Piping construction

Abstract

To promote drainage from a temporary storage tank and reduce abnormal noise at a branch part.SOLUTION: A piping structure 20 comprises: a branch part to branch drainage discharged from a temporary storage tank 30 from a single channel 63 into a plurality of channels; a horizontal pipe 42 that is connected to the branch part and discharges the drainage stored in the temporary storage tank in a lateral direction; a vertical pipe 46 to generate siphon force in the horizontal pipe 42; an air supply part to supply air to the branch part; and a core component 70, which has an air supply channel to make the air pass to the branch part and a body part 72 in which cross sectional area of the channel at a lower part of the air supply part is smaller than cross sectional area of the opening and a drainage guide surface 76 extending from the single channel 63 toward the plurality of channels is formed so that a downstream end 76E of the drainage guide surface 76 protrudes toward a lower side of top edges of the plurality of channels and a recessed part 78 that is formed on the body part 72 into a shape recessed upward so as to decrease a part at which the drainage guide surface 76 overlaps the plurality of channels in a drainage direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a piping structure. [Background technology]

[0002] The following Patent Document 1 describes a siphon drainage system that applies siphon force to wastewater discharged from a plumbing fixture and stored in a temporary storage tank to cause it to flow out. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-256557 Summary of the Invention [Problem to be solved by the invention]

[0004] In the siphon drainage system of Patent Document 1, there are more siphon drainage pipes than drainage inlet pipes that lead drainage to the temporary storage tank, and the siphon drainage pipes, each having a horizontal pipe and a vertical pipe, merge with the drainage standpipe. According to the siphon drainage system of Patent Document 1, by having multiple siphon routes, drainage from the temporary storage tank can be promoted.

[0005] However, when siphon force is generated in a siphon drain pipe, not only does water flow through the siphon drain pipe at full capacity, but it has also been confirmed that air is intermittently sucked into the siphon drain pipe. Furthermore, in cases where a temporary storage tank is provided to temporarily store wastewater, it has been confirmed through experiments that the siphon force is promoted by the suction of air when siphon force is generated. In cases where multiple siphon drain pipes are provided, the air suction configuration must be devised to prevent the sound generated by the suction of air from becoming too loud.

[0006] In view of the above, an object of the present invention is to provide a piping structure that promotes drainage from a temporary storage tank and reduces abnormal noise at branching portions. [Means for solving the problem]

[0007] The piping structure of the first aspect includes a temporary storage tank that stores wastewater discharged from a plumbing fixture, a branching section that branches the wastewater discharged from the temporary storage tank from a single flow path into multiple flow paths, a horizontal pipe connected to the branching section and discharging the wastewater stored in the temporary storage tank in a horizontal direction, a vertical pipe that generates a siphon force in the horizontal pipe by causing the wastewater from the horizontal pipe to flow down, an air supply section connected to an upper part of the branching section and supplying air to the branching section, an opening formed in the air supply section, and air exhausted from the opening. The air supply passage is arranged within the air supply section so that air can be discharged therefrom, and allows air to pass to the branch section; a main body section in which the cross-sectional area of ​​the flow path at the bottom of the air supply section is smaller than the cross-sectional area of ​​the opening, and in which a drainage guide surface is formed from the single flow path to the multiple flow paths, the downstream end of which protrudes downward below the upper ends of the multiple flow paths; and a core member having a hollowed-out portion formed in the main body section and hollowed out upward so as to reduce the portion of the drainage guide surface that overlaps with the multiple flow paths in the drainage direction.

[0008] In the piping structure of the first embodiment, the wastewater stored in the temporary storage tank flows from multiple horizontal pipes to the vertical pipe, and the vertical pipe generates a siphon force on the horizontal pipe, thereby promoting drainage from the temporary storage tank compared to when there is only one horizontal pipe.

[0009] In addition, an air supply pipe is connected to the branching section that branches the wastewater discharged from the temporary storage tank from a single flow path into multiple flow paths, so that one air supply pipe can draw air into each of multiple horizontal pipes, efficiently improving the drainage capacity using siphon force.

[0010] A core member is disposed in the opening formed in the air supply section. This core member has a main body portion on which a drainage guide surface is formed extending from the single flow path of the branching section to the multiple flow paths, and the downstream end of the drainage guide surface protrudes downward below the upper ends of the multiple flow paths. Therefore, the portion of the drainage where the flow is fast is guided below the upper ends of the multiple flow paths, and a distance can be maintained between the upper part of the branching section and the air sucked in from the connected air supply section. This allows the air to flow gently into the multiple flow paths, making it possible to relatively reduce the noise generated by the air sucking in.

[0011] Furthermore, since the core member is arranged in the air supply section so that it can be removed from the opening, by removing the core member, the outflow section and the area near the outflow section of the temporary storage tank can be easily accessed from the opening and cleaned.

[0012] The core member has a hollowed-out portion formed on the main body that hollows out the drainage guide surface upward to reduce the overlap with the multiple flow paths in the drainage direction, allowing the drainage water to flow smoothly from the single flow path to the multiple flow paths.

[0013] The piping structure of a second aspect is the piping structure of the first aspect, wherein the recessed portion is formed so that the drainage guide surface does not overlap with the plurality of flow paths when the drainage guide surface is viewed from the drainage direction.

[0014] In this way, by forming the drainage guide surface so that it does not overlap with the plurality of flow paths when viewed from the drainage direction, it is possible to smoothly flow wastewater from a single flow path to the plurality of flow paths.

[0015] A piping structure of a third aspect is the piping structure of the first or second aspect, wherein the lower end of the drainage guide surface is shaped to linearly connect the plurality of flow paths at the downstream end.

[0016] In the piping structure of the third embodiment, on the upstream side between the multiple flow paths, the lower end of the drainage guide surface guides the part of the drainage where the flow is fast below the upper ends of the multiple flow paths, thereby creating a distance from the air being sucked in, slowing the flow of air into the multiple flow paths and making the sound generated by the suction of air relatively small.

[0017] The piping structure of the fourth aspect is a piping structure of any one of the first to third aspects, wherein each of the multiple flow paths has a smaller diameter than the single flow path, and the drain guide surface extends from the upper end of the single flow path.

[0018] According to the piping structure of the fourth aspect, wastewater can be smoothly passed through a plurality of flow paths each having a smaller diameter than a single flow path.

[0019] The piping structure of the fifth aspect is a piping structure of any one of the first to fourth aspects, wherein the lower end of the drainage guide surface is positioned at a height of 40% to 60% from the upper ends of the multiple flow paths at the downstream end.

[0020] In this way, by positioning the lower end of the drainage guide surface at the downstream end at a height of 40% to 60% from the upper ends of the multiple flow paths, the sound generated by air suction can be kept relatively small while allowing drainage water to flow smoothly from a single flow path to multiple flow paths. [Effects of the Invention]

[0021] According to the piping structure of the present invention, it is possible to promote drainage from the temporary storage tank and reduce abnormal noise at the branching portion. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a side view showing a piping structure according to an embodiment of the present invention; [Figure 2] 1 is a perspective view showing a piping structure according to an embodiment of the present invention; [Figure 3] 1 is a perspective view showing the vicinity of a branch joint of a piping structure according to an embodiment of the present invention. [Figure 4]FIG. 6 is a cross-sectional view taken along line BB in FIG. 5. [Figure 5] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 6] 1 is a view of a piping structure according to an embodiment of the present invention, viewed from the upstream side of a single flow path. [Figure 7] FIG. 2 is a perspective view of a core member according to an embodiment of the present invention. [Figure 8] 10A and 10B are diagrams showing piping structures according to modified examples (A) and (B) of the embodiment of the present invention, as viewed from the upstream side of a single flow path. [Figure 9] 10A and 10B are diagrams showing piping structures according to comparative examples (A) and (B) viewed from the upstream side of a single flow path. [Figure 10] 10 is a graph showing the relationship between the time from the start of drainage and noise in the vicinity of the branch joint. [Figure 11] 11 is a graph showing an enlarged view of the rectangular portion of FIG. 10. [Figure 12] 10 is a table showing the average noise and average water level after the siphon is activated. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, a piping structure according to an embodiment of the present invention will be described with reference to the drawings. Components indicated by the same reference numerals in the various drawings are the same components. However, unless otherwise specified in the specification, each component is not limited to one, and may be present in multiple numbers.

[0024] Furthermore, the description of the same components and symbols in each drawing may be omitted. Note that the present invention is not limited to the following embodiments, and may be implemented by making appropriate modifications, such as omitting components or replacing them with different components, within the scope of the object of the present invention.

[0025] In the drawing, arrow Z indicates the vertical upward direction, and arrows X and Y indicate directions that are orthogonal to each other in the horizontal direction.

[0026] <Piping structure> (Siphon drainage system)

[0027] 1 shows an outline of a piping structure 20 according to this embodiment. The piping structure 20 is a siphon drainage system structure that utilizes siphon force to discharge wastewater from a plumbing fixture 12. As an example, the piping structure 20 is used in an apartment building 10 that is constructed to have multiple floors.

[0028] The piping structure 20 is equipped with a drainage standpipe 22 that drains wastewater downward. The drainage standpipe 22 extends in the up-down direction (vertical direction) and penetrates the slab 14 of each floor of the apartment building 10. A plurality of drainage standpipes 22 are provided in different locations on the floor plan of the apartment building 10. The drainage standpipe 22 is housed, for example, in a piping space (also referred to as a pipe space, etc.) that is partitioned by walls from each dwelling on each floor of the apartment building 10.

[0029] Each dwelling unit in the apartment building 10 is provided with a plumbing fixture 12. The plumbing fixture 12 is, for example, a bathroom unit, and is formed by integrating a bathtub 12A and a washing area 12B. One end of a drainage inlet pipe 24 is connected to the plumbing fixture 12.

[0030] The other end of the wastewater inlet pipe 24 is connected to the temporary storage tank 30, which will be described later. As a result, the wastewater inlet pipe 24 introduces wastewater discharged from the bathtub 12A and the washing area 12B of the plumbing fixture 12 into the temporary storage tank 30. It is preferable that the wastewater inlet pipe 24 is arranged with a slope so that the temporary storage tank 30 side is lower.

[0031] As shown in Figure 2, the temporary storage tank 30 is capable of temporarily storing wastewater from the plumbing fixtures 12 and is formed in a substantially rectangular parallelepiped shape. An inlet section 30A is formed in one side wall of the temporary storage tank 30, and the other end of the wastewater introduction pipe 24 is connected to it. A protrusion 30B is formed in the lower part of the other side wall opposite the one side wall of the temporary storage tank 30. The inlet section 30A has a concave shape on the side where the wastewater introduction pipe 24 is connected.

[0032] A branch joint 60 serving as an outflow section, which will be described later, is connected to the protruding section 30B, and the siphon drain pipe 40 is connected via the branch joint 60. The protruding section 30B is formed in a convex shape that protrudes toward the side to which the branch joint 60 is connected, and has an outflow opening section 30C (see FIG. 4) that is a long hole that is long in the horizontal direction at its tip. The temporary storage tank 30 is formed from a resin material, for example, polyvinyl chloride or other such material.

[0033] An inspection hatch 32 is formed in the ceiling wall of the temporary storage tank 30, and the inspection hatch 32 is closed with a lid 34.

[0034] (Branch joint) 3 and 4, the branch joint 60 has a single flow path section 62 and a multiple flow path section 64. The single flow path section 62 extends from the protruding portion 30B, and within the single flow path section 62, there are formed one single flow path 63A that is continuous with the outflow opening 30C, and a single space 63B whose diameter is expanded from the single flow path 63A in the horizontal direction perpendicular to the single flow path 63A.

[0035] Two multi-channel sections 64 protrude in parallel from the single channel section 62 in the same direction as the single channel section 62, and two branch channels 65 are formed inside the multi-channel section 64 and arranged parallel to each other along the outer shape of the multi-channel section 64. Each branch channel 65 is continuous with the single space 63B and is connected to a horizontal pipe 42, which will be described later. As shown in FIG. 5 , the inner diameter of the single channel 63A is larger than the inner diameter of the branch channel 65, and the lower end of the single channel 63A is positioned at approximately the same height as the lower end of the branch channel 65, and the upper end of the single channel 63A is positioned at a higher position than the upper end of the branch channel 65.

[0036] An air supply connection 61 serving as an air supply section is formed at the top of the single passage section 62. The air supply connection 61 is generally cylindrical, and has a communicating passage 61A formed therein that communicates with the upper part of the single space 63B. An inspection opening 61B that opens upward from the communicating passage 61A is formed at the upper end of the air supply connection 61. The inspection opening 61B is closed by a lid 61D. Furthermore, a connection opening 61C that opens from the communicating passage 61A toward the vent pipe 50 is formed at the upper part of the side of the air supply connection 61. An air supply pipe 66 is connected to the connection opening 61C.

[0037] (Core material) A core member 70 is disposed within the air supply connection 61. As shown in Figure 7, the core member 70 is generally cylindrical and has a main body 72 and a locking portion 74. The locking portion 74 is annular, constitutes the upper end of the core member 70, and is locked to the inner circumferential wall that forms the inspection opening 61B of the air supply connection 61. The core member 70 can be removed from the inspection opening 61B to the outside of the communicating flow path 61A within the air supply connection 61.

[0038] The main body 72 extends downward from the locking portion 74 and is disposed in the communication flow path 61A. An air intake inlet space 72A and an air intake flow path space 72B, which serve as examples of air intake paths, are formed on the side surface of the main body 72. As shown in FIG. 4, the air intake inlet space 72A is formed in a position corresponding to the connection opening 61C of the air intake connection portion 61, so that the main body 72 is concave. The air intake flow path space 72B is formed in a position corresponding to the connection opening 61C of the air intake connection portion 61, so that the main body 72 is concave, as viewed from above. The air intake inlet space 72A is formed at a height corresponding to the connection opening 61C in the vertical direction (Z direction), and the air intake flow path space 72B is formed in a position corresponding to the upper end of the air intake inlet space 72A in the vertical direction (Z direction) to the lower end, and is communicated with the air intake inlet space 72A.

[0039] The side of the main body 72 where the air supply inlet space 72A and the air supply flow path space 72B are not formed is shaped to follow the inner wall of the air supply connection part 61. As shown in FIG. 5, the lower part (bottom surface) of the main body 72 extends from the upper end of the single flow path 63A of the branch joint 60 toward the branch flow path 65, and is inclined diagonally downward in two stages to form a drainage guide surface 76. The inclination angle of the drainage guide surface 76 relative to the horizontal in the drainage direction is set larger on the upstream side than on the downstream side. The downstream end 76E of the drainage guide surface 76 is located at the lowest point in the vertical direction (Z direction) within the single flow path 63A and is located at a position that protrudes downward below the upper end of the branch flow path 65. In this embodiment, the drainage guide surface 76 is located at a radius from the upper end of the branch flow path 65, in other words, at half the height of the branch flow path 65.

[0040] 6 and 7, a recessed portion 78 is formed in the lower part of the main body portion 72. The recessed portion 78 is formed at both ends in the horizontal direction as viewed from the drainage direction, by recessing the drainage guide surface 76 in an arc shape upward so as to reduce the portion that overlaps with the branch flow path 65. In this embodiment, the drainage guide surface 76 is shaped to conform to the branch flow path 65 so as not to overlap with the branch flow path 65 as viewed from the drainage direction. In other words, as viewed from the drainage direction, one end (the right end in FIG. 6) of the recessed portion 78, the downstream end 76E, and the other end (the left end in FIG. 6) of the recessed portion form a substantially U-shape as the lower side of the drainage guide surface 76.

[0041] The downstream ends 76E of the drainage guide surfaces 76 are connected in a straight line so that the radially inner ends of the recessed portions 78 are maintained at a height that is positioned at the vertically lowest position within the single flow path 63A. In other words, the downstream ends 76E of the drainage guide surfaces 76 are shaped to connect the branch flow paths 65 in a straight line in the horizontal direction when viewed from the drainage direction.

[0042] With the core member 70 disposed in the communicating flow path 61A, the main body 72 is disposed on the upstream side (left side in FIG. 5) in the direction of the drainage water flow inside the air intake connection 61. Therefore, the cross-sectional area of ​​the air intake flow path space 72B, which is the portion through which air flows at the bottom of the communicating flow path 61A, is smaller than the opening area of ​​the inspection opening 61B. In this embodiment, the cross-sectional area of ​​the lower end of the communicating flow path 61A is the opening area of ​​the air intake flow path space 72B to the single flow path 63A, and is the opening S.

[0043] A connection port 67A at one end of the air supply pipe 66 is connected to the connection opening 61C. A connection port 67B at the other end of the air supply pipe 66 is connected to the ventilation pipe 50.

[0044] (Siphon drain pipe) As shown in Figure 2, the siphon drain pipe 40 includes multiple (two in this embodiment) horizontal pipes 42 arranged along the slab 14, a confluence horizontal pipe 44, a vertical pipe 46, and a horizontal confluence joint member 48.

[0045] The horizontal drain pipe 42 discharges wastewater discharged from the plumbing fixtures 12 horizontally through multiple flow paths. The horizontal drain pipe 42 is formed, for example, from a polybutylene pipe with a nominal diameter of 25J (inner diameter of approximately 28 mm), and is arranged without a gradient along the horizontal direction on the slab 14. Note that "without a gradient" here does not necessarily have to be strictly horizontal, and also includes a slight step or gradient along the slab 14.

[0046] The "upstream" ends of the two horizontal pipes 42 are connected to the branch flow paths 65 of the branch joint 60. The "downstream" ends of the two horizontal pipes 42 are connected to one junction horizontal pipe 44 via a horizontal junction joint member 48. The junction horizontal pipe 44 is connected to the two horizontal pipes 4

[0047] 2. The confluence horizontal pipe 44 and the horizontal confluence joint member 48 may be integrally formed.

[0048] The total cross-sectional area of ​​the two horizontal pipes 42 is preferably less than the cross-sectional area of ​​the wastewater inlet pipe 24. In addition, the cross-sectional area of ​​the confluence horizontal pipe 44 is preferably less than the total cross-sectional area of ​​the two horizontal pipes 42. The cross-sectional areas of the confluence horizontal pipe 44 and the horizontal pipe 42 are set in consideration of the amount of wastewater discharged from the wastewater inlet pipe 24 so that the wastewater flows through the pipes at full flow as necessary.

[0049] As shown in Figures 1 and 2, a confluence horizontal pipe 44 is connected to the upstream side of the standpipe 46. The standpipe 46 is arranged in the up-down direction (vertical direction) along the drainage standpipe 22, and generates a siphon force in the horizontal pipe 42. The other end of the standpipe 46 is connected to a confluence joint 26. The confluence joint 26 is a joint member that merges the drainage water from the standpipe 46 into the drainage standpipe 22.

[0050] The confluence horizontal pipe 44 and the vertical pipe 46 are configured as a single continuous path without merging with other drainage pipes up to the confluence joint 26, and direct the drainage water to the drainage standpipe 22. Note that the connection between the confluence horizontal pipe 44 and the vertical pipe 46 is illustrated as a continuous vent pipe, but a coupling member such as an elbow may be placed in this vent pipe section. When a coupling member is placed, an inspection hatch or the like may be provided in the coupling member as appropriate.

[0051] As shown in FIG. 2, a vent pipe 50 is connected to the temporary storage tank 30. One end of the vent pipe 50 is connected to the upper part of the side wall of the temporary storage tank 30 where the protruding portion 30B is formed, and extends approximately parallel to the horizontal pipe 42. The other end of the vent pipe 50 is connected to the junction joint 26. A connection port 67B on the other end of the air supply pipe 66 is connected to a portion of the vent pipe 50 close to the temporary storage tank 30. The air supply pipe 66 is connected to the drainage standpipe 22 via the junction joint 26. Air flows in and out of the temporary storage tank 30 through the vent pipe 50 so that the pressure inside the temporary storage tank 30 becomes atmospheric pressure. Air is also supplied from the vent pipe 50 to the horizontal pipe 42 via the air supply pipe 66.

[0052] <Action and effect> Next, the operation and effects of the piping structure 20 of this embodiment will be described.

[0053] The wastewater discharged from the plumbing fixtures 12 flows into the temporary storage tank 30 from the inlet 30A via the wastewater inlet pipe 24. The wastewater that flows into the temporary storage tank 30 branches from the protruding part 30B through the branch joint 60 into two horizontal pipes 42, joins at the joining horizontal pipe 44, is led to the vertical pipe 46, and is discharged into the drainage standpipe 22.

[0054] In the initial stage of wastewater flowing into the temporary storage tank 30, the inside of the standpipe 46 is not yet full and no siphon force is generated, so the amount of wastewater discharged per unit time from the protruding portion 30B is less than the amount of wastewater flowing into the temporary storage tank 30 per unit time, causing the water level of the wastewater to rise in the temporary storage tank 30. As the water level of the wastewater in the temporary storage tank 30 rises, the air in the temporary storage tank 30 is pushed out and discharged to the drainage standpipe 22 via the vent pipe 50. This allows the wastewater to flow into the temporary storage tank 30 quickly and efficiently.

[0055] When the upright pipe 46 is filled with water and the wastewater falls down the upright pipe 46 due to gravity, a siphon force is generated due to the potential energy of the siphon head Hs. When the siphon force is generated, the wastewater in the temporary storage tank 30 is sucked in, increasing the drainage speed. In this embodiment, the wastewater stored in the temporary storage tank 30 is drained through two horizontal drain pipes 42. Therefore, the wastewater treatment capacity from the temporary storage tank 30 can be increased compared to a configuration in which only one horizontal drain pipe 42 is connected to the temporary storage tank 30.

[0056] When a siphon force is generated and drainage water is sucked from the temporary storage tank 30, negative pressure is created inside the temporary storage tank 30, causing air to be supplied to the temporary storage tank 30 through the vent pipe 50. Air is also appropriately drawn from the vent pipe 50 through the air supply pipe 66, through the air supply inlet space 72A in the air supply connection part 61, and through the air supply flow path space 72B into the branch flow path 65. The air drawn into the branch flow path 65 flows into the horizontal draw pipe 42. This air intake can promote the generation of siphon force in the siphon drain pipe 40. In this embodiment, a single air supply pipe 66 can draw air into each of the multiple horizontal draw pipes 42, thereby efficiently improving drainage capacity using siphon force.

[0057] Furthermore, in this embodiment, the drain guide surface 76 is disposed so as to extend from the upper end of the single flow path 63A in the branch joint 60 toward the branch flow path 65, and the downstream end 76E of the drain guide surface 76 protrudes downward from the upper end of the branch flow path 65. Therefore, the portion of the drain where the flow is fast is guided downward from the upper end of the branch flow path 65, and can be distanced from the sucked air. This allows the air to flow more slowly into the branch flow path 65, and the sound generated by the sucked air can be made relatively small.

[0058] Furthermore, the main body 72 of the core member 70 is formed with a recessed portion 78 that is recessed upward so as to reduce the portion of the drainage guide surface 76 that overlaps with the branch flow path 65 in the drainage direction. This allows the drainage water to flow smoothly from the single flow path 63A to the branch flow path 65. In particular, in this embodiment, the recessed portion 78 is shaped to follow the branch flow path 65 so that the drainage guide surface 76 does not overlap with the branch flow path 65 when viewed from the drainage direction, allowing the drainage water to flow more smoothly from the single flow path 63A to the branch flow path 65.

[0059] Furthermore, in this embodiment, the downstream end 76E of the drainage guide surface 76 has a shape that linearly connects the branch flow paths 65 at the downstream end when viewed from the drainage direction. Therefore, the downstream end 76E of the drainage guide surface 76 guides the part of the drainage path where the fast flow is below the upper end of the branch flow path 65. This allows a distance to be maintained between the part of the branch flow path 65 where the fast flow of the drainage is and the air being sucked in, which slows the flow of air into the branch flow path 65 and makes it possible to make the sound generated by the suction of air relatively small.

[0060] In this embodiment, the air supply pipe 66 is connected to the vent pipe 50, which is connected to the temporary storage tank 30. Therefore, when the water level in the temporary storage tank 30 rises and wastewater in the temporary storage tank 30 flows into the vent pipe 50, the wastewater can be made to flow out to the horizontal pipe 44 via the air supply pipe 66.

[0061] Furthermore, when performing maintenance and inspection of temporary storage tank 30, lid 34 is opened to access the interior of temporary storage tank 30 through inspection opening 32. Furthermore, lid 61D is opened, core member 70 is removed through inspection opening 61B, and branch joint 60 and protrusion 30B are accessed through communication flow path 61A of air supply connection part 61.

[0062] In this embodiment, protrusion 30B and branch joint 60, which are prone to accumulate dirt, can be easily accessed through inspection opening 61B. Furthermore, by arranging core member 70 in communication flow path 61A, the cross-sectional area of ​​the air flow path can be freely reduced even when inspection opening 61B is relatively large.

[0063] In this embodiment, two horizontal draw pipes 42 are provided, but three or more horizontal draw pipes 42 may be provided. In addition, in this embodiment, the horizontal draw pipes 42 are joined into one joining horizontal draw pipe 44, but instead of joining, each horizontal draw pipe 42 may be connected to an individual standpipe 46 and joined into the drainage standpipe 22. By joining the drainage into one standpipe 46 as in this embodiment, a large amount of drainage water is collected in the standpipe 46, so that the flow rate of drainage water required to generate siphon force can be quickly ensured and the siphoning time can be shortened.

[0064] In addition, in this embodiment, an example has been described in which the downstream end 76E of the drainage guide surface 76 is positioned at 1 / 2 the height of the branch flow path 65, but the position of the downstream end 76E may be lower than the upper end of the branch flow path 65, and it is preferable that it is positioned at a height of 40% to 60% from the upper end of the branch flow path 65.

[0065] (Other embodiments) In the above embodiment, an example was described in which the lower edge of the drainage guide surface 76 is formed in an approximately U-shape when viewed from the drainage direction (see Figure 6), but the recessed portion 78 and the downstream end 76E may be modified to give the lower edge of the drainage guide surface 76 another shape.

[0066] 8(A), the lower end 76AE of the drainage guide surface 76A can be formed so as to extend obliquely upward in a straight line from the center of the lower end 76AE toward each of the left and right ends when viewed from the drainage direction. In this case, the lower side of the drainage guide surface 76A becomes approximately V-shaped when viewed from the drainage direction.

[0067] 8(B), a hollowed-out portion 78B similar to hollowed-out portion 78 may be formed, and a central hollowed-out portion 79 may be formed in the center of lower end portion 78BE to hollow out drainage guide surface 76 upward. In this case, the lower side of drainage guide surface 76B has a substantially W-shape when viewed from the drainage direction.

[0068] [Test example] In order to confirm the effect of the piping structure according to the above embodiment, the following tests were carried out on five different shapes of the drainage guide surface of the core member 70.

[0069] (Test conditions) Examples of the present invention having a drainage guide surface 76 were: Example 1 (U-shaped) shown in FIG. 6; Example 2 (V-shaped) shown in FIG. 8(A) having a drainage guide surface 76A; and Example 3 (W-shaped) shown in FIG. 8(B) having a drainage guide surface 76B. Comparative Examples 1 (FIG. 9(A)) and 2 (FIG. 9(B)) having a drainage guide surface 76 without a recess were used as comparative examples. The drainage guide surfaces 76 of Comparative Example 1 and Comparative Example 2 have the same shape but are positioned differently. In Comparative Example 1, the downstream end 76E of the drainage guide surface 76 is positioned near the upper end of the branch flow path 65, while in Comparative Example 2, the downstream end 76E of the drainage guide surface 76 is positioned approximately halfway up the height of the branch flow path 65 (similar to FIG. 6).

[0070] The structures were identical except for the shape of the drainage guide surface. Evaluation was performed based on noise near the branch joint 60 and the water level in the temporary storage tank. FIG. 10 is a graph showing the relationship between the elapsed time from the start of drainage and noise, and FIG. 11 is an enlarged view of the rectangular frame in FIG. 10 after siphon activation. FIG. 12 also shows the average noise and average water level after siphon activation. All values ​​are expressed as relative indices. For noise, the larger the value, the louder the noise, and for water level, the larger the value, the higher the water level in the temporary storage tank. From the table shown in FIG. 12, it was confirmed that the average water level was lower in Examples 1 to 3 than in Comparative Examples 1 and 2, and that drainage from the temporary storage tank was promoted. It was also confirmed that abnormal noise was suppressed while maintaining the drainage promotion effect. [Explanation of symbols]

[0071] 12 Plumbing fixtures, 20 Piping structure, 30 Temporary storage tank 42 horizontal pipe, 46 vertical pipe, 60 branch joint (branch section) 61 Air supply connection part (air supply part), 61B Inspection opening (opening) 63A single flow path, 65 branch flow path, 70 core member 72 Main unit, 72B Air supply flow path space (air supply path) 76, 76A, 76B Drainage guide surface 76E Downstream end 78, 78B hollowed out part

Claims

1. a temporary storage tank for storing wastewater discharged from plumbing fixtures; a branching unit that branches the wastewater discharged from the temporary storage tank from a single flow path into multiple flow paths; a horizontal pipe connected to the branch portion and discharging the wastewater stored in the temporary storage tank in a horizontal direction; a vertical pipe that generates a siphon force in the horizontal pipe by causing the drainage water from the horizontal pipe to flow downward; an air supply unit connected to an upper portion of the branching unit and supplying air to the branching unit; an opening formed in the air supply section; a single core member having: an air supply passage arranged in the air supply section so as to be able to be extracted from the opening, and for passing air to the branch section; a main body section having a flow passage cross-sectional area at the bottom of the air supply section smaller than the cross-sectional area of ​​the opening, and a drainage guide surface formed from the single flow passage to the multiple flow passages, the downstream end of the drainage guide surface protruding downwardly beyond the upper ends of the multiple flow passages; and a scooped section formed in the main body section and shaped to scoop out the drainage guide surface upward so as to reduce the portion of the drainage guide surface that overlaps with the multiple flow passages in the drainage direction; A piping structure equipped with:

2. The piping structure according to claim 1 , wherein the recessed portion is formed so that the drainage guide surface does not overlap with the plurality of flow paths when viewed from the drainage direction.

3. The piping structure according to claim 1 , wherein a lower end of the drainage guide surface is shaped to linearly connect the plurality of flow paths at a downstream end.

4. Each of the plurality of flow paths has a diameter smaller than that of the single flow path, and the drain guide surface extends from an upper end of the single flow path. The piping structure according to claim 1 .

5. The lower end of the drainage guide surface is disposed at a height of 40% to 60% from the upper ends of the plurality of flow paths at the downstream end. The piping structure according to any one of claims 1 to 4.

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