JP2020020211A - Drainage structure - Google Patents

Abstract

To provide a drainage structure capable of maintaining a water seal in a trap without depending on a vent valve.SOLUTION: The drainage structure of the present invention comprises: wet area equipment; a drainage pipe connected to the wet area equipment; a trap provided in the drainage pipe on a downstream side of the wet area equipment and provided with a storage part in which drainage can be stored; and a filling mechanism for filling the storage part of the trap with water after the drainage is completed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a drainage structure.

In recent years, a so-called siphon drainage structure has been proposed as an alternative to the conventional gradient drainage structure. The siphon drainage structure connects the siphon drainage pipe to the plumbing equipment, and uses the siphon force (negative pressure) generated by the vertical pipe forming the hanging part of the siphon drainage pipe to improve the drainage efficiency from the plumbing equipment. It is a structure to make it.
Here, the siphon drainage structure includes a plumbing device, a drainage pipe connected to the plumbing device, and a trap provided downstream of the plumbing device and having a storage part in which drainage can be accumulated. Can be. In such a siphon drainage structure, in order to prevent the drainage in the trap from decreasing due to the generation of the siphon force and to prevent the breakage of water (breakage), the siphon force is reduced downstream of the portion where the seal water can exist. A vent valve that can take in air when it occurs may be provided (for example, Patent Document 1). The intake of air suppresses the effect of the siphon force on water sealing, and the space between the upstream side and the downstream side of the trap is shut off through the water sealing by the water that has sufficiently accumulated in the trap storage section. (Hereinafter, “the state in which the space between the upstream side and the downstream side of the trap is blocked” is also referred to as “water sealing state”).

JP 2015-98702 A

  By the way, in the above-mentioned drainage structure, a vent valve is provided, for example, to simplify the drainage structure or to cope with a situation in which the vent valve does not operate normally and air intake is not sufficiently performed. A drainage structure that can keep the trap in a sealed state without it or without relying on a vent valve.More specifically, even if water breaks out in the trap due to the generation of siphon force, water is sealed. There is a need for a drainage structure that can be filled.

  The present invention solves the above-mentioned problem, and an object of the present invention is to provide a drainage structure capable of maintaining a trap in a sealed state without using a vent valve.

The drainage structure of the present invention is a trap provided with a plumbing device, a drainage pipe connected to the plumbing device, and a storage portion provided in the drainage pipe downstream of the plumbing device and capable of accumulating drainage. And a filling mechanism for filling the storage portion of the trap with water after drainage is completed.
ADVANTAGE OF THE INVENTION According to the drainage structure of this invention, a trap can be maintained in a water-sealed state irrespective of a ventilation valve.
In the present invention, the "drainage completed" state does not mean a state in which the drainage is strictly exhausted, for example, the user of the plumbing device has finished using the plumbing device and no water is supplied. Later, it means that the inside of the pipe from the plumbing device to the front of the trap is substantially filled with air. Further, it is assumed that “drainage” of “drainage is completed” does not include, for example, drainage that can be temporarily held by a holding unit described later.

  In the drainage structure of the present invention, the filling mechanism has an opening through which a part of the wastewater can flow, and a holding part capable of temporarily holding the wastewater, and a discharge passage for discharging the wastewater held by the holding part. It is preferable to provide: According to this configuration, the trap can be effectively maintained in the water-sealed state without depending on the ventilation valve.

  In the drainage structure according to the aspect of the invention, it is preferable that the drainage structure includes a tubular portion provided on an inner surface of the plumbing device and forming the holding portion together with the inner surface. According to this configuration, the drainage structure can be provided with a filling mechanism effectively.

  In the drainage structure of the present invention, it is more preferable that the tubular portion is provided on a drainage outlet at the bottom of the plumbing device. According to this configuration, the drainage structure is provided with a filling mechanism effectively. be able to.

  In the drainage structure according to the aspect of the invention, it is preferable that the drainage structure further include a tubular portion provided on an inner surface of the drainage pipe and forming the holding portion together with the inner surface. According to this configuration, the drainage structure can be provided with a filling mechanism effectively.

  In the drainage structure according to the aspect of the invention, it is more preferable that the tubular portion be provided detachably. According to this configuration, the drainage structure can be easily provided with the filling mechanism.

In the drainage structure of the present invention, it is preferable that the discharge passage is a through hole formed below a side surface of the tubular portion. According to this configuration, the drainage structure can be provided with a filling mechanism effectively.
Alternatively, in the drainage structure according to the aspect of the invention, it is preferable that the discharge path includes the through hole formed below a side surface of the tubular portion, and a tubular body extending from the through hole. With this configuration also, the drainage structure can be provided with a filling mechanism effectively.

  In the drainage structure according to the aspect of the invention, it is preferable that a volume of the drainage that can be temporarily held by the holding unit is larger than a minimum volume of water for sealing the storage in the storage unit of the trap. According to this configuration, it is possible to surely recover the water sealing even if the water sealing is exhausted.

  ADVANTAGE OF THE INVENTION According to this invention, the drainage structure which can maintain a trap in a water-sealed state irrespective of a ventilation valve can be provided.

It is the schematic which shows an example of the drainage system using the drainage structure which concerns on one Embodiment of this invention. It is sectional drawing which shows the drainage structure which concerns on one Embodiment of this invention, after the drainage is completed and the water-filled state was carried out. FIG. 3 is an enlarged perspective view showing a part of the drainage structure shown in FIG. 2. It is a perspective view which expands and shows a part of 1st modification of the drainage structure shown in FIG. It is a perspective view which expands and shows a part of 3rd modification of the drainage structure shown in FIG. It is sectional drawing which shows the 4th modification of the drainage structure shown in FIG. 2 in the state after drainage was completed and the water-filled state was exhausted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, an example of a drainage system using a drainage structure according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating an example of a drainage system using the drainage structure.
The drainage system 10 shown in FIG. 1 includes a plumbing device 11, a first drainage pipe 12, a trap 13, a straight pipe 14, a horizontal drawing pipe 15, a vertical pipe 16, and a merging pipe connected via a merging joint 17. 18. Specifically, on the floor panel 20 of the house, a plumbing device 11 such as a wash basin is disposed, and the drainage system 10 is connected to the plumbing device 11 from the plumbing device 11. It has a drain pipe 12 and a trap 13 provided on the downstream side of the plumbing device 11 and provided with a storage part in which drainage can be stored.
Next, the drainage system 10 is connected to the downstream side of the trap 13, and is connected to a straight pipe 14 for guiding drainage to the vicinity of the floor slab 21 under the floor panel 20, and is connected to a downstream side of the straight pipe 14, and is connected in a horizontal direction. The extending horizontal drawing pipe 15, a vertical pipe 16 connected to the downstream side of the horizontal drawing pipe 15 and penetrating through the piping hole 22 of the floor slab 21, and connected to the downstream side of the vertical pipe 16 via a joint 17. And a merging pipe 18. The horizontal drawing pipe 15 is formed of a pipe thinner than a pipe used for conventional gradient drainage, and is installed substantially horizontally (substantially no gradient). By having such a structure, the drainage flowing from the plumbing device 11 is liable to be filled with the drainage inside the horizontal drawing pipe 15. Wastewater flows in, and siphon power can be generated by flowing the wastewater downward. The lateral drawing pipe 15 is drained by being pulled by the generated siphon force. The siphon force continues to be generated as long as there is drainage, and when the amount of drainage is reduced and air is entrained and the inside of the horizontal drawing tube 15 is not fully filled, the siphon force is not generated.
In addition, the drainage pipe 23 described later of the drainage structure according to the embodiment of the present invention is formed by at least the first drainage pipe 12 and the trap 13 (in the drainage system of this example, the first drainage pipe 12 and the trap 13 A straight pipe 14, a horizontal drawing pipe 15, and a vertical pipe 16) are formed.

  The merging pipe 18 is a pipe having a larger diameter than the horizontal drawing pipe 15 and the vertical pipe 16 and is provided to penetrate a building vertically. As described above, the merging pipe 18 is connected to the drainage flow path from the plumbing device 11, but is also connected to the drainage flow channel from another plumbing device (not shown), and is connected to a septic tank (not shown) on the downstream side. I have.

Next, an example of the drainage structure according to the embodiment of the present invention will be described with reference to FIGS.
The drainage structure according to the embodiment of the present invention includes the plumbing device 11, the drainage pipe 23, and the trap 13 as described above, and further, as shown in FIG. Has a filling mechanism 30 that fills the storage section 131 with water.

  In the present embodiment, the plumbing device 11 only needs to perform drainage, and the type thereof is not particularly limited. A kitchen sink, a dishwasher, a wash basin, a washing machine, a bathtub provided in a bath such as a unit bath, and the like A washing place, a toilet, etc. can be mentioned, and other things may be used.

In the present embodiment, the drain pipe 23 is connected to a drain port on the bottom of the plumbing device 11. The drainage pipe 23 has a trap 13 provided with a storage part 131 in the middle of the flow path (in the drainage pipe 23 on the downstream side of the plumbing device 11) in which drainage can accumulate.
In the example of FIG. 2, the drain pipe 23 is connected to a first folded portion 132, which is folded downward from the lower side toward the downstream side and rises upward, and to the downstream side of the first folded portion 132, And a second folded portion 133 that is folded back toward the bottom and goes down.
More specifically, in the example of FIG. 2, the drain pipe 23 is connected to at least the first drain pipe 12 connected to the drain port of the plumbing device 11 and the downstream side of the first drain pipe 12. A downstream drain pipe 134, a first folded portion 132 connected to the downstream side of the downstream drain pipe 134, an upstream drain pipe 135 connected to the downstream side of the first folded portion 132, The second folded portion 133 connected to the downstream side of the upstream drainage pipe 135 (that is, the second folded portion 133 is indirectly connected to the first folded portion 132 via the upstream drainage pipe 135) ), And a second drain pipe 136 connected to the downstream side of the second turn-up portion 133.
In the example of FIG. 2, the storage section 131 in which the drainage can be stored is configured to include the first folded section 132. More specifically, the storage section 131 is provided as a down drain pipe 134, a first folded section 132, and an up drain pipe 135.
The trap 13 is formed by a down drain pipe 134, a first folded section 132, an up drain pipe 135, and a second folded section 133.
In the illustrated example, a ventilation valve is not connected to the pipe on the downstream side of the sealed water, but a ventilation valve may be provided on the downstream side of the storage section 131.

  The trap 13 is an S-shaped trap in the example of FIG. 2, and is, for example, a resin molded product. In the storage portion 131 of the trap 13, water (sealed water) is stored in a normal state where water is not drained. Then, the sealed water sufficiently accumulates in the first folded portion 132, and the space between the upstream side and the downstream side of the trap 13 is shut off through the sealed water (also referred to as a sealed state), so that the downstream of the trap 13 is closed. The odor emitted from the side and the pests climbing from the downstream side can be prevented from reaching the plumbing equipment 11.

  In the present embodiment, the filling mechanism 30 is not particularly limited as long as it fills the storage portion 131 of the trap 13 with water after drainage is completed, but as shown in FIG. It is possible to provide a mechanism including a holding unit 31 having a simple opening 311 and capable of temporarily holding drainage, and a discharge path 32 for discharging the drainage held by the holding unit 31.

The operation and effect of the drainage structure according to the embodiment of the present invention will be described.
In the conventional drainage structure, to prevent the generated siphon force from affecting the trap and causing breakage in the trap, it is necessary to provide a vent valve downstream of the portion where the seal can exist. is there. The ventilation valve allows air to be taken in when a siphon force is generated, and the introduced air returns the pressure in the piping near the ventilation valve (for example, in the piping downstream of water sealing) to normal pressure. The sealed condition is maintained.
On the other hand, in the drainage structure according to the embodiment of the present invention, the drainage structure has the filling mechanism 30 that fills the storage portion 131 of the trap 13 with water after the drainage is completed. When the user finishes using the water and the drainage is no longer supplied to the trap 13, even if the trap 13 breaks due to the remaining siphon force, the water is subsequently sealed by the holding unit 31. Can be filled. That is, the trap 13 can be maintained in the water-sealed state without providing the vent valve in the drainage structure, or irrespective of the ventilated valve even if the vent valve provided in the drainage structure does not operate normally. .

  When the filling mechanism 30 includes, for example, the above-described holding unit 31 and the discharge path 32, a part of the drainage when the plumbing device 11 is used in the holding unit 31, for example. Flows through the opening 311 of the holding unit 31 and temporarily holds the drainage (the drainage accumulates in the holding unit 31). Then, even if the drainage stops being supplied to the trap 13 and the trap 13 runs out of water, the drainage retained by the holding unit 31 is supplied to the storage unit 131 of the trap 13 via the discharge path 32 and sealed. It becomes possible to fill with water.

  Here, in the present embodiment, as shown in the example of FIG. 2, the holding portion 31 is formed by the inner surface of the water-drainage device 11 and the tubular portion 111 provided on the inner surface of the water-drainage device 11. be able to. Since the plumbing device 11 is provided with the tubular portion 111 in this manner, the plumbing device is opened through the opening 311 of the holding portion 31 formed by the upper end portion of the tubular portion 111 and the inner surface of the plumbing device 11. A part of the drainage when using 11 flows into the holding unit 31, and the holding unit 31 temporarily holds the drainage. By forming the holding portion 31 in this way, the holding portion 31 can temporarily easily hold the drainage without obstructing the flow of the drainage to the drainage port. Can be prepared.

  In the example of FIG. 2, the cylindrical portion 111 is detachably provided on the drain port at the bottom of the plumbing device 11 from the viewpoint of more easily providing the filling mechanism in the drain structure. Further, the cylindrical portion 111 can be made of, for example, a resin, and the inner diameter thereof is substantially the same as that of the first drain pipe 12. The inner diameter and the outer diameter of the cylindrical portion 111 are the same as those of the cylindrical portion 111. Are substantially constant in the axial direction. The cylindrical portion 111 has a circular cross section (a cylindrical shape as a whole) in the illustrated example, but may have an arbitrary shape.

As shown in the example of FIG. 2, the drainage port of the plumbing device 11 has a cutout having an inner diameter that is the same as or slightly larger than the outer diameter of a portion attached to the drainage port of the tubular portion 111. Thereby, the cylindrical portion 111 and the drain port can be fitted. Further, in order to perform the fitting more securely, for example, a rubber packing can be attached to a portion where the tubular portion 111 is attached to the drain port.
In the example of FIG. 2, the tubular portion 111 is detachable from the drainage structure as described above. For example, the plumbing device 11 and the tubular portion 111 may be integrated, or the drainage pipe may be drained. The drain pipe 23 and the cylindrical portion 111 can be integrated by passing the drain 23 through the drain port of the plumbing device 11.

In the present embodiment, as shown in FIGS. 2 and 3, the discharge path 32 is a through hole 33 formed below the side surface of the tubular portion 111. Therefore, it is possible to more effectively provide the drainage structure with the filling mechanism. In addition, “below” the side surface of the cylindrical portion 111 means a lower portion in a state where the cylindrical portion 111 is attached to the plumbing device 11, and the lower portion of the side surface of the cylindrical portion 111 is a through hole 33. It is a portion of the side surface of the cylindrical portion 111 near the drain port of the plumbing device 11.
In addition, in the illustrated example, as shown in FIG. 3, the discharge path 32 includes a row of a plurality of circular through holes 33 (three in the figure) arranged in the axial direction of the cylindrical portion 111. It is formed by providing it around. However, the discharge path 32 is not limited to the shape and number in the example shown in the figure, and further to the arrangement form. The mesh may be formed arbitrarily, such as a mesh formed on a part (for example, below the side surface) or all of the part 111.

  In the present embodiment, as shown in FIG. 2, the volume (maximum volume) of the drainage that can be temporarily held by the holding unit 31 is the minimum amount of water that is required to be in the sealed state in the storage unit 131 of the trap 13. It is larger than the volume. In other words, as shown in FIG. 2, the volume of the donut-shaped holding portion 31 formed by the inner side surface of the plumbing device 11 and the cylindrical portion 111 is a part of the volume of the first folded portion 132. In the cross-sectional view of FIG. 2, the first folded portion 132 is moved from the bottom point (the lowest point in the drawing) of the inner surface on the outer peripheral side (the lower portion in the drawing) of the first folded portion 132. The volume is larger than the volume up to the bottom point (the lowest point in the figure) of the inner surface on the inner peripheral side (the upper part in the figure). This makes it possible to reliably recover the water sealing even when the water sealing is exhausted. The minimum volume of water to be in the sealed state in the storage section 131 of the trap 13 can vary depending on the size of the pipe used for the drainage structure, and therefore, the drainage that the holding section 31 can temporarily hold. Can also vary. In the present embodiment, the volume of the drainage that can be temporarily held by the holding unit 31 is equal to the maximum amount of water that can be sealed in the storage unit 131 of the trap 13 from the viewpoint of more surely sealing the water. It is more preferable that the volume is larger than the volume (the maximum volume of water to be in a sealed state in the storage portion 131 of the trap 13 is defined by the first folded portion 132 and the The volume of the storage portion 131 up to the vertex of the inner surface (the lowermost portion in the drawing) of the inner surface of the second folded portion 133 (the lower portion in the drawing).)

  In the example shown in FIG. 2, the plumbing device 11 has a wall surface 112 and a gentle slope 113 slightly inclined from the horizontal direction so that the drainage flows toward the drainage port in the cross-sectional view of FIG. 2. Further, a concave portion 114 having a shape depressed downward from the gentle inclined portion 113 is provided. Since the plumbing device 11 has the concave portion 114, the drainage can be easily held by the holding portion 31.

  In the example shown in FIG. 2, the opening 311 of the holding portion 31 and the opening of the cylindrical portion 111 are not covered, and, for example, a lid for removing dust in drainage is not provided. In order to reduce the inflow of dust into the base 31, a lid having a mesh shape or a grid shape can be arranged.

When the filling mechanism 30 includes the holding unit 31 and the discharge path 32, the area of the opening of the discharge path 32 (when there are a plurality of discharge paths 32 as shown in FIG. Is preferably 4 to 50 mm ^2, and more preferably, the entire area of the opening of the discharge passage 32 is 9 to 18 mm ² . By setting the entire area of the opening of the discharge passage 32 to 4 mm ² or more, the drainage held by the holding portion 31 can be effectively discharged from the discharge passage 32, and all of the opening of the discharge passage 32 By setting the area to 50 mm ² or less, when the siphon force in the trap 13 is removed, the holding portion 31 can effectively hold drainage. The “area of the opening of the discharge path” refers to the area of the opening that opens to the outside of the opening inside and outside of the holding portion 31 of the discharge path 32.

  Here, as a first modification of the drainage structure of the drainage structure of the embodiment illustrated in FIGS. 2 and 3, as shown in FIG. And a tubular body 34 extending from the through hole 33. Specifically, the number of the discharge paths 32 in the discharge path 32 illustrated in FIG. 4 is smaller than the number of the discharge paths 32 illustrated in FIG. Further, in the discharge path 32 illustrated in FIG. 4, the opening area per discharge path 32 (through hole 33) is relatively larger than that of the discharge path 32 (through hole 33) in FIG. Further, the discharge path 32 illustrated in FIG. 4 has a tubular body 34 extending from the through hole 33, and the tubular body 34 is arranged so as to extend around the cylindrical portion 111 along the bottom surface of the holding portion 31. . In the modification illustrated in FIG. 4, drainage of the holding unit 31 is performed by drainage flowing into the opening at the end of the tubular body 34 and discharging from the through hole 33 of the tubular part 111. . By forming the discharge path 32 with the through hole 33 and the tubular body 34, the tubular body 34 can also serve as a holding unit. In the example of FIG. 4, the discharge of the drainage to the outside of the holding unit 31 is performed by the drainage flowing from the axial end of the tubular body 34. One or a plurality of openings may be provided at an arbitrary location other than the end portion (for example, in the middle of the tubular body 34) on the vertically upper side wall of the tubular body 34 to further facilitate drainage. .

  Further, as a second modified example in which the drainage path 32 of the drainage structure of the embodiment illustrated in FIGS. 2 and 3 is modified, although not shown, for example, the plumbing device 11 in which the holding portion 31 is formed is illustrated. A groove extending toward the drain port and opening to the drain port is formed on the surface of the bottom of the cylinder so that the cylindrical portion (which may or may not have a through hole) covers the groove ( By providing the drainage device 32 on the bottom surface of the plumbing device 11 so that the inside of the groove is not blocked, the discharge passage 32 can be a groove on the bottom surface of the plumbing device 11. Alternatively, the bottom part of the plumbing device 11 that forms the holding part 31 and the first drain pipe 12 may be a communication part that communicates with, for example, a tubular body.

  In addition, as a third modified example in which the filling mechanism of the drainage structure of the embodiment illustrated in FIGS. 2 and 3 is modified, the holding unit 31 and the discharge path 32 illustrated in FIGS. As shown in FIG. Specifically, as shown in FIG. 5, by providing the holding portion 31 with the partial cylindrical portion 115 cut in the axial direction on the inner side surface of the water circulating device 11, the inner surface of the water circulating device 11 and the partial cylindrical portion are provided. 115, and the discharge passage 32 can be a through hole formed below the side surface of the partial cylindrical portion 115.

Next, a fourth modification in which the drainage structure of the embodiment illustrated in FIGS. 2 and 3 is modified will be described with reference to FIG.
In the embodiment illustrated in FIGS. 2 and 3, the cylindrical portion 111 is provided on the inner side surface of the plumbing device 11. In the fourth modification illustrated in FIG. 6, the cylindrical portion 121 is attached to the drain pipe 23. Provided. That is, in the fourth modified example illustrated in FIG. 6, the holding unit 31 is formed by the inner surface of the drain pipe 23 and the cylindrical part 121 provided on the inner surface of the drain pipe 23. Specifically, as shown in FIG. 6, the cylindrical portion 121 of the second modified example has a lower portion whose diameter decreases from one axial end side (downstream side of the drain pipe 23 in the drawing) of the cylindrical portion 121. And an upper portion having a substantially constant diameter. The lower portion has a discharge passage 32, and the upper portion mainly forms a volume for holding the drainage of the holding portion 31 together with the inner side surface of the drainage pipe 23. Since the drainage pipe 23 has the tubular portion 121 in this manner, the water sealing in the trap 13 can be maintained without providing a filling mechanism in the plumbing device 11.

  As shown in FIG. 6, the cylindrical portion 121 is provided detachably from the drain pipe 23 from the viewpoint of maintenance of the filling mechanism 30. Further, the tubular portion 121 is provided at the upstream end of the drain pipe 23 from a similar viewpoint. The cylindrical portion 121 has a circular cross section (a cylindrical shape as a whole) in the illustrated example, but may have any shape. In the example of FIG. 6, the tubular portion 121 is detachable from the drain pipe 23 as described above. However, for example, the drain pipe 23 and the tubular portion 121 may be integrated.

  In the fourth modification illustrated in FIG. 6, the discharge path 32 is a through hole formed in a lower portion of the cylindrical portion 121 (in the drawing, a through hole is provided in the entire lower portion). However, the shape, number, and arrangement of the through holes can be arbitrarily set.

  As described above, the embodiments of the present invention have been described with reference to the drawings. However, the drainage structure of the present invention is not limited to the above example, and can be appropriately modified. Further, the present invention can be applied to a siphon drainage system, but can also be applied to a conventional drainage system other than the siphon drainage system.

  ADVANTAGE OF THE INVENTION According to this invention, the drainage structure which can maintain the water sealing in a trap independently of a ventilation valve can be provided.

10: Drainage system, 11: Plumbing equipment, 111: Tubular part, 112: Wall surface, 113: Slowly inclined part, 114: Concave part, 115: Partial cylindrical part, 12: First drain pipe, 13: Trap, 131: Reservoir, 132: first turn-back part, 133: second turn-back part, 134: down drain pipe, 135: up drain pipe, 136: second drain pipe 136, 14: straight pipe, 15: horizontal draw pipe , 16: vertical pipe, 17: merging joint, 18: merging pipe, 20: floor panel, 21: floor slab, 22: pipe hole, 23: drain pipe 30: filling mechanism, 31: holding section, 32: discharge path 311: Opening (of the holding portion) 33: Through hole 34: Tubular body 121: Tubular portion

Claims (9)

  A plumbing device, a drain pipe connected to the plumbing device, a trap provided in the drain pipe on the downstream side of the plumbing device, and a trap provided with a storage portion capable of accumulating drainage, and after drainage is completed A filling mechanism for filling the storage portion of the trap with water. The filling mechanism,
A holding portion having an opening through which a part of the drainage can flow and capable of temporarily holding the drainage,
A discharge path for discharging the waste water held by the holding unit,
The drainage structure according to claim 1, comprising:   The drainage structure according to claim 2, further comprising: a tubular portion provided on an inner surface of the plumbing device and forming the holding portion together with the inner surface.   The drainage structure according to claim 3, wherein the tubular portion is provided on a drainage outlet at a bottom of the plumbing device.   The drainage structure according to claim 2, further comprising: a tubular portion provided on an inner surface of the drainage pipe and forming the holding portion together with the inner surface.   The drainage structure according to any one of claims 3 to 5, wherein the tubular portion is detachably provided.   The drainage structure according to any one of claims 3 to 6, wherein the discharge path is a through hole formed below a side surface of the tubular portion.   The drainage structure according to any one of claims 3 to 6, wherein the discharge path includes the through hole formed below a side surface of the cylindrical portion, and a tubular body extending from the through hole.   The drainage according to any one of claims 2 to 8, wherein a volume of the drainage that can be temporarily held by the holding unit is larger than a minimum volume of water to be in a sealed state in the storage unit of the trap. Construction.

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