Piping structure

Abstract

To provide piping structure that enhances an effect of water stopping performance against water immersion from the outside.SOLUTION: A piping structure comprises: a sheath pipe 21 that has an outdoor-side opening part that is embedded in a foundation and opens to an outdoor-side surface of the foundation, and an indoor-side opening part that opens to an indoor-side surface of the foundation; a drainage pipe 26 that is disposed inside the sheath pipe 21 and has a socket part 28A at least on an outdoor-side; a packing 50 that is installed between the outdoor-side opening part 2 and the socket part 28A; and a first spacer 60A that is installed between the sheath pipe 21 and the drainage pipe 26. The first spacer 60A has a spacer inner surface 60b in contact with the drainage pipe 26 and a spacer outer surface 60a in contact with the sheath pipe 21.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A conventional foundation penetration pipe is described in Patent Document 1. The foundation penetration pipe includes a sheath pipe that is buried in the foundation and has both ends that open to the outdoor surface of the foundation and the outdoor surface of the foundation, a drain pipe that is placed inside the sheath pipe and has a socket at the outdoor end, and a packing that is provided between the sheath pipe and the socket. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-159938 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional foundation penetration piping has room for improvement in terms of improving the waterproofing effect against water intrusion from the outside.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a piping structure that enhances the waterproofing effect against water intrusion from the outdoors. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention has the following aspects. (1) A piping structure comprising: a sheath pipe buried in a foundation and having an outdoor opening that opens to the outdoor surface of the foundation and an indoor opening that opens to the indoor surface of the foundation; a drain pipe arranged inside the sheath pipe and having a receiving portion on at least the outdoor side; a gasket installed between the outdoor opening and the receiving portion; and a first spacer installed between the sheath pipe and the drain pipe, wherein the first spacer has an inner spacer surface that contacts the drain pipe and an outer spacer surface that contacts the sheath pipe. (2) In the above (1), the drain pipe has a concave or convex engaging portion on the outer surface of the drain pipe, The first spacer may have, on the inner surface of the spacer, a convex or concave locked portion corresponding to the locking portion. (3) In the above (1) or (2), the first spacer may have a tapered guide surface at its tip. (4) In any one of the above (1) to (3), the first spacer may have a higher modulus of elasticity than the packing. (5) In any one of the above (1) to (4), the first spacer may be composed of at least a first divided piece and a second divided piece. (6) In any of (1) to (5) above, a second spacer may be installed between the sheath pipe and the drain pipe, the sheath pipe having a curved pipe portion between the outdoor opening and the indoor opening, and the second spacer may be positioned between the first spacer and the curved pipe portion. (7) In any of (1) to (6) above, a third spacer may be provided between the sheath pipe and the drain pipe, the first spacer being positioned at the outdoor opening, and the third spacer being positioned at the indoor opening. [Effects of the Invention]

[0007] According to the present invention, a piping structure can be provided that enhances the waterproofing effect against water intrusion from the outdoors. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a cross-sectional view schematically illustrating a piping structure according to an embodiment of the present invention, taken along the axial direction of a drainage pipe. [Figure 2] FIG. 2 is a detailed view of the α portion of FIG. [Figure 3] 1 is a cross-sectional view along the pipe axis direction of a drainage pipe, schematically showing a packing that constitutes a piping structure according to one embodiment of the present invention. FIG. [Figure 4] 1 is a cross-sectional view along the pipe axis direction of a drainage pipe, schematically showing a spacer that constitutes a piping structure according to one embodiment of the present invention. [Figure 5] 1 is an exploded front view of a spacer constituting a piping structure according to an embodiment of the present invention; [Figure 6] 1 is an assembled front view of a spacer constituting a piping structure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Piping structure] A piping structure 20 according to one embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of the piping structure 20 according to one embodiment of the present invention, taken along the pipe axis direction X of the drain pipe 26. FIG. 2 is a detailed view of the α portion of FIG. 1. FIG. 3 is a schematic cross-sectional view of a gasket 50 constituting the piping structure 20 according to one embodiment of the present invention, taken along the pipe axis direction X of the drain pipe 26. FIG. 4 is a schematic cross-sectional view of a spacer 60 constituting the piping structure 20 according to one embodiment of the present invention, taken along the pipe axis direction X of the drain pipe 26. FIG. 5 is an exploded front view of the spacer 60 constituting the piping structure 20 according to one embodiment of the present invention. FIG. 6 is an assembled front view of the spacer 60 constituting the piping structure 20 according to one embodiment of the present invention.

[0010] As shown in Fig. 1, a piping structure 20 of this embodiment is applied to a foundation 12 of a building 11 such as a house. The piping structure 20 connects a drainage fixture arranged inside the building 11 to a drainage basin arranged outside the building 11. The piping structure 20 discharges wastewater from the drainage fixture into the drainage basin. Examples of drainage fixtures include toilets, vanities, and bathrooms.

[0011] The foundation 12 has a pressure-resistant plate 13 provided on the ground G and a rising portion 14 standing upward from the outer edge of the pressure-resistant plate 13. In this example, the outer surface 13a of the pressure-resistant plate 13 and the outer surface 14a of the rising portion 14 are flush with each other. The lower part of the pressure-resistant plate 13 is buried in the ground G. The upper part of the rising part 14 is connected to a wall 15. For example, the pressure-resistant plate 13 and the rising part 14 are integrally formed from reinforced concrete or the like.

[0012] The piping structure 20 includes a sheath pipe (piping material) 21, a drain pipe (inner pipe material) 26, a packing 50, and spacers 60 (first spacer 60A, second spacer 60B, third spacer 60C). Hereinafter, the pipe axis direction X of the sheath pipe 21 may be simply referred to as the axial direction.

[0013] (sheath tube) The sheath pipe 21 is buried in the foundation 12. Both ends of the sheath pipe 21 open to the outdoor surface of the foundation 12 and the outdoor surface of the foundation 12, respectively. That is, the sheath pipe 21 has an outdoor opening 21e that opens to the outdoor surface of the foundation 12 and an indoor opening 21i that opens to the indoor surface of the foundation 12. In the illustrated example, the sheath tube 21 opens to both the outer surface 13 a and the top surface 13 b of the pressure-resistant platen 13 .

[0014] The sheath pipe 21 has a first straight pipe section 22, a curved pipe section (bent pipe section) 23, and a second straight pipe section 24. The first straight pipe section 22, the second straight pipe section 24, and the curved pipe section 23 are integrally molded from a resin such as polyvinyl chloride. The curved pipe section 23 is formed by bending a pipe into a curved shape. The pipe axis direction X of the curved pipe section 23 follows, for example, an arc shape having a predetermined curvature. The first straight pipe section 22 and the second straight pipe section 24 are formed into a tubular shape that extends straight. The first straight pipe section 22 is connected to a first end, which is one end of the curved pipe section 23. The second straight pipe section 24 is connected to a second end, which is the other end of the curved pipe section 23.

[0015] The end of the first straight pipe section 22 that is not connected to the curved pipe section 23 opens to the outer surface 13a of the pressure-resistant plate 13. The end of the second straight pipe section 24 that is not connected to the curved pipe section 23 opens to the upper surface 13b of the pressure-resistant plate 13. It is preferable that anti-termite tape 41 be attached to the outer circumferential surface of sheath pipe 21. For example, anti-termite tape 41 is a thin, plate-shaped, non-vulcanizing adhesive plastic body made of butyl rubber. Anti-termite tape 41 is attached to the end of sheath pipe 21 that is closest to the interior of building 11.

[0016] (drain pipe) Drain pipe 26 is disposed inside sheath pipe 21. Drain pipe 26 includes a pipe body 27, a first socket 28, and a second socket 29. Drain pipe 26 may include a connecting member 25 that connects first socket 28 and pipe body 27. Drain pipe 26 may also include a connecting member (not shown) that connects second socket 29 and pipe body 27. 2, the connecting member 25 may connect the first socket 28 and the pipe main body 27 by spanning the first socket 28 and the pipe main body 27 and fitting into recesses and projections formed on their outer peripheral surfaces. The connecting member 25 has, for example, recesses and projections (annular grooves 25Q1) on its inner peripheral surface 25b that correspond to the locking protrusions 26P formed on the outer peripheral surface of the first socket 28. The connecting member 25 has, for example, recesses and projections (annular grooves 25Q2) on its inner peripheral surface 25b that correspond to the recesses and projections formed on the outer peripheral surface of the pipe main body 27. The connecting member 25 has a locking portion 25p that fits into a locked portion 60Q formed on the inner surface of the spacer 60.

[0017] The pipe body 27 is a flexible pipe having flexibility. The pipe body 27 is deformable in the radial direction of the pipe body 27. The pipe body 27 has both a predetermined bending property (flexibility) and a predetermined strength property. The pipe body 27 may have a structure including, for example, a long cylindrical base portion and a plurality of rib portions formed at intervals along the longitudinal direction of the base portion on the outer circumferential surface of the base portion, or a so-called bellows structure. In this case, it is preferable to form the base portion from a flexible material such as polyethylene resin. The bellows structure of the pipe body 27 may have, as shown in FIG. 2, rib portions (protrusions) that are annularly bulging outward and have a relatively large outer diameter, and groove portions (recesses) that are annularly bulging and have a relatively small outer diameter, alternately formed. The inner surface of the pipe body 27 may be flat without any irregularities.

[0018] The first socket 28 and the second socket 29 are provided at both ends of the pipe body 27, respectively. The first socket 28 is provided at the outdoor end of the pipe body 27. The second socket 29 is provided at the indoor end of the pipe body 27. The first socket 28 is disposed within the end 22a of the first straight pipe section 22. The second socket 29 is disposed within the end 24a of the second straight pipe section 24. In the illustrated example, a portion of the second socket 29 protrudes from the end 24a to the outside of the sheath pipe 21.

[0019] The first socket 28 and the second socket 29 are both receiving ports. A first connecting pipe 31 is connected to the first socket 28. The first connecting pipe 31 is also connected to a drain box. A second connecting pipe 32 is connected to the second socket 29. The second connecting pipe 32 is also connected to a drain fixture.

[0020] As shown in FIGS. 1 and 2, a protrusion 28a is provided on the outer peripheral surface of the first socket 28. The protrusion 28a abuts against a second base portion 52 (described later) of the packing 50 in the axial direction to restrict movement of the packing 50. The protrusion 28a is provided around the entire circumferential direction of the first socket 28. Only one protrusion 28a is provided in the axial direction. In other words, multiple protrusions 28a are not lined up in the axial direction. When the protrusion 28a is viewed in a cross section passing through the axis of the first socket 28, the protrusion 28a is formed in a rectangular shape. The protrusion 28a is preferably provided on the outer surface of the receiving portion 28A of the first socket 28 to restrict the position of the packing 50.

[0021] The protrusion 28a may extend continuously around the entire circumference in the circumferential direction, or may be arranged discontinuously around the entire circumference in the circumferential direction. There may be only one protrusion 28a in the circumferential direction, or multiple protrusions 28a may be arranged in the circumferential direction. The first socket 28 or the second socket 29 is formed by, for example, injection molding a resin into a mold.

[0022] (rubber seal) As shown in Figures 1 and 2, the packing 50 is provided between the outdoor opening 21A of the sheath pipe 21 and the outdoor receiving portion 28A of the first socket 28 that constitutes the drain pipe 26. The packing 50 prevents water from entering between the sheath pipe 21 and the first socket 28 and between the sheath pipe 21 and the drain pipe 26. The packing 50 may also function as an anti-termite packing. The packing 50 is formed, for example, from SBR (styrene butadiene rubber) or the like.

[0023] As shown in FIGS. 2 and 3, the packing 50 includes a first base portion 51, a second base portion 52, an outer surface side projection 53, an inner surface side projection 54, and a stopper 55.

[0024] The first base portion 51 is fitted between the sheath tube 21 and the first socket 28. The first base portion 51 is cylindrical. The outer peripheral surface of the first base portion 51 contacts (closely contacts) the inner peripheral surface of the sheath tube 21. The inner peripheral surface of the first base portion 51 contacts (closely contacts) the outer peripheral surface of the first socket 28.

[0025] The second base 52 is a portion of the packing 50 that supports the outer surface side protrusions 53 and the inner surface side protrusions 54 (a portion that forms the base of the outer surface side protrusions 53 and the inner surface side protrusions 54). The second base 52 is annular. The second base 52 protrudes axially from the first base 51. The second base 52 is located on the indoor side of the first base 51. The second base 52 is disposed between the inner circumferential surface of the sheath tube 21 and the outer circumferential surface of the first socket 28. In this embodiment, the packing inner circumferential surface 52b of the second base 52 is in contact (close contact) with the outer circumferential surface of the first socket 28. In addition, there are portions of the packing outer circumferential surface 52a of the second base 52 that are not in contact with the inner circumferential surface of the sheath tube 21, making it easier to insert the packing 50.

[0026] The outer surface projection 53 is annular. The outer surface projection 53 projects from the second base 52 toward the inner peripheral surface of the sheath tube 21. The outer surface projection 53 is a protrusion that projects radially outward from the packing outer peripheral surface 52a of the second base 52 (the surface facing the inner peripheral surface of the sheath tube 21). In this embodiment, a plurality (two) of the outer surface projections 53 are arranged at intervals in the axial direction of the first socket 28, but this is not limiting and at least one or more projections may be provided. It is preferable that the tip of each outer surface projection 53, which is the end on the outer side in the radial direction (toward the sheath tube 21), is in contact (close contact) with the inner circumferential surface of the sheath tube 21. Each outer surface projection 53 gradually becomes thinner from the inner side toward the outer side in the radial direction of the first socket 28.

[0027] The inner surface side protrusion 54 is annular. The inner surface side protrusion 54 protrudes from the second base 52 toward the outer peripheral surface of the first socket 28. The inner surface side protrusion 54 is a protrusion that protrudes radially inward of the second base 52 from the packing inner peripheral surface (the inner surface facing the outer peripheral surface of the first socket 28) 52b of the second base 52. In the present embodiment, a plurality (two) of the inner surface side protrusions 54 are arranged at intervals in the axial direction of the first socket 28, but this is not limiting and at least one or more protrusions may be provided. It is preferable that the tip of each inner surface protrusion 54, which is the end on the radially inner side (first socket 28 side), is in contact (close contact) with the outer peripheral surface of first socket 28. Each inner surface protrusion 54 gradually becomes thinner from the radially inner side of first socket 28 to the radially outer side. Furthermore, if the watertightness of the inner surfaces of the first socket 28 and the packing 50 is ensured, for example, by making the inner diameter of the second base 52 gradually narrower, the inner surface protrusion 54 does not necessarily have to be provided.

[0028] (spacer) As shown in FIGS. 1 and 2, the piping structure 20 includes a first spacer 60A (spacer 60) that is installed between the sheath pipe 21 and the drain pipe 26. In detail, the piping structure 20 includes a first spacer 60A that is installed between the sheath pipe 21 and the connecting member 25 that constitutes the drain pipe 26. The first spacer 60A is provided between the sheath pipe 21 and the connecting member 25. As shown in Figures 2 and 4, the first spacer 60A has a spacer inner surface 60b that contacts the drain pipe 26 (the connecting member 25 that constitutes the drain pipe 26) and a spacer outer surface 60a that contacts the sheath pipe 21. This allows the drain pipe 26 to be positioned radially relative to the sheath pipe 21, and prevents the drain pipe 26 from becoming eccentric relative to the sheath pipe 21. Therefore, an annular gasket 50 can be inserted and placed in an appropriate position in the annular gap between the sheath pipe 21 and the drain pipe 26, which is secured uniformly around the entire circumference by the first spacer 60A. This improves the water-stopping effect against water seepage from outdoors.

[0029] Specifically, as shown in FIGS. 4 and 5, the first spacer 60A is annular. The outer shape of the first spacer 60A is, for example, a circular shape having an outer diameter corresponding to the inner diameter of the sheath tube 21. The inner shape of the first spacer 60A is, for example, a circular shape having an inner diameter corresponding to the outer diameter of the drain pipe 26 (the connecting member 25 that constitutes the drain pipe 26).

[0030] Here, as shown in FIG. 2, the drain pipe 26 (the connecting member 25 that constitutes the drain pipe 26) has a concave or convex locking portion 25p on the drain pipe outer surface 26a (the outer surface of the connecting member 25 that constitutes the drain pipe 26). The first spacer 60A has a convex or concave locked portion 60Q on the spacer inner surface 60b that corresponds to the locking portion 25p. Here, the locked portion 60Q is an annular groove. The locking portion 25p of the drain pipe 26 is fitted into the locked portion 60Q of the first spacer 60A. Here, the shoulder portion where the outer peripheral surface 25a of the connecting member 25 abuts against the axial end face 25x is the locking portion 25p. As a result, the locked portion 60Q of the first spacer 60A fits into the locking portion 25p of the drain pipe 26, preventing the first spacer 60A from moving relative to the drain pipe 26 along the pipe axis direction X, and appropriately restricting the position of the first spacer 60A relative to the drain pipe 26. The first spacer 60A then restricts radial movement of the drain pipe 26, suppressing eccentricity of the drain pipe 26 relative to the sheath pipe 21. Therefore, an appropriate space for inserting the gasket 50 can be secured between the sheath pipe 21, the drain pipe 26, and the first spacer 60A.

[0031] 2 and 4, the first spacer 60A has a tapered guide surface 65 at its tip in the pipe axis direction X. The guide surface 65 may be a flat surface or a curved surface that increases in diameter from the tip to the center of the first spacer 60A in a cross-sectional view along the pipe axis direction X. The guide surface 65 may be provided not only on the outer circumferential surface of the first spacer 60A, but also on the outer circumferential surface and inner circumferential surface. This reduces resistance that could cause the first spacer 60A to get caught on the sheath pipe 21 or the drain pipe 26 during installation, making it easier to insert and remove the first spacer 60A from the gap between the sheath pipe 21 and the drain pipe 26.

[0032] The first spacer 60A preferably has a higher elastic modulus than the packing 50. Similarly, the first spacer 60A preferably has a higher hardness than the packing 50. The first spacer 60A may be made of a hard plastic, such as polyvinyl chloride, ABS, or polyolefin. This allows the drain pipe 26, inserted into the sheath pipe 21 with the curved pipe portion 23 while undergoing bending deformation, to elastically return to its original straight state before insertion. Even if an eccentric force acts on the drain pipe 26 in an eccentric direction (the direction in which the axis of the drain pipe 26 moves away from the axis of the sheath pipe 21), the eccentric force is received by the first spacer 60A, which has a high elastic modulus, thereby suppressing the eccentric displacement of the drain pipe 26. Therefore, an appropriate space for inserting the packing 50 can be secured between the sheath pipe 21, the drain pipe 26, and the first spacer 60A, and the packing 50, which has a relatively low elastic modulus, can be prevented from being crushed.

[0033] 5 and 6, the first spacer 60A may be composed of at least a first divided piece 61 and a second divided piece 62. That is, the first spacer 60A may be composed of a plurality of pieces divided in the circumferential direction. The number of divisions is not limited to two, and may be three or more. 5 and 6, when the first spacer 60A is composed of two segments, a first segment 61 and a second segment 62, the first segment 61 and the second segment 62 have the same shape. The first segment 61 has an engaging portion 61g for engaging with the engaged portion 62h of the second segment 62, and an engaged portion 61h for engaging with the engaging portion 62g of the second segment 62. Similarly, the second segment 62 has an engaging portion 62g for engaging with the engaged portion 61h of the first segment 61, and an engaged portion 62h for engaging with the engaging portion 61g of the first segment 61. As a result, even after the drain pipe 26 has been placed inside the sheath pipe 21, the annular first spacer 60A can be placed between the sheath pipe 21 and the drain pipe 26 by attaching the first segment 61 and the second segment 62 separately and then engaging them with each other.

[0034] As shown in FIG. 1, the piping structure 20 may further include a second spacer 60B disposed between the sheath pipe 21 and the drain pipe 26. The sheath pipe 21 may have a curved pipe portion 23 between the outdoor opening 21e and the indoor opening 21i. The second spacer 60B may be disposed between the first spacer 60A and the curved pipe portion 23. This allows the drain pipe 26 to be supported at least at two locations in the pipe axis direction X by the first spacer 60A and the second spacer 60B. Therefore, compared to when the drain pipe 26 is supported solely by the first spacer 60A, the pipe axis of the drain pipe 26 can be aligned more parallel to the pipe axis direction X of the sheath pipe 21, thereby further reducing eccentricity of the drain pipe 26 at the outdoor opening 21e. This reduces uneven crushing of the gasket 50 and improves watertightness.

[0035] As shown in FIG. 1, a third spacer 60C may be provided between the sheath pipe 21 and the drain pipe 26. The first spacer 60A may be disposed at the outdoor opening 21e, and the third spacer 60C may be disposed at the indoor opening 21i. This allows the drain pipe 26 to be supported at at least two locations, the outdoor opening 21e and the indoor opening 21i, by the first spacer 60A and the third spacer 60C and bent along the pipe axis direction X. Compared to when the drain pipe 26 is supported solely by the first spacer 60A, the pipe axis of the drain pipe 26 at the outdoor opening 21e can be aligned more parallel to the pipe axis direction X of the sheath pipe 21, thereby further reducing eccentricity of the drain pipe 26 at the outdoor opening 21e. This reduces uneven crushing of the gasket 50 and improves watertightness.

[0036] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0037] The piping structure 20 according to this embodiment includes a sheath pipe 21 buried in a foundation 12 and having an outdoor opening 21e opening to the outdoor surface of the foundation 12 and an indoor opening 21i opening to the indoor surface of the foundation 12, a drain pipe 26 disposed inside the sheath pipe 21 and having a receiving portion 28A at least on the outdoor side, a gasket 50 installed between the outdoor opening 21e and the receiving portion 28A, and a first spacer 60A installed between the sheath pipe 21 and the drain pipe 26. The first spacer 60A has a spacer inner surface 60b that contacts the drain pipe 26 and a spacer outer surface 60a that contacts the sheath pipe 21. This allows the drain pipe 26 to be positioned radially relative to the sheath pipe 21, thereby preventing the drain pipe 26 from becoming eccentric relative to the sheath pipe 21. Therefore, the annular gasket 50 can be inserted and placed in an appropriate position in the annular gap between the sheath pipe 21 and the drain pipe 26, which is secured uniformly around the entire circumference by the first spacer 60A. This improves the watertightness against water seepage from the outdoors. [Explanation of symbols]

[0038] 11 Buildings 12 Basics 13 Pressure-resistant plate 13a External surface 13b Top surface 14 Rising section 14a External surface 15 Wall 20 Piping structure 21 Sheath pipe (piping material) 21A opening 21e Outdoor opening 21i Indoor opening 22 1st straight pipe section 22a (first straight pipe section) end 23 Curved pipe section (bent pipe section) 24 2nd straight pipe section 24a (Second straight pipe section) end 26 Drain pipe (inner pipe material) 26a Outer surface of drain pipe 25p locking part 26P locking protrusion 27 Tube body 28 1st Socket (Socket) 28a protrusion 28A socket part 29 Second socket (socket) 31 1st connecting pipe 32 2nd connecting pipe 41 Anti-termite tape 50 packing 51 1st base 52 Second base 52a Outer surface of packing 52b Inner surface of packing 53 External protrusion 54 Inner surface protrusion 55 Stopper 56 Recess 60 spacer 60a Outer surface of spacer 60b Spacer inner surface 60A First Spacer 60B Second spacer 60C 3rd spacer 60Q Locked part 61 1st division piece 62 Second division piece 61g,62g engaging part 61h,62h Engaged part 65 Guide surface G Ground X Tube axis direction

Claims

1. A sheath pipe that is buried in a foundation and has an outdoor opening that opens to an outdoor surface of the foundation and an indoor opening that opens to an indoor surface of the foundation; A drain pipe disposed inside the sheath pipe and having a receiving portion at least on the outdoor side; a packing installed between the outdoor opening and the receiving port; a first spacer disposed between the sheath pipe and the drain pipe; The first spacer has an inner spacer surface that contacts the drain pipe and an outer spacer surface that contacts the sheath pipe, The drain pipe has a concave or convex engaging portion on the outer surface of the drain pipe, The first spacer has a convex or concave locked portion on the inner surface of the spacer, the locked portion corresponding to the locking portion. Piping structure.

2. A sheath pipe that is buried in a foundation and has an outdoor opening that opens to an outdoor surface of the foundation and an indoor opening that opens to an indoor surface of the foundation; A drain pipe disposed inside the sheath pipe and having a receiving portion at least on the outdoor side; a packing installed between the outdoor opening and the receiving port; a first spacer disposed between the sheath pipe and the drain pipe; The first spacer has an inner spacer surface that contacts the drain pipe and an outer spacer surface that contacts the sheath pipe, The first spacer is composed of at least a first divided piece and a second divided piece. Piping structure.

3. The first spacer has a tapered guide surface at its tip. The piping structure according to claim 1 or 2.

4. The first spacer has a higher elastic modulus than the packing. The piping structure according to any one of claims 1 to 3.

5. a second spacer disposed between the sheath pipe and the drain pipe; The sheath pipe has a curved pipe portion between the outdoor opening and the indoor opening, The second spacer is disposed between the first spacer and the bending tube portion. The piping structure according to any one of claims 1 to 4.

6. a third spacer disposed between the sheath pipe and the drain pipe; the first spacer is disposed at the outdoor opening, The third spacer is disposed at the indoor opening. The piping structure according to any one of claims 1 to 5.

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