JP7050512B2 - Drainage device - Google Patents

Description

The present invention relates to a drainage device for draining rainwater.

Conventionally, a configuration has been proposed in which the drainage efficiency of rainwater is improved by inducing a siphon phenomenon (see, for example, Patent Document 1).

For example, in the configuration shown in Patent Document 1, the outlet of the water reservoir provided directly under the eaves gutter is reduced in diameter, and the siphon phenomenon is induced in this reduced diameter portion.

Japanese Patent No. 5828066

However, when the inside of the vertical pipe is filled with rainwater by utilizing the siphon phenomenon, negative pressure is generated due to the water falling in the pipe, and cavitation is likely to occur near the inlet of the vertical pipe. Cavitation is a physical phenomenon in which bubbles are generated and disappear in a short time due to a pressure difference in a fluid flow.

When such cavitation occurs, an impact is generated, so that the inner surface of the pipe is damaged and the life is shortened, and the impact causes discomfort to the resident. In addition, especially when a rainwater drainage device using the siphon phenomenon is introduced in a high-rise building such as a building, the water falling speed becomes faster due to the large height difference, and negative pressure is likely to occur and cavitation is likely to occur. ..

An object of the present invention is to provide a drainage device capable of suppressing the occurrence of cavitation.

In order to achieve the above object, the drainage device according to the first invention is a drainage device for draining rainwater, and includes a vertical pipe portion and a siphon inducer portion. The vertical pipe portion has a first pipe portion and a second pipe portion, and the first pipe portion has a first flow path cross-sectional area and is arranged along the vertical direction. The second piping section has a second flow path cross section smaller than the first flow path cross section, and is arranged below the first piping section along the vertical direction. The siphon inducer is arranged above the vertical pipe portion and induces the occurrence of the siphon phenomenon in the rainwater drained by the vertical pipe portion. Assuming that the length of the vertical pipe portion is L1 and the length of the second pipe portion is L2, the following equation (1) is satisfied.

0.3 ≤ L2 / L1 ≤ 0.8 ... (1)
In this way, the first piping portion is provided below the siphon inducing portion, and the second piping portion having a cross section smaller than that of the first piping portion is provided below the first piping portion, thereby providing the second piping portion. It is possible to suppress the falling speed of water when it flows into. Therefore, the negative pressure in the first piping portion can be reduced, and the occurrence of cavitation can be suppressed.

In particular, when a drainage device is introduced into a high-rise building, the rainwater will have a large potential energy due to the addition of attractive force and gravity due to the siphon phenomenon, so the cross-sectional area of the second piping section should be larger than that of the first piping section. The effect of suppressing the occurrence of cavitation by making it smaller becomes remarkable.

The drainage device according to the second invention is the drainage device according to the first invention, in which the first piping portion has an inner diameter of the first diameter and the second piping portion is smaller than the first diameter. It has two diameters.

In this way, the first piping portion is provided below the siphon inducing portion, and the second piping portion having an inner diameter smaller than that of the first piping portion is provided below the first piping portion to reach the second piping portion. It is possible to suppress the falling speed of water when it flows in.

In particular, when a drainage device is introduced into a high-rise building, the rainwater has a large potential energy due to the addition of attractive force and gravity due to the siphon phenomenon, so the diameter of the second piping section is reduced from that of the first piping section. As a result, the effect of suppressing the occurrence of cavitation becomes remarkable.

The drainage device according to the third invention is the drainage device according to the second invention, and when the first diameter is D1 and the second diameter is D2, the following formula (2) is satisfied.

0.20≤ (D1-D2) / D1 ... (2)
By using the first piping portion and the second piping portion having the inner diameter of such a relationship, the occurrence of cavitation can be further reduced.

The drainage device according to the fourth invention is the drainage device according to any one of the first to third inventions, and L1 satisfies the following formula (3).

50 meters ≤ L1 ... (3)
The longer the length of the pipes arranged in the vertical direction, the faster the falling speed and the more likely it is that cavitation will occur. The effect of suppressing can be remarkably exhibited.

The drainage device according to the fifth invention is the drainage device according to the second or third invention, the upper end of the vertical pipe portion is the upper end of the first piping portion, and the lower end of the vertical pipe portion is the second. It is the lower end of the piping portion, the first diameter is the maximum inner diameter in the vertical pipe portion, and the second diameter is the minimum inner diameter in the vertical pipe portion.

As a result, the negative pressure in the first piping portion can be reduced, and the occurrence of cavitation can be suppressed.

The drainage device according to the sixth invention is the drainage device according to any one of the first to fifth inventions, and the lower end of the first piping portion and the upper end of the second piping portion are directly or via a joint. Is indirectly connected.

This makes it possible to move the rainwater linearly downward from the siphon inducer.

The drainage device according to the seventh invention is the drainage device according to any one of the first to fifth inventions, and the vertical pipe section further includes a third piping section. The third piping section has an inner diameter of a third diameter that is smaller than the first diameter and larger than the second diameter. The third piping portion is arranged between the first piping portion and the second piping portion.

By reducing the diameter in a plurality of steps in this way, the potential energy of rainwater can be gradually reduced by friction. Therefore, noise and the like on the downstream side of the pipe can be reduced.

According to the drainage device according to the present invention, the occurrence of cavitation can be suppressed.

The schematic diagram which shows the structure of the rainwater drainage system in embodiment which concerns on this invention. FIG. 6 is a cross-sectional view of a drainage device in the rainwater drainage system of FIG. (A) A front view showing the configuration of the siphon generator in the drainage device of FIG. 2, (b) and a plan view of the siphon generator of FIG. 3 (a). The figure which shows the table of the inner diameter in the type of piping for each nominal diameter. The figure which shows the state which the drainage device of FIG. 2 is fixed to a slab. The plan view which shows the drainage pipe structure of the rainwater drainage system of FIG. The figure which shows the table of the result of Examples 1 to 16 and Comparative Examples 1 to 4 which concerns on this invention. The figure which shows the modification of the drainage apparatus of embodiment which concerns on this invention. The figure which shows the modification of the drainage pipe structure of embodiment which concerns on this invention. The figure which shows the structure of the rainwater drainage system of the modification of embodiment which concerns on this invention. The figure which shows the structure of the drainage apparatus of the modification of embodiment which concerns on this invention.

The rainwater drainage system 10 according to the embodiment of the present invention will be described with reference to the drawings.

<1. Configuration>
FIG. 1 is a diagram showing a configuration of a rainwater drainage system 10 according to the present embodiment.

The rainwater drainage system 10 of the present embodiment is installed in a building 100 such as a building. The building 100 is a three-story building, and slabs 101 are provided between the first and second floors and between the second and third floors, respectively.

(1-1. Stormwater drainage system 10)
As shown in FIG. 1, the rainwater drainage system 10 includes a drainage device 20 and a drainage pipe structure 30. The rooftop 105 of the building 100 is provided with a drainage ditch 102 along the edge of the rooftop 105. The drainage ditch 102 may be inclined toward either one in the longitudinal direction. Further, the rooftop 105 may be inclined from the center toward the drainage ditch 102. Further, in FIG. 1, the drainage ditch 102 is provided only in the vicinity of the two opposite sides of the square rooftop 105, but may be provided in the vicinity of all four sides.

As shown in FIG. 1, drainage devices 20 are provided at six locations (three locations along each of the two opposing sides), and are directed downward from the drainage ditch 102 along the inside of the wall 104. It is provided. The drainage device 20 moves rainwater that has fallen to the rooftop 105 of the building 100 and has flowed into the drainage ditch 102 to the vicinity of the ground. The drainage pipe structure 30 is arranged on the downstream side of the drainage device 20, and discharges rainwater moved to the vicinity of the ground by the drainage device 20 to the sewer pipe.

(1-2. Drainage device 20)
The drainage device 20 is arranged inside the building 100 (inside the outer wall) so as to penetrate the slab 101 on each floor. The drainage device 20 is provided downward from the drainage ditch 102.

FIG. 2 is a cross-sectional configuration diagram of the drainage device 20. In detail, FIG. 2 shows the rightmost drainage device 20 among the three drainage devices 20 on the front side of the paper in FIG. 1. In FIG. 2, the siphon induction portion 21 of the drainage device 20 is shown in a front view instead of a cross section.

As shown in FIG. 2, the drainage device 20 includes a siphon inducing unit 21, a vertical pipe unit 26, and a connecting member 25 (see FIG. 5).

The vertical pipe portion 26 is arranged downward from the drainage ditch 102. An opening 103 formed in the bottom surface of the drainage ditch 102 communicates with the vertical pipe portion 26. The connecting member 25 connects and fixes the vertical pipe portion 26 to the slab 101.

(1-2-1. Siphon inducer 21)
As shown in FIG. 2, the siphon inducer 21 is arranged so as to close the opening 103 of the drainage ditch 102.

As the material of the siphon inducer 21, for example, an olefin resin such as PE (polyethylene) or PP (polypropylene), a vinyl chloride resin, or a metal such as aluminum, an aluminum alloy, or stainless steel can be used.

By using a resin, aluminum, or an aluminum alloy, the siphon inducer 21 having a desired shape can be obtained at low cost and light weight.

FIG. 3 (a) is a plan view of the siphon inducing unit 21, and FIG. 3 (b) is a cross-sectional view taken along the line between AA'in FIG. 3 (a).

The siphon inducing portion 21 has a base portion 41, a lid portion 42, and a rectifying fin 43.

As shown in FIGS. 3A and 3B, the base portion 41 has an annular bottom surface 41a, a drop opening 41b formed at substantially the center of the bottom surface 41a for dropping rainwater, and a tubular portion 41c. And have. The drop opening 41b is formed at the upper end of the tubular portion 41c. The tubular portion 41c is arranged in the vertical pipe portion 26.

As shown in FIGS. 3A and 3B, the bottom surface 41a is an annular member having a drop opening 41b formed in a substantially central portion. A plurality of rectifying fins 43 are arranged at equal angular intervals on the annular bottom surface 41a with the drop opening 41b at the center.

As shown in FIG. 3A, the drop opening 41b is a through hole formed in the central portion of the base portion 41, and is formed inside the tubular portion 41c. Then, the drop opening 41b communicates with the upper end portion of the vertical pipe portion 26, and rainwater flowing in from the direction of 360 degrees to the siphon inducing portion 21 is dropped into the vertical pipe portion 26.

As shown in FIGS. 3A and 3B, the tubular portion 41c is a cylindrical member, which is connected to the bottom surface 41a at the upper end thereof and is formed so as to protrude downward from the bottom surface 41a. Has been done. Then, a drop opening 41b is formed inside the tubular portion 41c.

As shown in FIGS. 3A and 3B, the lid portion 42 is a circular plate concentrically arranged above the base portion 41 with a drop opening 41b formed in the center of the base portion 41. It is a shaped member and is supported by a plurality of rectifying fins 43 erected on the bottom surface 41a of the base portion 41. Further, as shown in FIG. 3B, the lid portion 42 is arranged above the base portion 41 (drop opening 41b) with a predetermined gap G size (height) from the bottom surface 41a. ..

As shown in FIGS. 3A and 3B, the plurality of rectifying fins 43 are provided on the bottom surface 41a of the base portion 41 in order to regulate the flow of rainwater flowing into the drop opening 41b. More specifically, as shown in FIG. 3A, the plurality of rectifying fins 43 are plate-shaped members arranged substantially in the vertical direction, and are centered on the bottom surface 41a and the drop opening 41b. Eight are provided at equal intervals on the circumference of the circle.

Further, the eight rectifying fins 43 are arranged along the radial direction on the bottom surface 41a of the annular shape, respectively.

As a result, as shown in FIG. 3A, even when the rainwater flowing into the gap G between the bottom surface 41a of the base portion 41 and the lid portion 42 infiltrates in a spiral shape (see the alternate long and short dash line in the figure). The rectifying fins 43 can rectify the rainwater and guide the rainwater toward the center of the drop opening 41b.

Therefore, it is possible to prevent rainwater from flowing into the vertical pipe portion 26 in a spiral shape and forming an air column in the central portion thereof.

As a result, the rectifying fins 43 prevent the formation of an air column at the center of the rainwater flowing into the drop port 41b, thereby preventing the occurrence of the siphon phenomenon occurring in the first vertical piping portion 22. It can be effectively eliminated.

(1-2-2. Standing pipe part 26)
As shown in FIG. 2, the vertical pipe portion 26 has a first vertical pipe portion 22, a second vertical pipe portion 23, and a joint 24.

The upper end of the first vertical pipe portion 22 coincides with the upper end 26a of the vertical pipe portion 26, and the first vertical pipe portion 22 is arranged downward from the drainage ditch 102. An opening 103 formed in the bottom surface of the drainage ditch 102 communicates with the first vertical piping portion 22.

The second vertical piping section 23 is arranged below the first vertical piping section 22. The lower end of the second vertical pipe portion 23 coincides with the lower end 26b of the vertical pipe portion 26. The joint 24 connects the lower end 22a of the first vertical piping portion 22 and the upper end 23a of the second vertical piping portion 23.

(A. First vertical piping section 22)
As shown in FIG. 2, the first vertical pipe portion 22 is composed of a pipe 221 having an inner diameter D1. The pipe 221 is a tubular member made of PE (polyethylene), and is arranged along a substantially vertical direction (which can also be said to be a vertical direction) as shown in FIG.

The upper end of the pipe 221 is connected to the drainage ditch 102 from below and is connected to the opening 103. The lower end of the pipe 221 (which can also be said to be the lower end 22a of the first vertical pipe portion 22) is connected to the second vertical pipe portion 23 via a joint 24 described later.

For the pipe 221, pipes having nominal diameters of 200 A, 150 A, 125 A and 100 A are used. The inner diameter D1 is determined for each nominal diameter for each type of pipe (the same applies to the inner diameters D2, D3, and D4 described later). The types of pipes include, for example, polyethylene pipes and polyvinyl chloride depending on the material. There are three types of polyethylene pipes, for example, SDR11, SDR21, and SDR26, and there are two types of polyvinyl chloride pipes, for example, VP pipes and VU pipes.

FIG. 4 is a diagram showing the maximum value and the minimum value of the inner diameter in the type of piping for each nominal diameter. For example, in the case of the 75A pipe of SDR11, the outer diameter is 89 mm, the margin of error is 0.3 mm, the thickness is 8.1 mm, and the margin of error is +1.1 mm. Therefore, the minimum value of the inner diameter of the 75A pipe of SDR11 is calculated as (89-0.3)-(8.1 + 1.1) × 2 = 70.3. The maximum value is calculated as (89 + 0.3) -8.1 × 2 = 73.1.

FIG. 4 also shows the diameter expansion ratio when the diameter is increased from the 75A pipe to the 125A pipe. Further, 75A → 125A, the minimum side indicates the minimum value of the diameter expansion ratio from 75A to 125A in SDR11, and is the diameter expansion from the maximum inner diameter (73.1) to the minimum inner diameter (111). Therefore, it is calculated as (111-73.1) /73.1 = 0.518.
Further, 75A → 125A, the maximum side indicates the maximum value of the diameter expansion ratio from 75A to 125A in SDR11, and the diameter is expanded from the minimum inner diameter (70.3) to the maximum inner diameter (114.8). Therefore, it is calculated as (114.8-70.3) /70.3=0.633.

In the present embodiment, the first vertical pipe portion 22 is composed of one pipe 221 but may be composed of a plurality of pipes 221 and joints connecting them.

(B. Second vertical piping section 23)
The second vertical pipe portion 23 is composed of a pipe 231 having an inner diameter D2. The pipe 231 is a tubular member made of PE (polyethylene), and as shown in FIG. 2, is arranged below the first vertical pipe portion 22 along a substantially vertical direction (which can also be said to be a vertical direction). The diameter D2 is set smaller than the diameter D1. The pipe 231 is arranged coaxially with the pipe 221.

The upper end of the pipe 231 (which can also be said to be the upper end 23a of the second vertical piping portion 23) is connected to the joint 24. The lower end of the pipe 231 is connected to a first horizontal pulling pipe portion 31 (described later) arranged in a substantially horizontal direction via joints 314 and 315 described later.

For the second vertical piping section 23, pipes having nominal diameters of 150A, 125A, 100A, and 75A are used.

In the present embodiment, the second vertical pipe portion 23 is composed of one pipe 231 but may be composed of a plurality of pipes 231 and joints connecting them.

In the present embodiment, by reducing (reducing the diameter) the inner diameter of the pipe from the first vertical pipe portion 22 to the second vertical pipe portion 23, resistance to rainwater is generated and the falling speed of rainwater can be suppressed. Therefore, it is possible to suppress the occurrence of cavitation at the inlet (near the opening 103) of the first vertical piping portion 22.

(C. Fitting 24)
The joint 24 is a reducer and is a tubular member made of PE (polyethylene). As shown in FIG. 2, the joint 24 connects the first vertical piping portion 22 and the second vertical piping portion 23. When connecting a resin pipe and a joint, for example, a mechanical joint (for example, a flexible joint) can be used as the joint 24.
The joint 24 has a first connecting portion 241 which is a cylindrical space, a second connecting portion 242 which is a cylindrical space, and a reduced diameter portion 243.

The first connecting portion 241 and the second connecting portion 242 are arranged coaxially along the vertical direction. The lower end of the pipe 221 is inserted into and fixed to the first connection portion 241. The inner diameter of the first connection portion 241 substantially coincides with the outer diameter of the pipe 221. The upper end of the pipe 231 is inserted into and fixed to the second connection portion 242. The inner diameter of the second connecting portion 242 substantially coincides with the outer diameter of the pipe 231.

The reduced diameter portion 243 connects between the first connecting portion 241 and the second connecting portion 242. It is a truncated cone-shaped space, and is formed so that the inner diameter is reduced from the first connection portion 241 to the second connection portion 242.

(1-2-3. Connecting member 25)
The connecting member 25 is a member for fixing the first vertical piping portion 22 or the second vertical piping portion 23 to the slab 101.

FIG. 5 is a diagram showing a state in which the second vertical piping portion 23 is fixed to the slab 101 by the connecting member 25.

For example, as shown in FIG. 5, the connecting member 25 uses a member such as a so-called floor band, which uses two members to fix the outer peripheral surface of the pipe 231 of the second vertical piping portion 23 so as to be sandwiched by the holding portion 25a. be able to.

In FIG. 5, the second vertical piping portion 23 is fixed to the slab 101 so that its upper end 23a is arranged at a height h1 (for example, within 0.2 m) from the upper surface 101a of the slab 101. Here, in the portion where the diameter is reduced, the energy loss of rainwater may increase and noise may be generated. However, by arranging the joint 24 close to the fixed position, the effect of suppressing the noise can be obtained. It is demonstrated.

Although the second vertical piping portion 23 is fixed to the slab 101 in FIG. 5, the first vertical piping portion 23 is fixed according to the lengths of the first vertical piping portion 22 and the second vertical piping portion 23, which will be described later. The portion 22 may be fixed to the slab 101, and even when the second vertical piping portion 23 is fixed, it does not have to be fixed in the vicinity of the lower part of the joint 24 as shown in FIG.

(1-2-4. Piping length, diameter reduction ratio)
As shown in FIG. 2, the first vertical pipe portion 22 is composed of a substantially circular pipe 221 having an inner diameter D1. The second vertical pipe portion 23 has a length in the vertical direction of L2 and is composed of a substantially circular pipe 231 having an inner diameter D2.

The length L1 from the upper end 26a to the lower end 26b of the vertical pipe portion 26 and the length L2 of the second vertical pipe portion 23 satisfy the following formula (1).

0.3 ≤ L2 / L1 ≤ 0.8 ... (1)
By satisfying the above formula (1), the falling speed of rainwater in the vicinity of the entrance (opening 103) to the first vertical piping portion 22 can be suppressed, and cavitation can be suppressed.

When L2 / L1 is smaller than the lower limit value of 0.3, the function of the reduced diameter portion of the vertical pipe becomes weak and cavitation is likely to occur at the entrance. Further, when L2 / L1 is larger than the upper limit value of 0.8, the reduced diameter pipe is too long and cavitation is likely to occur in the reduced diameter portion.

Further, 0.4 ≦ L2 / L1 ≦ 0.7 may be satisfied.
Further, the diameter reduction ratio ((D1-D2) / D1) between the inner diameter D1 of the inner diameter of the pipe 221 and the diameter D2 of the inner diameter of the pipe 231 satisfies the following formula (2).

0.20≤ (D1-D2) / D1 ... (2)
If it is smaller than the lower limit of 0.20, the effect of diameter reduction does not occur so much and cavitation may occur. Therefore, (D1-D2) / D1 is preferably 0.20 or more.

Further, the length L1 of the vertical pipe portion 26 satisfies the following formula (3).
50 meters ≤ L1 ... (3)
L1 is not limited to the range of the above formula (3), but cavitation is more likely to occur when the length of the vertical pipes arranged in the vertical direction is 50 meters or more, and this embodiment is the present embodiment. The effect of suppressing cavitation can be obtained.

(1-3. Drainage pipe structure 30)
FIG. 6 is a plan view showing the drainage pipe structure 30. The drainage pipe structure 30 includes a first horizontal pulling pipe section 31, a second horizontal pulling piping section 32, a third horizontal pulling piping section 33, a joint 34, and a joint 35.

The first horizontal pulling pipe section 31 collects rainwater from a plurality of drainage devices 20. The second horizontal pulling pipe section 32 sends the rainwater collected by the first horizontal pulling piping section 31 to the mass 110. The joint 34 connects the first horizontal pulling pipe portion 31 and the second horizontal pulling pipe portion 32. The joint 35 connects the second horizontal pulling pipe portion 32 and the third horizontal pulling pipe portion 33.

(1-3-1. First horizontal pulling piping section 31)
As shown in FIG. 1, the first horizontal pulling pipe portion 31 is arranged underground so as to be along the lower end of the wall of the building 100. The first horizontal pipe section 31 serves as a water collecting pipe that collects rainwater flowing through three drainage devices 20 arranged in the vertical direction along one wall 104 of the building 100 and guides it to the mass 110. Have.

The first horizontal pulling pipe portion 31 is arranged substantially horizontally, but is slightly inclined so as to be lowered toward the mass 110 side in the longitudinal direction thereof. As a result, the collected rainwater smoothly moves to the mass 110.

The first horizontal pulling pipe portion 31 has three pipes 311 and 312, 313 and joints 314 and 315. The three pipes 311 and 312, 313 are tubular members made of PE (polyethylene) and are arranged coaxially side by side. In this embodiment, the pipes 311 and 312, 313 have the same inner diameter D3. The pipes 311 and 312, 313 are arranged in the order of the pipe 313, the pipe 312, and the pipe 311 from the side closer to the mass 110. As the pipes 311 and 312, 313, pipes having a nominal diameter of 75A, 100A, 125A, or 150A are used. As described above, as the pipe 313, a pipe having a nominal diameter of 75 A or more (inner diameter of 71.7 mm or more) is used.

The second vertical pipe portion 23 of the drainage device 20 on the leftmost side (opposite side to the mass 110) in FIG. 1 is connected to the leftmost side pipe 311 via a joint 314. The joint 314 is made of PE (polyethylene) and is a two-sided joint bent at a right angle.

The second vertical pipe portion 23 of the central drainage device 20 is connected to the leftmost pipe 311 and the central pipe 312 via a PE (polyethylene) joint 315. The joint 315 is a three-way joint.

The second vertical pipe portion 23 of the drainage device 20 on the right side is connected to the pipe 312 in the center and the pipe 313 on the right side via a joint 315.
The configuration of the first horizontal pulling pipe portion 31 is not limited to the configuration of the present embodiment.

(1-3-2. Second horizontal pulling piping part 32, joint 34)
The second horizontal pulling pipe portion 32 is arranged on the mass 110 side (downstream side) of the first horizontal pulling pipe portion 31, and has the pipe 321 as shown in FIG. The pipe 321 is a tubular member made of PE (polyethylene) and is arranged coaxially with the pipe 311. The diameter D4 of the inner diameter of the pipe 321 is larger than the diameter D3 of the inner diameter of the pipe 313. As the pipe 321, a pipe having a nominal diameter of 100 A, 125 A, 150 A or 200 A is used.

In the present embodiment, the second horizontal pulling pipe portion 32 is composed of one pipe 321 but may be composed of a plurality of pipes 321 and joints connecting them.

The joint 34 is a so-called incrementer, and connects the pipe 313 of the first horizontal pulling pipe portion 31 and the pipe 321 of the second horizontal pulling pipe portion 32 having an inner diameter larger than that of the pipe 313.

(1-3-3. Third horizontal piping section 33, joint 35)
The third horizontal pulling pipe portion 33 is arranged between the second horizontal pulling pipe portion 32 and the mass 110, and has a pipe 331. The pipe 331 is a tubular member made of PE (polyethylene). In the present embodiment, the inner diameter D5 of the inner diameter of the pipe 321 is set to be the same as the diameter D4 of the inner diameter of the pipe 331, but may be larger than the pipe 313. As the pipe 331, a pipe having a nominal diameter of 100 A, 125 A, 150 A or 200 A is used.

One end of the pipe 331 is connected to the mass 110, and the other end is connected to the pipe 321 via the joint 35.

In the present embodiment, the third horizontal pulling pipe portion 33 is composed of one pipe 331, but may be composed of a plurality of pipes 331 and joints connecting them.

The joint 35 is a so-called elbow joint, which is a tubular member made of PE (polyethylene). The joint 35 connects the pipe 321 and the pipe 331 so that the pipe 331 is inclined with respect to the pipe 321.

As described above, the pipe 321 having a diameter larger than that of the pipe 313 is arranged on the downstream side of the pipe 313, the inclined joint 35 is arranged on the downstream side of the pipe 321, and the pipe 331 is connected to the joint 35.

As a result, the rainwater flowing through the pipe 313 and the pipe 321 hits the inclined joint 35. Here, since the pipe 321 having a diameter larger than that of the pipe 313 is provided on the upstream side of the joint 35, the rainwater colliding with the joint 35 can return to the pipe 321 while generating a swirling flow. Therefore, the speed of the water flowing into the mass 110 can be reduced. The rainwater that has flowed into the mass 110 flows into the sewer pipe through the pipe 400.

(1-3-4. Tilt of piping, diameter expansion ratio)
Assuming that the angle formed by the central axis A1 of the pipe 321 formed by the joint 35 and the central axis A2 of the pipe 331 is θ (which can be said to be an inclination with respect to the central axis A2), the angle θ satisfies the following equation (α).

20 degrees ≤ θ ≤ 80 degrees ・ ・ ・ ・ ・ ・ ・ ・ Equation (α)
As will be described in detail in Examples described later, the speed of water flowing into the mass 110 can be reduced by satisfying the above equation (α).

For example, at 0 degrees outside the above range, no swirling flow is generated and the flow velocity hardly changes, so that the effect is difficult to be exhibited. Therefore, it is technically important that the value is equal to or higher than the above lower limit. Further, at 90 degrees outside the above range, violent vibration due to the thrust force occurs in the elbow portion, and stable drainage cannot be performed. Therefore, it is technically important that the value is not less than the above upper limit.

Further, assuming that the inner diameter of the inner diameters of the pipes 311 and 312, 313 of the first horizontal pulling pipe portion 31 is D3 and the diameter of the inner diameter of the pipe 321 of the second horizontal pulling pipe portion 32 is D4, the diameter expansion ratio ((D4-D4-). D3) / D3) satisfies the following equation (β).

0.13 ≦ (D4-D3) / D3 ≦ 0.67 ・ ・ ・ ・ ・ ・ Equation (β)
For example, when pipes with nominal diameters of 125A and 150A are used as pipes 313 and 321 in the VP shown in the table of FIG. 4, the diameter expansion ratio is 0.138, which is the smallest, as shown on the minimum side of FIG. Therefore, when piping with nominal diameters of 75A and 125A is used in the VP, the diameter expansion ratio is 0.662, which is the largest, as shown on the maximum side of FIG. As a result, the upper limit value and the lower limit value of the equation (β) are set.

When the diameter expansion ratio is 0.1, which is outside the above range, the amount of expansion is small and the flow velocity hardly changes, so that the effect is difficult to be exhibited. Therefore, it is technically important that the value is equal to or higher than the above lower limit.

Further, by using a pipe with a nominal diameter of 75 A for the pipe 313 and a pipe with a nominal diameter of 150 A for the pipe 321, the diameter expansion ratio is set to 0.95, the displacement is set to 40 L / s, and the elbow angle θ is set to 45 °. As a result of the evaluation, the mass popping out condition is very good, the vibration is good, and the overall evaluation is very good. However, when the diameter expansion ratio is larger than 0.67 outside the above range, the effect of suppressing the occurrence of pop-out and vibration reaches a plateau and the workability deteriorates. Therefore, the upper limit is set to 0.67. The workability means that the weight of the pipe is heavy and it is difficult to pipe, and that the excavation depth for the pipe and mass equipment is large, which requires a significant amount of time and man-hours.

<2. Operation>
Rainwater that has fallen on the roof 105 of the building 100 flows into the drainage ditch 102, passes through the siphon inducer 21 of the drainage device 20, and flows into the pipe 221. Here, since the siphon phenomenon occurs, the pipe 221 becomes full and a large amount of rainwater can be drained.

When the rainwater drops the pipe 221, friction occurs with the pipe 231 whose diameter is smaller than that of the pipe 221 and the falling speed is suppressed. This reduces the occurrence of cavitation at the inlet of the pipe 221.

The rainwater that has fallen through the plurality of drainage devices 20 is collected in the first horizontal pulling pipe section 31 and supplied to the second horizontal pulling piping section 32 via the joint 34. The rainwater supplied to the second horizontal pulling pipe portion 32 collides with the joint 35, and a swirling flow toward the upstream is generated. This swirling flow returns to the pipe 321 whose diameter is larger than that of the pipe 313, collides with the rainwater toward the mass 110, and the speed of the rainwater is reduced in the pipe 321. As a result, even when a large flow rate of rainwater is drained by the siphon inducing portion 21, the rainwater is decelerated in the second horizontal pulling pipe portion 32, so that the splashing or vibration of the rainwater in the mass 110 is reduced. be able to.

<3. Example of drainage device 20>
In this embodiment, when a pipe having a nominal diameter of 100 A is used for the pipe 221 and a pipe having a nominal diameter of 75 A is used for the pipe 231 (which can be said to be a reduced diameter portion) in the drainage device 20, the total length L1 of the vertical pipe portion 26 and the pipe are used. Examples 1 to 16 and Comparative Examples 1 to 4 when the total length L2 of 231 is changed and the reduction ratio is changed are shown.

FIG. 7 is a table showing Examples 1 to 16 and Comparative Examples 1 to 4. In FIG. 7, the diameter reduction ratio is shown as a percentage ((D1-D2) / D1 × 100 (%)).

The evaluation criteria were that the pressure balance in the pipe was good and cavitation was unlikely to occur. Double circles (⊚) indicate a state in which cavitation does not occur at all and the pressure balance is very good. Circles (○) indicate a state in which cavitation does not occur and the pressure balance is good. A triangle (Δ) indicates a state in which cavitation hardly occurs and the pressure balance is generally good. The state where cavitation occurred and the pressure balance was poor is indicated by a cross (x).

(Example 1)
In Example 1, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 15 m (L2 / L1 = 0.3) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 2)
In Example 2, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 20 m (L2 / L1 = 0.4) and a diameter reduction ratio of 20%, the state between the triangle and the circle was obtained. ..

(Example 3)
In Example 3, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 25 m (L2 / L1 = 0.5) and a diameter reduction ratio of 20%, the above-mentioned round state is obtained and cavitation occurs. However, the pressure balance was very good.

(Example 4)
In Example 4, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 35 m (L2 / L1 = 0.7) and a diameter reduction ratio of 20%, the state between the triangle and the circle was obtained. ..

(Example 5)
In Example 5, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 40 m (L2 / L1 = 0.8) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 6)
In Example 6, as a result of evaluating cavitation by setting L1 = 100 m and L2 = 30 m (L2 / L1 = 0.3) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 7)
In Example 7, as a result of evaluating cavitation by setting L1 = 100 m and L2 = 80 m (L2 / L1 = 0.8) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 8)
In Example 7, as a result of evaluating cavitation by setting L1 = 200 m and L2 = 60 m (L2 / L1 = 0.3) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 9)
In Example 9, as a result of evaluating cavitation by setting L1 = 200 m and L2 = 160 m (L2 / L1 = 0.8) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 10)
In Example 10, as a result of evaluating cavitation by setting L1 = 300 m and L2 = 90 m (L2 / L1 = 0.3) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 11)
In Example 11, as a result of evaluating cavitation by setting L1 = 300 m and L2 = 240 m (L2 / L1 = 0.8) and a diameter reduction ratio of 20%, the above triangular state is obtained and cavitation is almost generated. The pressure balance was generally good.

(Example 12)
In Example 12, for example, as shown in FIG. 8 described later, the diameter was reduced in three stages, and L1 = 50 m and L2 = 15 m (L2 / L1 = 0.3) and a diameter reduction ratio of 37% were set. Here, L2 is the length of the portion below the reduced diameter of the first stage from the top (in FIG. 8, for example, the length of the third vertical piping portion 27 and the length of the second vertical piping portion 23). As a result of evaluating cavitation in such a configuration, the above-mentioned round state was obtained, cavitation did not occur, and the pressure balance was good.

(Example 13)
In Example 13, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 25 m (L2 / L1 = 0.5) and a diameter reduction ratio of 37%, the state between the circle and the double circle there were.

(Example 14)
In Example 14, for example, as shown in FIG. 8 described later, the diameter was reduced in three stages, and L1 = 50 m and L2 = 40 m (L2 / L1 = 0.8) and a diameter reduction ratio of 37% were set. Here, L2 is the length of the portion below the reduced diameter of the first stage from the top (in FIG. 8, for example, the length of the third vertical piping portion 27 and the length of the second vertical piping portion 23). As a result of evaluating cavitation in such a configuration, the above-mentioned round state was obtained, cavitation did not occur, and the pressure balance was good.

(Example 15)
In Example 15, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 15 m (L2 / L1 = 0.3) and a diameter reduction ratio of 49%, the above-mentioned round state is obtained and cavitation occurs. The pressure balance was good.

(Example 16)
In Example 16, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 25 m (L2 / L1 = 0.5) and a diameter reduction ratio of 49%, the cavitation was in the double circle state. It did not occur at all and the pressure balance was very good.

(Example 17)
In Example 17, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 40 m (L2 / L1 = 0.8) and a diameter reduction ratio of 49%, the above-mentioned round state is obtained and cavitation occurs. The pressure balance was good.

(Example 18)
In Example 18, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 15 m (L2 / L1 = 0.3) and a diameter reduction ratio of 61%, the state between the circle and the double circle there were.

(Example 19)
In Example 19, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 25 m (L2 / L1 = 0.5) and a diameter reduction ratio of 61%, the cavitation was in the double circle state. It did not occur at all and the pressure balance was very good.

(Example 20)
In Example 20, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 40 m (L2 / L1 = 0.8) and a diameter reduction ratio of 61%, the state between the circle and the double circle there were.

(Comparative Example 1)
In Comparative Example 1, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 10 m (L2 / L1 = 0.2) and a diameter reduction ratio of 20%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 2)
In Comparative Example 2, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 45 m (L2 / L1 = 0.9) and a diameter reduction ratio of 20%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 3)
In Comparative Example 3, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 15 m (L2 / L1 = 0.3) and a diameter reduction ratio of 18%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 4)
In Comparative Example 4, cavitation was evaluated by setting L1 = 50 m and L2 = 40 m (L2 / L1 = 0.8) and a diameter reduction ratio of 18%. , The pressure balance was bad.

(Comparative Example 5)
In Comparative Example 5, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 10 m (L2 / L1 = 0.2) and a diameter reduction ratio of 37%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 6)
In Comparative Example 5, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 10 m (L2 / L1 = 0.2) and a diameter reduction ratio of 49%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 7)
In Comparative Example 7, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 10 m (L2 / L1 = 0.2) and a diameter reduction ratio of 61%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 8)
In Comparative Example 8, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 45 m (L2 / L1 = 0.9) and a diameter reduction ratio of 37%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 9)
In Comparative Example 9, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 45 m (L2 / L1 = 0.9) and a diameter reduction ratio of 49%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

(Comparative Example 10)
In Comparative Example 10, as a result of evaluating cavitation by setting L1 = 50 m and L2 = 45 m (L2 / L1 = 0.9) and a diameter reduction ratio of 61%, the above-mentioned cross state occurs and cavitation occurs. , The pressure balance was bad.

From the results of Example 1 and Comparative Example 1, Example 12 and Comparative Example 5, Example 15 and Comparative Example 6, and Example 18 and Comparative Example 7, when L2 / L1 is smaller than the lower limit of 0.3. It can be seen that the function of the reduced diameter part of the vertical pipe becomes weaker and cavitation is more likely to occur at the entrance.

Further, from the results of Example 5 and Comparative Example 2, Example 14 and Comparative Example 8, Example 17 and Comparative Example 9, and Example 20 and Comparative Example 10, L2 / L1 is larger than the upper limit value of 0.8. In this case, it can be seen that the reduced diameter tube is too long and cavitation is likely to occur in the reduced diameter portion.

Further, from the results of Example 1 and Comparative Example 3 and Example 2 and Comparative Example 4, when the diameter reduction ratio is not 20% or more, the effect of diameter reduction can hardly be exhibited and cavitation is likely to occur. Understand.

Even at a diameter reduction ratio of 61%, the occurrence of cavitation can be suppressed as shown in FIG. 7, so there is no upper limit to the reduction ratio for exerting the effect of suppressing the occurrence of cavitation, but in reality, the drainage performance. Is extremely low, so that the diameter reduction ratio is rarely made larger than 61%. Therefore, from the viewpoint of drainage performance, the upper limit of the diameter reduction ratio may be set to 61%.

<4. Features, etc.>
(1)
The drainage device 20 (an example of the drainage device) of the present embodiment is a drainage device for draining rainwater, and includes a vertical pipe portion 26 and a siphon induction portion 21. The vertical pipe section 26 has a first vertical piping section 22 (an example of a first piping section) and a second vertical piping section 23 (an example of a second vertical piping section). The first vertical piping section 22 has a diameter. It has a substantially circular area of D1 (an example of the first flow path cross-sectional area), and is arranged along the vertical direction. The second vertical piping portion 23 has a substantially circular area with a diameter D2 (an example of a second flow path cross-sectional area) smaller than the substantially circular area with a diameter D1, and the first vertical piping portion 23 has a first vertical area. It is arranged under the piping portion 22. The siphon induction unit 21 is arranged above the vertical pipe portion 26, and induces the occurrence of the siphon phenomenon in the rainwater drained by the vertical pipe portion 26. Assuming that the length of the vertical pipe portion 26 is L1 and the length of the second vertical pipe portion 23 is L2, the equation (1) is satisfied.

0.3 ≤ L2 / L1 ≤ 0.8 ... (1)
In this way, the first vertical piping section 22 is provided below the siphon inducing section 21, and the second vertical piping section 23 having a smaller cross-sectional area than the first vertical piping section 22 is provided below the first vertical piping section 22. By providing the above, the falling speed of the water flowing into the second vertical piping portion 23 can be suppressed. Therefore, the negative pressure in the first vertical piping portion 22 can be reduced, and the occurrence of cavitation can be suppressed.

In particular, when the drainage device 20 is introduced into a high-rise building, the rainwater has a large potential energy due to the addition of attractive force and gravity due to the siphon phenomenon. The effect of suppressing the occurrence of cavitation by making the cross-sectional area smaller than that of 22 becomes remarkable.

(2)
In the drainage device 20 (an example of a drainage device) of the present embodiment, the first vertical piping section 22 (an example of the first piping section) has an inner diameter of D1 (an example of the first diameter), and the second vertical piping section 22 has an inner diameter. The piping unit 23 (an example of a second piping unit) has a diameter D2 (an example of a second diameter) smaller than the diameter D1.

In this way, the first vertical piping section 22 is provided below the siphon inducing section 21, and the second vertical piping section 23 having an inner diameter smaller than that of the first vertical piping section 22 is provided below the first vertical piping section 22. By providing the water, it is possible to suppress the falling speed of water when it flows into the second vertical piping portion 23.

In particular, when the drainage device 20 is introduced into a high-rise building, the rainwater has a large potential energy due to the addition of attractive force and gravity due to the siphon phenomenon. The effect of suppressing the occurrence of cavitation by reducing the diameter from 22 becomes remarkable.

(3)
In the drainage device 20 (an example of the drainage device) of the present embodiment, the diameter D1 and the diameter D2 satisfy the formula (1) and the following formula (2).

0.20≤ (D1-D2) / D1 ... (2)
By using the first vertical piping section 22 and the second vertical piping section 23 having such an inner diameter, the occurrence of cavitation can be further reduced.

(4)
In the drainage device 20 (in an example of the drainage device) of the present embodiment, L1 satisfies the following formula (3).

50 meters ≤ L1 ... (3)
The longer the length of the pipes arranged in the vertical direction, the faster the falling speed and the more likely it is that cavitation will occur. The effect of suppressing can be remarkably exhibited.

(5)
In the drainage device 20 (an example of the drainage device) of the present embodiment, the upper end 26a of the vertical pipe portion 26 is the upper end of the first vertical pipe portion 22, and the lower end 26b of the vertical pipe portion 26 is the second vertical pipe portion. The lower end of 23, the diameter D1 is the maximum inner diameter in the vertical pipe portion, and the diameter D2 is the minimum inner diameter in the vertical pipe portion 26.

As a result, the negative pressure in the first vertical piping portion 22 can be reduced, and the occurrence of cavitation can be suppressed.

(6)
In the drainage device 20 (an example of the drainage device) of the present embodiment, the lower end 22a of the first vertical piping section 22 and the upper end 23a of the second vertical piping section 23 are directly or indirectly connected via a joint. Has been done.

As a result, rainwater can be linearly moved downward from the siphon inducer 21.

(7)
The drainage pipe structure 30 of the present embodiment is a drainage pipe structure that is connected to the mass 110 and discharges rainwater to the mass 110, and is a first horizontal pulling pipe section 31, a second horizontal pulling piping section 32, and a second. 3 A horizontal pulling pipe portion 33 and a joint 35 (an example of a bent portion) are provided. The first horizontal pulling pipe portion 31 has a circular area having a diameter D3 (an example of a first flow path cross section). The second horizontal pulling pipe portion 32 has a circular area having a diameter D4 larger than the circular area having a diameter D3 (an example of the cross section of the second flow path), and is downstream of the first horizontal pulling pipe portion 31. It is placed on the side. The third horizontal pulling pipe portion 33 is arranged on the downstream side of the second horizontal pulling pipe portion 32 and is connected to the mass 110. The joint 35 has the second horizontal pulling pipe section 32 and the third horizontal pulling piping section 33 so that the axis A2 direction of the third horizontal pulling piping section 33 is inclined with respect to the axis A1 direction of the second horizontal pulling piping section 32. connect. Assuming that the bending angle of the third horizontal pulling pipe portion 33 in the axial direction with respect to the axial direction of the second horizontal pulling pipe portion 32 is θ, the following equation (α) is satisfied.

20 degrees ≤ θ ≤ 80 degrees ... Equation (α)
As a result, the rainwater supplied to the first horizontal pulling pipe section 31 hits the inner wall of the joint 35 via the second horizontal pulling piping section 32, and a swirling flow in the direction of returning to the upstream is generated. Here, since the second horizontal pulling piping portion 32 is formed to have a larger flow path cross-sectional area than the first horizontal pulling piping section 31, the swirling flow has a larger flow path cross-sectional area than the first horizontal pulling piping section 31. It becomes possible to return to the second horizontal pulling pipe section 32, and the rainwater toward the mass 110 collides with the swirling flow in the second horizontal pulling piping section 32 and is decelerated.

In this way, even when a large flow rate of rainwater is drained, the rainwater is decelerated in the second horizontal pulling pipe portion 32 to reduce the splash of rainwater from the mass 110 or the vibration in the mass 110. can.

(8)
In the drainage pipe structure 30 of the present embodiment, the first horizontal pulling pipe portion 31 has a substantially circular cross-sectional view and has an inner diameter of D3 (an example of the first diameter). The second horizontal pulling pipe portion 32 has a substantially circular cross-sectional view and has an inner diameter of D4 (an example of the second diameter) larger than the diameter D3. The third horizontal pulling pipe portion 33 has a substantially circular cross-sectional view and has an inner diameter of D5 (an example of a third diameter) having a diameter of D4 or more.

In this way, since the second horizontal pulling pipe portion 32 has a larger diameter than the first horizontal pulling pipe portion 31, the swirling flow has a larger diameter than the first horizontal pulling pipe portion 31. It becomes possible to return to 32, and the rainwater heading for the mass 110 collides with the swirling flow at the second horizontal pulling pipe portion 32 and is decelerated.

(9)
In the drainage pipe structure 30 of the present embodiment, the inner diameter D3 is 71 mm or more.

As a result, the flow velocity can be suppressed even when a large amount of rainwater is flowed.
(10)
In the drainage pipe structure 30 of the present embodiment, the amount of drainage supplied to the first horizontal pulling pipe portion 31 is 20 L / s (seconds) or more.

When draining with such a large amount of drainage, the effect of slowing down the flow velocity of rainwater can be remarkably exhibited, and the splash of rainwater from the mass 110 or the vibration in the mass 110 can be reduced.

(11)
In the drainage pipe structure 30 of the present embodiment, the diameter D3 and the diameter D4 satisfy the following formula (β). 0.13 ≦ (D4-D3) / D3 ≦ 0.67 ・ ・ ・ ・ ・ ・ Equation (β)
This makes it possible to provide a space for the above-mentioned swirling flow to flow backward.

<5. Other embodiments>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention.

(A)
In the above embodiment, as shown in FIG. 2, the diameter is reduced by only one step from the first vertical piping section 22 to the second vertical piping section 23, but as shown in FIG. 8, the diameter is reduced to a plurality of steps. May be good. In FIG. 8, a third vertical piping section 27 (an example of a third vertical piping section) is provided between the first vertical piping section 22 and the second vertical piping section 23. The third vertical piping section 27 is composed of a single piping 271. The diameter D7 of the inner diameter of the pipe 271 (an example of the third diameter) is smaller than the diameter D1 of the inner diameter of the pipe 221 and larger than the diameter D2 of the inner diameter of the pipe 231. In FIG. 8, the third vertical pipe portion 27 is composed of one pipe 271, but may be composed of a plurality of pipes and joints. Further, the pipe 221 and the pipe 271 are connected by a joint 28 (reducer), and the pipe 271 and the pipe 231 are connected by a joint 29 (reducer).

The combination of the pipe 221 and the pipe 271 and the pipe 231 includes, for example, a combination of pipes having nominal diameters of 125A, 100A and 75A, a combination of pipes of 150A, 125A and 100A, and a combination of pipes of 200A, 150A and 125A. Etc. can be used.

By reducing the diameter in a plurality of steps in this way, the potential energy of rainwater can be gradually reduced by friction. Therefore, noise and the like on the downstream side of the pipe can be reduced.

(B)
In the above embodiment, as shown in FIG. 6, the diameter is increased from the pipe 313 to the pipe 321 by one step, but the diameter may be increased to a plurality of steps as shown in FIG. In FIG. 9, a fourth horizontal pulling pipe section 36 is provided between the first horizontal pulling piping section 31 and the second horizontal pulling piping section 32. The inner diameter D6 of the fourth horizontal pulling pipe portion 36 (an example of the fourth diameter) is larger than the inner diameter D3 of the inner diameter of the first horizontal pulling pipe portion 31 and larger than the inner diameter D4 of the second horizontal pulling pipe portion 32. Is also small. The fourth horizontal pulling pipe section 36 is arranged coaxially with the first horizontal pulling piping section 31 and the second horizontal pulling piping section 32. The fourth horizontal pulling pipe portion 36 is composed of one pipe 361. The pipe 313 and the pipe 361 are connected by a joint 38 of the incrementer. The pipe 361 and the pipe 321 are connected by a joint 39 of the incrementer. In FIG. 9, the fourth horizontal pulling pipe portion 36 is composed of one pipe 361, but may be composed of a plurality of pipes and joints.

The combination of the pipe 313, the pipe 361, and the pipe 321 includes, for example, a combination of pipes having nominal diameters of 75A, 100A, and 125A, a combination of pipes of 100A, 125A, and 150A, and a combination of pipes of 125A, 150A, and 200A. Etc. can be used.
By expanding the diameter in a plurality of stages in this way, the flow velocity of rainwater can be gradually reduced.

(C)
In the above embodiment, the pipe and the pipe are connected by a joint, but the present invention is not limited to this, and the pipe and the pipe may be directly connected.

(D)
In the above embodiment, the rainwater from the three drainage devices 20 is collected into one and drained to the mass 110 by the first horizontal pulling pipe portion 31 of the drainage pipe structure 30, but the rainwater is collected into one. It does not have to be.

For example, as shown in the rainwater drainage system 10'shown in FIG. 10, a drainage pipe structure 30'and a mass 110 may be provided for each drainage device 20. In this case, the first horizontal pulling pipe portion 31'of the drainage pipe structure 30' has only the pipe 313, and the pipe 313 is connected to the pipe 231 of the drainage device 20 via the joint 314.

The rainwater drainage system 10'shown in FIG. 10 includes 6 sets including the drainage device 20 and the drainage pipe structure 30', but the number is not limited to this, and even if only one set is provided. good.

(E)
In the drainage device 20 of the above embodiment, the first vertical piping section 22 and the second vertical piping section 23 have a circular cross section (flow path cross section) perpendicular to the flow path direction, but the cross section is not limited to the circular shape. It may have an elliptical shape, a quadrangular shape, or the like. In short, the cross-sectional area through which the flow path flows may be similar to the relationship of the drainage device 20 of the above embodiment. That is, it is sufficient that the second flow path cross section of the second vertical piping section 23 is smaller than the first flow path cross section of the first vertical piping section 22.

Further, when the third vertical piping section 27 is provided between the first vertical piping section 22 and the second vertical piping section 23, the third flow path cross-sectional area of the third vertical piping section 27 is It may be smaller than the first flow path cross section and larger than the second flow path cross section.

(F)
In the drainage pipe structure 30 of the above embodiment, the first horizontal pulling pipe section 31, the second horizontal pulling piping section 32, and the third horizontal pulling piping section 33 have a cross section (flow path cross section) perpendicular to the flow path direction. Although it has a circular shape, it is not limited to a circular shape, and may be an elliptical shape, a quadrangular shape, or the like. In short, the cross-sectional area through which the flow path flows may be similar to the relationship of the water pipe structure 30 of the above embodiment. That is, the second cross-sectional area of the second flow path of the second horizontal pulling piping section 32 is larger than the cross-sectional area of the first flow path of the first horizontal pulling piping section 31, and the third horizontal pulling piping section 33 has a second cross-sectional area. It suffices if the cross-sectional area of the flow path of 3 is equal to or larger than the cross-sectional area of the second flow path.

Further, when the fourth horizontal pulling pipe section 36 is provided between the first horizontal pulling piping section 31 and the second horizontal pulling piping section 32, the fourth flow path of the fourth horizontal pulling piping section 36 is provided. The cross section may be larger than the first flow path cross section and smaller than the second flow path cross section.

(G)
In the drainage device 20 of the above embodiment, the first vertical piping section 22 and the second vertical piping section 23 are connected, and rainwater does not move laterally from the siphon inducing section 21 to the vicinity of the ground linearly by the vertical pipe. However, a horizontal drainage pipe may be provided between the siphon inducer 21 and the ground. For example, a horizontal pulling pipe may be provided in the middle of the first vertical piping section 22, in the middle of the second vertical piping section 23, or between the first vertical piping section 22 and the second vertical piping section 23.

FIG. 11 is a schematic view showing a drainage device 20'showing a configuration in which a horizontal pull pipe is provided in the middle of the first vertical piping portion. In the drainage device 20'shown in FIG. 11, a horizontal pull pipe 200 is provided in the middle of the first vertical piping portion 22'. That is, the upper portion 221'of the first vertical piping portion 22'is connected to the drainage groove 102, and is arranged substantially horizontally between the lower end of the upper portion 221' and the upper end of the lower portion 222'of the first vertical piping portion 22'. The horizontal pull pipe 200 is connected. The lower end of the lower portion 222'of the first vertical piping portion 22'is connected to the second vertical piping portion 23 via the joint 24. The vertical pipe portion 26'is the sum of the upper portion 221', the lower portion 222', the joint 24, and the second vertical pipe portion 23, and this sum is the length L1 of the vertical pipe portion 26'.

(H)
In the above embodiment, an example in which a floor band is used as the connecting member 25 has been described. However, the present invention is not limited to this.
For example, a vertical band may be used as the connecting member.
Further, when dew condensation or the like generated on the surface of the connecting member becomes a problem, a configuration in which a member having a sleeper attached to the U band and an L-shaped metal fitting may be used as the connecting member.

(I)
In the above embodiment, it has been described that the pipes 221, 231, 311, 312, 313, 321 and 322 are made of PE, but the present invention is not limited thereto.

For example, in addition to PE, other olefin resins such as PP (polypropylene) and other resins such as PVC (vinyl chloride) may be used.

Even in this case, as in the above embodiment, the weight of the rainwater drainage device can be reduced, and the workability of the slab penetrating portion and the workability of the entire pipe can be improved.

Further, the pipes 221, 231, 311, 312, 313, 321 and 322 are not limited to those made of resin, and may be made of metal.

(J)
In the above embodiment, it has been described that the joints 24, 34, 35, 314, and 315 are made of PE (polyethylene), but the present invention is not limited thereto.

For example, in addition to PE, other olefin resins such as PP (polypropylene) and other resins such as PVC (vinyl chloride) may be used.

Further, the joints 24, 34, 35, 314, and 315 are not limited to those made of resin, and may be made of metal. When connecting a metal joint to a pipe, for example, a screw connection, a mechanical joint (for example, a flexible joint), or a flange is used.

The drainage device of the present invention has an effect of suppressing the occurrence of cavitation, and is widely applicable to various rainwater drainage systems for draining rainwater.

20: Drainage device 21: Siphon inducer 22: 1st vertical piping section 23: 2nd vertical piping section 26: Vertical pipe section 30: Drainage piping structure 31: 1st horizontal pulling piping section 32: 2nd horizontal pulling piping section 33 : Third horizontal pulling piping part 34: Joint 110: Mass

Claims (7)

A drainage device that drains rainwater
It has a first flow path cross-sectional area, a first piping section arranged along the vertical direction, and a second flow path cross-sectional area smaller than the first flow path cross-sectional area, and has a vertical flow path cross-sectional area. A vertical pipe portion having a second pipe portion arranged below the first pipe portion along the line, and a vertical pipe portion.
A siphon-inducing portion, which is arranged above the vertical pipe portion and induces the occurrence of a siphon phenomenon in the rainwater drained by the vertical pipe portion, is provided.
Assuming that the length of the vertical pipe portion is L1 and the length of the second pipe portion is L2, the following equation (1) is satisfied.
Drainage device.
0.3 ≤ L2 / L1 ≤ 0.8 ... (1) The first piping portion has a circular cross section of the flow path and has an inner diameter of the first diameter.
The second piping portion has a circular cross section of the flow path and has a second diameter smaller than the first diameter.
The drainage device according to claim 1. Assuming that the first diameter is D1 and the second diameter is D2, the following equation (2) is satisfied.
The drainage device according to claim 2.
0.20≤ (D1-D2) / D1 ... (2) L1 satisfies the following equation (3).
The drainage device according to any one of claims 1 to 3.
50 meters ≤ L1 ... (3) The upper end of the vertical pipe portion is the upper end of the first pipe portion.
The lower end of the vertical pipe portion is the lower end of the second pipe portion.
The first diameter is the maximum inner diameter of the vertical pipe portion, and is the maximum inner diameter.
The second diameter is the minimum inner diameter of the vertical pipe portion.
The drainage device according to claim 2 or 3. The lower end of the first piping portion and the upper end of the second piping portion are directly or indirectly connected via a joint.
The drainage device according to any one of claims 1 to 5. The vertical pipe portion is
Further having a third piping section having an inner diameter of a third diameter smaller than the first diameter and larger than the second diameter.
The third piping portion is arranged between the first piping portion and the second piping portion.
The drainage device according to any one of claims 1 to 5.

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