Piping structure and prefabricated piping

Abstract

The present invention provides a piping structure that can suppress the reduction in the compressibility of sealing members, and a prefabricated piping system equipped with such a piping structure. [Solution] The piping structure 100 comprises a first piping member 10, a second piping member 20, and a sealing member 30, wherein at least one of the first piping member 10 and the second piping member 20 is made of a resin material, the first piping member 10 has a first tubular portion 11 and a first bulge portion 12, the second piping member 20 has a second tubular portion 21 and a second bulge portion 22, and the first bulge portion 12 has a second bulge portion 22 The first tubular portion 11 has a closed annular groove formed in the circumferential direction of the opening, facing the first tubular portion 12, and the second bulging portion 22 has a closed annular protruding portion that fits into the groove, facing the first bulging portion 12 and formed in the circumferential direction of the opening of the second tubular portion 21, and the sealing member 30 is housed in the groove, and the first piping member 10 and the second piping member 20 are surrounded and fixed from the outer circumference by the closed annular joining member 90, and are in contact with the protruding portion.

Description

Technical Field

[0001] The present invention relates to a piping structure and a prefabricated pipe.

Background Art

[0002] Conventionally, resin piping members have been used as pipes for allowing a fluid to flow therethrough. As a structure for connecting such piping members, there is known a piping structure in which flanges provided at the ends of the piping members are opposed to each other, and the flanges are engaged with each other with a packing (sealing member) sandwiched between the flanges (see, for example, Patent Document 1). As applications of the piping structure, pipes for water supply, hot water supply, drainage, air conditioning, gas, and fuel are known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the piping structure described in Patent Document 1 above, there is a risk that the compression rate of a seal portion, for example, a gasket or packing, installed at the pipe end during use may decrease. This is caused by deformation around the seal portion or a gap between members. At this time, there is a demand for a method that can solve the above problems and minimize the reduction in workability.

[0005] In the above piping, it is effective to use a resin pipe from the viewpoints of construction time and labor. For the joint portion of the above piping, there is a construction method using a housing joint excellent in workability.

[0006] However, as described above, when a resin pipe is used, deformation around the seal portion becomes larger than that of a metal pipe, and it is conceivable that a gap between members with the resin pipe occurs due to the use of a housing joint.

[0007] Based on the above, a method is needed that uses resin pipes and housing joints while suppressing deformation around the sealing area and minimizing the gap between the housing joint and the resin pipe.

[0008] This disclosure is made in view of these circumstances and aims to provide a piping structure that can suppress the reduction in the compressibility of the sealing member. It also aims to provide a prefabricated piping structure equipped with such a piping structure. [Means for solving the problem]

[0009] [1] A first piping member, a second piping member connected to the first piping member, and a closed annular sealing member that is liquid-tightly sandwiched between the first piping member and the second piping member at the connection point between the first piping member and the second piping member, wherein at least one of the first piping member and the second piping member is made of a resin material, the first piping member has a tubular first tubular portion with both ends open and a first bulge portion provided at one end of the first tubular portion, and the second piping member has a tubular second tubular portion with both ends open, and the A piping structure comprising: 2. A tubular portion having a second bulge portion provided at one end and facing the first bulge portion, wherein the first bulge portion has a closed annular recess portion formed in the circumferential direction of the opening of the first tubular portion and facing the second bulge portion, and the second bulge portion has a closed annular convex portion formed in the circumferential direction of the opening of the second tubular portion and facing the first bulge portion, and fitting into the recess portion, the sealing member being housed in the recess portion, the first piping member and the second piping member being surrounded and fixed from the outer circumference by a closed annular joining member, and in contact with the convex portion.

[0010] [2] The piping structure according to [1], wherein the radially inner side of the groove is exposed to the opening of the first tubular portion.

[0011] [3] The piping structure according to [2], wherein the sealing member has a groove that opens on the inner circumference and is continuous in the circumferential direction.

[0012] [4] The piping structure according to [2] or [3], wherein the first tubular portion has a first support projection that protrudes into the interior of the groove portion and supports the sealing member.

[0013] [5] The piping structure according to any one of [2] to [4], wherein the second tubular portion has a second support projection at the tip end of the protruding portion that supports the sealing member from the inner circumference.

[0014] [6] The inner surface of the protruding portion is located on the innermost part of the inner surface of the second piping member. The piping structure according to any one of [2] to [5].

[0015] [7] The connecting member surrounds and fixes the first bulge and the second bulge from the outer circumference at the connection point, and is a closed annular pipe structure according to any one of [1] to [6].

[0016] [8] The inner circumferential surface of the closed annular joint member has a plurality of protrusions, as described in any one of [1] to [6], the piping structure described in any one of the above.

[0017] A prefabricated pipe having the piping structure described in any one of items [9][1] to [8], wherein a fitting made of resin or metal is connected to at least one of the other end of the first tubular section and the other end of the second tubular section. [Effects of the Invention]

[0018] According to this disclosure, it is possible to provide a piping structure that can suppress the decrease in the compressibility ratio of the sealing member. Furthermore, it is possible to provide prefabricated piping equipped with such a piping structure. In addition, it has the effect of not reducing workability. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a schematic perspective view showing the piping structure. [Figure 2] Figure 2 is a cross-sectional view taken along the line segment II-II in Figure 1. [Figure 3]Figure 3 is an enlarged end view of the connection point of the piping structure. [Figure 4] Figure 4 is a partial end view for explaining the piping structure. [Figure 5] Figure 5 is a partial end view for explaining the piping structure. [Figure 6] Figure 6 is a partial end view for explaining the piping structure. [Figure 7] Figure 7 is a partial end view showing the structure for preventing the packing from falling off. [Figure 8] Figure 8 is a partial end view showing the structure for preventing the packing from falling off. [Figure 9] Figure 9 is a partial end view showing the structure for preventing the packing from falling off. [Figure 10] Figure 10 is a partial end view showing the structure for preventing the packing from falling off. [Figure 11] Figure 11 is a cross-sectional view of a piping member having a joint. [Figure 12] Figure 12 is a cross-sectional view showing an example of the prefabricated piping of the first embodiment. [Figure 13] Figure 13 is a partial end view of the piping structure according to the second embodiment. [Figure 14A] Figure 14A is a cross-sectional view showing the protrusion of the joining member. [Figure 14B] Figure 14B is a cross-sectional view showing the protrusion of the joining member. [Figure 15] Figure 15 is a partial end view of the piping structure according to the third embodiment.

Mode for Carrying Out the Invention

[0020] [First Embodiment] Hereinafter, the piping structure and the prefabricated piping according to the first embodiment of the present disclosure will be described with reference to FIGS. 1 to , 14A, and 14B. In all the following drawings, for the sake of clarity of the drawings, the dimensions and ratios of each component are appropriately different.

[0021] [Piping Structure] Figure 1 is a schematic perspective view showing the piping structure 100. Figure 2 is a cross-sectional view taken along the line segment II-II in Figure 1.

[0022] As shown in Figures 1 and 2, the piping structure 100 comprises a first piping member 10, a second piping member 20, and a packing (sealing member) 30. In the piping structure 100, the first piping member 10 and the second piping member 20 are connected. The packing 30 is sandwiched at the connection point between the first piping member 10 and the second piping member 20. Note that in the piping structure 100 shown in Figures 1 and 2, the packing 30 is not sandwiched between the first piping member 10 and the second piping member 20. The following explains the process step by step.

[0023] 《First Piping Component》 The first piping member 10 according to this embodiment is a pipe material having an internal space 10S and formed from a resin material. A thermoplastic resin can be suitably used as the resin material constituting the first piping member 10. The thermoplastic resin can be arbitrarily set to rigid polyvinyl chloride resin, ABS, AES, etc., but for example, from the viewpoint of seismic resistance and durability, a polyolefin resin is preferred.

[0024] Piping components made from polyolefin resin (polyolefin resin pipes) have a higher tensile elongation at break, as measured according to JIS K 6815-1 and JIS K 6815-3, compared to piping components made from rigid polyvinyl chloride (rigid polyvinyl chloride resin pipes). While the tensile elongation at break of rigid polyvinyl chloride pipes is 50-150%, the tensile elongation at break of polyolefin resin pipes is 350% or more. In particular, when using high-density polyethylene pipes of PE100 using the extrapolation method specified in ISO / TR9080, the tensile elongation at break is 500% or more. Therefore, for example, damage to the first piping component 10 due to an earthquake can be suppressed.

[0025] Furthermore, while the polyolefin resin is not particularly limited, examples of suitable polyolefin resins include polypropylene, polybutene, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, atactic polypropylene, isotactic polypropylene, syndiotactic polypropylene, and poly-αolefin.

[0026] The melt mass flow rate (MFR) of the thermoplastic resin is preferably, for example, 0.1 to 25 g / 10 min, more preferably 0.1 to 10 g / 10 min, and even more preferably 0.29 to 0.45 g / 10 min. If the MFR is above the lower limit, molding becomes easier. If the MFR is below the upper limit, thermal stability can be further improved. MFR can be measured according to JIS K 7210:1999, at a test temperature of 220°C and a test load of 10 kg.

[0027] The specific gravity of thermoplastic resins is, for example, 942-953 kg / m³. 3 It is preferable. The specific heat of the thermoplastic resin is preferably, for example, 1.9 to 2.3 kJ / kg·K. The thermal conductivity of the thermoplastic resin is preferably, for example, 0.46 to 0.5 W / m·K.

[0028] The melting point of the thermoplastic resin (i.e., the melting temperature of the first piping member 10) is preferably 150°C to 260°C, and more preferably 180°C to 240°C.

[0029] The above-mentioned resin material may contain, in addition to thermoplastic resin, known additives such as pigments, ultraviolet absorbers, antioxidants, and lubricants, as well as fillers.

[0030] The first piping member 10 may be a single-layer pipe or may have a multi-layer structure having a surface layer on at least one of the outer peripheral surface and the inner peripheral surface. The surface layer may contain, for example, at least one of inorganic fibers and organic fibers. Examples of the inorganic fibers include glass fibers, carbon fibers, silicon-titanium-carbon composite fibers, boron fibers, or metal fibers. Examples of the organic fibers include, for example, aramid fibers, vinylon fibers, polyester fibers, or polyamide fibers. When the surface layer contains these fibers, the tensile strength of the first piping member 10 can be increased and thermal expansion can be further suppressed.

[0031] Further, the surface layer may contain a fluororesin. By containing fluorine in the surface layer, the resistance (chemical resistance) to acids, alkalis, etc. can be enhanced.

[0032] Also, a layer similar to the above surface layer may be provided inside the wall of the first piping member 10.

[0033] The first piping member 10 may be a multi-layer pipe having three or more layers including a metal layer as an intermediate layer. As the metal material constituting the metal layer, for example, iron, brass, copper, stainless steel, aluminum, titanium, silver alloy, etc. are preferably used.

[0034] The first piping member 10 has a tubular first tubular portion 11 having both ends open and a first bulging portion 12 provided at one end 11E of the first tubular portion 11.

[0035] (First Tubular Portion) The first tubular portion 11 has a pipe body 111 and a reduced-diameter portion 112 that is reduced in diameter radially inward of the pipe body 111 on one end side of the pipe body 111. That is, in the first tubular portion 11, the inner diameter W11 (mm) of the pipe body 111 is larger than the inner diameter W12 (mm) of the portion with the minimum diameter in the reduced-diameter portion 112 (W11>W12).

[0036] On the outer circumferential surface of the first tubular portion 11 (outer circumferential surface 10x of the first piping member 10), a first recess 10C is formed adjacent to the first bulging portion 12 at a position that overlaps with the retracted portion 112 in a field of view perpendicular to the axis (central axis) Ax of the piping structure 100. The first recess 10C is formed in an endless, closed annular shape in the circumferential direction of the first tubular portion 11.

[0037] The inner circumferential surface of the first tubular portion 11 (the inner circumferential surface 10y of the first piping member 10) is composed of surface 10y1, which is the inner circumferential surface of the pipe body 111 and is aligned with the axis Ax; surface 10y2, which is the inner circumferential surface of the retracted pipe portion 112 and is aligned with the axis Ax; and an inclined surface 10y3 that connects surface 10y1 and surface 10y2.

[0038] (1st bulge) The first bulge portion 12 has a structure that protrudes in an annular shape radially outward from the first piping member 10 in the retracted pipe portion 112. The first bulge portion 12 faces the second bulge portion 22 (described later) of the second piping member 20 and sandwiches the packing 30 at the surface facing the second bulge portion 22.

[0039] The first bulge 12 has a closed annular groove 101 facing the second bulge 22. The groove 101 is formed in the circumferential direction of the opening 11a of the first tubular portion 11 (i.e., the opening 10a of the first piping member 10) and accommodates the packing 30.

[0040] The radially inner side of the recessed portion 101 is exposed to the opening 11a of the first tubular portion 11. The recessed portion 101 has an annular opposing surface 101a facing the second bulging portion 22, and a cylindrical side surface 101b that is continuous with the opposing surface 101a and extends in the direction of the axis Ax. The recessed portion 101 has a bulging portion end surface 12a that is planar and extends perpendicular to the axis Ax and is continuous with the side surface 101b. The bulging portion end surface 12a is formed at the tip of the first piping member 10 on the second piping member 20 side in the direction of the pipe axis.

[0041] In other words, the end face of the first piping member 10 is composed of a recessed portion 101 (opposing surface 101a, side surface 101b) and a bulging end face 12a that is continuous with the side surface 101b.

[0042] 《Second Piping Component》 The second piping member 20 in this embodiment is a pipe material having an internal space 20S and formed of a resin material. At least one of the first piping member 10 and the second piping member 20 is formed of a resin material. The second piping member 20 can be formed of the same material as the first piping member 10.

[0043] The second piping member 20 has a tubular second tubular portion 21 with both ends open, and a second bulging portion 22 provided at one end 21E of the second tubular portion 21.

[0044] (Second tubular part) The second tubular section 21 has a pipe body 211 and a constricted section 212 at one end of the pipe body 211 that is constricted radially inward from the pipe body 211. That is, in the second tubular section 21, the inner diameter W21 (mm) of the pipe body 211 is larger than the inner diameter W22 (mm) of the smallest diameter point of the constricted section 212 (W21 > W22).

[0045] On the outer circumferential surface of the second tubular portion 21 (outer circumferential surface 20x of the second piping member 20), a second recess 20C is formed adjacent to the second bulging portion 22 at a position that overlaps with the retracted portion 212 in a field of view perpendicular to the axis Ax (radial arrow view). The second recess 20C is formed in an endless, closed annular shape in the circumferential direction of the second tubular portion 21.

[0046] The inner circumferential surface of the second tubular portion 21 (the inner circumferential surface 20y of the second piping member 20) is composed of a surface 20y1 which is the inner circumferential surface of the pipe body 211 and is aligned with the axis Ax, a surface 20y2 which is the inner circumferential surface of the retracted pipe portion 212 and is aligned with the axis Ax, and an inclined surface 20y3 which connects surface 20y1 and surface 20y2.

[0047] (Second bulge) The second bulge 22 has a structure that protrudes in an annular shape radially outward from the second piping member 20 in the constricted pipe section 212. The second bulge 22 has a closed annular protrusion 201 that faces the first bulge 12. The protrusion 201 fits into the recessed portion 101 of the first piping member 10 in a field of view along the axis Ax.

[0048] The protruding portion 201 is formed in the circumferential direction of the opening 21a of the second tubular portion 21 (i.e., the opening 20a of the second piping member 20). The outer diameter W23 (mm) of the protruding portion 201 is formed to a size that can be fitted into the recessed portion 101, and is smaller than the outer diameter W13 of the recessed portion 101. As a result, the protruding portion 201 fits into the recessed portion 101. The protruding portion 201 contacts the packing 30 at the connection point between the first piping member 10 and the second piping member 20, and presses the packing 30 in a direction parallel to the axis Ax.

[0049] The inner diameter W24 (mm) of the protruding portion 201 is the same as the opening diameter of the second tubular portion 21 (inner diameter W22 in the retracted portion 212) (W22 = W24). The protruding portion 201 has an annular opposing surface 201a facing the first bulging portion 12, and a cylindrical side surface 201b that is continuous with the opposing surface 201a and along the axis Ax. The protruding portion 201 has a bulging end surface 22a that is planar and extends perpendicular to the axis Ax and is continuous with the side surface 201b. The opposing surface 201a is formed at the tip of the second piping member 20 on the first piping member 10 side in the direction of the pipe axis.

[0050] In other words, the end face of the second piping member 20 is composed of a protruding portion 201 (opposing surface 201a, side surface 201b) and a bulging end face 22a that is continuous with the side surface 201b. The inner circumferential surface of the protruding portion 201 is located at the innermost part of the inner circumferential surface of the second piping member 20, that is, at the innermost part in the radial direction.

[0051] In Figure 2, the cross-sectional shape of the protruding portion 201 is shown as roughly rectangular, but it is not limited to this, and may be semicircular, semielliptical, or other shapes. Packing (sealing material)

[0052] The packing 30 is housed in the recessed portion 101 at the connection point between the first piping member 10 and the second piping member 20, and is pressed from the convex portion 201, thereby being liquid-tightly sandwiched between the first piping member 10 and the second piping member 20. The packing 30 is a closed annular shape.

[0053] The packing 30 can be manufactured using resin materials commonly used as packing materials. Examples of materials for the packing 30 include ethylene-propylene rubber, isoprene rubber, chloroprene rubber, chlorosulfonated rubber, nitrile rubber, styrene-butadiene rubber, chlorinated polyethylene, fluororubber, and EPDM (ethylene-propylene-diene rubber).

[0054] Furthermore, the packing 30 may have a reinforcing fabric made of polyamide or nylon (registered trademark) inserted into it.

[0055] The packing 30 can be of various known shapes. Among these, lip packings (V packings, U packings, L packings, J packings, etc.) and squeeze packings (O-rings, X-rings, D-rings) as specified in JIS B 0116 are preferred as packing 30. Among these, X or U packings are preferred as packing 30. Figure 2 shows the case where a U packing is used as packing 30.

[0056] Figure 3 is an enlarged end view of the connection point of the piping structure 100. Figure 3 shows the packing 30 being sandwiched between the first piping member 10 and the second piping member 20. Note that in Figure 3, only the dividing member 91 side of the joining member 90, which will be described later, is shown in an enlarged view.

[0057] As shown in Figure 3, the packing 30, which is a U-shaped packing, has a groove 301 that opens on the inner circumference (radially inward) and is continuous in the circumferential direction. In the cross-sectional view of Figure 3 (viewed by an arrow perpendicular to axis Ax), a pair of ribs (lips) 302 are formed on the inner diameter side of the groove 301. The pair of ribs 302 protrude radially inward. The pair of ribs 302 are provided continuously in the circumferential direction.

[0058] The pair of ribs 302 comprises a first rib 302a on the concave portion 101 side and a second rib 302b on the convex portion 201 side, in a field of view perpendicular to the axis Ax (radial arrow view). In the radial direction, the height ha of the first rib from the groove 301 to the tip of the first rib 302a is preferably 20 mm or less. In the radial direction, the height hb of the second rib from the groove 301 to the tip of the second rib 302b is preferably 20 mm or less. The first rib height ha and the second rib height hb may be the same (ha=hb) or different. In this embodiment, the first rib height ha is longer than the second rib height hb (ha>hb). The second rib height hb may be longer than the first rib height ha (ha <hb)。 One of the pair of ribs 302 (either the first rib 302a or the second rib 302b) has a shape that opens outward in the axial direction. In this embodiment, the second rib 302b on the side of the protruding ridge 201 has a shape that opens outward in the axial direction.

[0059] The packing 30 is housed in the grooved portion 101. In the radial direction, the inner circumferential ends of the pair of ribs 302 are located radially outward from the inner circumferential ends of the grooved portion 101. The packing 30 housed in the recessed portion 101 is exposed to the internal spaces 10S and 20S of the piping structure 100, and the groove 301 is also exposed to the internal spaces 10S and 20S.

[0060] In such a piping structure 100, when water flows through the internal spaces 10S and 20S, the packing 30 is subjected to a load due to water pressure (indicated by F1 in Figure 3). At this time, the water in the internal spaces 10S and 20S enters the groove 301 of the packing 30, applying an isotropic load to the packing 30. As a result, the packing 30 is pushed inward radially due to the load in the recessed portion 101 (indicated by F2 in Figure 3).

[0061] Furthermore, the water in the internal spaces 10S and 20S expands the rib 302 and applies a load in a direction that presses it against the first bulge 12 and the second bulge 22 (reference numeral F3 in Figure 3). At this time, the packing 30 comes into contact with the protruding portion 201. Specifically, the second rib 302b opens in a direction that comes into contact with the opposing surface 201a of the protruding portion 201. In this embodiment, the packing 30 has a shape in which one of the pair of ribs 302 (the second rib 302b) opens outward in the axial direction.

[0062] As described above, when internal pressure is applied to the packing 30 from the water in the internal spaces 10S and 20S, surface pressure is generated as indicated by the arrows F2 and F3, and a sealing effect is obtained. In the following explanation, a seal that utilizes the surface pressure received from the water in the internal spaces 10S and 20S in this way may be referred to as a "self-seal."

[0063] Furthermore, in this configuration, where the protruding portion 201 fits into the recessed portion 101 as shown in Figure 3, a winding path, a so-called labyrinth structure, is formed in the gap between the protruding portion 201 and the packing 30, the gap between the first bulge portion 12 and the second bulge portion 22 which are outside the recessed portion 101, more specifically the gap between the side surface 101b and the side surface 201b, and the gap between the bulge portion end surface 12a and the bulge portion end surface 22a. Therefore, in the configuration shown in Figure 3, an improvement in the sealing effect can be expected compared to the case where flat surfaces without recessed portions 101 and protruding portions 201 are brought together.

[0064] As described above, the packing 30 can obtain both the surface pressure obtained when it is tightened between the first piping member 10 and the second piping member 20, and the surface pressure (self-sealing) generated when internal pressure is applied from the water in the internal spaces 10S and 20S. As a result, the packing 30 is pressed against the wall surface in the space surrounded by the recessed portion 101 and the convex portion 201, providing a high sealing effect in a compact piping structure.

[0065] The effects described above also apply when using various packings having grooves 301 that open to the inner circumference. In other words, even when using the lip packing or squeeze packing described above, if the grooves of the packing are exposed to the internal spaces 10S and 20S of the piping structure 100, a similar sealing effect can be expected.

[0066] 《Jointing Members》 As shown in Figures 1 and 2, the piping structure 100 has a closed annular connecting member 90 that surrounds and fixes the first piping member 10 and the second piping member 20 from the outer periphery at the connection point. In detail, the connecting member 90 surrounds and fixes the first bulge 12 and the second bulge 22 from the outer periphery.

[0067] The joining member 90 has a pair of divided members 91 and 92 formed in a semi-circular arc shape, and a fastener 93 for fixing the divided members 91 and 92.

[0068] The divided member 91 has a housing portion 911 formed in a substantially arc shape and having a housing space on its inner circumference, and a pair of connecting portions 912 provided at the end of the housing portion 911. In the view shown by the arrow in Figure 2 (viewpoint perpendicular to axis Ax), the housing portion 911 of the divided member 91 has a top plate portion 911c and a first contact tapered surface 911a and a second contact tapered surface 911b at both ends of the top plate portion 911c that face each other in the direction of the pipe axis. The first contact tapered surface 911a and the second contact tapered surface 911b are symmetrical in the direction of the pipe axis, and are further apart in the direction of the pipe axis as they are radially inward. The first contact tapered surface 911a has a tapered shape equivalent to the first tapered surface 12b of the first bulge portion 12, and the second contact tapered surface 911b has a tapered shape equivalent to the second tapered surface 22b of the second bulge portion 22.

[0069] The divided member 92 has a housing portion 921 formed in a substantially arc shape and having a housing space on its inner circumference, and a pair of connecting portions 922 provided at the end of the housing portion 921. In the view shown by the arrow in Figure 2 (viewpoint perpendicular to axis Ax), the housing portion 921 of the divided member 922 has a top plate portion 921c and a first contact tapered surface 921a and a second contact tapered surface 912b at both ends of the top plate portion 921c that face each other in the direction of the pipe axis. The first contact tapered surface 921a and the second contact tapered surface 921b are symmetrical in the direction of the pipe axis, and are further apart in the direction of the pipe axis as they are radially inward. The first contact tapered surface 921a has a tapered shape equivalent to the first tapered surface 12b of the first bulge portion 12, and the second contact tapered surface 921b has a tapered shape equivalent to the second tapered surface 22b of the second bulge portion 22. The divided members 91 and 92 may have the same shape.

[0070] The fastener 93 has a bolt 931 and a nut 932.

[0071] In this type of joint member 90, the first bulge 12 and the second bulge 22 are sandwiched between the dividing members 91 and 92, and the bolts 931 are inserted through the through holes 912a of the joint 912 and 922a of the joint 922, and secured with nuts 932, thereby surrounding the bulges (first bulge 12 and second bulge 22) from the outer circumference.

[0072] At this time, as shown in Figure 2, the inner circumferential ends of the joining member 90 (end 91a of the dividing member 91 and end 92a of the dividing member 92) are inserted into the first recess 10C and the second recess 20C. This suppresses misalignment of the joining member 90.

[0073] Furthermore, the connecting member 90 that abuts the first bulge 12 in the first recess 10C is tightened with the fixing device 93, generating a component force in the axial Ax direction at the contact point between the first bulge 12 and the connecting member 90, pressing the first bulge 12 toward the second piping member 20. Similarly, the connecting member 90 that abuts the second bulge 22 in the second recess 20C presses the second bulge 22 toward the first piping member 10. As a result, the first piping member 10 and the second piping member 20 are pressed against each other and strongly connected.

[0074] Figure 14A shows a cross-sectional view of the divided member 91 showing the protrusions (internal protrusions) 300a and 300b of the joining member 90. Figure 14B shows a cross-sectional view of the divided member 91 showing the protrusions 310a, 311a, 310b, and 311b of the joining member 90. In Figures 14A and 14B, the protrusions 300a, 300b, 310a, 311a, 310b, and 311b of the divided member 91 of the joining member 90 will be explained.

[0075] The inner circumferential surface of the joining member 90 has multiple protrusions. For example, as shown in Figure 14A, multiple protrusions 300a and 300b are provided on the inner circumferential surface 911cr of the top plate portion 911c. Preferably, the protrusions 300a and 300b are provided axially symmetric with respect to the central axis Az of the joining member 90, as shown in Figure 14A. In the cross-section shown in Figure 14A, one protrusion 300a and one protrusion 300b are provided on each side with respect to the central axis Az. Two or more protrusions 300a and 300b may be provided on each side with respect to the central axis Az. Multiple projections 300a may be scattered at intervals around the circumferential direction of the top plate portion 911c, or they may be provided around the entire circumferential direction. Multiple projections 300a may be scattered at equal intervals around the circumferential direction of the top plate portion 911c. Multiple projections 300b may be scattered at intervals around the circumferential direction of the top plate portion 911c, or they may be provided around the entire circumferential direction. Multiple projections 300b may be scattered at equal intervals around the circumferential direction of the top plate portion 911c. When multiple protrusions 300a and 300b are provided at intervals, it is preferable that the multiple protrusions 300a and 300b be the same size, but they may be of different sizes. In the illustrated example, the protrusions 300a and 300b are arranged at intervals in the direction of the pipe axis. The plan view shape of projections 300a and 300b can be, for example, circular or rectangular. The cross-sectional shape of projections 300a and 300b can be any convex shape that protrudes radially inward. The cross-sectional shape of projections 300a and 300b can be, for example, round, triangular, or trapezoidal. The height of the radial projections 300a and 300b of the divided member 91 is preferably 0.5 mm or more, and more preferably 1 mm or more. The height of the radial projections 300a and 300b of the divided member 91 is preferably 10 mm or less, and more preferably 6 mm or less. The heights of multiple projections 300a and 300b are preferably equal.

[0076] The protrusions 300a and 300b may be integrally formed from the same material as the divided member 91, or they may be separate components from the divided member 91. If the protrusions 300a and 300b and the divided member 91 are separate components, the protrusions 300a and 300b are manufactured and connected to the inner circumferential surface 911cr of the top plate portion 911c.

[0077] Furthermore, as shown in Figure 14B, for example, multiple protrusions 310a, 311a are provided on the first contact tapered surface 911a, and multiple protrusions 310b, 311b are provided on the second contact tapered surface 911b.

[0078] As shown in Figure 14B, the multiple protrusions 310a, 311a provided on the first contact tapered surface 911a may be located at different heights (different radial distances) in the line of sight of the arrows in Figure 14B. The protrusions 310a and 311a may be scattered at intervals along the circumferential direction of the first contact tapered surface 911a, or they may be provided around the entire circumference. The protrusions 310a and 311a may also be scattered at equal intervals along the circumferential direction of the first contact tapered surface 911a. When multiple protrusions 310a and 311a are provided at a distance, it is preferable that the multiple protrusions 310a and 311a are the same size, but they may be of different sizes. The plan view shape of the projections 310a and 311a can be, for example, circular or rectangular. The cross-sectional shape of the projections 310a and 311a can be any convex shape that protrudes inward from the divided member 91. The cross-sectional shape of the projections 310a and 311a can be, for example, round, triangular, or trapezoidal. The height of the projections 310a and 311a in the inner direction of the divided member 91 is preferably 0.5 mm or more, and more preferably 1 mm or more. The height of the projections 310a and 311a in the inner direction of the divided member 91 is preferably 10 mm or less, and more preferably 6 mm or less. The heights of the multiple projections 310a and 311a are preferably equal.

[0079] The protrusions 310a and 311a may be integrally formed from the same material as the divided member 91, or they may be separate components from the divided member 91. If the protrusions 310a and 311a and the divided member 91 are separate components, the protrusions 310a and 311a are manufactured and connected to the first contact tapered surface 911a.

[0080] Similarly, as shown in Figure 14B, the multiple protrusions 310b, 311b provided on the second contact tapered surface 911b may be located at different heights (different radial distances) in the line of sight of the arrows in Figure 14B. The protrusions 310b and 311b may be scattered at intervals along the circumferential direction of the second contact tapered surface 911b, or they may be provided around the entire circumference. The protrusions 310b and 311b may also be scattered at equal intervals along the circumferential direction of the second contact tapered surface 911b. When multiple protrusions 310b and 311b are provided at a distance, it is preferable that the multiple protrusions 310b and 311b are the same size, but they may be of different sizes. The plan view shape of the projections 310b and 311b can be, for example, circular or rectangular. The cross-sectional shape of the projections 310b and 311b can be any convex shape that protrudes inward from the divided member 91. The cross-sectional shape of the projections 310b and 311b can be, for example, round, triangular, or trapezoidal. The height of the projections 310b and 311b in the inner direction of the divided member 91 is preferably 0.5 mm or more, and more preferably 1 mm or more. The height of the projections 310b and 311b in the inner direction of the divided member 91 is preferably 10 mm or less, and more preferably 6 mm or less. The heights of the multiple projections 310b and 311b are preferably equal.

[0081] The protrusions 310b and 311b may be integrally formed from the same material as the divided member 91, or they may be separate components from the divided member 91. If the protrusions 310b and 311b and the divided member 91 are separate components, the protrusions 310b and 311b are manufactured, and the manufactured protrusions 310b and 311b are connected to the second contact tapered surface 911b.

[0082] It is preferable that the projections 310a, 311a provided on the first contact tapered surface 911a and the projections 310b, 311b provided on the second contact tapered surface 911b are located at the same height (same inner diameter) as seen through the arrows in Figure 14B.

[0083] It is preferable that the divided member 91 is provided with projections (310a, 311a and 310b, 311b) on both the first contact tapered surface 911a and the second contact tapered surface 911b. The divided member 91 may also have projections 300a, 300b provided on the inner circumferential surface 911cr of the top plate portion 911c, and projections (310a, 311a and 310b, 311b) provided on both contact tapered surfaces (911a and 911b).

[0084] Similarly, the inner circumferential surface of the dividing member 92 of the joining member 90, which is not shown in Figures 14A and 14B, also has multiple protrusions. Specifically, multiple protrusions are provided on the inner circumferential surface 921cr of the top plate portion 921c of the dividing member 92. In addition, multiple protrusions are provided on the first contact tapered surface 921a of the dividing member 92, and multiple protrusions are provided on the second contact tapered surface 921b. The protrusions provided on the dividing member 92 are provided at positions corresponding to the protrusions (300a, 300b, 310a, 311a, 310b, 311b) provided on the dividing member 91.

[0085] As described above, the piping structure 100 according to this embodiment has a plurality of protrusions on the inner circumferential surface of the joining member 90. As a result, the protrusions bite into the first piping member 10 and the second piping member 20, thereby suppressing movement and deformation of the first piping member 10 and the second piping member 20.

[0086] Although the connecting member 90 is shown as being separated into dividing members 91 and 92, it is not limited to this configuration. The dividing members 91 and 92 may be hinged together at one of the connecting portions 912 and 913, and fixed only at the other connecting portion 912 and 913 with a fastener 93.

[0087] The detailed shape and configuration of the piping structure 100 will be described below using Figures 4-6. Figures 4-6 are partial end views illustrating the piping structure 100.

[0088] Furthermore, the first piping member 10 and the second piping member 20 are assumed to have the same shape except for the configuration of the recessed portion 101 and the convex portion 201. Therefore, in the following explanation, when describing a configuration common to the first piping member 10 and the second piping member 20, the explanation of one configuration (for example, the first piping member 10) can be replaced with the explanation of the other configuration (for example, the second piping member 20) for better understanding.

[0089] (Thickness of the bulge) As shown in Figure 4, in the piping structure 100, in a field of view perpendicular to the axis Ax, the thickness A1 (mm) of the first bulge 12 in the same direction as the axis Ax (see Figure 2) is equal to the thickness A2 (mm) of the second bulge 22 (A1 = A2). Thickness A1 is the distance between the bulge end face 12a and the first tapered surface 12b, along the same direction as the axis Ax, in a field of view perpendicular to the axis Ax. Thickness A2 is the distance between the bulge end face 22a and the second tapered surface 22b, along the same direction as the axis Ax, in a field of view perpendicular to the axis Ax. Thicknesses A1 and A2 may be, for example, 10 mm or more, 15 mm or more, or 20 mm or more.

[0090] The first tapered surface 12b is a tapered surface provided on the first bulge 12 on the side opposite to the bulge end face 12a in the axial direction of the pipe. The first tapered surface 12b is a tapered surface whose diameter decreases as it is located on the side opposite to the bulge end face 12a in the axial direction of the pipe. The second tapered surface 22b is a tapered surface provided on the second bulge 22 on the side opposite to the bulge end face 22a in the axial direction of the pipe. The second tapered surface 22b is a tapered surface whose diameter decreases as it is located on the side opposite to the bulge end face 22a in the axial direction of the pipe. The second tapered surface 22b has the same taper as the first tapered surface 12b.

[0091] When the thickness A1 of the first bulge 12 and the thickness A2 of the second bulge 22 have the above-described relationship, the shape of the joining member 90 can be made symmetrical with respect to a virtual plane perpendicular to the axis Ax, and the way stress is applied by the joining member 90 becomes well-balanced.

[0092] However, this is not limited to this, and as shown in the end view of Figure 5, the thickness A1 of the first bulge 12 may be thicker than the thickness A2 of the second bulge 22 (A1 > A2). In this case, the shapes of the recessed portion 101 and the convex portion 201 may be adjusted so that the packing 30 is positioned in the center of the first bulge 12 and the second bulge 22 inside the piping structure 100 (A3 = A4). Thickness A3 (mm) is the distance between the center of the packing 30 and the first tapered surface 12b, aligned in the same direction as axis Ax, in a field of view perpendicular to axis Ax. Thickness A4 (mm) is the distance between the center of the packing 30 and the second tapered surface 22b, aligned in the same direction as axis Ax, in a field of view perpendicular to axis Ax.

[0093] (Thickness of the recess) Furthermore, as shown in Figure 4, the thickness B1 (mm) of the first tubular portion 11 (retracted portion 112) at the position of the first recess 10C should be equal to or greater than the thickness B2 (mm) of the main body of the pipe 111 (B1 ≥ B2). Thicknesses B1 and B2 are lengths along the radial direction. This relationship helps to suppress a decrease in strength in the retracted portion 112.

[0094] (Slope of the recess) Furthermore, as shown in Figure 4, the bottom surface 10C1 of the first recess 10C and the first tapered surface 12b of the first bulge 12 continuous with the bottom surface 10C1 may be perpendicular, and the angle θ between the bottom surface 10C1 and the first tapered surface 12b may be 30° or more and 80° or less. The angle θ may also be 30° or more and 70° or less, or 30° or more and 60° or less.

[0095] When the angle θ is less than 30°, the housing portions 911 and 921 are less likely to catch on the first bulge portion 12 when joining the first piping member 10 and the second piping member 20 using the joining member 90. Therefore, for example, if a stress is generated that pulls the first piping member 10 away in the direction of the axis Ax, the pull-out force (the force required to pull the first piping member 10 away from the joining member 90) decreases.

[0096] When the angle θ exceeds 80°, stress may concentrate when the aforementioned tensile force occurs, making it difficult to distribute the generated stress, which may lead to a decrease in strength.

[0097] The angle θ can be defined as the angle formed by a virtual line L1, which is parallel to the axis Ax and tangent to the base surface 10C1 in the cross-section of Figure 4, and a tangent line L2 at the radial center of the first tapered surface 12b. The contour line formed in the cross-section of Figure 4 of the first tapered surface 12b may be a straight line or a curve.

[0098] Because the angle θ is set to the above value, stress is less likely to concentrate at the intersection of the first recess 10C and the first bulge 12, thereby suppressing damage.

[0099] (Depth of the recess) Furthermore, the radial height Z1 (mm) from the inner surface of the main tube 211 to the inner surface of the retracted tube 212 should be equal to or greater than the radial height Z2 (mm) from the outer surface of the main tube 211 to the bottom surface 20C1 of the second recess 20C (Z1 ≥ Z2). This suppresses the reduction in strength at the location of the second recess 20C. Heights Z1 and Z2 are lengths along the radial direction.

[0100] (Location of the recessed area) It is preferable that the recessed portion 101 does not interfere with (overlap with) the first recess 10C in the field of view along the axis Ax.

[0101] (Depth of the concave section, protrusion of the convex section) The length of the recessed portion 101 in the same direction as the axis Ax (the length from the opposing surface 101a to the bulging end surface 12a in the same direction as the axis Ax) C1 (mm) is greater than the length of the convex portion 201 in the same direction as the axis Ax (the length from the opposing surface 201a to the bulging end surface 22a in the same direction as the axis Ax) C2 (mm) (C1 > C2). It is advisable to set lengths C1 and C2 considering the thickness of the packing 30 when it is liquid-tightly sandwiched between the recessed portion 101 and the convex portion 201 (length in the same direction as the axis Ax).

[0102] As shown in Figure 3, if the packing 30 has a groove 301 on its inner circumference, a self-sealing effect can be obtained. However, if the pair of ribs 302 (first rib 302a, second rib 302b) are compressed by the protruding ridge 201 to the point of contact, it may be difficult for internal water pressure to be applied from inside the groove 301 in a direction that expands the ribs 302, and self-sealing may not be possible. For this reason, lengths C1 and C2 should be such that the pair of ribs 302 do not come into contact with each other.

[0103] (Location of the recessed area) As shown in Figure 6, the groove portion 105 may be provided on the first bulge portion 12 without being exposed on the inner circumference side of the first piping member 10. In this case, a wall portion 106 will be formed between the groove portion 105 and the internal spaces 10S, 20S of the piping structure, along the same direction as the axis Ax. The packing 31 will be housed and held in the groove portion 105 without being exposed to the internal spaces 10S, 20S of the piping structure. In this case, an O-ring is preferable as the packing 31.

[0104] Furthermore, at this time, the inner diameter W24 of the protruding portion 201 is larger than the inner diameter W15 of the recessed portion 105, and the outer diameter W23 of the protruding portion 201 is smaller than the outer diameter W16 of the recessed portion 105. As a result, the protruding portion 201 fits into the recessed portion 105. The protruding portion 201 presses the packing 31 in a direction parallel to the axis Ax at the connection point between the first piping member 10 and the second piping member 20.

[0105] In this configuration, a winding path, a so-called labyrinth structure, is formed in the gap between the wall portion 106 and the protruding portion 201, the gap between the protruding portion 201 and the packing 30, and the gap between the first bulge portion 12 and the second bulge portion 22 located outside the recessed portion 101. Therefore, a high sealing effect can be expected even with the configuration shown in Figure 6.

[0106] (Amount of protrusion of the bulge) Both the first piping member 10 and the second piping member 20 are configured to have bulging sections (first bulging section 12, second bulging section 22) in their retracted sections 112 and 212. The amount of radial outward protrusion of the bulging section is the distance from the outer surface of the pipe body 211 to the outermost radial part of the second bulging section 22 (indicated by the symbol X in Figure 4).

[0107] On the other hand, when a bulge is provided in a tubular section that does not have a retracted section (first tubular section 11, second tubular section 21), the amount of protrusion of the bulge corresponds to the distance Y (see Figure 4) from the bottom surface 20C1 of the second recess 20C to the outermost radial part of the second bulge 22.

[0108] In other words, in the piping structure 100, by providing bulging sections (first bulging section 12, second bulging section 22) in the tubular sections (first tubular section 11, second tubular section 21) having constricted sections 112, 212, the amount of protrusion X of the bulging sections can be suppressed. As a result, in the piping structure 100, when attempting to improve sealing performance by using a large sealing member 30, even if the bulging sections of the piping members (first piping member 10, second piping member 20) are also enlarged to match the size of the sealing member 30, the outermost dimensions of the piping members can be suppressed, and a decrease in work efficiency can be suppressed.

[0109] (Structure to prevent gasket detachment) Figures 7-10 are partial end views showing the packing detachment prevention structure. When the recessed portion 101 is exposed on the inner circumference side of the first tubular portion 11, as described above, there is no structure to support the packing 30 from the inner circumference side of the first tubular portion 11, making the packing 30 prone to displacement or detachment. For this reason, the first piping member 10 and the second piping member 20 may be configured as shown in Figures 7-10 below.

[0110] As shown in Figure 7, the first piping member 10 may have a support recess 102 at the outer corner of the grooved portion 101 into which a part of the packing 30 is inserted and which supports the sealing member. The support recess 102 has a shape that is recessed radially outward. The support recess 102 is provided in the circumferential direction of the first piping member 10 along the corner of the grooved portion 101.

[0111] The support recesses 102 may be provided around the entire circumference of the first piping member 10, or multiple support recesses may be scattered at equal intervals around the circumference of the first piping member 10. When multiple support recesses 102 are scattered, the multiple support recesses 102 may be the same size or may be of different sizes.

[0112] In this case, it is desirable that a portion 30a of the packing 30 inserted into the support recess 102 is molded to be the same shape as the cross-sectional shape of the support recess 102. The portion 30a is provided on the outer circumferential surface of the packing 30. The portion 30a is located radially outside the first rib 302a, but may also be located radially outside the second rib 302b.

[0113] Furthermore, as shown in Figure 8, the first piping member 10 may have a first support projection 103 at the inner circumference end of the recessed portion 101 (the end on the axis Ax side of the recessed portion 101) that protrudes into the interior of the recessed portion 101 and supports the packing 30. The first support projection 103 protrudes in the direction of the axis Ax.

[0114] Furthermore, as shown in Figure 9, the first piping member 10 may have a first support projection 104 at the leading end of the recessed portion 101 (the end on the bulging end face 12a side of the recessed portion 101) that protrudes into the recessed portion 101 and supports the packing 30. The first support projection 104 protrudes radially inward.

[0115] The first support protrusions 103 and 104 may be provided around the entire circumference of the first piping member 10, or they may be provided discretely. Furthermore, both of these first support protrusions 103 and 104 may be formed on the groove portion 101.

[0116] Furthermore, as shown in Figure 10, the second tubular portion 21 may have a second support projection 202 at the tip end of the protruding portion 201, more specifically at the inner circumferential end of the protruding portion 201, which supports the packing 30 from the inner circumferential side. The second support projection 202 protrudes radially inward.

[0117] The second support projection 202 may be provided around the entire circumference of the second tubular portion 21, or multiple support projections may be scattered at equal intervals around the second piping member 20. When multiple support projections 202 are scattered, the multiple support projections 202 may be the same size or may be of different sizes.

[0118] The first piping member 10 and the second piping member 20 have structures to prevent them from falling off, thereby suppressing displacement of the packing 30 and improving work efficiency.

[0119] [Prefabricated piping] Figures 11 and 12 are explanatory diagrams of an example of prefabricated piping 200 having the piping structure 100 described above.

[0120] Figure 11 is a cross-sectional view of a piping member 50 having a joint 40. The piping member 50 has the first piping member 10, the joint 40, the piping member 41, and the socket portion 42, which are connected in this order in the axial direction. The joint 40 connects the first piping member 10 and the piping member 41. The socket portion 42 is located at the end of the piping member 41.

[0121] The first piping member 10, which constitutes the piping member 50, has a first bulge 12 with a recessed groove 101 at one end 11E1 of the first tubular portion 11, and is connected to a joint 40 at the other end 11E2 of the first tubular portion 11. The method of connecting the first tubular portion 11 and the joint 40 can be selected according to the material characteristics of the first tubular portion 11 and the joint 40, such as fusion bonding or adhesive bonding.

[0122] The joint 40 is made of resin or metal material. In this embodiment, the joint 40 is a piping member (pipe joint) made of resin material and is connected to the first piping member 10 to route the piping member along the intended path. As the material of the joint 40, the resin material described above can be used as the material of the first piping member 10. Examples of metal materials include iron, brass, copper, stainless steel, aluminum, titanium, silver alloy, etc. Furthermore, the inner surface of the metal pipe may be lined with a resin material such as fluororesin.

[0123] The piping member 41 is a straight pipe formed from a resin material. The resin material described above can be used as the material for the first piping member 10.

[0124] The socket portion 42 is a so-called electrofusion joint and has a heating element inside. The socket portion 42 has terminals 42x connected to the heating element. The socket portion 42 is connected to the piping member 41.

[0125] In the piping member 50, the internal space 10S of the first piping member 10, the internal space of the joint 40, the internal space of the piping member 41, and the internal space of the socket portion 42 are continuous and communicate from the opening 10a at the end of the first piping member 10 to the opening 42a at the end of the socket portion 42.

[0126] Although Figure 11 shows a curved pipe as a joint, various known joints can be used.

[0127] At the connection points between the first piping member 10 and the joint 40, and between the joint 40 and the piping member 41, a bead B is formed, which is a continuous bulge of molten resin on the inner and outer surfaces of the pipe. On the inner circumference side of the first tubular portion 11, the radial height Z1 from the inner surface of the pipe body 111 to the inner surface of the constricted portion 112 is preferably equal to or lower than the height Z3 of the bead B. This makes it possible to suppress pressure loss due to the constricted portion 112.

[0128] Figure 12 is a cross-sectional view showing an example of the prefabricated piping 200 of this embodiment. In the prefabricated piping 200, a fitting 40 is connected to at least one of the other end 11E2 of the first tubular section 11 and the other end of the second tubular section 21. In this embodiment, in the prefabricated piping 200, the fitting 40 is connected to the other end 11E2 of the first tubular section 11 of the first piping member 10 of the piping structure 100 described above, and a tee 60 is connected to the second piping member 20. A bead B is formed at the connection point between the second piping member 20 and the tee 60.

[0129] The tee 60 is a piping member (pipe fitting) made of resin material and is connected to the second piping member 20 to branch the piping member to an intended path. The tee 60 has a main pipe 61 and a branch pipe 62 that is connected to and communicates with the main pipe 61.

[0130] The prefabricated piping 200 shown in the figure is just one example, and various known configurations can be used as fittings. Furthermore, known configurations that connect to piping may be connected to the ends of the fittings.

[0131] In the prefabricated piping 200, for example, the first piping member 10 is installed on equipment set up at the construction site (e.g., pumps, water heaters, other prefabricated piping, etc.), the connecting piping member is the second piping member 20, and the first bulge 12 and the second bulge 22 are butted together and fixed, thereby enabling easy piping work at the construction site.

[0132] In addition, since there is no need to create a bulge at the construction site, butt welding at the construction site can be eliminated. As a result, no weld bead is formed near the bulge of the prefabricated pipe 200 due to butt welding.

[0133] In a piping structure 100 with the above configuration, stable sealing performance can be ensured without excessive enlargement.

[0134] Furthermore, the prefabricated piping 200 with the above configuration is equipped with the aforementioned piping structure 100, making it easy to handle during installation and ensuring stable sealing performance.

[0135] In this embodiment, both the first piping member 10 and the second piping member 20 are made of resin material, but this is not limited to this. At least one of the first piping member 10 and the second piping member 20 is made of resin material. For example, the other of the first piping member 10 and the second piping member 20 may be a metal pipe made of a metal material, and they may be connected in a dissimilar configuration.

[0136] Examples of the above-mentioned metal materials include iron, brass, copper, stainless steel, aluminum, titanium, and silver alloys. Furthermore, the inner surface of the metal tube may be lined with a resin material such as fluororesin.

[0137] [Second Embodiment] Figure 13 is a partial end view of the piping structure 150 according to the second embodiment of this disclosure, and is an end view corresponding to Figure 4. Components common to the first embodiment in the second embodiment are denoted by the same reference numerals, and detailed descriptions are omitted.

[0138] In the first embodiment, the first tubular portion 11 has a constricted portion 112, and the inner circumferential surface 10y of the first piping member 10 is composed of a surface 10y1, a surface 10y2, and an inclined surface 10y3, but the embodiment is not limited to this. In the piping structure 150 according to the second embodiment, as shown in Figure 13, the first piping member 10 does not have a constricted portion 112, and the inner circumferential surface 10y of the first piping member 10 has the same diameter at the position of the first recess 10C and at the position where the first recess 10C is not formed. Alternatively, the outer diameter of the first tubular portion 161 may be a constant outer diameter, and the inner circumferential surface 160y of the first piping member 160, excluding the groove portion 101, may have a constant diameter.

[0139] Similarly, in the first embodiment, the second tubular portion 21 has a constricted portion 212, and the inner circumferential surface 20y of the second piping member 20 is composed of a surface 20y1, a surface 20y2, and an inclined surface 20y3, but the embodiment is not limited to this. In the piping structure 150 according to the second embodiment, as shown in Figure 13, the second piping member 20 does not have a constricted portion 212, and the inner circumferential surface 20y of the second piping member 20 has the same diameter at the position of the second recess 20C and at the position where the second recess 20C is not formed. Furthermore, the outer diameter of the second tubular portion 171 may be a constant outer diameter, and the inner circumferential surface 170y of the second piping member 170 may also be a constant diameter.

[0140] [Third Embodiment] Figure 15 is a partial cross-sectional view of a piping structure 350 according to the third embodiment of this disclosure, and is an end view corresponding to Figure 2. Components common to the first embodiment in this embodiment are denoted by the same reference numerals, and detailed descriptions are omitted.

[0141] As shown in Figure 15, the piping structure 350 comprises a first piping member 70, a second piping member 80, and a packing (sealing member) 30. In the piping structure 350, the first piping member 70 and the second piping member 80 are connected by a connecting member 95. The packing 30 is sandwiched at the connection point between the first piping member 70 and the second piping member 80.

[0142] 《First Piping Component》 The first piping member 70 is a pipe material made of resin material and has an internal space 70S. The first piping member 70 can be made of the same material as the first piping member 10 described above. The first piping member 70 has a tubular first tubular portion 71 with both ends open, and a first stub portion 72 provided at one end of the first tubular portion 71. The first stub portion 72 corresponds to the "first bulge portion 12" in the first embodiment.

[0143] (First stub section) The first stub portion 72 has a structure that protrudes in an annular shape radially outward from the first piping member 70. The first stub portion 72 faces the second stub portion 82 (described later) of the second piping member 80 and sandwiches the packing 30 between the two surfaces.

[0144] The first stub portion 72 has a closed annular groove portion 701 facing the second stub portion 82. The groove portion 701 can adopt the same configuration as the groove portion 101 described above.

[0145] 《Second Piping Component》 The second piping member 80 is a pipe material made of resin material and has an internal space 80S. The second piping member 80 can be made of the same material as the first piping member 70. The second piping member 80 has a tubular second tubular portion 81 with both ends open, and a second stub portion 82 provided at one end of the second tubular portion 81. The second stub portion 82 corresponds to the "second bulge portion 22" in the first embodiment.

[0146] (Second stub section) The second stub portion 82 has a structure that protrudes in an annular shape radially outward from the second piping member 80. The second stub portion 82 has a closed annular protrusion portion 801 that faces the first stub portion 72. The protrusion portion 801 can adopt the same configuration as the protrusion portion 201 described above. That is, the protrusion portion 801 fits into the recessed portion 701 and presses the packing 30 in a direction parallel to the axis Ax at the connection point between the first piping member 70 and the second piping member 80.

[0147] 《Jointing Members》 The piping structure 350 has a connecting member 95 that connects the first piping member 70 and the second piping member 80 by sandwiching the first stub portion 72 and the second stub portion 82 from both sides in the axial direction Ax at the connection point.

[0148] The joining member 95 has a pair of flanges 96 and 97 and a fastener 98 for fixing the flanges 96 and 97.

[0149] The flange 96 is a loose-fitting flange formed in an annular shape and having a through hole 96a that penetrates through the center in the thickness direction. The flange 96 may be a known plate flange or a hub flange.

[0150] The first tubular portion 71 of the first piping member 70 is inserted through the through hole 96a. The outer diameter of the through hole 96a is smaller than the outer diameter of the first stub portion 72.

[0151] Furthermore, the flange 96 has a plurality of through holes 96b that penetrate in the thickness direction. The plurality of through holes 96b are arranged at equal intervals in the circumferential direction.

[0152] The flange 97 is formed similarly to the flange 96 and has a through hole 97a that penetrates through the thickness direction in the center, and a plurality of through holes 97b that penetrate through the thickness direction. The plurality of through holes 97b are arranged at equal intervals in the circumferential direction.

[0153] The second tubular portion 81 of the second piping member 80 is inserted through the through hole 97a. The outer diameter of the through hole 97a is smaller than the outer diameter of the second stub portion 82.

[0154] The fastener 98 has a bolt 981 and a nut 982. The fastener 98 is fastened by inserting the bolt 981 through the through hole 96b of the flange 96 and the through hole 97b of the flange 97, and using the nut 982. As a result, the first piping member 70 and the second piping member 80 are pressed against each other and strongly connected.

[0155] Even with the piping structure 350 having the configuration described above, high sealing performance is achieved by sandwiching the packing 30 between the recessed portion 701 and the convex portion 801. Therefore, with the piping structure 350 having the configuration described above, stable sealing performance can be ensured without excessive enlargement.

[0156] Furthermore, prefabricated piping with a piping structure 350 having the above configuration is easy to handle during construction and ensures stable sealing performance.

[0157] Preferred embodiments of the present disclosure have been described above with reference to the attached drawings, but the present disclosure is not limited to these examples. The shapes and combinations of the components shown in the above examples are examples only, and can be modified in various ways based on design, specifications, etc., without departing from the spirit of the present disclosure. [Explanation of Symbols]

[0158] 10, 70…First piping member, 10a, 11a, 20a, 21a…Opening, 10x, 20x…Outer surface, 10C…First recess, 11, 71…First tubular section, 12…First bulge, 20, 80…Second piping member, 20C…Second recess, 21, 81…Second tubular section, 22…Second bulge, 30…Packing (sealing member), 30a…Part, 40…Joint, 50…Piping member, 91a, 92a…End, 100…Piping Structure, 101, 105, 701... recessed section, 102... support recess, 103, 104... first support projection, 11E2... other end, 200... prefabricated piping, 201, 801... raised section, 202... second support projection, 301... groove, 302... rib, 300a, 300b, 310a, 310b, 311a, 311b... projection, W11, W12, W15, W21, W22, W24... inner diameter, W13, W16, W23... outer diameter

Claims

1. a first pipe member, a second pipe member connected to the first pipe member, at the connection location between the first pipe member and the second pipe member, a closed-ring seal member that is liquid-tightly sandwiched between the first pipe member and the second pipe member, comprising: at least one of the first pipe member and the second pipe member is formed of a resin material, the first pipe member has a first tubular portion that is tubular with both ends open, and a first bulging portion provided at one end of the first tubular portion, and the second pipe member has a second tubular portion that is tubular with both ends open, and a second bulging portion provided at one end of the second tubular portion and facing the first bulging portion, and the first bulging portion has a closed-ring concave groove portion formed in the circumferential direction of the opening of the first tubular portion and facing the second bulging portion, the second bulging portion has a closed-ring convex groove portion formed in the circumferential direction of the opening of the second tubular portion and facing the first bulging portion, and fitting into the concave groove portion, the seal member is housed in the concave groove portion, and the first pipe member and the second pipe member are surrounded and fixed from the outer peripheral side by a closed-ring joining member, and the pipe structure that contacts the convex groove portion.

2. The pipe structure according to claim 1, wherein the radially inner side of the concave groove portion is exposed at the opening of the first tubular portion.

3. The pipe structure according to claim 2, wherein the seal member has a groove that opens on the inner peripheral side and is continuous in the circumferential direction.

4. The pipe structure according to claim 2 or 3, wherein the first tubular portion has a first support protrusion that protrudes into the concave groove portion and supports the seal member.

5. The pipe structure according to claim 2 or 3, wherein the second tubular portion has a second support protrusion that supports the seal member from the inner peripheral side at the tip-side end portion of the convex groove portion.

6. The pipe structure according to claim 2 or 3, wherein the inner peripheral surface of the convex groove portion is located at the innermost side of the inner peripheral surface of the second pipe member.

7. The pipe structure according to claim 2 or 3, wherein the joining member surrounds and fixes the first bulging portion and the second bulging portion from the outer peripheral side at the connection location and is closed-ring shaped.

8. The pipe structure according to claim 2 or 3, wherein the inner peripheral surface of the closed-ring joining member has a plurality of protrusions.

9. having the pipe structure according to any one of claims 1 to 3, a prefabricated pipe in which a joint formed of a resin or metal material is connected to at least one of the other end of the first tubular portion and the other end of the second tubular portion.

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