JP7431638B2 - drainage system - Google Patents

Description

TECHNICAL FIELD The present invention relates to drainage systems.

Conventionally, rainwater basins have been placed in roadside gutters to drain rainwater (for example, see Patent Document 1).

The rainwater basin shown in Patent Document 1 includes a main body, an upper frame placed on the upper part of the main body, and a metal lid placed on the upper frame, and a drainage pipe is connected to the lower end of the main body. . Rainwater flowing in from the metal lid flows into the drainage pipe through the rainwater basin.

A rainwater catchment is also installed at the end of the viaduct. A viaduct is made up of piers and girders, but because these parts are not connected, the girders move differently than the piers when an earthquake occurs. For this reason, the rainwater drainage pipes laid from the rainwater basins in the deck slabs are connected between the bridge piers and the bridge girders using telescopic pipes.

JP2016-156243A

However, if a siphon flow is generated in the rainwater flowing through the rainwater drainage pipe mentioned above in order to perform drainage at a high flow rate, negative pressure will be created above the vertically installed vertical pipe, and the telescopic pipe will be installed at this position. In some cases, the pipes could not withstand the negative pressure and deformed, impeding drainage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a drainage system capable of suppressing the obstruction of drainage due to deformation of an extensible pipe and performing drainage at a high flow rate.

In order to achieve the above object, a drainage system according to a first invention includes a drainage basin section, a drainage member, a piping section, and a pressure regulating valve. The drainage basin is placed on the bridge. The drainage member is arranged inside the drainage basin and induces the occurrence of a siphon effect. The piping section is connected to the drain port of the drainage member and has an expandable pipe. The pressure regulating valve is provided in a piping section upstream or downstream of the telescoping pipe. The regulated pressure P1 by the pressure regulating valve is 0. 7≦ P1 /P2 ≦1. 4 is satisfied. The installation position of the pressure regulating valve is within 1 m downstream or upstream of the installation position of the telescopic pipe.

By providing the pressure regulating valve in this manner, the piping section near the telescopic pipe is limited to a certain negative pressure value, so that deformation of the telescopic pipe can be reduced while generating a siphon effect.

Therefore, it is possible to prevent drainage from being inhibited by deformation of the expandable pipe and to perform drainage at a high flow rate.

When P1/P2 is smaller than 0.7, the drainage flow rate due to the siphon phenomenon is significantly reduced, and when it is larger than 1.4 times, the expandable pipe may be deformed and the flow rate may be reduced.

The drainage system according to the second invention is the drainage system according to the first invention, in which the amount of air flowing in from the pressure regulating valve is 4 L/s or more and 8 L/s or less.

If the amount of air flowing into the pressure regulating valve is less than 4L/s, there will be a delay in pressure relief, which may cause the telescopic tube to be slightly deformed.If it exceeds 8L/s, the amount of air supplied will be excessive, so it is necessary to stop or stop the air supply. Repeatedly, the pressure inside the pipe may become somewhat unstable.

Therefore, for stable pressure adjustment, it is preferable that the amount of air flowing in from the pressure regulating valve is 4 L/s or more and 8 L/s or less. It becomes possible to carry out drainage of water.

A drainage system according to a third invention is the drainage system according to either the first or second invention, in which the head of the piping part from the lower end of the drainage basin is 3 m or more and 20 m or less.

If the distance is less than 3 m, the siphon phenomenon will not occur sufficiently, and therefore high flow rate drainage may not be possible. Furthermore, if the length exceeds 20 m, the vacuum pressure generated within the piping gradually increases, so the maximum drainage flow rate in the siphon flow may decrease somewhat.

Therefore, by setting the head of the piping section from the lower end of the drainage basin to 3 m or more and 20 m or less, it is possible to more reliably suppress drainage obstruction due to deformation of the expandable pipe and perform high-flow drainage. .

According to the present invention, it is possible to provide a drainage system capable of suppressing the obstruction of drainage due to deformation of the expandable pipe and performing drainage at a high flow rate.

FIG. 1 is a side view showing a viaduct in which a drainage system according to an embodiment of the present invention is used. FIG. 1 is a schematic cross-sectional view showing an example in which a drainage system according to an embodiment of the present invention is used in a viaduct. FIG. 3 is a cross-sectional view showing the vicinity of the drainage basin of the drainage system shown in FIG. 2; FIG. 4 is an exploded perspective view showing the lid and drainage basin portion of FIG. 3; FIG. 4 is a perspective view showing the siphon drain member of FIG. 3; FIG. 4 is a perspective cross-sectional view showing the siphon drain member of FIG. 3; Front view of FIG. 6. (a) A cross-sectional configuration diagram of a pressure regulation valve of the drainage system of FIG. 2, (b) a cross-sectional configuration diagram showing the pressure regulation valve in an open state. FIG. 1 is a diagram showing the configuration of a drainage system according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Below, the drainage system based on embodiment of this invention is demonstrated based on drawing.
<Configuration>
(Configuration of viaduct)
First, the viaduct 200 on which the drainage system of this embodiment is installed will be described. FIG. 1 is a side view showing an overview of the viaduct 200. In the viaduct 200, girders 202 are arranged on opposing abutments 201 via supports 203. A bridge pier 204 is arranged between the abutments 201 and supports the girder 202 via a support 205. A floor slab 206 is formed on the upper surface of the girder 202. Expanding and retracting devices 207 are provided at both ends of the girder 202. Furthermore, railings 208 are provided at both ends of the girder 202 in the width direction.

In this way, the girder 202 is supported by the pier 204 and the abutment 201 via the supports 203 and 205, and is not directly connected to the pier 204 and the abutment 201.

(Overview of drainage system 1)
A plurality of drainage systems 1 according to the present embodiment are arranged along the side gutter of the viaduct 200. Rainwater falling on the viaduct 200 flows into the drainage system 1 and is drained outside the viaduct 200.

FIG. 2 is a diagram showing an example in which the drainage system 1 of this embodiment is applied to a viaduct 200. FIG. 3 is a sectional view showing the vicinity of the drainage basin section 20. The drainage system 1 of this embodiment includes a lid 10, a drainage basin section 20, a siphon drain member 30, a piping section 40, and a pressure regulating valve 50.

The lid 10 is arranged so as to close the upper part of the drainage basin part 20. Rainwater that has fallen on the floor slab 206 flows into the drainage basin part 20 via the lid 10. The siphon drain member 30 induces the occurrence of a siphon phenomenon in the waste water flowing through the connected piping section 40.

(lid)
FIG. 4 is an exploded perspective view of the lid 10 and the drainage basin part 20.

The lid 10 is made of metal, for example, and has a plurality of holes. The plurality of holes may have any shape as long as it does not impede the inflow of rain; for example, they may be formed in a mesh shape like a grating, or may have a plurality of rectangular holes. The lid 10 is supported by a drainage basin part 20, and rainwater flows into the drainage basin part 20 from the lid 10. Although the lid 10 has a rectangular shape as an example in this embodiment, the lid 10 is not limited to this and may have a polygonal shape other than a square, a circle, or an ellipse.

(Drainage basin)
The drainage basin section 20 is made of FRP, for example, and includes an upper basin 21, a lower basin 22, and a formwork pipe 23, as shown in FIG. The inside of the upper basin 21 corresponds to the opening 20a of the drainage basin part 20, and the lid 10 is disposed thereon. The lower basin 22 is arranged below the upper basin 21. The formwork pipe 23 is arranged in the lower chamber 22.

The upper basin 21 has a side wall part 24 and a lid placement part 25. The side wall portion 24 is formed to surround the lid 10. The side wall portion 24 is arranged substantially vertically. The lid placement portion 25 is formed approximately perpendicularly to the side wall portion 24 from the lower end of the side wall portion 24 toward the inside. The lid 10 is placed on the lid placement part 25.

The lower basin 22 has a side wall portion 26 and a bottom surface 27. The side wall portion 26 is provided downward from the inner end of the lid placement portion 25. A bottom surface 27 is arranged at the lower end of the side wall portion 26 .

The bottom surface 27 is provided to face the opening 20a. The bottom surface 27 is formed to have a smaller area than the opening 20a. As shown in FIG. 2, the bottom surface 27 is disposed closer to one of the left and right than the center of the opening 20a in the left-right direction.

As shown in FIG. 3, the side wall portion 26 is formed from the inner end of the lid placement portion 25 to the periphery of the bottom surface 27. It is formed to become smaller toward the bottom surface 27 so that the cross-sectional area along the direction parallel to the opening 20a becomes the size of the bottom surface 27. As a result, rainwater that has flowed into the drainage basin section 20 moves toward the bottom surface 27 (see arrow A). A through hole 27a is formed in the bottom surface 27, and a siphon drain member 30, which will be described later, is disposed therein.

The formwork tube 23 has a cylindrical shape and is arranged around the bottom surface 27 facing downward. The form pipe 23 protects piping and the like from concrete.

(Siphon drain member)
The siphon drain member 30 (an example of a drainage member) induces the occurrence of a siphon phenomenon in the water drained to the connected piping section 40, thereby causing a siphon flow to occur. The siphon drain member 30 is a drainage member having a high drainage function for improving the drainage capacity of rainwater flowing into the drainage basin portion 20.

FIG. 5 is a perspective view showing the siphon drain member 30. FIG. 6 is a perspective cross-sectional view of the siphon drain member 30. FIG. 7 is a front view of FIG. 6.

The siphon drain member 30 can be made by injection molding using a synthetic resin such as hard vinyl chloride resin, polycarbonate, ABS, or AES. Note that the material is not limited to synthetic resin, and may be a cast product made of cast iron, aluminum alloy, or the like using a mold.

The siphon drain member 30 includes a lid member 31, a mounting tube 32, and a plurality of vertical ribs 33.

The lid member 31 is plate-shaped and formed into a disk shape. The mounting cylinder 32 is formed into a cylindrical shape. The central axes of the lid member 31 and the mounting tube 32 are arranged on a common axis and coincide with each other in the vertical direction. This common axis is defined as a drain axis O, the mounting cylinder 32 of the siphon drain member 30 along the direction of the drain axis O is defined as the lower side, and the side of the lid member 31 is defined as the upper side. Further, in a plan view of the siphon drain member 30 from the direction of the drain axis O, the direction perpendicular to the drain axis O is defined as the radial direction, and the direction in which the siphon drain member 30 goes around the drain axis O is defined as the circumferential direction.

The mounting tube 32 has a tube portion 71 that forms the drop opening 34 and a plate-shaped collar portion 72 that extends radially outward from the upper end of the tube portion 71 . The connecting portion 32a on the inner surface side where the cylindrical portion 71 and the flange portion 72 are connected is formed in a bell mouth shape with a tapered surface or a curved surface.

The droplet part 34 is a part that drains rainwater, and the opening at the upper end of the droplet part 34 (which can also be called the inner side of the upper end of the cylindrical part 71) is the drain port 34a. The drain port 34a can also be said to be inside the collar portion 72. The distance from the drain port 34a to the lid member 31 is approximately the same as the distance from the collar portion 72 to the lid member 31. In the direction along the drain axis O, the positions of the drain port 34a and the collar portion 72 generally coincide.

The opening 34b of the droplet portion 34 is located below the drain port 34a and has a constant diameter, and the opening diameter of the opening 34b is indicated as R1 (see FIG. 7). Further, the area of the opening 34b having an opening diameter of R1 is defined as the opening area of the droplet portion 34. Note that the opening diameter R1 corresponds to the inner diameter of the cylindrical portion 71, and the opening area of the droplet portion 34 corresponds to the area whose diameter is the inner diameter of the cylindrical portion 71. Moreover, the diameter gradually increases from the opening 34b toward the drain port 34a due to the connecting portion 32a.

Also, in this embodiment. Since the drain axis O, which is the central axis of the siphon drain member 30, coincides with the vertical direction, the area of the lid member 31 and the opening area of the droplet 34 are the projection of the lid member 31 on a plane perpendicular to the vertical direction. This corresponds to the area and the projected area of the opening of the droplet portion 34. In this embodiment, the outer diameter of the lid member 31 and the outer diameter of the flange 72 are formed to be substantially the same.

As shown in FIGS. 5 and 6, a portion formed between the outer circumferential edge 31a of the lid member 31 and the outer circumferential edge 72a of the collar portion 72 is an inflow opening through which rainwater flows into the drain port 34a of the droplet portion 34. 30a (see arrow B in FIG. 6). The size and height shape of the lid member 31 are adjusted so that the area of the inflow opening 30a is larger than the opening area (portion with diameter R1) of the opening 34b of the droplet portion 34.

As shown in FIG. 6, the plurality of vertical ribs 33 connect the upper surface 72d of the flange 72 of the mounting tube 32 and the outer circumference of the lower surface 31c of the lid member 31. The lid member 31 is supported from below by a plurality of vertical ribs 33, and is supported at a position at a predetermined height H1 from the mounting tube 32, as shown in FIG. The plurality of vertical ribs 33 are provided in the inflow opening 30a, are formed along the radial direction in plan view, and are formed to intersect with the circumferential direction. The vertical ribs 33 have a function of rectifying rainwater flowing into the droplet 34 from the inflow opening 30a. In this embodiment, six vertical ribs 33 are formed, and the six vertical ribs 33 are provided at equal intervals (approximately 60 degree intervals) around the drain axis O. It is not limited.

The lid member 31 is arranged so as to close the opening 34b of the droplet portion 34 when viewed from above in the vertical direction. Further, the area of the lid member 31 (see diameter R2) is set larger than the opening area of the opening 34b of the droplet portion 34 (see diameter R1). Note that in this embodiment, the center of the lid member 31 and the center of the opening of the droplet portion 34 are aligned in the vertical direction, but in the case where the lid member 31 and the droplet portion 34 are both tilted and disposed diagonally. If the lid area of the lid member 31 is the same as the opening area of the droplet part 34, the opening 34b of the droplet part 34 cannot be closed when viewed from the vertical direction, and the lid member 31 and the droplet part 34 cannot be closed. A gap (an air core caused by the eddy current) is created between the two.

Therefore, it is preferable that the projected area of the lid member 31 with respect to a plane perpendicular to the vertical direction be set larger than the projected area of the opening 34b of the droplet portion 34.

Note that the upper surface 31b of the lid member 31 is provided with gripping ribs 35 that protrude upward and are arranged at intervals in the circumferential direction. The gripping rib 35 is gripped by an operator when connecting the siphon drain member 30 to the piping section 40 .

The siphon drain member 30 is disposed inside the drainage basin part 20 by inserting the cylinder part 71 into the through hole 27a formed in the bottom surface 27 of the drainage basin part 20 from above. A collar portion 72 of the drainage basin portion 20 is arranged on the bottom surface 27. Further, the cylindrical portion 71 is inserted into the elbow pipe 41 of the piping portion 40.

(Piping section)
The piping section 40 is connected to the siphon drain member 30. As the piping used in the drainage system 1 of this embodiment, for example, one having a diameter of 75A to 125A can be used. The diameter is selected depending on the required drainage flow rate, but if the diameter is too large, it becomes difficult to generate a siphon flow, so preferably 75A to 100A is used.

As shown in FIG. 2, the piping section 40 includes an elbow pipe 41, an elbow pipe 42, a merging joint 43, a vertical pipe 44, an expandable pipe 45, and a vertical pipe 46.

The cylindrical portion 71 of the siphon drain member 30 is inserted inside one upper end of the elbow pipe 41. The elbow pipe 41 is bent horizontally toward the inside of the girder 202 from the vertical direction. One end of the elbow tube 42 is connected to the other end of the elbow tube 41, and the elbow tube 42 is bent downward from the horizontal direction. The merging joint 43 is connected to the other end of the elbow pipe 42 . The merging joint 43 is a joint that connects a plurality of drainage systems 1 arranged along the viaduct 200 with each other through piping. The vertical pipe 44 has one upper end connected to the merging joint 43 and is arranged along the vertical direction.

Although only one side is shown in FIG. 2, the girder 202 has a substantially T-shaped cross section in the longitudinal direction, and has a horizontal portion 202a and a vertical portion 202b. The horizontal portion 202a protrudes from the width of the vertical portion 202b to both sides in the width direction. The elbow pipe 41 is supported by the girder 202 at its horizontal portion by a support 47 attached to the lower side of the horizontal portion 202a.

Further, the vertical pipe 44 is supported by the girder 202 by a plurality of supports 48 attached to the vertical portion 202b of the girder 202.

The telescopic pipe 45 is connected to the lower end of the vertical pipe 44 . The extensible tube 45 is a cylindrical pipe made of rubber. As the type of rubber, EPDM (ethylene propylene diene rubber), NBR (nitrile rubber), CR (chloroprene rubber), IIR (butyl rubber), etc. can be used. The telescopic tube 45 is formed into a bellows shape. The expandable tube 45 is arranged along the vertical direction.

The vertical pipe 46 is connected to the lower end of the telescopic pipe 45. Although not shown, the vertical pipe 46 is supported by a support on the pier 204.

It can also be said that the expandable pipe 45 is disposed in the middle of the vertical pipe section 49, which is a combination of the vertical pipes 44 and 46.

In this way, the piping is cut off between the girder 202 and the pier 204. Here, generally, due to thermal expansion and contraction of the girder 202, a misalignment of ±10 to 20 mm occurs between the vertical pipes 44 and 46. Furthermore, when an earthquake occurs, a misalignment of ±100 to 200 mm occurs between the vertical pipes 44 and 46. A telescopic tube 45 is provided to buffer this misalignment.

(Pressure control valve)
The pressure regulating valve 50 is provided on the upstream or downstream side of the telescopic pipe 45 . In addition, in this embodiment, it is provided in the vertical pipe 44 on the upstream side of the expandable pipe 45, as an example. FIG. 8(a) is a cross-sectional configuration diagram of the pressure regulating valve 50. The pressure regulating valve 50 includes a housing 51, a valve body 52, and a spring member 53. The housing 51 is formed with an inflow path 51a through which air flows, an outflow path 51b through which air flows out, and a flow path space 51c that connects the inflow path 51a and the outflow path 51b. A valve body 52 and a spring member 53 are housed in the flow path space 51c. The inflow path 51a communicates the flow path space 51c with the outside. The outflow path 51b communicates the flow path space 51c with the outside.

The valve body 52 includes a spherical valve body portion 52a and a biased portion 52b disposed on the outflow path 51b side of the valve body portion 52a. The valve body portion 52a and the biased portion 52b are connected. The biased portion 52b is biased by a spring member 53. The valve body 52 is pressed against the edge of the opening of the inflow path 51a to the flow path space 51c by the biasing force of the spring member 53 so that the valve body portion 52a closes the inflow path 51a from the flow path space 51c side. .

The spring member 53 has one end fixed to the peripheral edge 51d of the opening of the outflow passage 51b to the flow passage space 51c, and the other end fixed to the biased part 52b.

In this embodiment, the outflow passage 51b is inserted into the vertical pipe 44 so as to communicate with the flow path inside the vertical pipe 44.

When the siphon drain member 30 induces a siphon phenomenon in the waste water flowing through the piping section 40 and the upper part of the piping section 40 becomes negative pressure, the valve body 52 moves toward the outflow path 51b against the biasing force of the spring member 53. The inflow path 51a and the flow path space 51c communicate with each other. FIG. 8(b) is a cross-sectional view showing a state in which the valve body 52 moves and the inflow path 51a and the flow path space 51c communicate with each other.

As shown in FIG. 8(b), air flows into the vertical pipe 44 from the outside through the inflow path 51a, the flow path space 51c, and the outflow path 51b. Therefore, even if the pressure inside the vertical pipe 44 becomes negative, it is possible to prevent the pressure from falling below the predetermined negative pressure set by the pressure regulating valve 50.

It should be noted that the adjusted pressure P1 by the pressure regulating valve 50 is 0. 7≦ P1 /P2 ≦1. Must be 4 . However, P1 and P2 are negative values. Further, it is preferable that the amount of air flowing in from the pressure regulating valve 50 is 4 L/s or more and 8 L/s or less.

When P1/P2 is smaller than 0.7, the drainage flow rate due to the siphon phenomenon is significantly reduced, and when it is larger than 1.4 times, the telescopic pipe 45 is deformed and the flow rate is reduced.

Furthermore, if the amount of air flowing in through the pressure control valve 50 is less than 4 L/s, there will be a delay in pressure relief, which may cause the telescopic tube 45 to deform to some extent, and if it exceeds 8 L/s, the amount of air supplied will be excessive. The pressure inside the pipe may become somewhat unstable due to repeated supply and stop of air.

Further, the installation position of the pressure regulating valve 50 needs to be within 1 m upstream or downstream of the installation position of the telescopic pipe 45. If the pressure control valve 50 is located within 1 m downstream, the pressure control valve 50 is attached to the vertical pipe 46 . A pressure regulating valve 50 attached to the vertical pipe 46 is shown by a two-dot chain line.

Moreover, it is preferable that the height of the piping part 40 from the lower end of the drainage basin part 20 is 3 m or more and less than 20 m. If it is less than 3 m, a siphon phenomenon will occur, but the amount of drainage will be reduced, so there is a possibility that the required flow rate cannot be secured. Furthermore, if the length exceeds 20 m, the vacuum pressure generated within the piping gradually increases, so the maximum drainage flow rate in the siphon flow may decrease somewhat.

<Effect>
Rainwater falling on the bridge flows into the drainage basin part 20 through the lid 10. The rainwater that has flowed in passes through the inlet opening 30a of the siphon drain member 30, flows into the drain port 34a, passes through the opening 34b of the droplet part 34, and flows into the piping part 40. A siphon phenomenon is induced in the rainwater flowing into the piping section 40 by the siphon drain member 30, resulting in a siphon flow.

When a siphon flow occurs, the upper part of the vertical pipe section 49 that includes the vertical pipes 44 and 46 becomes negative pressure, but when the pressure becomes more negative than the set value, the pressure control valve 50 is opened and air flows into the vertical pipe section. do. As a result, since the negative pressure is limited to a certain value, it is possible to prevent deformation and damage of the expandable pipe 45 installed in the middle of the piping while generating a siphon flow.

(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 changes can be made without departing from the gist of the invention.

(A)
In the embodiment described above, the lid 10 is placed directly on the upper basin 21, but the present invention is not limited to this, and a frame body for housing the lid 10 may be further provided inside the upper basin 21. Further, a mechanism for adjusting the height of the frame relative to the upper basin 21 may be provided.

(B)
In the above embodiment, the lid 10 is made of metal and the drainage basin part 20 is made of FRP, but the invention is not limited to this.

(C)
In the above embodiment, the cylindrical portion 71 is inserted inside the elbow tube 41, but the present invention is not limited to this, and the elbow tube 41 may be inserted inside the cylindrical portion 71. Further, for example, a male thread is formed on the outer periphery of the cylindrical portion 71, and a female thread is formed on the inside of the upper end member of the elbow pipe 41, and the cylindrical portion 71 and the elbow pipe 41 are connected by screwing the male thread and the female thread. may be done. Further, the cylindrical portion 71 and the elbow pipe 41 may be connected with adhesive or the like.

(D)
In the above embodiment, the expandable pipe 45 is arranged between the vertical pipe 44 and the vertical pipe 46, but it is not limited to the vertical pipe. The telescopic tube 45 is not limited to the vertical direction, but may be arranged diagonally.

Next, the drainage system of this embodiment will be explained using an example.
FIG. 9 is a diagram for explaining the configuration of the drainage system 1' of this embodiment.

In this embodiment, the lower basin 22 is used, and the lid 10 and the upper basin 21 are not provided.
As shown in FIG. 9, this embodiment has a piping section 40' having a different configuration from the piping section 40 of FIG. 2 described above.

The piping section 40' includes a vertical pipe 90, an elbow joint 91, a horizontal pipe 92, an elbow joint 93, a vertical pipe 94, an expansion pipe 45, a vertical pipe 95, an elbow joint 96, and a horizontal pipe 97. , and an elbow joint 98.

In the drainage system 1' shown in FIG. 9, a vertical pipe 90 is connected to the cylindrical portion 71 of the siphon drain member 30 disposed on the bottom surface 27 of the lower basin 22.

An elbow joint 91 is connected to the lower end of the vertical pipe 90, and a horizontal pipe 92 is connected to the elbow joint 91. The horizontal pipe 92 has no slope and extends from the elbow joint 91 in the horizontal direction. An elbow joint 93 is connected to the other end of the horizontal pipe 92, and a vertical pipe 94 is connected to the elbow joint 93. The vertical pipe 94 extends downward from the elbow joint 93. A telescopic pipe 45 is connected to the lower end of the vertical pipe 94 . A vertical pipe 95 is connected to the lower end of the telescopic pipe 45 . The vertical pipe 95 extends downward from the telescopic pipe 45. An elbow joint 96 is arranged at the lower end of the vertical pipe 95, and a horizontal pipe 97 is connected to the elbow joint 96. The horizontal pipe 97 is flat from the elbow joint 96 and extends in the horizontal direction. An elbow joint 98 is connected to the other end of the horizontal pipe 97, and the other end of the elbow joint 98 faces downward and is connected to a drainage basin.

Further, the length of the long side of the lower pipe 22 is set to 500 mm, the length of the vertical pipe 90 is set to 500 mm, the length of the horizontal pipe 92 is set to 5000 mm, and the length of the vertical pipe 94 and the telescopic pipe 45 are set to 500 mm. The length of the vertical pipe portion 99 including the pipe 95 is changed as the head L depending on the embodiment and the comparative example. Further, the length of the horizontal pipe 97 is set to 1500 mm.

As shown in Table 1 below, the pipe size, the presence or absence of the siphon drain member 30 (indicated as a high drainage drain in the table), the head L, the deformation vacuum pressure and installation position of the telescopic tube 45, and the settings of the pressure control valve 50 Drainage systems having the configurations of Examples 1 to 8 and Comparative Examples 1 to 5 in which the adjusted pressure P1, air inflow amount, and installation position were changed were used. In each of the drainage systems of Examples 1 to 9 and Comparative Examples 1 to 5, the drainage flow rate was increased while measuring the pressure inside the telescopic tube 45, and the presence or absence of siphon flow was determined to the set pressure of the pressure control valve 50. The flow rate at the time of reaching (maximum drainage flow rate) and the presence or absence of deformation of the telescopic tube 45 are shown. In addition, the determination threshold value of the maximum drainage flow rate was determined to be good if it was twice or more of Comparative Examples 4 and 5 in which the siphon drain member 30 was not used in each diameter. That is, for a diameter of 100A, 20L/s or more was considered good, and for a diameter of 75A, 10L/s or more was considered good.

From the above, the adjusted pressure P1 by the pressure regulating valve 50 is 0. 7≦ P1 /P2 ≦1. 4 , the expandable pipe 45 is not deformed and drainage can be performed at a high flow rate.

Moreover, by installing the pressure regulating valve 50 within 1 m upstream or downstream of the installation position of the telescoping pipe 45, drainage can be performed at a high flow rate without deforming the telescoping pipe 45.

The drainage system of the present invention has the effect of suppressing the obstruction of drainage due to deformation of the expandable pipe and can perform drainage at a high flow rate, and is useful as a rainwater drainage system placed on a bridge or the like.

1 : Drainage system 20 : Drainage basin part 30 : Siphon drain member 34a : Drain port 40 : Piping part 45 : Telescopic pipe 50 : Pressure control valve

Claims (3)

A drainage basin placed on the bridge,
a drainage member disposed inside the drainage basin and inducing the occurrence of a siphon phenomenon;
a piping section connected to the drain port of the drainage member and having an expandable pipe;
a pressure regulating valve provided in the piping section upstream or downstream of the telescopic pipe,
The regulated pressure P1 by the pressure regulating valve and the deformation pressure P2 of the telescopic tube are negative values,
The adjustment pressure P1 and the deformation pressure P2 are 0. 7≦ P1 /P2 ≦1. 4 ,
The installation position of the pressure regulating valve is within 1 m downstream or upstream of the installation position of the telescopic pipe,
drainage system. The amount of air flowing in from the pressure regulating valve is 4 L/s or more and 8 L/s or less,
A drainage system according to claim 1. The head of the piping part from the lower end of the drainage basin part is 3 m or more and 20 m or less,
A drainage system according to claim 1 or 2.

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