JP7312307B2 - rainwater drainage - Google Patents

Description

The present invention relates to a rainwater drainage device that collects and drains rainwater.

In recent years, with the increase in the frequency of torrential rains, rainwater pipes have become larger in order to efficiently drain rainwater from roofs of buildings.

On the other hand, by using the siphon phenomenon, a rainwater removal means is used that makes it possible to reduce the diameter of rainwater pipes and reduce the number of rainwater stand pipes.

For example, Patent Literature 1 discloses a siphon type rainwater drainage device that can drain a large amount of rainwater extremely efficiently by siphoning during heavy rain, and does not increase the cost or spoil the appearance of the house.

Japanese Patent Application Laid-Open No. 2004-308399 (Patent No. 4130616)

However, the above-described conventional rainwater drainage apparatus has the following problems.
That is, in the rainwater drainage device disclosed in the above publication, the upper end of a siphon pipe having an opening area of 3 to 13 cm2 is arranged vertically along the outer wall material of the house at the bottom of the water collection pipe attached to the eaves. is connected.

With such a configuration, rainwater can be efficiently drained by the siphon action. An air column may be formed at the center of the rainwater that swirls into the interior of the hood, reducing the efficiency of drainage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rainwater drainage device capable of effectively generating a siphon phenomenon in a drainage pipe, eliminating factors that hinder the generation of the siphon phenomenon, and efficiently draining rainwater. be.

A rainwater drainage device according to a first aspect of the invention is a rainwater drainage device for collecting rainwater and draining it from a drainage pipe, and includes a base portion, a lid portion, and a plurality of straightening fins. The base portion has a bottom surface and a drop opening for dropping rainwater at a substantially central portion of the bottom surface, and the drop opening is connected to a drain pipe. The lid portion is arranged above the drop opening of the base portion with a predetermined gap from the bottom surface. A plurality of straightening fins are arranged on the outer peripheral side of the bottom surface of the base portion, and straighten the flow of rainwater flowing into the drop opening. The plurality of rectifying fins are arranged along the radial direction of a virtual circle inscribed in the face of the lid facing the drop opening, and the outer peripheral ends thereof protrude from the outer edge of the lid.

A rainwater drainage device according to a second invention is the rainwater drainage device according to the first invention, wherein the straightening fins are arranged at equal angular intervals around the drop opening.

A rainwater drainage device according to a third invention is the rainwater drainage device according to the first or second invention, and satisfies the following relational expression (2), where a is the inner diameter of the drop opening.

0.22≤h/a≤0.37 (2)
Here, the relationship between the size (height) h of the gap between the bottom surface and the lid portion and the inner diameter a of the drop opening provided in the base portion is defined.

As a result, the ratio of the inner diameter a of the drop opening to the size (height) h of the gap between the bottom surface and the lid portion is set so as to fall within the above range. It is possible to control the flow rate of rainwater falling into the drainpipe through the drop port from between the cover and the lid arranged with a gap between them so that the inside of the drainpipe is in a state of full flow.

As a result, the siphon phenomenon can be effectively induced and rainwater can be drained efficiently.

A rainwater drainage device according to a fourth invention is the rainwater drainage device according to any one of the first to third inventions, wherein the size h of the gap is 15 mm or more and 40 mm or less.

Here, an appropriate range is defined for the size (height) h of the gap between the bottom surface of the base portion and the lid portion.

Thereby, the height of the rainwater flowing into the drop opening can be restricted by the lid.

As a result, it is possible to more effectively induce the occurrence of the siphon phenomenon by controlling the inflow of rainwater that falls from between the bottom surface of the base portion and the lid portion to the drainage pipe through the drop port. .

A rainwater drainage device according to a fifth invention is the rainwater drainage device according to any one of the first to fourth inventions, wherein the virtual circle has a diameter b of 130 mm or more and 300 mm or less.

Here, an appropriate range is defined for the diameter b of the imaginary circle inscribed in the surface of the lid facing the drop opening.

As a result, the height of the rainwater flowing into the drop hole can be restricted by the cover portion whose inscribed circle has a size within a predetermined range.

As a result, it is possible to more effectively induce the occurrence of the siphon phenomenon by controlling the inflow of rainwater that falls from between the bottom surface of the base portion and the lid portion to the drainage pipe through the drop port. .

A rainwater drainage device according to a sixth invention is the rainwater drainage device according to any one of the first to fifth inventions, wherein the lid portion is a circular plate-like member.

Here, a circular plate member is used as the lid.
As a result, the rainwater flowing between the lid portion and the bottom surface of the base portion from the periphery of the lid portion can be made to flow substantially evenly into the drop opening.

As a result, it is possible to more effectively induce the occurrence of the siphon phenomenon by controlling the inflow of rainwater that falls from between the bottom surface of the base portion and the lid portion to the drainage pipe through the drop port. .

ADVANTAGE OF THE INVENTION According to the rainwater drainage apparatus which concerns on this invention, while a siphon phenomenon is effectively generated in a drainage pipe, the factor which inhibits generation|occurrence|production of a siphon phenomenon can be eliminated, and rainwater can be drained efficiently.

The figure which shows the drainage system containing the rainwater drainage apparatus which concerns on one Embodiment of this invention. (a) is sectional drawing of the rainwater drainage apparatus of FIG. (b) is a plan view thereof. FIG. 6 is a diagram showing the results of comparison between Examples 1 to 7 of the present invention and Comparative Examples 1 to 4 regarding the presence or absence of vortex generation and siphon phenomenon. (a) is a side view showing the configuration of a rainwater drainage device according to another embodiment of the present invention. (b) is a plan view showing the configuration of a rainwater drainage device according to still another embodiment of the present invention. (a) is a side view showing the configuration of a rainwater drainage device according to still another embodiment of the present invention. (b) is a side view showing the configuration of a rainwater drainage device according to still another embodiment of the present invention.

A rainwater drainage device 10 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 2(b).

The rainwater drainage device 10 constitutes part of a rainwater drainage system 50 installed in a building 30, as shown in FIG.

The building 30 shown in FIG. 1 is a three-story building, and slabs 20 are provided between the first and second floors and between the second and third floors.

(Rainwater drainage system 50)
The rainwater drainage system 50 includes a rainwater drainage device 10, a roof drain 21 (part of a drainage pipe), a water collection pipe 22, and a drainage port 23, as shown in FIG.

The roof drain 21 is provided to drain rainwater that has fallen on the flat roof of a structure 30 such as a building to the water collecting pipe 22 . As shown in FIG. 1, the roof drains 21 are installed along the roof of the building 30 at three locations on each side, for a total of six locations.

The roof drain 21 may be, for example, a pipe with an outer diameter of 50A and a circular cross section, and may be connected to the water collection pipe 22 via a pipe with an outer diameter of 65A.

The water collection pipes 22 are provided to collect rainwater drained from each roof drain 21 and lead it to the drain port 23 . As shown in FIG. 1 , the water collection pipe 22 is arranged on the side of the flat roof of the building 30 so as to be inclined downward toward the connection side with the drain pipe 14 . Furthermore, the water collection pipe 22 is connected to the drain pipe 14 at the downstream end in the direction of rainwater movement.

In addition, for the water collection pipe 22, for example, a member having a circular or elliptical cross-sectional shape can be used.

The drain port 23, as shown in FIG. 1, is connected to the most downstream side of the drain pipe 14, and drains rainwater collected through the roof drain 21 near the ground.

For the drain port 23, for example, a pipe having an outer diameter of 100A to 150A and a circular cross section can be used. A pipe having an outer diameter of 100A arranged at the connecting portion with the drain pipe 14 and a pipe having an outer diameter of 150A arranged at the end on the drain side may be used in combination.

(Rainwater drainage device 10)
The rainwater drainage device 10 is arranged directly above each roof drain 21, as shown in FIG.

As for the material of the rainwater drainage device 10, similar to the drainage pipe 14, for example, olefin resin such as PE (polyethylene) and PP (polypropylene), vinyl chloride resin, or metal such as aluminum, aluminum alloy, stainless steel, etc. can be used.

By using resin, aluminum, or an aluminum alloy, it is possible to obtain the rainwater drainage device 10 having a desired shape with a light weight and low cost.

As shown in FIGS. 2(a) and 2(b), the base portion 11 has an annular bottom surface 11a, a drop hole 11b for allowing rainwater to drop substantially at the center of the bottom surface 11a, and a cylindrical portion 11c. are doing. A cylindrical portion 11 c forming the drop opening 11 b is connected to the upper end portion of the roof drain 21 .

As shown in FIGS. 2A and 2B, the bottom surface 11a is an annular member with a drop opening 11b formed substantially in the center. A plurality of rectifying fins 13 are arranged at equal angular intervals on the annular bottom surface 11a with the drop opening 11b as the center.

As shown in FIG. 2(a), the drop opening 11b is a through hole formed in the center of the base portion 11 and formed inside the cylindrical portion 11c. The drop opening 11b communicates with the upper end of the roof drain 21, and drops rainwater that has flowed into the rainwater drainage device 10 from 360-degree directions into the roof drain 21. - 特許庁

As shown in FIGS. 2(a) and 2(b), the tubular portion 11c is a cylindrical member that is connected at its upper end to the bottom surface 11a and protrudes downward from the bottom surface 11a. It is A drop opening 11b is formed inside the tubular portion 11c.

As shown in FIGS. 2(a) and 2(b), the lid portion 12 is a circular plate arranged above the base portion 11 concentrically with a drop opening 11b formed in the center of the base portion 11. It is a shaped member supported by a plurality of rectifying fins 13 erected on the bottom surface 11 a of the base portion 11 . Further, as shown in FIG. 2A, the lid portion 12 is arranged above the base portion 11 (drop opening 11b) with a predetermined gap G size (height) h from the bottom surface 11a. there is Further, the lid portion 12 is formed so that the circular surface facing the drop opening 11b has a diameter b (the diameter of an imaginary circle inscribed in the surface of the lid portion 12).

In this embodiment, since the lid portion 12 is a circular plate-like member, the diameter b of the inscribed circle of the lid portion 12 corresponds to the diameter of the circular lid portion 12 as it is.

As shown in FIGS. 2(a) and 2(b), a plurality of straightening fins 13 are provided on the bottom surface 11a of the base portion 11 in order to regulate the flow of rainwater flowing into the drop opening 11b. More specifically, as shown in FIG. 2(b), the plurality of rectifying fins 13 are plate-like members arranged substantially in the vertical direction, and are arranged on the bottom surface 11a with the drop opening 11b as the center. 8 are provided at equiangular intervals on the circumference of the circle with .

The eight rectifying fins 13 are arranged along the radial direction on the annular bottom surface 11a.

As a result, as shown in FIG. 2(b), even when rainwater that has flowed into the gap G between the bottom surface 11a of the base portion 11 and the lid portion 12 enters in a vortex (see the dashed line in the figure), The straightening fins 13 straighten the rainwater and guide the rainwater toward the center of the drop opening 11b.

Therefore, it is possible to prevent rainwater from flowing into the roof drain 21 in a vortex and forming an air column at the center thereof.

As a result, the rectifying fins 13 prevent the formation of an air column in the center of the rainwater flowing into the drop opening 11b, thereby effectively eliminating the factors that hinder the occurrence of the siphon phenomenon that occurs within the roof drain 21. can do.

<Relationship between base portion 11 and lid portion 12>
In the rainwater drainage device 10 of the present embodiment, in the above-described configuration, the diameter b of the circular lid portion 12 facing the drop opening 11b of the base portion 11 and the size (height) h of the predetermined gap G are as follows. is configured to satisfy the relational expression (1).

6≦b/h≦11 (1)
Thus, the relationship between the diameter b of the lid portion 12 and the size h of the gap G between the bottom surface 11a of the base portion 11 and the lid portion 12 is configured to satisfy the relational expression (1). The flow rate of rainwater falling from between the bottom surface 11a of the base portion 11 and the lid portion 12 to the roof drain 21 through the drop port 11b is controlled so that the inside of the roof drain 21 is in a full flow state. can be done.

As a result, the siphon phenomenon can be effectively generated in the roof drain 21, and the factors that hinder the siphon phenomenon can be eliminated to efficiently drain rainwater.

Furthermore, assuming that the inner diameter of the drop opening 11b of the base portion 11 is a, the following relational expression (2) is satisfied.

0.2≤h/a≤0.5 (2)
In this manner, the ratio of the inner diameter a of the drop opening 11b to the size h of the gap G between the bottom surface 11a of the base portion 11 and the lid portion 12 satisfies the relational expression (2). , the flow rate of rainwater falling from between the bottom surface 11a of the base portion 11 and the lid portion 12 to the roof drain 21 through the drop port 11b is stabilized so that the inside of the roof drain 21 is in a full flow state. can be controlled.

As a result, the siphon phenomenon can be effectively generated in the roof drain 21, and the factors that hinder the siphon phenomenon can be eliminated to efficiently drain rainwater.

Here, the size (height) h of the predetermined gap G formed between the bottom surface 11a of the base portion 11 and the lid portion 12 described above satisfies the above relational expression (1) and is 15 mm or more. It is preferably set to be within a range of 40 mm or less.

As a result, the amount of rainwater falling from between the bottom surface 11a of the base portion 11 and the lid portion 12 to the roof drain 21 through the drop opening 11b is restricted in the height direction, so that the inside of the roof drain 21 is fully filled. It can be controlled to flow.

As a result, it is possible to more effectively control the flow rate of rainwater flowing into the roof drain 21 and induce the occurrence of the siphon phenomenon within the roof drain 21 .

Furthermore, the diameter b (diameter of the virtual circle) of the circular lid portion 12 described above is preferably set to be within the range of 110 mm or more and 155 mm or less while satisfying the above relational expression (1). .

As a result, the amount of rainwater that falls from between the bottom surface 11a of the base portion 11 and the lid portion 12 to the roof drain 21 through the drop opening 11b is restricted in the plane direction of the lid portion 12, thereby preventing the roof drain 21 from flowing out. It is possible to control the inside so that it is in a state of full flow.

As a result, it is possible to more effectively control the flow rate of rainwater flowing into the roof drain 21 and induce the occurrence of the siphon phenomenon within the roof drain 21 .
<Comparison between Examples 1 to 7 and Comparative Examples 1 to 4>
FIG. 3 compares Examples 1 to 7 of the present invention with Comparative Examples 1 to 4 in terms of the presence or absence of eddies of rainwater when flowing into the roof drain 21 and the presence or absence of the siphon phenomenon in the roof drain 21. The results are shown.

In Example 1, the experimental results were obtained with the inner diameter a of the drain port 11b of the rainwater drainage device 10 = 53.5 mm, the height of the lid portion 12 (size h of the gap G) = 15 mm, and the diameter b of the lid portion = 150 mm. showing.

In this case, when b/h = 10.0 and h/a = 0.28, and the diameter of the roof drain 21 was 50A, there was no vortex of rainwater flowing into the roof drain 21 from the drop opening 11b. . Then, the occurrence of the siphon phenomenon in the roof drain 21 was confirmed.

As a result, according to the rainwater drainage device 10 of Example 1, the rainwater flowing into the roof drain 21 did not vortex, and the rainwater was efficiently drained by the action of the siphon phenomenon.

In Example 2, experimental results are shown where the inner diameter a of the drain port 11b of the rainwater drainage device 10 is 71 mm, the height of the lid portion 12 (the size h of the gap G) is 20 mm, and the diameter b of the lid portion is 190 mm. there is

In this case, when b/h=9.5 and h/a=0.28, and the diameter of the roof drain 21 was 75A, there was no eddy of rainwater flowing into the roof drain 21 from the drop opening 11b. . Then, the occurrence of the siphon phenomenon in the roof drain 21 was confirmed.

As a result, according to the rainwater drainage device 10 of Example 2, the rainwater flowing into the roof drain 21 did not vortex, and the rainwater was efficiently drained by the action of the siphon phenomenon.

In Example 3, experimental results are shown where the inner diameter a of the drain port 11b of the rainwater drainage device 10 is 109 mm, the height of the lid portion 12 (the size h of the gap G) is 40 mm, and the diameter b of the lid portion is 300 mm. there is

In this case, when b/h = 7.5 and h/a = 0.37, and the diameter of the roof drain 21 was 100A, there was no eddy of rainwater flowing into the roof drain 21 from the drop opening 11b. . Then, the occurrence of the siphon phenomenon in the roof drain 21 was confirmed.

As a result, according to the rainwater drainage device 10 of Example 3, the rainwater flowing into the roof drain 21 did not vortex, and the rainwater was efficiently drained by the action of the siphon phenomenon.

In Example 4, the experimental results were obtained with the inner diameter a of the drain port 11b of the rainwater drainage device 10 = 53.5 mm, the height of the lid portion 12 (size h of the gap G) = 19 mm, and the diameter b of the lid portion = 150 mm. showing.

In this case, when b/h = 7.9 and h/a = 0.36, and the diameter of the roof drain 21 was 50A, no vortex of rainwater flowing into the roof drain 21 from the drop opening 11b was generated. . Then, the occurrence of the siphon phenomenon in the roof drain 21 was confirmed.

As a result, according to the rainwater drainage device 10 of Example 4, the rainwater flowing into the roof drain 21 did not vortex, and the rainwater was efficiently drained by the action of the siphon phenomenon.

In Example 5, experimental results are shown where the inner diameter a of the drain port 11b of the rainwater drainage device 10 is 68 mm, the height of the lid portion 12 (the size h of the gap G) is 15 mm, and the diameter b of the lid portion is 130 mm. there is

In this case, when b/h = 8.7 and h/a = 0.22, and the diameter of the roof drain 21 was 65A, there was no vortex of rainwater flowing into the roof drain 21 from the drop opening 11b. . Then, the occurrence of the siphon phenomenon in the roof drain 21 was confirmed.

As a result, according to the rainwater drainage device 10 of Example 5, the rainwater flowing into the roof drain 21 did not vortex, and the rainwater was efficiently drained by the action of the siphon phenomenon.

In Example 6, experimental results are shown where the inner diameter a of the drain port 11b of the rainwater drainage device 10 is 71 mm, the height of the lid portion 12 (the size h of the gap G) is 25 mm, and the diameter b of the lid portion is 220 mm. there is

In this case, b/h = 8.8, h/a = 0.35, and when the diameter of the roof drain 21 was 75A, there was no vortex of rainwater flowing into the roof drain 21 from the drop opening 11b. . Then, the occurrence of the siphon phenomenon in the roof drain 21 was confirmed.

As a result, according to the rainwater drainage device 10 of Example 6, the rainwater flowing into the roof drain 21 did not vortex, and the rainwater was efficiently drained by the action of the siphon phenomenon.

In Example 7, experimental results are shown where the inner diameter a of the drain port 11b of the rainwater drainage device 10 is 109 mm, the height of the lid portion 12 (the size h of the gap G) is 30 mm, and the diameter b of the lid portion is 250 mm. there is

In this case, when b/h = 8.3 and h/a = 0.28, and the diameter of the roof drain 21 was 50A, there was no vortex of rainwater flowing into the roof drain 21 from the drop opening 11b. . Then, the occurrence of the siphon phenomenon in the roof drain 21 was confirmed.

As a result, according to the rainwater drainage device 10 of Example 7, the rainwater flowing into the roof drain 21 did not vortex, and the rainwater was efficiently drained by the action of the siphon phenomenon.
(Summary of Examples 1 to 7)
As described above, according to the configurations of Examples 1 to 7, rainwater flowing into the roof drain 21 did not generate eddies, and the rainwater was efficiently drained by the action of the siphon phenomenon. .

Comparative example 1

On the other hand, in Comparative Example 1, the experimental results were obtained with the inner diameter a of the drop opening 11b of the rainwater drainage device = 53.5 mm, the height of the lid portion (the size h of the gap G) = 15 mm, and the diameter b of the lid portion = 60 mm. showing.

In this case, b/h = 4.0, h/a = 0.28, and when the roof drain had a diameter of 50A, a vortex of rainwater flowing into the roof drain from the drop opening was observed. And no siphon phenomenon occurred in the drain pipe.

That is, in Comparative Example 1, among the parameters, b/h and h are out of the ranges specified in the above embodiment.

As a result, according to the rainwater drainage device of Comparative Example 1, eddies were generated in the rainwater flowing into the roof drain, and the siphon phenomenon could not be generated, so the rainwater could not be drained efficiently.

Comparing Comparative Example 1 and Example 1, which is similar to this configuration, it can be seen that the diameter b of the lid portion is different.

Therefore, with respect to b/h, favorable results were obtained with 10.0 of Example 1, but favorable results were not obtained with 4.0 of Comparative Example 1, which does not satisfy the above relational expression (1).

In addition, although favorable results were obtained when the diameter b of the lid portion was 150 mm in Example 1, the diameter b of Comparative Example 1 was 60 mm, which was preferable because the lid portion was too small to stabilize the inflow of rainwater. No results were obtained.

Comparative example 2

Comparative Example 2 shows the results of an experiment in which the inner diameter of the drop opening of the rainwater drainage device was a = 53.5 mm, the height of the lid portion (the size h of the gap G) was 50 mm, and the diameter b of the lid portion was 250 mm. .

In this case, b/h = 5.0, h/a = 0.93, and when the roof drain diameter was 50A, a vortex of rainwater flowing into the roof drain from the drop opening was observed. And no siphon phenomenon occurred in the roof drain.

That is, in Comparative Example 2, among the parameters, b/h, h/a, h and b are all out of the ranges specified in the above embodiment.

As a result, according to the rainwater drainage device of Comparative Example 2, eddies were generated in the rainwater flowing into the roof drain, and the siphon phenomenon could not be generated, so the rainwater could not be drained efficiently.

Comparative example 3

Comparative Example 3 shows the results of an experiment in which the inner diameter of the drop opening of the rainwater drainage device was a = 53.5 mm, the height of the lid (the size h of the gap G) was 15 mm, and the diameter of the lid was b = 190 mm. .

In this case, when b/h = 12.7 and h/a = 0.28, and the diameter of the roof drain was 50A, no vortex of rainwater flowing into the roof drain from the drop opening was observed. , there was no siphon phenomenon in the roof drain.

That is, in Comparative Example 3, among the parameters, b/h and b are out of the range specified in the above embodiment.

As a result, according to the rainwater drainage device of Comparative Example 3, although no vortex was generated in the rainwater flowing into the roof drain, the siphon phenomenon could not be generated, so the rainwater could not be drained efficiently.

Comparative example 4

Comparative Example 4 shows the results of an experiment in which the inner diameter a of the drain port of the rainwater drainage device was 71 mm, the height of the lid portion (the size h of the gap G) was 45 mm, and the diameter b of the lid portion was 190 mm.

In this case, b/h = 4.2, h/a = 0.63, and when the roof drain diameter was 75A, a vortex of rainwater flowing into the roof drain from the drop opening was observed. And no siphon phenomenon occurred in the roof drain.

That is, in Comparative Example 4, among the parameters, b/h, h/a, h and b are all out of the ranges specified in the above embodiment.

As a result, according to the rainwater drainage device of Comparative Example 4, vortices were generated in the rainwater flowing into the roof drain, and the siphon phenomenon could not be generated, so the rainwater could not be drained efficiently. .

Comparing Comparative Example 4 with Example 2, which approximates this configuration, it can be seen that h is different.

Therefore, with respect to b/h, favorable results were obtained with 9.5 of Example 2, but with 4.2 of Comparative Example 4, the position of the lid portion was too high to stabilize the inflow of rainwater. I couldn't get good results.

Also, with respect to h/a, although favorable results were obtained with 0.28 in Example 2, favorable results were not obtained with 0.63 in Comparative Example 4.

Furthermore, when the size h of the gap G was 20 mm in Example 2, favorable results were obtained, but when it was 45 mm in Comparative Example 4, favorable results were not obtained.
(summary)
(About b/h)
As a result of the above Examples 1 to 7, the ratio b/h between the diameter b of the lid portion 12 and the height of the lid portion 12 (the size h of the gap G) is 7.5 or more and 10.0 or less. , a siphon phenomenon could be generated without generating a vortex in the roof drain 21 .

On the other hand, as a result of the above Comparative Examples 1 to 4, when b/h is 5.0 or less and 12.7 or more, a vortex is generated in the roof drain 21, and a siphon phenomenon cannot be generated. Therefore, it was found that rainwater could not be drained efficiently.

Therefore, as described in the above embodiment, b/h is preferably set so as to satisfy the following relational expression (1).

7.5≤b/h≤10.0 (1)
(About h/a)
Next, as a result of the above Examples 1 to 7, the ratio h/a between the inner diameter a of the drop opening 11b and the height of the lid portion 12 (the size h of the gap G) is 0.22 or more and 0.37 or less. If so, the siphon phenomenon could be generated without generating a vortex in the drain pipe 14 .

On the other hand, as a result of the above Comparative Examples 1 to 4, when h/a is 0.28 or less and 0.63 or more, a vortex is generated in the drain pipe 14, and a siphon phenomenon cannot be generated. As a result, it was found that rainwater could not be drained efficiently.

Therefore, as described in the above embodiment, h/a is preferably set so as to satisfy the following relational expression (2).

0.22≤h/a≤0.37 (2)
(Regarding the size h of the gap G)
Next, as a result of the above Examples 1 to 7, if the size h of the gap G is 15 mm or more and 40 mm or less, a siphon phenomenon can be generated without generating a vortex in the roof drain 21. .

On the other hand, as a result of the above Comparative Examples 1 to 4, when the size h of the gap G is 15 mm or less or 45 mm or more, a vortex is generated in the roof drain 21, and a siphon phenomenon cannot be generated. Therefore, it was found that rainwater could not be drained efficiently.

Therefore, as described in the above embodiment, the size h of the gap G is preferably set within the range of 15 mm or more and 40 mm or less.

(About diameter b)
Furthermore, as a result of the above Examples 1 to 7, if the diameter b of the lid portion 12 is 130 mm or more and 300 mm or less, a siphon phenomenon can be generated without generating a vortex in the drain pipe 14. .

On the other hand, as a result of the above Comparative Examples 1 to 4, when the diameter b of the lid portion 12 is 60 mm or less and 190 mm or more, a vortex is generated in the drain pipe 14, and the siphon phenomenon cannot be generated. As a result, it was found that rainwater could not be drained efficiently.

Therefore, as described in the above embodiment, the diameter b of the lid portion 12 is preferably set within the range of 130 mm or more and 300 mm or less.

[Other embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the invention.

(A)
In the above embodiment, an example in which a plurality of straightening fins 13 are radially provided along the outer peripheral portion of the bottom surface 11a of the base portion 11 of the rainwater drainage device 10 has been described. However, the invention is not limited to this.

For example, as shown in FIG. 4( a ), the rainwater drainage device 110 may have no straightening fins on the bottom surface 11 a of the base portion 11 .

Even in this case, by stabilizing the amount of rainwater flowing into the roof drain, the siphon phenomenon can be effectively generated inside the roof drain, so that the same effect as above can be obtained.

(B)
In the above-described embodiment, an example in which the eight straightening fins 13 are radially provided along the outer peripheral portion of the bottom surface 11a of the base portion 11 of the rainwater drainage device 10 has been described. However, the invention is not limited to this.

For example, as shown in FIG. 4(b), a rainwater drainage device 210 having half the number of straightening fins 13, namely four, may be used.

That is, the number of rectifying fins is not particularly limited, and may be any number.
Furthermore, the rectifying fins are not limited to being arranged radially along the radial direction of a circle centered on the drop opening 11b of the base portion 11, but may be arranged diagonally with respect to the radial direction. good too.

(C)
In the above-described embodiment, an example of using a smooth plate-like member as the lid portion 12 has been described. However, the present invention is not limited to this.

For example, as shown in FIG. 5A, a rainwater drainage device 310 including a lid portion 312 having a recessed surface facing the drop opening 11b may be used.

Alternatively, as shown in FIG. 5B, a rainwater drainage device 410 including a lid portion 412 having a recessed surface opposite to the surface facing the drop opening 11b may be used.

In addition, in the configurations of these rainwater drainage devices 310 and 410, the size (height) h of the gap G used in the above relational expression is the minimum gap between the surface facing the drop opening 11b and the bottom surface 11a. It is sufficient if it is set using the height.

(D)
In the above-described embodiment, an example using the lid portion 12 configured by a circular plate-like member has been described. However, the present invention is not limited to this.

For example, the shape of the lid is not limited to circular, and may be other shapes such as elliptical and polygonal.
If the lid has a shape other than a circle, it may be configured so as to satisfy the above relational expression, where b is the diameter of the circle inscribed in the surface of the lid facing the drop opening.

However, it is preferable to use a circular lid portion as in the above-described embodiment in order to allow the rainwater flowing into the drop hole to flow uniformly over the entire circumference of 360 degrees.

(E)
In the above-described embodiment, an example in which the rainwater drainage device 10 is installed inside the water collecting pipe 22 arranged in the vicinity of the lower end portion of the roof R along the substantially horizontal direction has been described. However, the present invention is not limited to this.

For example, the rainwater drainage device of the present invention may be installed on the roof or at the edge of a flat roof.

The rainwater drainage device of the present invention effectively generates a siphon phenomenon in the drainage pipe, eliminates factors that inhibit the occurrence of the siphon phenomenon, and can efficiently drain rainwater. It can be widely applied to various drainage systems using the siphon phenomenon.

10 Rainwater drainage device 11 Base portion 11a Bottom surface 11b Drop port 11c Cylindrical portion 12 Lid portion 13 Straightening fin 14 Drainage pipe 20 Slab 21 Roof drain 22 Water collection pipe 23 Drainage port 30 Building 50 Rainwater drainage system 110 Rainwater drainage device 210 Rainwater drainage device 310 rainwater drainage device 312 lid portion 410 rainwater drainage device 412 lid portion a inner diameter b diameter h size of gap G gap R roof

Claims (8)

A rainwater drainage device for collecting rainwater and draining it from a drainage pipe,
a base portion having a bottom surface and a drop hole for dropping rainwater at a substantially central portion of the bottom surface, the drop hole being connected to the drain pipe;
a lid portion disposed above the drop opening of the base portion with a predetermined gap from the bottom surface;
a plurality of rectifying fins disposed on the outer peripheral side of the bottom surface of the base portion and regulating the flow of rainwater flowing into the drop hole;
with
The plurality of rectifying fins are arranged along the radial direction of an imaginary circle inscribed in the surface of the lid facing the drop opening such that the upper end surface of the end on the inner diameter side thereof is in contact with the lower surface of the lid. , the outer peripheral end of which protrudes from the outer edge of the lid,
Rainwater drainage system. The rectifying fins are arranged at equal angular intervals around the drop opening,
The rain water drainage device according to claim 1. Assuming that the size of the gap is h and the inner diameter of the drop opening is a, the following relational expression (2) is satisfied.
The rainwater drainage device according to claim 1 or 2.
0.22≤h/a≤0.37 (2) The size h of the gap is 15 mm or more and 40 mm or less.
The rainwater drainage device according to any one of claims 1 to 3. The diameter b of the virtual circle is 130 mm or more and 300 mm or less.
The rainwater drainage device according to any one of claims 1 to 4. The lid portion is a circular plate-shaped member,
The rainwater drainage device according to any one of claims 1 to 5. The base portion has, between the bottom surface and the drop opening, an inclined surface that slopes downward from the bottom surface toward the drop opening.
The rainwater drainage device according to any one of claims 1 to 6. In a range from the inner edge portion of the rectifying fin to the outer peripheral edge of the lid portion, the upper end of the rectifying fin and the lower surface of the lid portion are arranged so as to be in contact with each other.
The rainwater drainage device according to any one of claims 1 to 7.

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