to the drain pipe portion 2 is the first opening 3a, and the opening at the end of the small diameter portion 32 on the drain pipe portion 2 side is the second opening 3b.

[0054] As can be seen from Figures 2 and 7, in this embodiment, the funnel portion 3 is not located inside the drain pipe portion 2. Here, in the direction of the central axis C2 of the drain pipe portion 2, the distance between the second opening 3b and the drain pipe portion 2 is preferably less than half the distance between the first opening 3a and the drain pipe portion 2. In this embodiment, the end of the small-diameter cylindrical portion 32 of the funnel portion 3 on the drain pipe portion 2 side (second opening 3b) and the upstream end 2a of the drain pipe portion 2 are on the same plane. In other words, the minimum distance between the funnel portion 3 and the drain pipe portion 2, i.e., the distance between the second opening 3b and the drain pipe portion 2, is 0.

[0055] As can be seen from Figures 4 and 5, the central axis C3 of the funnel portion 3 coincides with the central axis of the reduced diameter portion 31, the central axis of the small diameter cylindrical portion 32, and the central axis of the flange 33.

[0056] In the funnel portion 3, the first surface 311 of the reduced diameter portion 31 and the first surface 331 of the flange 33 constitute the surface of the funnel portion 3 opposite to the drain pipe portion 2. In the funnel portion 3, the second surface 312 of the reduced diameter portion 31 and the second surface 332 of the flange 33 constitute the surface of the funnel portion 3 facing the drain pipe portion 2. Furthermore, the outer circumference 33a of the flange 33 constitutes the outer circumference of the funnel portion 3 when viewed from the direction of the central axis C2 of the drain pipe portion 2.

[0057] Let d be the diameter representing the outer shape of the funnel portion 3 as viewed from the direction of the central axis C2 of the drain pipe portion 2. Preferably, d is set to satisfy 0.6D ≤ d ≤ 1.5D. In this embodiment, d ≤ 1.0D. Here, the diameter d may be the diameter of the largest circle that tangent to any two points of the funnel portion 3 as viewed from the direction of the central axis C2 of the drain pipe portion 2. In this embodiment, since the funnel portion 3 is circular as viewed from the direction of the central axis C2 of the drain pipe portion 2, the diameter d is equal to the diameter of the funnel portion 3 (especially the diameter of the flange 33) as viewed from the direction of the central axis C2 of the drain pipe portion 2.

[0058] As shown in Figures 3 to 5, in this embodiment, there are five blades 4. The five blades 4 are the same shape. As shown in Figure 4, when viewed from the direction of the central axis C2 of the drain pipe 2, the five blades 4 are arranged at equal intervals around the central axis C2 of the drain pipe 2.

[0059] The blades 4 connect the drain pipe section 2 and the funnel section 3. More specifically, the blades 4 connect the upstream end 2a of the drain pipe section 2 to the side of the funnel section 3 opposite to the drain pipe section 2. In other words, the funnel section 3 is positioned at the upstream end 2a of the drain pipe section 2 so as to be suspended from the blades 4.

[0060] The wing 4 comprises a main body 41, an arm 42, and a reinforcing part 43.

[0061] The main body portion 41 is plate-shaped. In particular, the main body portion 41 is rectangular plate-shaped. The main body portion 41 protrudes from the upstream end 2a of the drain pipe portion 2. In particular, the main body portion 41 protrudes from the upstream end 2a of the drain pipe portion 2 along the central axis C2 of the drain pipe portion 2. The direction of the central axis C2 of the drain pipe portion 2 corresponds to the height direction of the main body portion 41. The main body portion 41 extends in the radial direction of the drain pipe portion 2 when viewed from the direction of the central axis C2 of the drain pipe portion 2. The radial direction of the drain pipe portion 2 corresponds to the length direction of the main body portion 41. The width direction (thickness direction) of the main body portion 41 is perpendicular to the radial direction of the drain pipe portion 2 when viewed from the direction of the central axis C2 of the drain pipe portion 2. The width of the main body portion 41 defines the width of the blade 4. If the width of the blade 4 is t, it is preferable that the drain 1 satisfies 2 mm ≤ t ≤ 6 mm.

[0062] The main body portion 41 has a first end portion 41a, a second end portion 41b, a third end portion 41c, and a fourth end portion 41d.

[0063] The first end 41a and the second end 41b are the ends of the main body 41 in the longitudinal direction. In particular, the first end 41a is the end of the drain pipe 2 on the side of the central axis C2 when viewed from the direction of the central axis C2 of the drain pipe 2. The second end 41b is the end of the drain pipe 2 on the opposite side of the central axis C2 when viewed from the direction of the central axis C2 of the drain pipe 2.

[0064] As can be seen from Figures 2 and 5, the corner of the first end 41a of the main body 41 is fillet-shaped when viewed from the direction of the central axis C2 of the drain pipe 2. In particular, the corner of the first end 41a of the main body 41 is a convex fillet shape. This makes it less likely for the worker's hand to hurt when touching the corner of the first end 41a when holding the blade 4 during the installation of the drain 1. Therefore, it becomes easier for the worker to hold the blade 4 during the installation of the drain 1. Note that the corner of the first end 41a of the main body 41 may be tapered when viewed from the direction of the central axis C2 of the drain pipe 2.

[0065] In the blade 4, as shown in Figures 2 and 5, the distance between the first end 41a of the main body 41 and the central axis C2 of the drain pipe 2, as viewed from the direction of the central axis C2 of the drain pipe 2, is denoted as b. It is preferable that b is set to satisfy 0.40d ≤ b ≤ 0.75d. When b is 0.40d or greater, the space between the drain pipe 2, the funnel 3, and the blade 4 can be widened while obtaining the flow straightening effect of the blade 4, thereby further suppressing the deterioration of drainage function caused by foreign matter. On the other hand, if b becomes too large, the entire drain 1 will become larger, so it is preferable that b be 0.75d or less.

[0066] In particular, in this embodiment, when viewed from the direction of the central axis C2 of the drain pipe section 2, the first end portion 41a of the main body section 41 is located outside the reduced diameter section 31. This allows for a further widening of the space between the drain pipe section 2, the funnel section 3, and the blades 4. Therefore, it is possible to further suppress the deterioration of drainage function caused by foreign matter. In addition, a swirling flow is more likely to occur between the reduced diameter section 31 and the blades 4, and an improvement in drainage function can be expected.

[0067] In particular, in this embodiment, when viewed from the direction of the central axis C2 of the drain pipe section 2, the first end portion 41a of the main body section 41 is located outside the flange 33. This configuration allows for a further widening of the space between the drain pipe section 2, the funnel section 3, and the vane 4. Therefore, it is possible to further suppress the deterioration of drainage function caused by foreign matter.

[0068] On the other hand, when viewed from the direction of the central axis C2 of the drain pipe section 2, the first end portion 41a of the main body section 41 is located inside the outlet 2c of the drain pipe section 2. This allows for an improvement in the flow straightening effect of the blades 4.

[0069] As shown in Figures 2 and 7, the first end portion 41a of the main body portion 41 is inclined to move away from the central axis C2 of the drain pipe portion 2 as it approaches the drain pipe portion 2. This allows for a wider space between the drain pipe portion 2, the funnel portion 3, and the blades 4. This further suppresses the deterioration of drainage function caused by foreign matter.

[0070] As can be seen from Figures 3 and 4, when viewed from the direction of the central axis C2 of the drain pipe section 2, the corners (both corners in this embodiment) of the second end 41b of the main body section 41 are fillet-shaped. In particular, the corners of the second end 41b of the main body section 41 are convex fillet-shaped. This makes it less likely for a worker's hand to hurt when touching the corners of the second end 41b when holding the blades 4 during the installation of the drain 1. Therefore, it becomes easier for a worker to hold the blades 4 during the installation of the drain 1. Note that when viewed from the direction of the central axis C2 of the drain pipe section 2, the corners of the second end 41b of the main body section 41 may be tapered.

[0071] The third end 41c and the fourth end 41d are the ends of the main body 41 in the height direction. In particular, the third end 41c is the end opposite to the drain pipe 2 in the direction of the central axis C2 of the drain pipe 2. The fourth end 41d is the end on the drain pipe 2 side in the direction of the central axis C2 of the drain pipe 2.

[0072] The third end portion 41c is further from the drain pipe portion 2 than the first surface 331 of the flange 33 of the funnel portion 3, in the direction of the central axis C2 of the drain pipe portion 2. In the direction of the central axis C2 of the drain pipe portion 2, the distance between the end portion (third end portion 41c) of one or more blades 4 opposite to the drain pipe portion 2 and the surface of the funnel portion 3 opposite to the drain pipe portion 2 (first surface 331 of the flange 33) is 5 mm or more and 15 mm or less. That is, as shown in Figure 6, if a1 is the distance between the end portion (third end portion 41c) of one or more blades 4 opposite to the drain pipe portion 2 in the direction of the central axis C2 of the drain pipe portion 2 and the drain pipe portion 2, and a2 is the distance between the surface of the funnel portion 3 opposite to the drain pipe portion 2 (first surface 331) and the drain pipe portion 2 in the direction of the central axis C2 of the drain pipe portion 2, then the condition 5 mm ≤ a1 - a2 ≤ 15 mm is satisfied. Here, if we let a1-a2=a, then a represents the distance between the end of the blade 4 opposite to the drain pipe section 2 (third end 41c) and the surface of the funnel section 3 opposite to the drain pipe section 2 (first surface 331) in the direction of the central axis C2 of the drain pipe section 2. This makes it possible to improve the strength of the connection between the funnel section 3 and the blade 4. Here, it is more preferable that a(=a1-a2)=9mm.

[0073] The fourth end portion 41d is also the portion of the main body 41 that is connected to the drain pipe portion 2.

[0074] In the direction of the central axis C2 of the drain pipe section 2, the main body 41 is connected to the flange 22 and the cylindrical section 21 of the drain pipe section 2, but does not reach the top 24a of the protruding portion 24. That is, when viewed from the direction of the central axis C2 of the drain pipe section 2, it does not protrude from the top 24a of the protruding portion 24 toward the central axis C2. This allows for a wider space between the drain pipe section 2, the funnel section 3, and the blades 4. This further suppresses the deterioration of drainage function caused by foreign matter. Furthermore, since the main body 41 extends not only to the flange 22 of the drain pipe section 2 but also to the cylindrical section 21, the strength of the blades 4 can be maintained.

[0075] In this embodiment, as shown in Figures 4 and 6, the main body portion 41 has fillets 41e, 41e at the end (fourth end portion 41d) on the drain pipe portion 2 side, which increase in width as it approaches the drain pipe portion 2 in the direction of the central axis C2 of the drain pipe portion 2. In this embodiment, the fillets 41e, 41e are located on both sides in the width direction of the main body portion 41. The surface of the fillets 41e is concave. The fillets 41e enable improved strength of the vanes 4 against the drain pipe portion 2. In this embodiment, as shown in Figures 4 and 7, the fillets 41e extend along the main body portion 41 and, like the main body portion 41, extend not only to the flange 22 of the drain pipe portion 2 but also to the cylindrical portion 21, but do not reach the top portion 24a of the protruding portion 24. The fillets 41e include a first portion 41e1 on the flange 22 and a second portion 41e2 on the cylindrical portion 21. In particular, in the second portion 41e2, at least one of the radius of curvature or width of the fillet 41e decreases from the second end 41b to the first end 41a of the main body 41. This allows for improved drainage function by the fillet 41e. In the second portion 41e2, the radius of curvature or width of the fillet 41e may be reduced to 0.

[0076] The arm portion 42 connects the funnel portion 3 to the main body portion 41 on the side opposite to the drain pipe portion 2 (first surface 311, 331). The arm portion 42 protrudes toward the funnel portion 3 from the end of the main body portion 41 opposite to the drain pipe portion 2 (third end portion 41c). When viewed from the direction of the central axis C2 of the drain pipe portion 2, the arm portion 42 extends in the radial direction of the drain pipe portion 2. The width direction of the arm portion 42 is perpendicular to the radial direction of the drain pipe portion 2 when viewed from the direction of the central axis C2 of the drain pipe portion 2. As an example, the width of the arm portion 42 is preferably 2 mm or more and 6 mm or less.

[0077] As shown in Figures 2 to 4, the arm portion 42 extends from the main body portion 41 to the first surface 331 of the flange 33 and the first surface 311 of the reduced diameter portion 31 of the funnel portion 3. The arm portion 42 connects the flange 33 and the reduced diameter portion 31 to the main body portion 41. In other words, the arm portion 42 has a first portion 42a and a second portion 42b. The first portion 42a is the part of the arm portion 42 that is connected to the flange 33. The second portion 42b is the part of the arm portion 42 that is connected to the reduced diameter portion 31. The height of the first portion 42a relative to the drain pipe portion 2 does not change as it approaches the center of the reduced diameter portion 31. The height of the second portion 42b relative to the drain pipe portion 2 decreases as it approaches the center of the reduced diameter portion 31. The height of the first part 42a or the second part 42b relative to the drain pipe section 2 is the distance between the end of the first part 42a or the second part 42b opposite to the drain pipe section 2 in the direction of the central axis C2 of the drain pipe section 2 and the drain pipe section 2. This makes it possible to increase the inflow of rainwater into the funnel section 3. Furthermore, even when rainwater flows into the funnel section 3, the possibility of vortex formation in the drain pipe section 2 can be reduced.

[0078] As shown in Figures 2 and 4, let c be the length of the connection between the arm portion 42 and the funnel portion 3 as viewed from the direction of the central axis C2 of the drain pipe portion 2. In this embodiment, c is equal to the distance between the tip of the arm portion 42 and the outer circumference of the funnel portion 3 (outer circumference 33a of the flange 33) as viewed from the direction of the central axis C2 of the drain pipe portion 2. It is preferable that c be set to satisfy 0.1d ≤ c ≤ 0.5D. When c is 0.1d or greater, it is possible to improve the strength of the connection between the funnel portion 3 and the blade 4. When c is 0.5D or less, it is possible to form a first opening 3a and a second opening 3b of sufficient size in the funnel portion 3. As shown in Figures 2 and 4, let e be the distance between the tip of the arm portion 42 and the central axis C2 of the drain pipe portion 2 as viewed from the direction of the central axis C2 of the drain pipe portion 2. It is preferable that e ≤ 0.25d. This is possible to improve the strength of the connection between the funnel portion 3 and the blade 4.

[0079] In this embodiment, as shown in Figures 4 and 7, the width of the arm portion 42 increases as it approaches the central axis C2 of the drain pipe portion 2 when viewed from the direction of the central axis C2 of the drain pipe portion 2. In particular, at the tip portion of the second portion 42b of the arm portion 42, the width of the arm portion 42 increases as it approaches the central axis C2 of the drain pipe portion 2 when viewed from the direction of the central axis C2 of the drain pipe portion 2. This makes it possible to improve the strength of the connection between the funnel portion 3 and the blades 4. The minimum width of the arm portion 42 is equal to the width of the main body portion 41.

[0080] In the present embodiment, as shown in FIGS. 4, 7, and 8, the arm portion 42 has fillets 42c, 42c at the end portion (lower end portion) on the side of the drain cylinder portion 2, and the width of the arm portion 42 increases as it approaches the drain cylinder portion 2 in the direction of the central axis C2 of the drain cylinder portion 2. In the present embodiment, the fillets 42c, 42c are on both sides in the width direction of the arm portion 42. The surface of the fillet 42c is a concave surface. The fillet 42c enables an improvement in the strength of the connection between the funnel portion 3 and the blade 4. In the present embodiment, as shown in FIGS. 4 and 7, the fillet 42c extends along the arm portion 42, and like the arm portion 42, it extends not only to the flange 33 of the funnel portion 3 but also to the reduced-diameter portion 31. Particularly, at the tip of the fillet 42c, at least one of the radius of curvature or the width of the fillet 42c decreases as it approaches the central axis C2 of the funnel portion 3. This enables an improvement in the drainage function by the fillet 42c. At the tip of the fillet 42c, the radius of curvature or the width of the fillet 42c may decrease to 0.

[0081] The reinforcing portion 43 is provided to improve the strength of the blade 4. As shown in FIG. 4, the reinforcing portion 43 is located at a position overlapping with the outer peripheral portion of the funnel portion 3 (the outer peripheral portion 33a of the flange 33) when viewed from the direction of the central axis C2 of the drain cylinder portion 2. The width direction of the reinforcing portion 43 is orthogonal to the radial direction of the drain cylinder portion 2 when viewed from the direction of the central axis C2 of the drain cylinder portion 2. Particularly, as understood from FIG. 8, the width of the reinforcing portion 43 increases as it approaches the funnel portion 3 (flange 33) in the direction of the central axis C2 of the drain cylinder portion 2. When a force is applied to the funnel portion 3 or the blade 4, stress tends to concentrate at the portion of the blade 4 corresponding to the outer peripheral portion of the funnel portion 3. Therefore, the presence of the reinforcing portion 43 can reduce the possibility of damage to the blade 4 due to such stress. Let the maximum value of the width of the reinforcing portion 43 be t1. It is preferable that t1 is set to satisfy 1.1t < t1 < 1.4t.

[0082] In this embodiment, referring to Figures 2 and 3, in the direction of the central axis C2 of the drain pipe section 2, the surface 43a of the reinforcing section 43 on the drain pipe section 2 side is further away from the drain pipe section 2 than the surface on the outer circumference of the funnel section 3 on the drain pipe section 2 side (the second surface 332 of the flange 33). In Figure 2, the position of the surface 43a of the reinforcing section 43 on the drain pipe section 2 side is indicated by h1, and the position of the surface on the outer circumference of the funnel section 3 on the drain pipe section 2 side (the second surface 332 of the flange 33) is indicated by h2. As a result, when force is applied to the funnel section 3 or the blades 4, the reinforcing section 43 can more easily absorb the stress, and the possibility of damage to the blades 4 can be reduced.

[0083] In this embodiment, the reinforcing portion 43 is located between the main body portion 41 and the arm portion 42 when viewed from the direction of the central axis C2 of the drain pipe portion 2. When force is applied to the funnel portion 3 or the blade 4, stress tends to concentrate at the connection point between the main body portion 41 and the arm portion 42 in the blade 4. Therefore, the presence of the reinforcing portion 43 reduces the possibility of damage to the blade 4 due to such stress.

[0084] In this embodiment, the reinforcing portion 43 is positioned to overlap with the outer circumference of the funnel portion 3 (the outer circumference 33a of the flange 33) when viewed from the direction of the central axis C2 of the drain pipe portion 2. Furthermore, in the direction of the central axis C2 of the drain pipe portion 2, the surface 43a of the reinforcing portion 43 on the drain pipe portion 2 side is further away from the drain pipe portion 2 than the surface on the outer circumference of the funnel portion 3 on the drain pipe portion 2 side (the second surface 332 of the flange 33). As a result, as shown in Figure 2, there is a gap G between the main body portion 41 and the end of the outer circumference of the funnel portion 3 on the drain pipe portion 2 side. Due to this gap G, the blades 4 do not come into contact with the radially outer end of the drain pipe portion 2 on the second surface 332 of the flange 33. Due to this gap G, the main body portion 41 of the blades 4 and the flange 33 of the funnel portion 3 are spaced apart from each other in the radial direction of the drain pipe portion 2. Therefore, the space between the drain pipe section 2, the funnel section 3, and the blades 4 can be widened, making it possible to further suppress the deterioration of drainage function caused by foreign matter. In particular, the presence of the gap G makes it easier for swirling flow to occur between the reduced diameter section 31 and the blades 4, and an improvement in drainage function can be expected.

[0085] In this embodiment, as shown in Figure 2, the blades 4 do not come into contact with the surface of the funnel portion 3 on the drain pipe portion 2 side (second surfaces 312, 332). Therefore, the space between the funnel portion 3 and the drain pipe portion 2 can be widened, reducing the possibility of foreign objects getting stuck. Thus, the drain 1 enables improved flow straightening and suppression of the deterioration of drainage function caused by foreign objects. In particular, in this embodiment, the blades 4 are not located between the funnel portion 3 and the drain pipe portion 2. Therefore, the space between the funnel portion 3 and the drain pipe portion 2 can be widened even further, further reducing the possibility of foreign objects getting stuck. Thus, the drain 1 enables further suppression of the deterioration of drainage function caused by foreign objects.

[0086] Refer to Figure 2 again. The fitting 11 is used to connect the drain 1 to a piping member. The piping member may be, for example, a straight pipe, an elbow, or a socket. In this embodiment, the fitting 11 is connected to the vertical pipe 12 via a socket 13.

[0087] The joint 11 has a cylindrical portion 11a and a flange 11b. The cylindrical portion 11a is cylindrical in shape. Female threads 11d are formed on the inner circumferential surface of the cylindrical portion 11a. The inner diameter of the cylindrical portion 11a is larger than the outer diameter of the drain pipe portion 2 of the drain 1. The female threads 11d of the cylindrical portion 11a correspond to the male threads 21c of the drain pipe portion 2 of the drain 1. The flange 11b is located at the upstream end of the cylindrical portion 11a (the upstream end in Figure 2) and extends radially outward from the cylindrical portion 11a. In this embodiment, there is a connecting portion 11c between the upstream end of the cylindrical portion 11a and the flange 11b. The connecting portion 11c is cylindrical in shape, with its inner diameter gradually increasing from the cylindrical portion 11a toward the flange 11b.

[0088] In the gutter drainage structure 100, the drain 1 is fixed to the gutter 10 using a joint 11. As shown in Figure 2, the drain 1 is positioned at the inlet 10b of the gutter 10. Here, the cylindrical portion 21 of the drain pipe 2 is located below the inlet 10b of the bottom wall 10a of the gutter 10, and the flange 22 of the drain pipe 2 is in contact with the upper surface around the inlet 10b of the bottom wall 10a of the gutter 10 on its downstream side. The joint 11 is attached to the cylindrical portion 21 of the drain pipe 2 below the inlet 10b. Specifically, the male thread 21c of the cylindrical portion 21 and the female thread 11d of the cylindrical portion 11a are connected. The flange 11b of the joint 11 is in contact with the lower surface around the inlet 10b of the bottom wall 10a of the gutter 10. In this way, the flange 22 of the drain 1 and the flange 11b of the joint 11 sandwich the bottom wall 10a of the gutter 10 from both the top and bottom sides, thereby attaching the drain 1 and the joint 11 to the gutter 10.

[0089] When the joint 11 is attached to the drain 1, the cylindrical portion 21 of the drain pipe portion 2 of the drain 1 is located within the cylindrical portion 11a and connecting portion 11c of the joint 11. The positional relationship between the joint 11 and the drain 1 is affected by the thickness of the bottom wall 10a of the gutter 10, but the upstream end of the cylindrical portion 11a of the joint 11 is located downstream of the upstream end of the cylindrical portion 21 of the drain pipe portion 2 in the direction of the central axis C2 of the drain pipe portion 2.

[0090] The vertical pipe 12 defines the vertical flow path. The vertical pipe 12 is fixed to the wall 220 of the building 200. In a rain gutter system, the vertical pipe 12 is also called a downpipe. The vertical pipe 12 is installed to drain rainwater from the inlet 10b. The vertical pipe 12 allows rainwater from the inlet 10b to flow vertically. The vertical pipe 12 is straight. The cross-section perpendicular to the central axis of the vertical pipe 12 is circular. The vertical pipe 12 is positioned so that the direction of its central axis coincides with the vertical direction. The vertical pipe 12 has an upstream end 12a and a downstream end 12b. The upstream end 12a is the end of the vertical pipe 12 that connects to the inlet 10b (the upper end in Figure 1). The downstream end 12b is the end of the vertical pipe 12 that is inserted into the manhole 310 (the lower end in Figure 1). In Figure 1, a pipe cover 12c is positioned to prevent rainwater from flowing into the manhole 310 through the gap between the vertical pipe 12 and the manhole 310. The length of the vertical pipe 12 is preferably 3m or more.

[0091] The socket 13 connects the fitting 11 and the vertical pipe 12. In this embodiment, the cylindrical portion 11a of the fitting 11 is connected to the upstream receiving end of the socket 13, and the upstream end 12a of the vertical pipe 12 is connected to the downstream receiving end of the socket 13.

[0092] For example, the material of the vertical pipe 12 and the socket 13 is rigid polyvinyl chloride. The dimensions of the vertical pipe 12, for example, the outer diameter and thickness, may be set in accordance with the standard for rigid polyvinyl chloride pipes (general) of JIS K 6741 "Rigid polyvinyl chloride pipes". The dimensions of the socket 13, for example, the outer diameter and thickness, may be set in accordance with the standard for sockets of JIS K 6739 "Rigid polyvinyl chloride pipe fittings for drainage".

[0093] [1.2 Effects, etc.] The drain 1 described above comprises a cylindrical portion 21 having a first opening 21a and a second opening 21b, and a flange 22 located at the end of the cylindrical portion 21 on the first opening 21a side and extending radially outward from the cylindrical portion 21. The inner circumferential surface of the cylindrical portion 21 includes a protruding portion 24 that projects toward the central axis C2 of the cylindrical portion 21 such that the flow path cross-sectional area of ​​the cylindrical portion 21 is smaller than the cross-sectional area of ​​the second opening 21b. The protruding portion 24 includes a top portion 24a where the flow path cross-sectional area is minimized. If r is the radius of the second opening 21b, h is the amount of protrusion at the top 24a of the protruding portion 24, L1 is the distance between the first opening 21a and the top 24a in the direction of the central axis C21, and L2 is the distance between the top 24a and the end 24b of the protruding portion 24 on the second opening 21b side in the direction of the central axis C2, then 0.05r ≤ h ≤ 0.30r, 0.1r ≤ L1 ≤ 0.7r, and L1 ≤ L2 ≤ 5L1. This configuration enables improved flow rate while ensuring mounting stability.

[0094] In the drain 1 described above, the protruding portion 24 is present across the entire inner surface when viewed from the direction of the central axis C21. This configuration allows for improved flow rate due to the protruding portion 24 across the entire inner surface of the cylindrical portion 21.

[0095] In the drain 1 described above, the inner circumferential surface 24c of the protruding portion 24 of the cylindrical portion 21 is curved in a cross-section passing through the central axis C21. This configuration enables further improvement of the flow rate.

[0096] In the drain 1 described above, in the direction of the central axis C21, the surface 22a of the flange 22 on the side of the first opening 21a lies on the same plane as the first opening 21a. This configuration makes it possible to reduce inlet losses at the first opening 21a, thereby enabling an improvement in flow rate.

[0097] In the drain 1 described above, the radius R1 of the first opening 21a is greater than the radius r of the second opening 21b. The cylindrical portion 21 has a reduced diameter section 23 on the first opening 21a side, where the inner radius decreases from the radius R1 of the first opening 21a to the radius r of the second opening 21b, from the first opening 21a toward the second opening 21b. The protruding portion 24 is located between the reduced diameter section 23 and the second opening 21b and is continuously connected to the reduced diameter section 23. This configuration makes it possible to reduce inlet loss at the first opening 21a, thereby enabling an improvement in flow rate.

[0098] In the drain 1 described above, in the cross-section passing through the central axis C21, the inner circumferential surface 23a and the outer circumferential surface 23b of the narrowed diameter portion 23 of the cylindrical portion 21 are curved. This configuration makes it possible to reduce inlet loss at the first opening 21a, thereby improving the flow rate.

[0099] In the drain 1 described above, in a cross-section passing through the central axis C21, the radius of curvature of the inner circumferential surface 23a at the reduced diameter portion 23 of the cylindrical portion 21 is greater than the radius of curvature of the outer circumferential surface 23b at the reduced diameter portion 23 of the cylindrical portion 21. This configuration allows for a reduction in inlet loss at the first opening 21a while suppressing a decrease in the width W of the flange 22, thereby enabling improved flow rate while ensuring mounting stability.

[0100] The drain 1 described above comprises a funnel portion 3 located on the first opening 21a side of the cylindrical portion 21, including a reduced diameter portion 31 in which the outer and inner diameters decrease as it approaches the cylindrical portion 21, and one or more vanes 4 connecting the funnel portion 3 to at least one of the cylindrical portion 21 and the flange 22. The one or more vanes 4 are spaced apart from the funnel portion 3 in a direction perpendicular to the direction of the central axis C21, and contact the surface of the funnel portion 3 opposite to the cylindrical portion 21 (first surface 311, 331) so as not to contact the surface of the funnel portion 3 on the cylindrical portion 21 side (second surface 312, 332). This configuration makes it possible to improve the flow straightening effect and suppress the deterioration of the drainage function caused by foreign matter.

[0101] In the drain 1 described above, one or more vanes 4 are not located between the funnel portion 3 and the cylindrical portion 21 and flange 22. This configuration makes it possible to further suppress the deterioration of drainage function caused by foreign matter.

[0102] In the drain 1 described above, one or more vanes 4 are not connected to the protruding portion 24 of the cylindrical portion 21. This configuration makes it possible to further suppress the deterioration of drainage function caused by foreign matter.

[0103] In the drain 1 described above, one or more blades 4 include a main body portion 41 that protrudes from at least one of the cylindrical portion 21 and the flange 22, and an arm portion 42 that connects the surface of the funnel portion 3 opposite to the cylindrical portion 21 (first surface 311, 331) to the main body portion 41. In the radial direction of the cylindrical portion 21, a gap G exists between the funnel portion 3 and the main body portion 41. This configuration allows for a wider space between the drain pipe portion 2, the funnel portion 3, and the main body portion 41 of the blades 4, further suppressing the reduction in drainage function (reduction in flow rate) caused by foreign matter.

[0104] [2. Variant] The embodiments of this disclosure are not limited to those described above. The embodiments can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure can be achieved. The following lists some modifications of the embodiments. The modifications described below can be combined and applied as appropriate.

[0105] The gutter drainage structure to which the drain 1 described above can be applied is not limited to the gutter drainage structure 100 shown in Figure 1.

[0106] [2.1 Variation 1] Figure 9 is a schematic diagram of the gutter drainage structure 100A according to the modified example 1. The gutter drainage structure 100A comprises a drain 1, a gutter 10, a joint 11, a vertical pipe 12, a horizontal pipe 14, a first elbow 15-1, and a second elbow 15-2.

[0107] In the eaves gutter drainage structure 100A, the vertical pipe 12 is connected to the joint 11 via the horizontal pipe 14, the first elbow 15-1, and the second elbow 15-2.

[0108] The horizontal pipe 14 defines a flow path that intersects the vertical direction. In a rain gutter system, the horizontal pipe 14 is also called a connecting pipe. The horizontal pipe 14 is the part that carries rainwater from the building 200 from the inlet 10b to the vertical pipe 12. The horizontal pipe 14 is located between the rainwater inlet 10b and the vertical pipe 12. The horizontal pipe 14 is straight. The cross section perpendicular to the central axis of the horizontal pipe 14 is circular. The horizontal pipe 14 is fixed so that the direction of the central axis of the horizontal pipe 14 is inclined with respect to the up and down direction (vertical direction). The horizontal pipe 14 has an upstream end 14a and a downstream end 14b. The upstream end 14a is the end of the horizontal pipe 14 that connects to the inlet 10b (the left end in Figure 9). The downstream end 14b is the end of the horizontal pipe 14 that connects to the vertical pipe 12 (the right end in Figure 9). For example, the material of the horizontal pipe 14 is rigid polyvinyl chloride. The dimensions of the horizontal pipe 14, for example, the outer diameter and thickness, may be set in accordance with the standard for rigid polyvinyl chloride pipes (general) in JIS K 6741 "Rigid Polyvinyl Chloride Pipes".

[0109] The first elbow 15-1 and the second elbow 15-2 change the direction of the flow path. The first elbow 15-1 and the second elbow 15-2 are connecting fittings that connect flow paths with different directions, such as a vertical pipe and a horizontal pipe.

[0110] Each of the first elbow 15-1 and the second elbow 15-2 has a curved section (bend) 15a and receiving openings 15b and 15c. The curved section 15a and the receiving openings 15b and 15c are formed as a continuous, integral part. As an example, the material of the first elbow 15-1 and the second elbow 15-2 is rigid polyvinyl chloride. The dimensions of the first elbow 15-1 and the second elbow 15-2 may be set in accordance with the JIS K 6739 standard "Rigid polyvinyl chloride pipe fittings for drainage".

[0111] Each of the first elbow 15-1 and the second elbow 15-2 is a 45° elbow (so-called 45L) as specified in JIS K 6739. In each of the first elbow 15-1 and the second elbow 15-2, the angle between the central axes of the sockets 15b and 15c is 45°.

[0112] In the eaves gutter drainage structure 100A, the cylindrical portion 11a of the joint 11 is connected to the receiving port 15b of the first elbow 15-1, and the upstream end 14a of the horizontal pipe 14 is connected to the receiving port 15c of the first elbow 15-1. The downstream end 14b of the horizontal pipe 14 is connected to the receiving port 15b of the second elbow 15-2, and the upstream end 12a of the vertical pipe 12 is connected to the receiving port 15c of the second elbow 15-2. In this way, a flow path for rainwater from the eaves gutter 10 to the drain section 310 is formed.

[0113] [2.2 Variation 2] Figure 10 is a schematic diagram of the gutter drainage structure 100B according to modified example 2. The gutter drainage structure 100B comprises a drain 1, a gutter 10, a joint 11, a vertical pipe 12, and an eccentric socket 16.

[0114] In the eaves gutter drainage structure 100B, the vertical pipe 12 is connected to the joint 11 via an eccentric socket 16.

[0115] The eccentric socket 16 has an eccentric portion 16a and receiving openings 16b and 16c. The eccentric portion 16a and receiving openings 16b and 16c are formed as a continuous, integral part. As an example, the material of the eccentric socket 16 is rigid polyvinyl chloride. The eccentric socket 16 may be a so-called S-socket.

[0116] In the eaves gutter drainage structure 100B, the cylindrical portion 11a of the joint 11 is connected to the receiving opening 16b of the eccentric socket 16, and the upstream end 12a of the vertical pipe 12 is connected to the receiving opening 16b of the eccentric socket 16. In this way, a flow path for rainwater from the eaves gutter 10 to the drain section 310 is formed.

[0117] [2.3 Variation 3] Figure 11 is a schematic diagram of the gutter drainage structure 100C according to the modified example 3. The gutter drainage structure 100C comprises a drain 1, gutters 10-1 and 10-2, a joint 11, vertical pipes 12-1 and 12-2, horizontal pipes 14-1 and 14-2, first to third elbows 15-1 to 15-3, a tee 17, a drain 18, and a piping member 19.

[0118] The gutter 10-1 receives rainwater from the roof 210 of the building 200. The gutter 10-1 is installed below the roof 210 of the building 200. The gutter 10-2 receives rainwater from a roof or eaves, etc., below the roof 210 of the building 200. For example, the gutter 10-2 is installed below the gutter 10-1.

[0119] Drain 1 is positioned at the inlet 10b of the gutter 10-1.

[0120] Drain 18 is located at the inlet 10b of the gutter 10-2. Drain 18 does not necessarily have the same configuration as drain 1. Drain 18 may have a well-known configuration.

[0121] The vertical pipe 12-1 is connected to the gutter 10-1 (drain 1 installed in the gutter 10-1) via the horizontal pipe 14-1, the first elbow 15-1, the second elbow 15-2, and the piping member 19. The vertical pipe 12-2 is connected to the gutter 10-2 (drain 18 installed in the gutter 10-2) via the horizontal pipe 14-2, the third elbow 15-3, and the tee 17.

[0122] Horizontal pipe 14-1 is located between the eaves gutter 10-1 and the vertical pipe 12-1. Horizontal pipe 14-2 is located between the eaves gutter 10-2 and the vertical pipe 12-2. Here, the length of horizontal pipe 14-1 is 2m or less, preferably 1m or less.

[0123] The first elbow 15-1 connects the gutter 10-1 to the upstream end 14a of the horizontal pipe 14-1. The second elbow 15-2 connects the downstream end 14b of the horizontal pipe 14-1 to the upstream end 12a of the vertical pipe 12-1. The third elbow 15-3 connects the gutter 10-2 to the upstream end 14a of the horizontal pipe 14-2.

[0124] In this modified example, the first elbow 15-1 is a 90° large-bend elbow (so-called LL) as defined in JIS K 6739. The second elbow 15-2 and the third elbow 15-3 are 90° elbows (so-called DL) as defined in JIS K 6739.

[0125] The cheese (Tee) 17 has an upward-facing first receiving port 17a, a downward-facing second receiving port 17b, and a laterally-facing third receiving port 17c. The cheese 17 combines the fluid flowing in from the first receiving port 17a with the fluid flowing in from the third receiving port 17c, and discharges it from the second receiving port 17b. The angle between the central axis of the first receiving port 17a and the central axis of the third receiving port 17c is 90° or less. As an example, the angle between the central axis of the first receiving port 17a and the central axis of the third receiving port 17c is set to 88.83°. As an example, the material of the cheese 17 is rigid polyvinyl chloride.

[0126] The first socket 17a is connected to the downstream end 12b of the vertical pipe 12-1. The second socket 17b is connected to the upstream end 12a of the vertical pipe 12-2. The third socket 17c is connected to the downstream end 14b of the horizontal pipe 14-2.

[0127] In the eaves gutter drainage structure 100C, a first elbow 15-1 and a second elbow 15-2 are provided between the eaves gutter 10-1 and the vertical pipe 12-1. The direction of the flow path changes in each of the first elbow 15-1 and the second elbow 15-2. When the direction of the flow path changes, pressure loss due to separation can be one of the causes of a decrease in flow rate. In this modified example, the radius of curvature of the second elbow 15-2 is smaller than the radius of curvature of the first elbow 15-1. Therefore, the pressure loss caused by the second elbow 15-2 tends to be greater than the pressure loss caused by the first elbow 15-1. To reduce the decrease in flow rate due to the pressure loss caused by the second elbow 15-2, a piping member 19 is provided.

[0128] The piping member 19 is positioned between the second elbow 15-2 and the vertical pipe 12-1. The piping member 19 comprises a straight pipe section 19a and a protruding member 19b.

[0129] The straight pipe section 19a is straight and has a socket 191 at its downstream end. The socket 191 is provided to connect the upstream end 12a of the vertical pipe 12-1 to the straight pipe section 19a. The upstream end of the straight pipe section 19a is connected to the socket 15c of the second elbow 15-2.

[0130] The projection member 19b is located downstream of the second elbow 15-2. More specifically, the projection member 19b is located on the inner circumference of the second elbow 15-2 within the straight pipe section 19a downstream of the second elbow 15-2 and is used to partially reduce the flow path cross-sectional area.

[0131] The surface of the projection member 19b has a curved shape that protrudes from the inner circumference to the outer circumference of the second elbow 15-2. The height of the projection member 19b varies along the direction of the central axis of the vertical pipe 12-1. The projection member 19b has a apex where its height is greatest, located between the upstream end and the downstream end. The height of the projection member 19b increases monotonically from the upstream end towards the apex. The height of the projection member 19b decreases monotonically from the apex towards the downstream end. At the apex, the projection member 19b minimizes the flow path cross-sectional area of ​​the vertical pipe 12-1.

[0132] Thus, by providing the projection member 19b, a reduced portion exists downstream of the second elbow 15-2 where the flow path cross-sectional area is smaller than that of the vertical pipe 12-1. The presence of such a projection member 19b is expected to (1) make it easier for the fluid to flow along the pipe wall than in the absence of the projection member 19b, and (2) reduce the number of areas where pressure loss may occur. Therefore, the projection member 19b can reduce the occurrence of pressure loss due to separation downstream of the second elbow 15-2 and improve the flow rate.

[0133] In the eaves gutter drainage structure 100C, rainwater from the eaves gutter 10-1 flows into the tee 17 through the first elbow 15-1, horizontal pipe 14-1, second elbow 15-2, piping member 19, and vertical pipe 12-1. Similarly, rainwater from the eaves gutter 10-2 flows into the tee 17 through the third elbow 15-3 and horizontal pipe 14-2. The rainwater from the eaves gutter 10-1 and the rainwater from the eaves gutter 10-2 then merge at the tee 17 and are discharged into the manhole 310 through the vertical pipe 12-2.

[0134] [2.4 Other variations] In one modified example, the drain pipe portion 2, the funnel portion 3, and one or more blades 4 may be formed by injection molding of a resin such as rigid polyvinyl chloride resin, polycarbonate, or ABS, or they may be made of a metal such as cast iron. The drain pipe portion 2, the funnel portion 3, and one or more blades 4 may be formed as a single continuous component, or they may be formed as separate parts.

[0135] In one modified example, the drain 1 does not necessarily have to have a funnel portion 3. Similarly, the drain 1 does not necessarily have to have one or more blades 4.

[0136] In one modified example, the cylindrical portion 21 does not necessarily have to have a reduced diameter portion 23. Even in this case, as described above, the flow rate can be improved by the protruding portion 24. When the cylindrical portion 21 does not have a reduced diameter portion 23, it is preferable that the end of the protruding portion 24 on the first opening 21a side coincides with the first opening 21a in the direction of the central axis C21.

[0137] In one modified example, in a cross-section passing through the central axis C21 of the cylindrical portion 21, at least one of the inner circumferential surface 23a and the outer circumferential surface 23b at the reduced diameter portion 23 of the cylindrical portion 21 may be tapered.

[0138] In one modified example, in a cross-section passing through the central axis C21 of the cylindrical portion 21, the radii of curvature of the inner circumferential surface 23a and the outer circumferential surface 23b at the reduced diameter portion 23 of the cylindrical portion 21 may be the same.

[0139] In one modified example, when viewed from the direction of the central axis C21 of the cylindrical portion 21, the protruding portion 24 does not necessarily have to extend across the entire inner surface of the cylindrical portion 21. Therefore, one or more protruding portions 24 may be provided on the inner surface of the cylindrical portion 21 as needed.

[0140] In one modified example, when viewed from the direction of the central axis C3 of the funnel portion 3, the outer shape of the funnel portion 3, for example, the reduced diameter portion 31, the small diameter cylindrical portion 32, or the outer shape of the flange 33, is not limited to a circular shape, but may be elliptical, polygonal, or other shapes.

[0141] In one modified example, the funnel portion 3 may not have to have either or both of the small-diameter cylindrical portion 32 and the flange 33.

[0142] In one modified example, the number of blades 4 is not particularly limited. The number of blades 4 may be one or more. The blades 4 may be located between the funnel portion 3 and the cylindrical portion 21 or flange 22, as long as they do not come into contact with the surface of the funnel portion 3 on the cylindrical portion 21 side (second surface 312, 332).

[0143] In one modified example, the arm portion 42 of the blade 4 does not necessarily have to extend to the reduced diameter portion 31. In other words, the arm portion 42 does not have to have a second portion 42b. The height of the second portion 42b relative to the drain pipe portion 2 does not have to decrease as it approaches the center of the reduced diameter portion 31.

[0144] In one modified example, the arm portion 42 of the blade 4 does not necessarily have to be connected to the flange 33, but may be connected only to the reduced diameter portion 31. In other words, the arm portion 42 may be connected to the reduced diameter portion 31 without being connected to the flange 33. In this case, there may be a gap between the first surface 331 of the flange 33 and the arm portion 42 in the direction of the central axis C2 of the drain pipe portion 2.

[0145] In one modified example, the first end portion 41a of the main body portion 41 does not have to be inclined to move away from the funnel portion 3 as it approaches the drain pipe portion 2. Therefore, the first end portion 41a may extend along the central axis C2 of the drain pipe portion 2.

[0146] In one modified example, the gap G may be provided by shortening the length of the main body portion 41 of the blade 4 in the radial direction of the drain pipe portion 2, or by forming a notch in the main body portion 41 on the funnel portion 3 side. In short, the gap G should be provided such that the flange 33 of the funnel portion 3 and the main body portion 41 of the blade 4 are spaced apart from each other in the radial direction of the drain pipe portion 2.

[0147] [3. Appearance] As will be apparent from the above embodiments and modifications, this disclosure includes the following aspects.

[0148] [Aspect 1] A cylindrical portion having a first opening and a second opening, A flange located at the first opening end of the cylindrical portion and extending radially outward from the cylindrical portion, Equipped with, The inner circumferential surface of the cylindrical portion includes a protruding portion that projects toward the central axis of the cylindrical portion such that the cross-sectional area of ​​the flow path of the cylindrical portion is smaller than the cross-sectional area of ​​the second opening. The aforementioned protruding portion includes the top portion where the cross-sectional area of ​​the flow path is minimized. Let the radius of the second opening be r. The amount of protrusion at the top of the protruding portion is h, L1 is the distance between the first opening and the top in the direction of the central axis. If L2 is the distance between the top and the second opening end of the protruding portion in the direction of the central axis, 0.05r ≤ h ≤ 0.30r, 0.1r ≤ L1 ≤ 0.7r, L1 ≤ L2 ≤ 5L1 Drain.

[0149] [Aspect 2] Viewed from the direction of the central axis, the protruding portion extends across the entire inner surface. Drain in embodiment 1.

[0150] [Aspect 3] In the cross-section passing through the central axis, the inner circumferential surface of the cylindrical portion at the protruding portion is curved. A drain according to embodiment 1 or 2.

[0151] [Aspect 4] In the direction of the central axis, the surface of the flange on the first opening side lies on the same plane as the first opening. A drain from any one of the three embodiments 1 to 3.

[0152] [Aspect 5] The radius of the first opening is greater than the radius of the second opening. The cylindrical portion has a reduced diameter section on the first opening side, where the inner radius decreases from the radius of the first opening to the radius of the second opening, from the first opening toward the second opening. The aforementioned protruding portion is located between the reduced diameter portion and the second opening and is continuously connected to the reduced diameter portion. A drain from any one of the embodiments 1 to 4.

[0153] [Aspect 6] In the cross-section passing through the central axis, the inner and outer surfaces of the cylindrical portion at the reduced diameter section are curved. Drain in aspect 5.

[0154] [Aspect 7] In the cross-section passing through the central axis, the radius of curvature of the inner circumferential surface at the reduced diameter portion of the cylindrical portion is greater than the radius of curvature of the outer circumferential surface at the reduced diameter portion of the cylindrical portion. Drain in aspect 6.

[0155] [Aspect 8] A funnel portion located on the first opening side of the cylindrical portion, which includes a reduced diameter portion in which the outer and inner diameters decrease as it approaches the cylindrical portion, One or more blades connecting at least one of the cylindrical portion and the flange to the funnel portion, Equipped with, The one or more blades are spaced apart from the funnel portion in a direction perpendicular to the direction of the central axis, and do not come into contact with the surface of the funnel portion on the side of the cylinder portion, but rather come into contact with the surface of the funnel portion on the side of the cylinder portion. A drain from any one of the embodiments 1 to 7.

[0156] [Aspect 9] The one or more blades mentioned above are not located between the funnel portion, the cylindrical portion, and the flange. Drain in aspect 8.

[0157] [Aspect 10] The aforementioned one or more feathers are, A main body portion protruding from at least one of the cylindrical portion and the flange, An arm portion connecting the funnel portion to the side opposite to the cylindrical portion and the main body portion, Includes, In the radial direction of the cylindrical portion, there is a gap between the funnel portion and the main body portion. A drain according to aspect 8 or 9.

[0158] The second through tenth aspects are not mandatory. [Industrial applicability]

[0159] This disclosure is applicable to drains. Specifically, this disclosure is applicable to drainage drains used in gutters. [Explanation of Symbols]

[0160] 1, 1A Drain 21 Cylinder part 21a 1st opening 21b 2nd opening 22 Flange 22a First surface (the surface on the first opening side of the flange) 23 Diameter reduction part 23a Inner surface 23b Outer surface 24 Protruding part 24a top 24b End (the end on the second opening side in the reduced diameter portion) 24c Inner surface 3, 3A funnel part 4 feathers

Claims

1. A cylindrical portion having a first opening and a second opening, A flange located at the first opening end of the cylindrical portion and extending radially outward from the cylindrical portion, Equipped with, The inner circumferential surface of the cylindrical portion includes a protruding portion that projects toward the central axis of the cylindrical portion such that the cross-sectional area of ​​the flow path of the cylindrical portion is smaller than the cross-sectional area of ​​the second opening. The aforementioned protruding portion includes the top portion where the cross-sectional area of ​​the flow path is minimized. The radius of the second opening is r, The amount of protrusion at the top of the protruding portion is h, L1 is the distance between the first opening and the top in the direction of the central axis. If L2 is the distance between the top and the second opening end of the protruding portion in the direction of the central axis, 0.05r ≤ h ≤ 0.30r, 0.1r ≤ L1 ≤ 0.7r, L1 ≤ L2 ≤ 5L1, Drain.

2. Viewed from the direction of the central axis, the protruding portion extends across the entire inner surface. The drain according to claim 1.

3. In the cross-section passing through the central axis, the inner circumferential surface of the cylindrical portion at the protruding portion is curved. A drain according to claim 1 or 2.

4. In the direction of the central axis, the surface of the flange on the first opening side lies on the same plane as the first opening. A drain according to claim 1 or 2.

5. The radius of the first opening is greater than the radius of the second opening. The cylindrical portion has a reduced diameter section on the first opening side, where the inner radius decreases from the radius of the first opening to the radius of the second opening, from the first opening toward the second opening. The aforementioned protruding portion is located between the reduced diameter portion and the second opening and is continuously connected to the reduced diameter portion. A drain according to claim 1 or 2.

6. In the cross-section passing through the central axis, the inner and outer surfaces of the cylindrical portion at the reduced diameter section are curved. The drain according to claim 5.

7. In the cross-section passing through the central axis, the radius of curvature of the inner circumferential surface at the reduced diameter portion of the cylindrical portion is greater than the radius of curvature of the outer circumferential surface at the reduced diameter portion of the cylindrical portion. The drain according to claim 6.

8. A funnel portion located on the first opening side of the cylindrical portion, which includes a reduced diameter portion in which the outer and inner diameters decrease as it approaches the cylindrical portion, One or more blades connecting at least one of the cylindrical portion and the flange to the funnel portion, Equipped with, The one or more blades are spaced apart from the funnel portion in a direction perpendicular to the direction of the central axis, and do not come into contact with the surface of the funnel portion on the side of the cylinder portion, but rather come into contact with the surface of the funnel portion on the side of the cylinder portion. A drain according to claim 1 or 2.

9. The one or more blades mentioned above are not located between the funnel portion, the cylindrical portion, and the flange. The drain according to claim 8.

10. The one or more feathers mentioned above are, A main body portion protruding from at least one of the cylindrical portion and the flange, An arm portion connecting the funnel portion to the side opposite to the cylindrical portion and the main body portion, Includes, In the radial direction of the cylindrical portion, there is a gap between the funnel portion and the main body portion. The drain according to claim 8.

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