Piping system

Abstract

To provide a piping system capable of reducing degradation of drainage performance due to a confluent part between a main pipe and a branch pipe and capable of stabilizing drainage from the branch pipe.SOLUTION: A main pipe of a piping system includes: a first downpipe connected to a first shoot port; a second downpipe that is disposed on the downstream side of the first downpipe and includes a part having pipe diameter larger than the first downpipe; a confluent part between the first downpipe and the second downpipe, to which an end on the downstream side of a branch pipe is connected; and a connection pipe that has pipe diameter equal to or smaller than the first downpipe and connects an end on the downstream side of the confluent part and an end on the upstream side of the second downpipe. The main pipe has an opening part to be opened in atmospheric pressure below the end on the downstream side of the confluent part, and the end on the downstream side of the pipe is connected to a pressure loss member causing pressure loss to the water flowing the main pipe. When h2 [m] is distance in a vertical direction from the end on the downstream side of the confluent part to the ground surface, and d [m] is distance in a vertical direction from the end on the downstream side of the confluent part to the opening part, 0.5≤d≤h2-0.5 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to piping systems. [Background technology]

[0002] Patent Document 1 discloses a rainwater drainage piping structure. The rainwater drainage piping structure disclosed in Patent Document 1 includes a siphon-type drainage member arranged on an upper floor, a main pipe through which rainwater flowing in from the siphon-type drainage member flows from the upper floor to the floor below, and a branch pipe connected to a junction located midway in the height direction of the main pipe and through which drainage water flows into the junction from the outside. The main pipe includes a first vertical pipe arranged on the upper side, and a curing pipe arranged below the first vertical pipe and having a larger flow path area than the first vertical pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-3217 Summary of the Invention [Problem to be solved by the invention]

[0004] In the storm water drainage piping structure disclosed in Patent Document 1, drainage from the branch pipes cannot join at the joining point, causing the drainage to flow back up the branch pipes, and in some cases, causing overflow.

[0005] The present disclosure provides a piping system that enables reduction in degradation of drainage performance due to the junction of a main pipe and a branch pipe, and enables stabilization of drainage from the branch pipe. [Means for solving the problem]

[0006] A piping system according to one embodiment of the present disclosure includes a main pipe connected to a first drop outlet of a first eaves gutter and a branch pipe connected to a second drop outlet of a second eaves gutter, the main pipe including a first downpipe connected to the first drop outlet, a second downpipe located downstream of the first downpipe and including a portion having a pipe diameter larger than that of the first downpipe, a junction portion located between the first downpipe and the second downpipe and to which the downstream end of the branch pipe is connected, and a pipe diameter equal to or smaller than that of the first downpipe and connecting the downstream end of the junction portion to the second downpipe. and a connecting pipe connecting the main pipe to the upstream end of the confluence, the main pipe has an open portion below the downstream end of the confluence that is open to atmospheric pressure, and the downstream end of the main pipe is connected to a pressure loss member that causes a pressure loss in the water flowing through the main pipe, and where the vertical distance from the downstream end of the confluence to the ground is h2 [m] and the vertical distance from the downstream end of the confluence to the open portion is d [m], the relationship 0.5≦d≦h2-0.5 is satisfied. Effect of the Invention

[0007] Aspects of the present disclosure enable reduction in degradation of drainage performance due to the junction between a main pipe and a branch pipe, and enable stabilization of drainage from the branch pipe. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram of a piping system according to a first embodiment. [Diagram 2] Graph of the results of the evaluation of the drainage performance of the piping system [Diagram 3] FIG. 13 is an explanatory diagram of a piping system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [1. Embodiment] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings in some cases. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents (e.g., the shape, dimensions, arrangement, etc. of each component). Positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Each figure described in the following embodiments is a schematic diagram, and the size and thickness ratios of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0010] In the following description, when it is necessary to distinguish between multiple components, prefixes such as "first" and "second" are added to the names of the components. However, when the components can be distinguished from one another by the symbols added to them, the prefixes such as "first" and "second" may be omitted in consideration of readability of the text.

[0011] [1.1 First embodiment] [1.1.1 Configuration] FIG. 1 is a schematic diagram of a piping system 1 according to a first embodiment. The piping system 1 constitutes, for example, a gutter system (drainage system) for a building having multiple roofs. The piping system 1 receives rainwater from multiple roofs of the building and drains it to a manhole 21 in the ground 20 through an elbow 60 and a buried pipe 22. The rainwater collected in the manhole 21 flows out from the manhole 21 into a storm drain. The building is, for example, a non-residential facility such as a store, office, factory, building, school, welfare facility, or hospital, and a residential facility such as a detached house, an apartment building, or each dwelling unit of a detached house or an apartment building. The non-residential facility also includes a theater, a movie theater, a public hall, an amusement park, a complex, a department store, a hotel, an inn, a kindergarten, a library, a museum, an art museum, an underground shopping mall, a station, and an airport. The building may include multiple roofs, eaves (small roofs), and a large roof.

[0012] The piping system 1 includes a first eaves gutter 31, a second eaves gutter 32, a main pipe 4, a branch pipe 5, a penetration pipe 6, and drains 71, 72.

[0013] The first eaves gutter 31 receives rainwater from, for example, the main roof of a building. The first eaves gutter 31 is installed under the main roof of the building. The first eaves gutter 31 is in the shape of a long barrel. The first eaves gutter 31 has a bottom wall 31a, and a first drop outlet 31b is provided in the bottom wall 31a. The main pipe 4 is connected to the first drop outlet 31b.

[0014] The drain 71 is disposed at the first drop opening 31b of the first eaves gutter 31. The drain 71 is used to promote the occurrence of the siphoning effect. The drain 71 reduces the occurrence of vortexes and air entrainment at the first drop opening 31b. The drain 71 has a structure that makes the siphoning effect more likely to occur compared to a case in which the drain 71 is not present. The main pipe 4 is connected to the drain 71. The drain 71 contributes to the occurrence of the siphoning effect, but it is a well-known fact that the occurrence of the siphoning effect can be related not only to the drain 71 but also to the structure of the main pipe 4.

[0015] The second eaves gutter 32 receives rainwater from, for example, the eaves of a building. The second eaves gutter 32 is installed under the eaves of the building. The second eaves gutter 32 is in the shape of a long bucket. The second eaves gutter 32 has a bottom wall 32a, and a second drop outlet 32b is provided in the bottom wall 32a. A branch pipe 5 is connected to the second drop outlet 32b.

[0016] The drain 72 is disposed at the second drop opening 32b of the second eaves gutter 32. The drain 72 is used to promote the occurrence of the siphoning phenomenon. The drain 72 reduces the occurrence of vortexes and air entrainment at the second drop opening 32b. The drain 72 has a structure that is more likely to cause the siphoning phenomenon than when the drain 72 is not disposed. The drain 72 contributes to the occurrence of the siphoning phenomenon, but it is a well-known fact that the occurrence of the siphoning phenomenon may be related not only to the drain 72 but also to the structure of the branch pipe 5. Unlike the first drop opening 31b, the drain 72 may not be disposed at the second drop opening 32b of the second eaves gutter 32. Alternatively, a drain or the like having a structure that is generally considered not to contribute to the occurrence of the siphoning phenomenon may be disposed at the second drop opening 32b.

[0017] The second eaves gutter 32 is located below the first eaves gutter 31. More specifically, the second eaves gutter 32 overlaps at least a portion of the first eaves gutter 31 in the vertical direction. The second eaves gutter 32 has an opening 32c at a portion that overlaps with the first drop opening 31b of the first eaves gutter 31 in the vertical direction. The opening 32c is a through hole that penetrates the bottom wall 32a of the second eaves gutter 32.

[0018] The through pipe 6 is disposed so as to penetrate the opening 32c of the bottom wall 32a of the second eaves gutter 32. The through pipe 6 covers the entire circumference of the opening 32c and is attached to the edge of the opening 32c in the bottom wall 32a of the second eaves gutter 32. The through pipe 6 has an upper wall portion 6a and a lower wall portion 6b. The upper wall portion 6a extends upward from the bottom wall 32a of the second eaves gutter 32. The lower wall portion 6b extends downward from the bottom wall 32a of the second eaves gutter 32. The upper wall portion 6a and the lower wall portion 6b reduce the possibility that rainwater in the second eaves gutter 32 leaks to the outside through the opening 32c. In this embodiment, the upper wall portion 6a and the lower wall portion 6b are straight pipe-shaped, and the cross section perpendicular to the pipe axis of the through pipe 6 is circular.

[0019] The main pipe 4 is installed to drain rainwater from the first drop outlet 31b of the first eaves gutter 31 by siphoning. The main pipe 4 drains rainwater from the first drop outlet 31b vertically. The upstream end 4a of the main pipe 4 is connected to the first drop outlet 31b. The downstream end 4b of the main pipe 4 is connected to an elbow 60.

[0020] The main pipe 4 includes a first downpipe 41, a second downpipe 42, a junction 43, a connecting pipe 44, and a cover 45.

[0021] The first downspout 41 is connected to the first drop outlet 31b of the first eaves gutter 31. The first downspout 41 extends downward from the first drop outlet 31b of the first eaves gutter 31. The first downspout 41 has an upstream end 41a and a downstream end 41b. The upstream end 41a is the end of the first downspout 41 that is connected to the first drop outlet 31b (the upper end in FIG. 1). The upstream end 41a of the first downspout 41 is connected to a drain 71 and connected to the first drop outlet 31b of the first eaves gutter 31. The downstream end 41b is located below the second eaves gutter 32.

[0022] The first downspout 41 passes through the opening 32c in the bottom wall 32a of the second eaves gutter 32 while being separated in terms of flow path from the second eaves gutter 32. Here, "the first downspout 41 passes through the opening 32c in the bottom wall 32a of the second eaves gutter 32 while being separated in terms of flow path from the second eaves gutter 32" means that the first downspout 41 passes through the opening 32c in the bottom wall 32a of the second eaves gutter 32 so that no fluid flows from the second eaves gutter 32 to the first downspout 41.

[0023] The first downpipe 41 has a straight pipe shape. The cross section of the first downpipe 41 perpendicular to the pipe axis is circular. The first downpipe 41 has a smaller diameter (inner diameter and outer diameter) than the through pipe 6. The first downpipe 41 is fixed to the wall surface of the building so that the direction of the pipe axis (central axis) of the first downpipe 41 coincides with the up-down direction (vertical direction). The upstream end 41a of the first downpipe 41 is the upstream end 4a of the main pipe 4.

[0024] The second downpipe 42 is located downstream of the first downpipe 41. The second downpipe 42 has an upstream end 42a and a downstream end 42b. The upstream end 42a is located below the downstream end 41b of the first downpipe 41. The upstream end 42a is connected to the downstream end 41b of the first downpipe 41 in terms of flow path. In other words, the upstream end 42a faces the downstream end 41b of the first downpipe 41 in the vertical direction. The downstream end 42b is the end (lower end in FIG. 1) of the second downpipe 42 that is connected to the elbow 60 and extends below the ground 20. The downstream end 42b of the second downpipe 42 is the downstream end 4b of the main pipe 4.

[0025] The junction 43 connects the branch pipe 5 to a midway portion of the main pipe 4. The junction 43 is located between the first downpipe 41 and the second downpipe 42. The junction 43 includes an upstream end 43a connected to the downstream end 41b of the first downpipe 41, a downstream end 43b connected to the upstream end 42a of the second downpipe 42, and a branch port 43c. The junction 43 is, for example, T-shaped. The junction 43 is a so-called T-pipe (tee pipe).

[0026] The connecting pipe 44 connects the downstream end 43b of the junction 43 and the upstream end 42a of the second downspout 42. The connecting pipe 44 has an upstream end 44a and a downstream end 44b. The upstream end 44a is connected to the downstream end 43b of the junction 43. The connecting pipe 44 is straight. The cross section perpendicular to the pipe axis of the connecting pipe 44 is circular. The connecting pipe 44 has a pipe diameter equal to or smaller than that of the first downspout 41. In this embodiment, the connecting pipe 44 has a pipe diameter (inner diameter and outer diameter) equal to that of the first downspout 41.

[0027] The second downspout 42 includes a vertical pipe 421 and an increaser 422 .

[0028] The vertical pipe 421 is a portion of the second downpipe 42 having a larger pipe diameter than the first downpipe 41. The vertical pipe 421 has an upstream end 421a and a downstream end 421b. The vertical pipe 421 is straight. A cross section perpendicular to the pipe axis of the vertical pipe 421 is circular. In this embodiment, the pipe diameter (inner diameter and outer diameter) of the vertical pipe 421 is larger than those of the first downpipe 41 and the connecting pipe 44. The vertical pipe 421 is fixed to the wall surface of the building so that the direction of the pipe axis of the vertical pipe 421 coincides with the up-down direction (vertical direction). The downstream end 421b of the vertical pipe 421 is the downstream end 42b of the second downpipe 42.

[0029] The increaser 422 connects the connecting pipe 44 and the vertical pipe 421. The diameter (inner diameter and outer diameter) of the connecting pipe 44 is smaller than the diameter (inner diameter and outer diameter) of the vertical pipe 421. The upstream end of the increaser 422 has a shape corresponding to the diameter (inner diameter and outer diameter) of the connecting pipe 44 so as to be connected to the downstream end 44b of the connecting pipe 44. The downstream end of the increaser 422 has a shape corresponding to the diameter (inner diameter and outer diameter) of the vertical pipe 421 so as to be connected to the upstream end 421a of the vertical pipe 421. In this embodiment, the upstream end of the increaser 422 is the upstream end 42a of the second downpipe 42.

[0030] In the main pipe 4, the material of the first downspout 41, the material of the vertical pipe 421, the material of the increaser 422, the material of the junction 43, and the material of the connecting pipe 44 are, for example, rigid polyvinyl chloride. The dimensions of the first downspout 41, the vertical pipe 421, and the connecting pipe 44, for example, the outer shape and thickness, may be set in accordance with the standard for rigid polyvinyl chloride pipes (general) of JIS K 6741 "rigid polyvinyl chloride pipes". As an example, the first downspout 41, the vertical pipe 421, and the connecting pipe 44 may be pipe materials with a nominal diameter of 65 or more in the VU or VP rigid polyvinyl chloride pipes in the standard for rigid polyvinyl chloride pipes (general) of JIS K 6741 "rigid polyvinyl chloride pipes", and may be pipe materials with a nominal diameter of 75, 100, or 125. In this embodiment, the vertical pipe 421 has a pipe diameter (inner diameter and outer diameter) larger than those of the first downpipe 41 and the connecting pipe 44. If the first downpipe 41 and the connecting pipe 44 are pipe materials with a nominal diameter of 75, the vertical pipe 421 may be pipe materials with a nominal diameter of 100, which is one size larger. The dimensions of the junction 43 may be set in accordance with the "Rigid PVC Fittings for Outdoor Drainage Equipment (VU Fittings)" standard of the PVC Pipe and Fittings Association.

[0031] The branch pipe 5 is installed to allow rainwater from the second drop outlet 32b of the second eaves gutter 32 to flow into the main pipe 4 through the junction 43. The branch pipe 5 directs rainwater from the second drop outlet 32b of the second eaves gutter 32 to the manifold 21 via the main pipe 4, elbow 60, and buried pipe 22. The branch pipe 5 has an upstream end 5a and a downstream end 5b. The upstream end 5a is the end of the branch pipe 5 that is connected to the second drop outlet 32b (the upper end in FIG. 1). The downstream end 5b is the end of the branch pipe 5 that is connected to the junction 43 (the left end in FIG. 1).

[0032] The branch pipe 5 includes a vertical pipe 51 , a nominal pipe 52 , and an elbow 53 .

[0033] The vertical pipe 51 is the upstream portion of the branch pipe 5. The vertical pipe 51 is straight. The cross section perpendicular to the pipe axis of the vertical pipe 51 is circular. The vertical pipe 51 is arranged so that the direction of the pipe axis of the vertical pipe 51 coincides with the up-down direction (vertical direction). The upstream end 5a of the branch pipe 5 is the upper end of the vertical pipe 51.

[0034] The nominal downpipe 52 is the downstream portion of the branch pipe 5. The nominal downpipe 52 is straight. The cross section of the nominal downpipe 52 perpendicular to the pipe axis is circular. The nominal downpipe 52 descends toward the junction 43. The gradient of the nominal downpipe 52 is 1 / 1000 or more. A first end (the right end in FIG. 1) of the nominal downpipe 52 is connected to the vertical pipe 51 via an elbow 53, and a second end (the left end in FIG. 1) of the nominal downpipe 52 is connected to the main pipe 4. The downstream end 5b of the branch pipe 5 is the second end of the nominal downpipe 52.

[0035] The material of the vertical pipe 51 and the material of the nominal conduit 52 are rigid polyvinyl chloride. The dimensions of the vertical pipe 51 and the nominal conduit 52, for example, the outer shape and thickness, may be set in accordance with the standard for rigid polyvinyl chloride pipes (general) of JIS K 6741 "Rigid Polyvinyl Chloride Pipes."

[0036] The elbow 53 connects the vertical pipe 51 and the call pipe 52. The elbow 53 has a first socket 53a connected to the lower end of the vertical pipe 51 and a second socket 53b connected to the first end of the call pipe 52. The elbow 53 is L-shaped. The material of the elbow 53 is, for example, rigid polyvinyl chloride. The dimensions of the elbow 53 may be set in accordance with the standard JIS K 6739 "Rigid polyvinyl chloride pipe joint for drainage". For example, the elbow 53 is a 90° bent elbow (so-called DL) specified in JIS K 6739.

[0037] As shown in FIG. 1, in a region below ground level 20, an elbow 60 and a buried pipe 22 are provided.

[0038] The elbow 60 connects the vertical pipe 421 and the buried pipe 22. The elbow 60 has a first socket 60a connected to the lower end 421b of the vertical pipe 421 and a second socket 60b connected to the first end 22a of the buried pipe 22. The elbow 60 is L-shaped. The material of the elbow 60 is, for example, rigid polyvinyl chloride. The dimensions of the elbow 60 may be set in accordance with the standard JIS K 6739 "Rigid polyvinyl chloride pipe joint for drainage". For example, the elbow 60 is a 90° bent elbow (so-called DL) specified in JIS K 6739.

[0039] The elbow 60 functions to forcibly change the flow direction of the rainwater flowing in the vertical pipe 421 from the vertical direction to the horizontal direction. The elbow 60 is a “pressure loss member” that causes a pressure loss in the rainwater flowing in the vertical pipe 421.

[0040] If a storm water inlet 21 is placed directly below the vertical pipe 421 and the downstream end 421b of the vertical pipe 421 is not connected to an elbow 60 and flows directly into the storm water inlet 21, then no pressure loss member would be connected.

[0041] The buried pipe 22 connects the elbow 60 and the manifold 21. The buried pipe 22 has a first upstream end 22a connected to the second socket 60b of the elbow 60, and a second downstream end 22b inserted into the manifold 21. The buried pipe 22 is straight. The cross section perpendicular to the pipe axis of the buried pipe 22 is circular. The buried pipe 22 is arranged so that the direction of the pipe axis of the buried pipe 22 coincides with the left-right direction (horizontal direction).

[0042] Although shown simply in FIG. 1, the buried pipe 22 may be composed of one or more pipes, and may include components such as joints that connect the pipes together.

[0043] As described above, the piping system 1 includes the main pipe 4 for draining water from the first drop outlet 31b, and the branch pipe 5 for draining water from the second drop outlet 32b. The branch pipe 5 is connected to the junction 43 of the main pipe 4. In the piping system 1, the first drainage path from the first drop outlet 31b is defined by the first downspout 41, the junction 43, the connecting pipe 44, and the second downspout 42 of the main pipe 4. The second drainage path from the second drop outlet 32b is defined by the branch pipe 5, the junction 43, the connecting pipe 44, and the second downspout 42 of the main pipe 4. In other words, the second drainage path utilizes a part of the first drainage path.

[0044] One of the causes of the siphoning phenomenon is the difference in potential energy between the top and bottom of the water surface when viewed vertically. It is believed that the greater the difference in potential energy, the greater the flow rate due to the increased flow velocity caused by the siphoning phenomenon.

[0045] Next, consider the improvement of drainage performance due to the siphoning effect in the piping system 1. When considering the improvement of drainage performance due to the siphoning effect, consider the vertical length of the area that can be filled with water in each of the first drainage path and the second drainage path. Note that the term "full water state" is not used in the strict sense, and includes a state filled with water to an extent that can be regarded as equivalent to a full water state (a state close to a full water state), or a state filled with water to an extent that the siphoning effect actually occurs.

[0046] The longer the vertical length of the area that can be filled with water in the first drainage path, the more the negative pressure at the first drop outlet 31b increases, and the more the suction force due to the siphon phenomenon can be increased. When the suction force due to the siphon phenomenon increases in the first drainage path, the action due to the siphon phenomenon in the main pipe 4 can be stably promoted. The vertical length of the area that can be filled with water in the first drainage path is the vertical distance h1 [m] from the first drop outlet 31b to the open part 4c. As an example, in the piping system 1, it is preferable to satisfy h1 ≧ 3. The open part 4c is a part of the main pipe 4 that is opened to atmospheric pressure downward from the end 43b on the downstream side of the junction 43. In the main pipe 4, the pipe diameter of the vertical pipe 421 of the second downspout 42 is larger than the pipe diameters of the first downspout 41 and the connecting pipe 44. The connecting pipe 44 is connected to the vertical pipe 421 via the increaser 422. Therefore, the main pipe 4 is open to atmospheric pressure at the connection portion between the connecting pipe 44 and the increaser 422. Therefore, the connection portion between the connecting pipe 44 and the increaser 422 becomes the open portion 4c. In this embodiment, the position of the upper end of the increaser 422 is the position of the connection portion between the connecting pipe 44 and the increaser 422.

[0047] The longer the vertical length of the area that can be filled with water in the second drainage path, the greater the negative pressure at the second drop outlet 32b, and the greater the suction force due to the siphon effect. When the suction force due to the siphon effect in the second drainage path increases, the siphon effect in the branch pipe 5 can be stably promoted. The vertical length of the area that can be filled with water in the second drainage path is the vertical distance from the second drop outlet 32b to the open portion 4c.

[0048] The first drainage path and the second drainage path join at the junction 43. From the perspective of the first drainage path, air may flow in from the branch pipe 5 at the junction 43, and the inflow of air from the branch pipe 5 may destabilize the occurrence of the siphoning phenomenon in the first drainage path and may be a factor in the deterioration of the drainage performance of the piping system 1. From the perspective of the second drainage path, air may flow in from the first downspout 41 at the junction 43, and the inflow of air from the first downspout 41 may destabilize the occurrence of the siphoning phenomenon in the second drainage path and may be a factor in the deterioration of the drainage performance of the piping system 1.

[0049] The inventor(s) evaluated the drainage performance of the piping system 1 with different positions of the junction 43 by changing the flow rate of the first drainage path and the flow rate of the second drainage path, and found that there is a preferable range for the vertical distance between the junction 43 and the open portion 4c. More specifically, if the vertical distance from the downstream end 43b of the junction 43 to the open portion 4c is d [m], and the vertical distance from the downstream end 43b of the junction 43 to the ground 20 is h2 [m], it is preferable to satisfy 0.5≦d≦h2-0.5. In particular, it is preferable to satisfy d≦h2-1. In addition, if the vertical distance from the downstream end 43b of the junction 43 to the upstream end 60a of the elbow 60 is h3 [m], it is even more preferable to satisfy 0.5≦d≦h3-1. In the main pipe 4, the open portion 4c is the downstream end 44b of the connecting pipe 44. Therefore, in the piping system 1A, d is the vertical distance from the downstream end 43b of the junction 43 to the connection between the connecting pipe 44 and the increaser 422. This distance is equal to the vertical length of the portion of the connecting pipe 44 exposed from the junction 43 and the increaser 422.

[0050] This point will be described with reference to Fig. 2. Fig. 2 is a graph showing the results of evaluation of the drainage performance of the piping system 1 of the first example.

[0051] In FIG. 2, the horizontal axis indicates the flow rate Q1 [l / s] of the first drainage path, and the vertical axis indicates the flow rate Q2 [l / s] of the second drainage path.

[0052] In FIG. 2, the range to the left of the straight line L1 is a range that satisfies Q1+Q2≦Q1max. Q1max [l / s] represents the maximum allowable flow rate of the first drainage path. It is preferable that the piping system 1 satisfies Q1+Q2≦Q1max. The range to the right of the straight line L2 is a range that satisfies Q1≧Q1min. Q1min [l / s] represents the minimum value of the flow rate when the siphon phenomenon occurs in the first drainage path. The range below the straight line L3 is a range that satisfies Q2≦Q2max. Q2max [l / s] represents the maximum allowable flow rate of the second drainage path. As an example, Q1max=21.5, Q1min=7, and Q2max=6. It is preferable that the piping system 1 is operated in the range surrounded by the straight lines L1, L2, and L3.

[0053] The straight line L1 is based on theoretical values, and in reality, the value of Q2 relative to Q1 decreases due to the influence of pressure loss occurring in the vertical pipe 421. Therefore, the relationship is not represented by the straight line L1 but by the straight line L4.

[0054] On the other hand, if the pressure loss occurring in the vertical pipe 421 can be reduced, the line L4 can be moved closer to the line L1 (arrow P) and Q2 can be increased. Increasing Q2 makes it possible to reduce the deterioration of the drainage performance caused by the junction 43 and to stabilize the drainage from the branch pipe 5.

[0055] In the piping system 1 shown in FIG. 1, the downstream end 421b of the vertical pipe 421 is connected to the elbow 60, which is a pressure loss member, and therefore the pressure loss occurring in the vertical pipe 421 is likely to be high. The shorter the distance (h2-3) from the open part 4c to the ground 20 and the distance (h3-d) from the open part 4c to the elbow 60, the greater the impact of the pressure loss. For this reason, it is preferable to set an upper limit on the length of d so that the lengths of h2-d and h3-d are secured to a certain extent. On the other hand, if the length of d is shortened, the effective siphon height h1 will also be shortened, so it is preferable to set a lower limit on the length of d.

[0056] Based on the above findings, the inventor(s) conducted various experiments and found that the preferred range of d in the piping system 1 shown in Fig. 1 in relation to h2 is 0.5≦d≦h2-0.5. Furthermore, it was found that d≦h2-1 is more preferable. Furthermore, it was found that the preferred range of d in the piping system 1 shown in Fig. 1 in relation to h3 is 0.5≦d≦h3-1.

[0057] In addition, Q1max and Q2max shown in FIG. 2 are values ​​theoretically calculated based on the configuration of the piping system 1. When the piping system 1 is commercialized, the maximum allowable flow rate (external guaranteed value / catalog value) guaranteed externally in a catalog or the like may be used. If the maximum allowable flow rates (external guaranteed value / catalog value) of the first drainage flow path and the second drainage flow path are Q1D [l / s] and Q2D [l / s], respectively, Q1D and Q2D are calculated by subtracting a safety margin from Q1max and Q2max. In FIG. 2, instead of the straight lines L1, L2, and L3 based on the theoretical values ​​of Q1 and Q2 (Q1max, Q2max), when the straight lines L1', L2', and L3' based on the external guaranteed values ​​of Q1 and Q2 (Q1D, Q2D) are used, it is preferable that the piping system 1 is operated within the range surrounded by the straight lines L1', L2', and L3'. It is preferable that the straight line L1' satisfies Q1+Q2≦Q1D.

[0058] [1.1.2 Effects, etc.] The piping system 1 described above comprises a main pipe 4 connected to the first drop outlet 31b of the first eaves gutter 31 and a branch pipe 5 connected to the second drop outlet 32b of the second eaves gutter 32. The main pipe 4 comprises a first downpipe 41 connected to the first drop outlet 31b, a second downpipe 42 located downstream of the first downpipe 41 and including a portion having a pipe diameter larger than that of the first downpipe 41, a junction 43 located between the first downpipe 41 and the second downpipe 42 and to which the downstream end 5b of the branch pipe 5 is connected, and a pipe diameter equal to or smaller than that of the first downpipe 41 and including a portion having a pipe diameter smaller than that of the first downpipe 41 and a junction 43 located upstream of the second downpipe 42. and a connecting pipe 44 connecting the downstream end 43b of the junction 43 to the open portion 42a, the main pipe 4 has an open portion 4c open to atmospheric pressure below the downstream end 43b of the junction 43, the downstream end 421b of the main pipe 4 is connected to an elbow 60 (pressure loss member) that generates a pressure loss for the water flowing through the main pipe 4, and the vertical distance from the downstream end 43b of the junction 43 to the ground 20 is h2 [m] and the vertical distance from the downstream end 43b of the junction 43 to the open portion 4c is d [m], satisfying 0.5≦d≦h2-0.5. This configuration makes it possible to reduce the deterioration of drainage performance caused by the junction 43 between the main pipe 4 and the branch pipe 5, and to stabilize drainage from the branch pipe 5.

[0059] In the piping system 1, d≦h2-1 is satisfied. This configuration makes it possible to reduce the deterioration of drainage performance caused by the junction 43 between the main pipe 4 and the branch pipe 5, and makes it possible to stabilize the drainage from the branch pipe 5.

[0060] In the piping system 1, if the vertical distance from the downstream end 421b of the junction to the upstream end 60a of the elbow 60 (pressure loss member) is h3 [m], then 0.5≦d≦h3-1 is satisfied.

[0061] In the piping system 1, if the vertical distance between the first drop outlet 31b and the upstream end 42a of the second downspout 42 is h1 [m], then h1 ≧ 3 is satisfied. This configuration makes it possible to promote the occurrence of the siphon effect.

[0062] The pressure loss member is the elbow 60 that is disposed below the ground surface 20. With this configuration, the effect of pressure loss due to the elbow 60 can be reduced.

[0063] In the piping system 1, the second downpipe 42 includes a vertical pipe 421 having a larger pipe diameter than the first downpipe 41, and an increaser 422 that connects the connecting pipe 44 to the vertical pipe 421, and the open area 4c is the connection between the connecting pipe 44 and the increaser 422. This configuration makes it possible to reduce the deterioration of drainage performance caused by the junction 43 of the main pipe 4 and the branch pipe 5, and to stabilize the drainage from the branch pipe 5.

[0064] In the piping system 1, if the maximum allowable flow rate (external guaranteed value) of the first drainage path from the first drop outlet 31b is Q1D, the flow rate of the first drainage path is Q1, and the flow rate of the second drainage path from the second drop outlet is Q2, then Q1D≧Q1+Q2 is satisfied. This configuration enables stable drainage in the first drainage path and the second drainage path.

[0065] In the piping system 1, the branch pipe 5 includes a drop conduit 52 that descends toward the junction 43, and the gradient of the drop conduit 52 is 1 / 1000 or more. This configuration makes it possible to promote drainage from the branch pipe 5.

[0066] In the piping system 1, the second eaves gutter 32 is located below the first eaves gutter 31, and the first vertical gutter 41 passes through an opening 32c in a bottom wall 32a of the second eaves gutter 32 while being separated in terms of flow path from the second eaves gutter 32. This configuration enables the piping system 1 to be space-saving.

[0067] The piping system 1 further includes a drain 71 disposed in the first drop outlet 31b. This configuration makes it possible to promote the occurrence of the siphoning effect.

[0068] [1.2 Second embodiment] [1.2.1 Configuration] 3 is an explanatory diagram of a piping system 1A according to embodiment 2. The piping system 1A includes a first eaves gutter 31, a second eaves gutter 32, a main pipe 4A, a branch pipe 5, a penetration pipe 6, and drains 71 and 72.

[0069] The main pipe 4A includes a first downpipe 41, a second downpipe 42A, a junction 43, a connecting pipe 44, and a cover 45.

[0070] The second downpipe 42A includes a vertical pipe 421 like the second downpipe 42 of the first embodiment, but unlike the second downpipe 42, does not include an increaser.

[0071] In the main pipe 4A, the downstream end 44b of the connecting pipe 44 is disposed inside the vertical pipe 421. That is, the connecting pipe 44 is connected to the junction 43 such that the downstream end 44b is inserted into the vertical pipe 421 from the upstream end 421a of the vertical pipe 421.

[0072] In the main pipe 4A, the open portion 4c is the downstream end 44b of the connecting pipe 44. Therefore, in the piping system 1A, d is the vertical distance from the downstream end 43b of the junction 43 to the downstream end 44b of the connecting pipe 44. Also in the piping system 1A, it is preferable that 0.5≦d≦h2-0.5 is satisfied.

[0073] 3, the vertical distance from the upstream end 421a of the vertical pipe 421 to the open area 4c is defined as h4 [m]. By ensuring a certain length of h4, it is possible to make it difficult for the connecting pipe 44 to come off from the vertical pipe 421, and to prevent water splashing at the open area 4c from reaching the outside through the end 421a. From this viewpoint, it is preferable to set h4≧0.2, for example.

[0074] [1.2.2 Effects, etc.] In the piping system 1A described above, the second downspout 42A includes a vertical pipe 421 having a larger pipe diameter than the first downspout 41. The downstream end 44b of the connecting pipe 44 is disposed inside the vertical pipe 421. The open portion 4c is the downstream end 44b of the connecting pipe 44. This configuration makes it possible to reduce the deterioration of drainage performance caused by the junction 43 of the main pipe 4A and the branch pipe 5, and makes it possible to stabilize the drainage from the branch pipe 5.

[0075] In the piping system 1A, if the vertical distance from the upstream end 421a of the vertical pipe 421 to the open portion 4c is h4 [m], then 0.2≦h4 is satisfied. This configuration makes it difficult for the connecting pipe 44 to come off the vertical pipe 421, and can prevent water splashing at the open portion 4c from reaching the outside via the end 421a of the vertical pipe 421.

[0076] [2. Modifications] The embodiments of the present disclosure are not limited to the above-mentioned embodiments. The above-mentioned embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Below, modified examples of the above-mentioned embodiments are listed. The modified examples described below can be applied in appropriate combination.

[0077] In the following, reference will be made to symbols used in the first embodiment even though they are applicable to either the first or second embodiment described above. However, this is merely for the purpose of simplifying the description and is not intended to exclude application to the second embodiment.

[0078] In one modified example, at least one of the material of the main pipe 4 and the material of the branch pipe 5 does not necessarily have to be rigid polyvinyl chloride. The material of the main pipe 4 and the material of the branch pipe 5 may be determined according to the requirements of the piping system 1, and may be, for example, a synthetic resin such as polyethylene, or may be a metal instead of a synthetic resin.

[0079] In one modified example, the first downspout 41 may be configured with one or more straight pipe members, and may further include a connection joint such as an elbow, a socket, or the like.

[0080] In one modified example, the dimensions of the main pipe 4 and the branch pipe 5 do not necessarily have to be set in accordance with the JIS K 6741 regulations.

[0081] In one modified example, the piping system 1 does not necessarily have to include the first eaves gutter 31 or the second eaves gutter 32. For example, if the building has a structure with an outlet such as a balcony, the main pipe 4 or the branch pipe 5 may be connected to the outlet of the building.

[0082] In one variation, the piping system 1 may correspond to a plurality of second drop outlets 32b. In the piping system 1, a plurality of branch pipes 5 may be connected to one or more junctions 43 of the main pipe 4.

[0083] In one modified example, the main pipe 4 may have a configuration different from that of the above embodiment. For example, the first downpipe 41 of the main pipe 4 may be composed of multiple pipe materials instead of a single pipe material. For example, the first downpipe 41 may include other piping components such as a nominal downpipe, an elbow, a socket, etc. in addition to a straight pipe material. In the main pipe 4, the number of the first downpipes 41, the number of the second downpipes 42, and the number of the junctions 43 are not particularly limited.

[0084] In one modification, the branch pipe 5 may have a configuration different from that of the above embodiment. The branch pipe 5 may have other piping components such as a socket. In the branch pipe 5, the number of vertical pipes 51, the number of nominal pipes 52, and the number of elbows 53 are not particularly limited. The elbows 53 may be 45° elbows as specified in JIS K 6739.

[0085] In one variant, the drains 71, 72 do not necessarily have to be drains for promoting siphoning. The drains 71, 72 may be omitted.

[0086] In one modified example, the elbow 60 is not limited to a 90° elbow, and may have any configuration as long as it generates a pressure loss for the rainwater flowing through the vertical pipe 421.

[0087] In one modified example, the piping system 1 is not limited to a rain gutter system. Examples of the piping system include a piping system for a water supply or a sewerage system, and a piping system for transporting a target fluid in a facility such as a factory. In other words, the fluid transported by the piping system is not limited to rainwater.

[0088] [3. Aspects] As is apparent from the above embodiment and modifications, the present disclosure includes the following aspects.

[0089] [Aspect 1] A main pipe connected to the first outlet of the first eaves gutter; A branch pipe connected to the second outlet of the second eaves gutter; Equipped with The main pipe is A first downspout connected to the first drop outlet; A second downpipe is located downstream of the first downpipe and includes a portion having a larger pipe diameter than the first downpipe; a junction portion between the first downpipe and the second downpipe and to which a downstream end of the branch pipe is connected; A connecting pipe having a pipe diameter equal to or smaller than that of the first downspout and connecting the downstream end of the confluence and the upstream end of the second downspout; Including, the main pipe has an open portion that is open to atmospheric pressure below a downstream end of the junction, and the downstream end of the main pipe is connected to a pressure loss member that generates a pressure loss for water flowing through the main pipe, If the vertical distance from the downstream end of the confluence to the ground is h2, and the vertical distance from the downstream end of the confluence to the open portion is d [mm], 0.5≦d≦h2-0.5 is satisfied. Piping system.

[0090] [Aspect 2] d≦h2-1 is satisfied. 2. The piping system of embodiment 1.

[0091] [Aspect 3] If the vertical distance from the downstream end of the confluence to the upstream end of the pressure loss member is h3 [m], 0.5≦d≦h3-1 is satisfied. 3. The piping system of embodiment 1 or 2.

[0092] [Aspect 4] If the vertical distance between the first drop outlet and the upstream end of the second downspout is h1 [m], h1 ≥ 3 is satisfied. 3. The piping system of embodiment 1 or 2.

[0093] [Aspect 6] The second downspout is A vertical pipe having a diameter larger than that of the first downpipe; an increaser connecting the connecting pipe to the vertical pipe; Including, The open portion is a connection portion between the connecting pipe and the increaser. The piping system according to any one of embodiments 1 to 5.

[0094] [Aspect 7] The second downpipe includes a vertical pipe having a larger pipe diameter than the first downpipe, A downstream end of the connecting pipe is disposed within the vertical pipe, The open portion is a downstream end portion of the connecting pipe. The piping system according to any one of embodiments 1 to 6.

[0095] [Aspect 8] The maximum allowable flow rate (external guaranteed value) of the first drainage route from the first drop outlet is Q1D, The flow rate of the first drainage path is Q1, If the flow rate of the second drainage path from the second drop outlet is Q2, Q1D≧Q1+Q2 is satisfied. The piping system according to any one of embodiments 1 to 7.

[0096] [Aspect 9] The branch pipe includes a drop pipe descending toward the junction, The gradient of the said call gutter is 1 / 1000 or more. The piping system according to any one of embodiments 1 to 8.

[0097] [Aspect 10] The second eaves gutter is located below the first eaves gutter, The first downspout passes through an opening in a bottom wall of the second eaves gutter while being separated from the second eaves gutter in terms of flow path. The piping system according to any one of embodiments 1 to 9.

[0098] [Aspect 11] Further comprising a drain disposed at the first drop outlet. The piping system according to any one of embodiments 1 to 10.

[0099] Aspects 2 to 11 are optional elements and are not essential. [Industrial Applicability]

[0100] The present disclosure is applicable to a piping system, particularly to a piping system including a main pipe and branch pipes. [Explanation of symbols]

[0101] 1,1A Piping System 21 Stormwater Inlet 22 Buried tube 31 First eaves gutter 31b First Drop Hole 32 Second eaves gutter 32a bottom wall 32b 2nd Drop Hole 32c aperture 4,4A main 4c open area 41 No. 1 downpipe 42,42A 2nd downpipe 42a Upstream end 421 Vertical pipe 422 Increaser 43 Junction 43b Downstream end 44 Connecting pipe 44b Downstream end 5 branch pipes 52 Call pipe 60 Elbow 71 Drain

Claims

1. A main pipe connected to a first outlet of the first eaves gutter; A branch pipe connected to a second outlet of the second eaves gutter; Equipped with The main pipe is A first downspout connected to the first drop outlet; a second downpipe located downstream of the first downpipe and including a portion having a pipe diameter larger than that of the first downpipe; a junction portion located between the first downpipe and the second downpipe and to which a downstream end of the branch pipe is connected; a connecting pipe having a pipe diameter equal to or smaller than that of the first downspout and connecting a downstream end of the confluence portion and an upstream end of the second downspout; Including, the main pipe has an open portion that is open to atmospheric pressure below a downstream end of the junction, and the downstream end of the main pipe is connected to a pressure loss member that generates a pressure loss for water flowing through the main pipe, If the vertical distance from the downstream end of the confluence to the ground is h2 [m], and the vertical distance from the downstream end of the confluence to the open portion is d [m], 0.5≦d≦h2-0.5 is satisfied; Piping system.

2. d≦h2−1 is satisfied. The piping system of claim 1.

3. If the vertical distance from the downstream end of the confluence to the upstream end of the pressure loss member is h3 [m], 0.5≦d≦h3-1 is satisfied; The piping system of claim 1.

4. If the vertical distance from the first drop hole to the open area is h1 [m], h1≧3 is satisfied. The piping system of claim 1.

5. The pressure loss member is an elbow located below ground level. The piping system of claim 1.

6. The second downspout is A vertical pipe having a pipe diameter larger than that of the first downpipe; an increaser connecting the connecting pipe to the vertical pipe; Including, The open portion is a connection portion between the connecting pipe and the increaser. The piping system of claim 1.

7. The second downpipe includes a vertical pipe having a larger pipe diameter than the first downpipe, A downstream end of the connecting pipe is disposed within the vertical pipe, The open portion is a downstream end portion of the connecting pipe. The piping system of claim 1.

8. The maximum allowable flow rate (external guaranteed value) of the first drainage path from the first drop outlet is Q1D, The flow rate of the first drainage path is Q1, If the flow rate of the second drainage path from the second drop outlet is Q2, Q1D≧Q1+Q2 is satisfied. The piping system of claim 1.

9. The branch pipe includes a drop pipe descending toward the junction, The gradient of the call gutter is 1 / 1000 or more. The piping system of claim 1.

10. The second eaves gutter is located below the first eaves gutter, The first downspout passes through an opening in a bottom wall of the second eaves gutter while being separated from the second eaves gutter in terms of flow path. The piping system of claim 1.

11. Further comprising a drain disposed at the first drop outlet. The piping system of claim 1.

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