JP2023124666A - rainwater drainage structure - Google Patents

Abstract

To provide a rainwater drainage structure capable of efficiently draining rainwater from a roof above a lean-to roof and rainwater from an eaves gutter of the lean-to roof, and improving workability and design of construction.SOLUTION: A rainwater drainage structure includes an eaves gutter installed on a building with a lean-to roof and attached to the eaves of the lean-to roof, an upper leader that drains rainwater from the roof above the lean-to roof, and a drain 40 attached to the through hole of the eaves gutter and drains rainwater from the eaves gutter downward, inducing a siphon effect. The upper drain member of the drain includes an upper flange attached to the top surface of the bottom plate of the eaves gutter, an upper cylindrical portion that passes through the through hole, a wing portion installed at a plurality of positions in the circumferential direction on the upper surface of the upper flange, and an upper leader connection portion that is supported by the wing portion and connects the upper leader. The lower drain member of the drain has a lower cylindrical portion that is provided below the lower flange and into which the upper cylindrical portion is inserted. The lower end of the upper leader connection position is located higher than the top surface of the upper flange.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to rainwater drainage structures for draining rainwater in buildings with sheds.

2. Description of the Related Art Conventionally, it has been practiced to collect rainwater that has flowed down an eaves gutter attached to the eaves of a building roof, send it to a downspout, and discharge it from below through the downspout. At this time, in order to increase the amount of wastewater treated in the downspout, it is conceivable to efficiently drain a large amount of rainwater by the siphon phenomenon.

Patent Literature 1 describes a rainwater drainage structure including an eaves gutter having a through hole in its bottom surface and a vertical gutter connected to a tubular portion on the lower side of a drainage member penetrating through the through hole. The drainage member of this rainwater drainage structure has a plate-like lid member arranged at the upper end, a mounting cylinder having a cylindrical portion, and a plurality of vertical ribs connecting the upper surface of the flange of the mounting cylinder and the lower surface of the lid member. and is said to cause a siphon phenomenon.

Japanese Patent No. 6279795

By the way, it is possible to install a rainwater drainage structure that efficiently drains a large amount of rainwater using the siphon phenomenon in a building with a shed and efficiently drain the rainwater from the shed eaves gutter attached to the eaves of the shed. Conceivable. Also, at this time, it is conceivable to drain the rainwater into the lower house eaves gutter by lowering the drain pipe from the roof above the lower house, for example, from the side of the large roof. However, in this configuration, there is a possibility that the water from the drain pipe hits the bottom surface of the lower eaves gutter and splashes. For this purpose, a drainage pipe from above is passed through a part of the eaves gutter, a drain is connected to a position different from the position where the drain pipe penetrates the eaves gutter, and the downstream end of the branch pipe connected to the drain is can be connected below the eaves gutter of the drain pipe. As a result, the rainwater flowing from the upper side of the drain pipe and the rainwater from the lower eaves gutter join together at the lower side of the drain pipe and then are discharged.

However, in this arrangement, the drain pipe from above is passed through the eaves gutter, and a through hole for drain connection is formed at a position different from the position where the drain pipe penetrates the eaves gutter, so that rainwater from the eaves gutter is drained into the drain pipe. branch pipes must be connected to the drainpipe to form a stormwater drainage structure. Such a rainwater drainage structure requires a considerable amount of time and effort to construct, resulting in poor construction workability. Moreover, there is also a problem that the drainage structure in which the branch pipe is connected to the drainage pipe has a poor design.

Therefore, the object of the present disclosure is to provide a rainwater drainage structure that can efficiently drain rainwater from the roof above the shed and the rainwater from the eaves gutter of the shed and can improve the workability and design of construction. to provide.

A rainwater drainage structure according to the present disclosure is installed in a building with a shed and drains rainwater from a roof above the shed and rainwater from the shed. An eaves gutter with a through-hole, an upper downpipe that drains rainwater from the roof above the shed, and an upper downspout that is attached to the through-hole and discharges rainwater from the eaves gutter downward, inducing a siphon phenomenon. a drain having an upper drain member and a lower drain member, the upper drain member including an upper flange attached to the upper surface of the bottom plate of the eaves gutter; An upper cylindrical portion that extends downward as it goes radially inward and penetrates the through hole, a blade portion that stands upright at a plurality of positions in the circumferential direction on the upper surface of the upper flange, and an upper vertical gutter supported by the blade portion. The lower drain member has a lower flange attached to the lower surface of the bottom plate of the eaves gutter, and the lower drain member is provided on the lower side of the lower flange, and the upper cylindrical portion is inserted inside. a lower tubular portion, the lower tubular portion being connected to a lower gutter for discharging rainwater downward, the lower end of the upper gutter connecting portion being higher than the upper surface of the upper flange; Drainage structure.

According to the rainwater drainage structure of one aspect of the present disclosure, rainwater from the eaves gutter at the eaves of the shed can be discharged to the lower gutter through the drain, and rainwater from the roof above the shed can be drained from the upper gutter. It can be discharged to the lower downpipe through the drain. At this time, since the inner side of the lower end of the upper downpipe can face the inner side of the upper cylindrical portion, it is possible to suppress splashing of rainwater discharged from the upper downspout in the eaves gutter. Also, the drain induces a siphon phenomenon. As a result, the rainwater from the upper downpipe and the rainwater from the eaves gutter merge at the drain, which makes it easy for the rainwater on the upstream side of the lower downpipe to become full. A large amount of rainwater can be efficiently drained to the side downspout. Furthermore, there is no need to form a separate through-hole in the eaves gutter at a position different from the through-hole through which the drain penetrates in order to drain rainwater from the roof above the shed. Thereby, the workability of the construction work can be improved. Furthermore, since it is not necessary to connect the branch pipe connected to the eaves gutter below the eaves gutter of the drain pipe, the design can be improved.

1 is a schematic perspective view showing part of a building in which a rainwater drainage structure of an embodiment is installed; FIG. 2 is an enlarged cross-sectional view of part A in FIG. 1; FIG. FIG. 3 is a front view of a drain provided in FIG. 2; FIG. 4 is a top view of the drain of FIG. 3; FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4; FIG. 6 is a view corresponding to FIG. 5 in a rainwater drainage structure of another example of the embodiment; FIG. 3 is a view corresponding to FIG. 2 in a rainwater drainage structure of another example of the embodiment; It is the figure which looked at FIG. 7 from the top.

Hereinafter, embodiments of the rainwater drainage structure according to the present disclosure will be described with reference to the drawings. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that the characteristic portions thereof will be appropriately combined to construct a new embodiment. The shapes, arrangements, numbers, materials, etc. described below are examples for explanation, and can be changed as appropriate according to the specifications of the rainwater drainage structure. In the following description, the same reference numerals are assigned to the same elements in all the drawings.

An embodiment will be described with reference to FIGS. 1 to 5. FIG. FIG. 1 is a schematic perspective view showing part of a building 100 in which a rainwater drainage structure 1 of the embodiment is installed. A building 100 provided with the rainwater drainage structure 1 includes an entrance door (not shown) and a shed 102 provided so as to protrude from a wall surface 101 above the windows on the first floor. The upper surface of the shed 102 is inclined with respect to the vertical direction so as to become lower toward the eaves, which is the front end.

The rainwater drainage structure 1 includes a shed eaves gutter 10 provided at the eaves of a shed 102, an upper gutter 18 and a lower gutter 20 arranged vertically along the wall surface 101 near the wall surface 101, and an upper and a drain 40 (FIG. 2) mounted in a through hole in the lower eaves gutter 10 between the downspout 18 and the lower downspout 20. As shown in FIG. The upper downspout 18 receives rainwater 106 from an upper eaves gutter 104 provided at the eaves of a large roof 103, which is a roof above the shed 102, through a call gutter 105, and causes the rainwater to flow down. Drain downwards. In FIG. 1, the rainwater 106 is indicated by the diagonal grid portion. In addition, the roof above the shed 102 is not limited to the large roof 103, and may be a roof other than the large roof such as a shed upstairs or a roof with a balcony function. In this example, the upper eaves gutter 104 extends along the left-right direction of the building 100, and the lower eaves gutter 10 extends along the front-rear direction perpendicular to the left-right direction.

The lower eaves gutter 10 is made of resin, for example, and has a groove shape in cross section in which the lower ends of a first wall 11 and a second wall 12 (FIG. 2) are connected by a bottom plate 13 and extends in the front-rear direction. The shed eaves gutter 10 is suspended by, for example, a hanger (not shown) attached to the building 100, attached to the eaves of the shed 102, and arranged to receive rainwater 106 flowing down from the shed 102. be. The lower eaves gutter 10 has an open upper surface and is closed at both left and right ends. The shed eaves gutter 10 may be fixed with a bracket fixed to the tip of the shed 102 so as to extend to the right. A through hole 14 (FIG. 2) is formed at the rear end of the bottom plate 13 of the lower eaves gutter 10 for connection to the lower gutter 20 via a drain 40 (FIG. 2), which will be described later.

The upper downspout 18 and the lower downspout 20 are each fixed at a plurality of vertical positions on the wall surface 101 by a plurality of fixing members that fit and fix the upper downspout 18 or the lower downspout 20 at a plurality of vertical positions. It is fixed near the wall surface 101 . The upper downspout 18 and the lower downspout 20 discharge rainwater downward.

The drain 40 is attached to the through hole 14 (FIG. 4) provided in the bottom plate 13 of the lower eaves gutter 10, and the upper end of the lower gutter 20 is connected to the portion projecting downward from the through hole 14. be done. Thereby, the drain 40 discharges the rainwater of the lower eaves gutter 10 to the lower side gutter 20.例文帳に追加

FIG. 2 is an enlarged cross-sectional view of part A in FIG. FIG. 3 is a front view of the drain 40 provided in FIG. FIG. 4 is a top view of the drain 40. FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4. FIG. The drain 40 is made of resin, for example, and has an upper drain member 41 and a lower drain member 61 .

The upper drain member 41 is installed on the upper surface of the bottom plate 13 of the eaves gutter 10 and has an upper flange 42 and an upper tubular portion 50 . The upper flange 42 is attached to the upper surface of the bottom plate 13 by sandwiching the bottom plate 13 with the lower flange 62 of the lower drain member 61 as will be described later. The upper cylindrical portion 50 extends downward from the radially inner end of the upper flange 42 toward the radially inner side. , and the lower side has a substantially cylindrical shape. The upper tubular portion 50 penetrates through the through hole 14 . It should be noted that the upper inner peripheral surface of the upper tubular portion may be provided with a tapered surface having a straight cross section, and the upper tubular portion may extend downward from the radially inner end of the upper flange 42 toward the radially inner side. good. The upper outer peripheral surface of the upper cylindrical portion 50 can be provided with a curved surface portion 52 having an arcuate cross section or a tapered surface having a straight cross section in accordance with the shape of the upper inner peripheral surface.

A male screw 53 for screwing with the lower drain member 61 is formed on the outer peripheral surface of the upper tubular portion 50 below the curved surfaces 51 and 52 . The upper drain member 41 is formed by injection molding of hard vinyl chloride resin, polycarbonate, ABS, or other resin. The upper drain member 41 may be made of metal such as cast iron.

Furthermore, the upper drain member 41 has a rainwater high drainage function that induces a siphon phenomenon when a large amount of rainwater flows into the eaves gutter 10 during heavy rain. For this reason, the upper drain member 41 includes blade portions 54 erected at a plurality of positions, specifically five positions, at approximately equal intervals in the circumferential direction on the upper surface of the upper flange 42 and the inner peripheral surface of the curved surface portion 51, It includes a cylindrical upper gutter connecting portion 58 that is connected to the radially inner ends of the plurality of blade portions 54 and supported so as to be coaxial with the upper cylindrical portion 50 .

A lower end 59 of the upper downspout connection 58 is positioned higher than the upper surface of the upper flange 42 . As a result, when the upper drain member 41 is viewed from one side in the horizontal direction as shown in FIG. S is formed. The upper downspout 18 is connected to the upper downspout connecting part 58 by fitting and fixing the lower end of the upper downspout 18 inside the upper downspout connecting part 58 . At this time, the lower end 19 of the upper downspout 18 is at a position higher than the upper surface of the upper flange 42 and at the same position as or higher than the lower end 59 of the upper downspout connecting portion 58 . Thereby, in this example, when the rainwater in the lower eaves gutter 10 is drained by the drain 40, it becomes easy to merge with the rainwater flowing down from the upper downspout 18.例文帳に追加

The plurality of blade portions 54 are plate-shaped and connected to a plurality of positions in the circumferential direction of the upper end of the upper cylindrical portion 50 so as to extend from the upper end of the outer peripheral portion of the upper flange 42 to the inner peripheral end of the lower end portion of the curved surface portion 51, It extends radially. A radially outer end of each blade portion 54 is formed as a flat surface substantially parallel to the center axis of the upper cylindrical portion 50 or a tapered surface slightly inclined radially outward toward the lower end. Both circumferential side surfaces of each blade portion 54 are flat surfaces. Although the number of blade portions 54 is five, it may be an odd number other than five.

A rectangular plate-like projecting portion 55 projecting upward is formed on the radially outer side of the upper end of each blade portion 54 . In the upper drain member 41, a portion above the upper side surface of the upper flange 42 and partitioned by a plurality of blade portions 54 is an inlet 44 for introducing rainwater that has flowed into the lower eaves gutter 10 into the upper drain member 41. Become. The plurality of vanes 54 have the function of rectifying rainwater that has flowed in from the inlet 44 . Therefore, the rainwater is rectified by the plurality of vanes 54 and flows, thereby inducing a siphon phenomenon.

On the other hand, the lower drain member 61 is in contact with the lower surface of the bottom plate 13 of the lower eaves gutter 10, and is attached to the lower surface of the bottom plate 13 by sandwiching the upper flange 42 and the bottom plate 13 as described later. and a lower tubular portion 70 provided on the lower side of the . The upper tubular portion 50 is inserted into the lower tubular portion 70, and the lower side thereof has a substantially cylindrical shape. In the case of this example, the upper end portion of the lower tubular portion 70 is formed with an inclined tubular portion 71 whose diameter decreases downward. The inner peripheral surface of the inclined tubular portion 71 is a tapered surface having a linear cross section, and the outer peripheral surface of the inclined tubular portion 71 is a curved surface having an arcuate cross section.

A female screw 72 for screwing with the male screw 53 of the upper drain member 41 is formed on the inner peripheral surface of the lower tubular portion 70 . The female screw 72 is divided in the circumferential direction of the lower cylindrical portion 70 and formed intermittently, but it may be formed as a continuous shape as a whole.

The lower drain member 61 is connected to the upper end portion of the lower gutter 20 by fitting the lower tubular portion 70 inside the large-diameter tubular portion 21 formed at the upper end of the lower gutter 20. be. Similarly to the upper drain member 41, the lower drain member 61 is also formed by injection molding of resin such as hard vinyl chloride resin. The lower drain member 61 may be made of metal such as cast iron. The lower end of the lower downpipe 20 may be connected to a drainage pipe buried in the ground so that the rainwater flowing down the inside of the lower downpipe 20 is drained to the drainage pipe.

Furthermore, the inner diameter d1 (FIG. 5) of the upper gutter connecting portion 58 is equal to the inner diameter d2 (FIG. 5) of the lower cylindrical portion 70.
less than As a result, the inner side of the lower end of the upper side gutter 18 connected to the upper side gutter connecting portion 58 tends to face the inner side of the upper cylindrical portion 50 .

A method of assembling the rainwater drainage structure 1 including the drain 40 will be described. First, the through hole 14 is formed in the bottom plate 13 of the eaves gutter 10 at the position where the upper drain member 41 is attached. Next, the upper cylindrical portion 50 of the upper drain member 41 is inserted into the through hole 14 from above to project downward, and the upper flange 42 is locked to the peripheral portion of the through hole 14 on the upper surface of the bottom plate 13 . At this time, an adhesive is applied between the lower surface of the upper flange 42 and the upper surface of the bottom plate 13 for water sealing. For example, the upper flange 42 is placed on the upper surface of the bottom plate 13 in a state in which adhesive is applied to the lower surface of the upper flange 42 in advance.

Then, a lower drain member 61 is screwed to the outer peripheral side of the upper cylindrical portion 50 projecting downward from the through hole 14 of the eaves gutter 10, and the upper flange 42 of the upper drain member 41 and the lower The lower flange 62 of the side drain member 61 and the bottom plate 13 of the lower eaves gutter 10 are sandwiched and fixed from both upper and lower sides. After that, the upper end of the lower gutter 20 is connected to the lower cylindrical portion 70 of the lower drain member 61 , and the lower end of the upper gutter 18 is connected to the upper gutter connecting portion 58 of the upper drain member 41 .

According to such a rainwater drainage structure 1, rainwater 106 falling on the shed 102 flows into the shed eaves gutter 10, and as shown in FIGS. 44 , passes through the inside of the upper cylindrical portion 50 and is introduced into the lower downpipe 20 . In addition, rainwater 106 falling on the large roof 103 is introduced from the upper eaves gutter 104 into the upper downspout 18, passes through the upper downspout 18, and then passes through the inside of the upper cylindrical portion 50 from the lower end to the lower downspout. 20. As a result, the rainwater from the large roof 103 and the rainwater from the shed 102 join inside the upper cylindrical portion 50 . When the rainwater flowing through the lower downpipe 20 reaches a predetermined flow rate or more, the rainwater flowing down the lower downpipe 20 is vigorously drained downward from the lower downpipe 20 by the siphon phenomenon.

Specifically, when the amount of rainwater flowing through the lower downpipe 20 reaches a predetermined flow rate or more, it becomes easier to form a plug clogged with rainwater in a part of the lower downpipe 20 . Then, a negative pressure is generated at the plug portion due to the difference in height, and the force that pulls the rainwater downward increases, causing a siphon phenomenon in which the rainwater flows down vigorously. According to the drain 40 described above, the plurality of vanes 54 can enhance the effect of rectifying the rainwater, so that when the rainwater flows into the inlet 44, the generation of vortices can be suppressed. As a result, it is possible to suppress the air from being sucked into the lower side gutter 20 by the vortex, so that a more excellent siphon performance can be exhibited and the drainage performance can be enhanced. In addition, since the rainwater from the upper vertical gutter 18 and the rainwater from the lower eaves gutter 10 join inside the upper tubular portion 50, the upper tubular portion 50 is easily filled with water. Further, at the inlet 44 , foreign matter entering the through hole 14 is restricted by the blades 54 adjacent in the circumferential direction. As a result, it is possible to prevent the through hole 14 from being clogged with the foreign matter.

According to the rainwater drainage structure 1, the rainwater from the eaves gutter 10 at the eaves of the shed 102 can be discharged to the lower gutter 20 through the drain 40, and the rainwater from the roof above the shed 102 can be discharged. It can be discharged from the upper downspout 18 to the lower downspout 20 through the drain 40. - 特許庁At this time, since the inner side of the lower end of the upper downpipe 18 can face the inner side of the upper cylinder part 50, splashing of rainwater discharged from the upper downspout 18 on the lower eaves gutter 10 can be suppressed. Also, the drain 40 induces a siphon phenomenon. As a result, the rainwater from the upper vertical gutter 18 and the rainwater from the lower eaves gutter 10 join together at the drain 40, which makes it easy for the rainwater to become full on the upstream side of the lower vertical gutter 20, resulting in a siphon phenomenon. can be used to efficiently drain a large amount of rainwater to the lower side gutter 20. - 特許庁Furthermore, for draining rainwater from the roof above the shed 102, there is no need to form another through hole in the shed eaves gutter 10 at a position different from the through hole 14 through which the drain 40 passes. Thereby, the workability of the construction work can be improved. Furthermore, since it is not necessary to connect the branch pipe connected to the lower eaves gutter below the lower eaves gutter of the drain pipe, the design can be improved.

In addition, since the upper cylindrical portion 50 has a curved surface portion 51 extending downward from the radially inner end of the upper flange 42 toward the radially inner side, the rainwater that has flowed above the upper flange 42 is It becomes easier to smoothly introduce it to the lower side of the upper cylindrical portion 50 .

FIG. 6 is a view corresponding to FIG. 5 in a rainwater drainage structure of another example of the embodiment. In the configuration of this example, with the lower end of the upper downspout 18 fixed to the inside of the upper downspout connecting portion 58, the lower end 19 of the upper downspout 18 is located at a position lower than the upper surface of the upper flange 42 and above the upper side. It is located inside the cylindrical portion of the tubular portion 50 . Thus, in the configuration of this example, the rainwater from the lower eaves gutter 10 and the rainwater from the upper downspout 18 are joined more downstream than in the configurations of FIGS. When the flow rate of rainwater from the upper downpipe 18 is large, it becomes easier to introduce rainwater from the upper downpipe 18 into the upper tubular portion 50 more effectively. 6 is selected when the scheduled drainage amount of rainwater flowing through the upper vertical gutter 18 is equal to or greater than the predetermined flow rate, and the configuration of FIG. You can choose the configuration. Other configurations and actions in this example are the same as those in FIGS.

FIG. 7 is a view corresponding to FIG. 2 in a rainwater drainage structure of another example of the embodiment. 8 is a top view of FIG. 7. FIG. 7 and 8, the upper drain member 80 constituting the drain 40a is indicated by a slanted lattice, the lower drain member 90 is indicated by coarse sand, and the upper downspout 18 is indicated by fine sand. In the configuration of this example, in the drain 40a, the number of blade portions 54 of the upper drain member 80 is four, and the four blade portions 54 are provided at substantially equal intervals in the circumferential direction.

Furthermore, the portion of the lower drain member 90 that connects to the lower flange 92 at the upper end of the lower tubular portion 91 is not formed with a curved surface portion, and the lower tubular portion 91 has a simple cylindrical shape. The lower downpipe 20 is fitted and fixed to the lower cylindrical portion 91 while being abutted against the lower surface of the lower flange 92 . 1 to 5, rainwater from the roof above the shed and the rainwater from the shed eaves gutter 10 can be efficiently drained, and construction workability is improved. And the effect that designability can be improved is acquired.

In each of the above examples, rainwater from the large roof 103 is introduced from the upper eaves gutter 104 through the call gutter 105 into the upper vertical gutter 18, but the upper eaves gutter is installed on the same wall surface as the lower eaves gutter 10. It is also possible to adopt a configuration in which rainwater is introduced from the upper eaves gutter to the upper vertical gutter 18 without passing through the call gutter.

1 rainwater drainage structure 10 lower eaves gutter 11 first wall 12 second wall 13 bottom plate 14 through hole 18 upper side gutter 19 lower end 20 lower side gutter 21 large diameter cylindrical portion 40, 40a drain, 41 upper drain member, 42 upper flange, 44 inlet, 50 upper cylindrical portion, 51, 52 curved surface portion, 53 male screw, 54 blade portion, 55 projecting portion, 58 upper gutter connection portion, 59 lower end, 61 Lower drain member 62 Lower flange 70 Lower tubular portion 71 Inclined tubular portion 72 Female screw 80 Upper drain member 90 Lower drain member 100 Building 101 Wall surface 102 Shed 103 Large roof 104 Upper eaves gutter, 105 calling gutter, 106 rainwater.

Claims (4)

A rainwater drainage structure installed in a building having a shed and draining rainwater from a roof above the shed and rainwater from the shed,
an eaves gutter attached to the eaves of the shed and having a through hole;
an upper downspout for letting rainwater flow down from the roof above the shed;
a drain that is attached to the through-hole, discharges rainwater from the eaves gutter downward, and induces a siphon phenomenon;
The drain has an upper drain member and a lower drain member,
The upper drain member includes an upper flange attached to the upper surface of the bottom plate of the eaves gutter, and an upper cylindrical portion extending downward from the radially inner end of the upper flange toward the radially inner side and passing through the through hole. and a blade portion erected at a plurality of positions in the circumferential direction of the upper surface of the upper flange, and an upper downspout connection portion supported by the blade portion and connecting the upper downspout,
The lower drain member has a lower flange attached to the bottom surface of the bottom plate of the eaves gutter, and a lower tubular portion provided below the lower flange and into which the upper tubular portion is inserted. death,
The lower tubular portion is connected to a lower gutter for discharging rainwater downward,
The lower end of the upper gutter connecting portion is located higher than the upper surface of the upper flange,
Rainwater drainage structure. In the rainwater drainage structure according to claim 1,
The rainwater drainage structure, wherein the inner diameter of the upper gutter connecting portion is smaller than the inner diameter of the lower cylindrical portion. In the rainwater drainage structure according to claim 1 or claim 2,
A rainwater drainage structure, wherein the lower end of the upper downpipe is positioned higher than the upper surface of the upper flange. In the rainwater drainage structure according to claim 1 or claim 2,
A rainwater drainage structure, wherein the lower end of the upper downpipe is positioned lower than the upper surface of the upper flange.

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