Piping components, piping structures, and methods for manufacturing piping components

Abstract

To provide a piping member, a piping structure, and a method of manufacturing a piping member which allow for sheet packing to be used in a connection part.SOLUTION: A piping member according to an aspect 1 of the invention includes a resin main pipe 11 including a main pipe flange 11f at an end part thereof, and an annular metal flange 12 disposed in the main pipe flange 11f.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a piping member, a piping structure, and a method for manufacturing the piping member.

Background Art

[0002] In building drainage structures and the like, piping structures provided with piping members are sometimes used. Non-Patent Document 1 discloses the types and standards of resin pipes.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand to use sheet packings, which are used for connecting portions of cast iron pipes, in combination with resin pipes. However, the sheet packing has high hardness, and when used for a resin flange, the resin pipe deforms, so there is a problem that they cannot be used in combination. In addition, when molding the flange of a glass fiber-containing three-layer pipe, there is a problem that the glass fibers are exposed on the water stop surface, which affects the water stopping performance.

[0005] The present invention has been made in view of the aforementioned circumstances, and an object thereof is to provide a piping member, a piping structure, and a method for manufacturing the piping member, in which a sheet packing can be used at a connecting portion.

Means for Solving the Problems

[0006] <1> A piping member according to embodiment 1 of the present invention comprises a resin main pipe having a main pipe flange at its end, and an annular metal flange disposed on the main pipe flange.

[0007] According to this invention, the system comprises a resin main pipe and a metal flange positioned on the main pipe flange at the end of the main pipe. This allows a sheet packing to be placed at the connection point of the piping member, even if the main pipe is made of resin. Therefore, for example, the piping member can be connected to a metal pipe. When the main pipe is a three-layer pipe containing glass fibers, it is possible to prevent the glass fibers from being exposed on the watertight surface.

[0008] <2> In the piping member according to embodiment 2 of the present invention, a recess is provided on the surface of the main pipe flange facing the metal flange, and a protrusion corresponding to the recess is provided on the surface of the metal flange facing the main pipe flange.

[0009] According to this invention, a recess is provided on the surface of the main pipe flange facing the metal flange, and a protrusion corresponding to the recess is provided on the surface of the metal flange facing the main pipe flange. As a result, the recess and the protrusion interlock, making it difficult for the main pipe flange and the metal flange to come apart.

[0010] <3> In the third embodiment of the present invention, the piping member is provided in the piping member according to the second embodiment, wherein the recess and the protrusion are provided over the circumferential direction of the pipe axis of the main pipe.

[0011] According to this invention, the recesses and protrusions are provided along the circumferential direction of the pipe axis of the main pipe. This makes it more reliable to prevent the main pipe flange and the metal flange from coming apart.

[0012] <4> The piping member according to embodiment 4 of the present invention is a piping member according to any one of embodiments 1 to 3, wherein the main pipe flange and the metal flange are provided with bolt holes.

[0013] According to this invention, bolt holes are provided in the main pipe flange and the metal flange. This allows the ends of the piping members to be bolted together.

[0014] <5> A piping structure according to aspect 5 of the present invention comprises a piping member according to aspect 4, a sheet packing disposed facing the metal flange of the piping member, and a fastening member connecting the piping member to other members.

[0015] According to this invention, the piping member comprises a sheet packing positioned facing the metal flange of the piping member, and a fastening member connecting the piping member to another member. In other words, the piping member and the other member can be connected via the sheet packing and the fastening member.

[0016] <6> A piping structure according to embodiment 6 of the present invention comprises a piping member according to any one of embodiments 1 to 3, a sheet packing disposed facing the metal flange of the piping member, and a loose flange connecting the piping member to other members.

[0017] According to this invention, the piping member comprises a sheet packing positioned facing the metal flange of the piping member, and a loose flange connecting the piping member to another member. In other words, the piping member and the other member can be connected via the sheet packing and the loose flange.

[0018] <7> A piping structure according to embodiment 7 of the present invention comprises a piping member according to any one of embodiments 1 to 3, a sheet packing disposed facing the metal flange of the piping member, and a housing connecting the piping member to other members.

[0019] According to this invention, the piping member comprises a sheet packing positioned facing the metal flange of the piping member, and a housing that connects the piping member to other members. In other words, the piping member and other members can be connected by the housing via the sheet packing.

[0020] <8>A method for manufacturing a piping member according to aspect 8 of the present invention is a method for manufacturing a piping member comprising a resin main pipe and an annular metal flange disposed at an end of the main pipe, the method comprising: a flange mounting step of mounting the metal flange on a mold body of a mold that includes the mold body and a plurality of outer molds that can be opened and closed in a radial direction of the mold body, and covering the metal flange with the plurality of outer molds; a connecting step of, in a state where at least one of the mold and the main pipe is preheated, inserting the end of the main pipe between the plurality of outer molds and pressurizing the end toward the metal flange, and cooling the mold and the main pipe to attach the metal flange to the end of the main pipe; and a taking-out step of moving the plurality of outer molds radially outward relative to the mold body to take the piping member out of the mold.

[0021] According to this invention, in a state where at least one of the mold and the main pipe is preheated, the end of the main pipe is inserted between the plurality of outer molds and pressurized toward the metal flange, and the mold and the main pipe are cooled, whereby the metal flange is attached to the end of the main pipe. Thereby, the metal flange can be attached to the end of the resin main pipe. Accordingly, a piping member connectable to a sheet packing or a metal pipe can be manufactured.

Effects of the Invention

[0022] According to the present invention, it is possible to provide a piping member, a piping structure, and a method for manufacturing the piping member that allow a sheet packing to be used at a connection portion.

Brief Description of the Drawings

[0023] [Figure 1] It is a partially cutaway front view of the first piping structure. [Figure 2] It is a side view in the direction II shown in FIG. 1 of the first piping member of the first piping structure. [Figure 3] It is a side view in the direction II shown in FIG. 1 of the metal flange of the first piping structure. [Figure 4] It is a modification of the first piping structure. [Figure 5]This is a flowchart showing the manufacturing method for piping components. [Figure 6] This is a cutaway front view of a portion of Figure 1 illustrating the manufacturing process of the first piping component. [Figure 7] This is a cutaway front view of a portion of Figure 2 illustrating the manufacturing process of the first piping component. [Figure 8] Figure 7 shows a cross-sectional view in the direction of VIII-VIII. [Figure 9] This is a cutaway front view of a portion of Figure 3, which illustrates the manufacturing process of the first piping component. [Figure 10] This is a front view showing a section of the second piping structure broken apart. [Figure 11] This is a front view showing a section of the third piping structure broken open. [Figure 12] This is a cutaway front view of a portion of Figure 1 illustrating the manufacturing process of the third piping component. [Modes for carrying out the invention]

[0024] (First Embodiment) Hereinafter, with reference to the drawings, the first piping member 10 (piping member) and the first piping structure 1 (piping structure) according to the first embodiment of the present invention will be described. First, the first piping member 10 provided in the first piping structure 1 will be described. As shown in Figure 1, the first piping member 10 comprises a main pipe 11 and a metal flange 12. The main pipe 11 is made of resin. Specifically, the main pipe 11 is made of polyolefin resin such as polyethylene resin or polybutene resin. The polyolefin resin may contain additives such as monomers. In addition, a three-layer pipe containing glass fibers may be used for the main pipe 11. A three-layer pipe is a pipe in which three layers are laminated in the radial direction (thickness direction of the main pipe 11). The glass fibers are contained in the outermost layer, for example. However, the main pipe 11 is not limited to a three-layer pipe. The main pipe 11 may be a single-layer pipe, or a multi-layer pipe other than a three-layer pipe (for example, a two-layer pipe or a four-layer pipe).

[0025] A parting line 11P is provided on the outer surface of the end of the main pipe 11. The parting line 11P extends from the axial end of the main pipe 11 in the axial direction of the main pipe 11 and stops partway along the axial direction of the main pipe 11. The parting line 11P is provided only on a portion of the main pipe 11 in the axial direction. The parting line 11P is formed when the first piping member 10 is manufactured, as will be described later. The main pipe 11 has multiple parting lines 11P (two in this example) at equal angles around its axis. The main pipe 11 is equipped with a main pipe flange 11f at its end in the direction of the pipe axis. As shown in Figure 2, the main pipe flange 11f is an annular portion that protrudes radially outward from the main pipe 11.

[0026] The metal flange 12 is an annular member positioned facing the main pipe flange 11f. In this embodiment, as shown in Figure 1, a recess 11d is provided on the surface of the main pipe flange 11f facing the metal flange 12. A protrusion 12p corresponding to the recess 11d is provided on the surface of the metal flange 12 facing the main pipe flange 11f. The recess 11d and the protrusion 12p are provided along the circumferential direction of the pipe axis of the main pipe 11. The recess 11d and the protrusion 12p interlock with each other, as shown in Figure 1. This makes it difficult for the main pipe flange 11f and the metal flange 12 to detach. To further prevent detachment, the cross-sectional shape of the protrusion 12p may be an inverted trapezoid or tapered shape, where the width on the main pipe flange 11f side is wider than the width on the metal flange 12 side.

[0027] In this embodiment, as shown in Figures 2 and 3, bolt holes BH are provided in the main pipe flange 11f and the metal flange 12, respectively. The bolt holes BH are provided at corresponding positions on the main pipe flange 11f and the metal flange 12 that face each other in the first piping member 10. For example, four bolt holes BH are provided at equal intervals in the circumferential direction of the pipe axis of the main pipe 11.

[0028] (1st piping structure 1) Next, the first piping structure 1 equipped with the first piping member 10 described above will be explained. The first piping structure 1 comprises the first piping member 10, a sheet packing 20, and a fastening member 30. The sheet packing 20 is positioned facing the metal flange 12 of the first piping member 10. Preferably, the sheet packing 20 is made of a sheet mixed with rubber such as nitrile rubber, butyl rubber, silicone rubber, EPDM, fluororubber, or PTFE, along with fibrous materials and fillers. The sheet packing 20 is provided with bolt holes BH corresponding to the main pipe flange 11f and the metal flange 12.

[0029] The fastening member 30 connects the first piping member 10 to other members. For example, a bolt B and a nut N are preferably used as the fastening member 30. Other components include, for example, the first piping member 10, as shown in Figure 1. In other words, in the first piping structure 1, for example, a pair of the above-mentioned first piping members 10 are provided and connected by a fastening member 30 via a sheet packing 20. Other components may include metal piping 40, as shown in Figure 4. In this case, the metal piping 40 is provided with a metal piping flange 40f corresponding to the main pipe flange 11f and metal flange 12, and bolt holes BH formed in the metal piping flange 40f. In other words, in the first piping structure 1, the first piping component 10 and the metal piping 40 may be connected by fastening members 30 via a sheet packing 20.

[0030] (Manufacturing method for the first piping member 10) Next, the manufacturing method (hereinafter referred to as the manufacturing method) of the first piping member 10 of this embodiment will be described. Figure 5 is a flowchart of the manufacturing method S1. First, the mold 100 used in manufacturing method S1 will be described using Figure 6. The mold 100 comprises a base mold 101, a core mold 102, and a pair of outer molds 103. The base mold 101 and the core molds 102 constitute the mold body 104. Furthermore, the number of external molds 103 provided in the mold 100 is not limited to one pair, but may be three or more.

[0031] The base type 101 is cylindrical. The base type 101 has a body 107 and a projection 108. The body 107 is formed in a cylindrical shape. The projection 108 is provided on the upper surface of the body 107. The projection 108 is formed in a trapezoidal cone shape. The projection 108 is provided to form the bolt hole BH of the main pipe flange 11f.

[0032] The core type 102 has a base portion 102a and a core portion 102b. The base portion 102a and the core portion 102b are each formed in a cylindrical shape and arranged coaxially. The base portion 102a fits onto the inner circumferential surface 107a of the main body 107 of the base type 101. The core portion 102b extends upward from the upper surface of the base portion 102a. The diameter of the core portion 102b gradually decreases as it extends upward. The diameter of the upper end of the core portion 102b is smaller than the inner diameter of the main pipe 11. The core type 102 can move (slide) in the axial direction of the main pipe 11 relative to the base type 101.

[0033] Each outer mold 103 is semi-circular in shape when viewed from above. Each outer mold 103 contacts the upper surface of the projection 108 of the base mold 101, as shown in Figure 6. The pair of outer molds 103 can open and close radially relative to the base mold 101 (mold body 104). That is, each of the pair of outer molds 103 can move radially outward relative to the base mold 101 to separate it from the base mold 101 (open), and can also move radially inward relative to the base mold 101 to move it closer to the base mold 101 (close). In the mold 100 configured as described above, a cavity C is formed between the base mold 101 and the pair of outer molds 103 and the core mold 102.

[0034] I will now explain manufacturing method S1 in detail. First, in the flange attachment process (step S10 shown in Figure 5), the metal flange 12 is attached to the core mold 102 of the mold body 104, as shown in Figure 7. At this time, as shown in Figure 8, the bolt holes BH that are pre-provided in the metal flange 12 are aligned with the projections 108 of the base mold 101. Then, as shown in Figure 9, the metal flange 12 is covered with a pair of outer molds 103. Once the flange mounting process S10 is completed, the process proceeds to step S12.

[0035] Next, in connection step S12, at least one of the mold 100 and the main pipe 11 is preheated (heated) with a heating heater (not shown). In this preheated state, the end of the main pipe 11 is inserted between a pair of outer molds 103 as shown in Figure 9, and pressure is applied toward the metal flange 12 (downward). The end of the main pipe 11 becomes easily deformable due to being preheated and melted. The end of the main pipe 11 deforms to match the spatial shape formed by the cavity C, the protrusion 108 of the base mold 101, and the convex portion 12p of the metal flange 12. As a result, the main pipe flange 11f is formed at the end of the main pipe 11. The protrusion 108 of the base mold 101 forms a bolt hole BH in the main pipe flange 11f. The convex portion 12p of the metal flange 12 forms a recess 11d in the main pipe flange 11f. In this way, the end of the main pipe 11 melts and deforms to correspond to the shape of the cavity C of the mold 100. At this time, a pair of parting lines 11P are formed on the outer surface of the end of the main pipe 11. The pair of parting lines 11P are formed in the gap (boundary) between the pair of outer molds 103 at the end of the main pipe 11.

[0036] Then, by cooling the mold 100 and the main pipe 11 by air cooling or the like, the metal flange 12 is attached to the end of the main pipe 11. In other words, the main pipe flange 11f of the main pipe 11 and the metal flange 12 are fixed together. Once the connection process S12 is completed, the process proceeds to step S14.

[0037] Next, in the removal process S14, the pair of outer molds 103 are moved radially outward relative to the mold body 104 to remove the first piping member 10 from the mold 100. In the removal process S14, the core mold 102 is moved downward relative to the base mold 101 to remove the core mold 102 from the metal flange 12. Once the extraction process S14 is completed, all steps of the manufacturing method S1 are finished, and the first piping member 10 is manufactured.

[0038] As described above, the first piping member 10 according to this embodiment comprises a resin main pipe 11 and a metal flange 12 positioned on the main pipe flange 11f provided at the end of the main pipe 11. This allows a sheet packing 20 to be placed at the connection portion of the piping member even if the main pipe 11 is made of resin. Therefore, for example, the piping member can be connected to a metal pipe. If the main pipe 11 is a three-layer pipe containing glass fibers, it is possible to prevent the glass fibers from being exposed on the watertight surface.

[0039] Furthermore, a recess 11d is provided on the surface of the main pipe flange 11f facing the metal flange 12, and a protrusion 12p corresponding to the recess 11d is provided on the surface of the metal flange 12 facing the main pipe flange 11f. As a result, the recess 11d and the protrusion 108 interlock, making it difficult for the main pipe flange 11f and the metal flange 12 to come apart.

[0040] Furthermore, the recessed portion 11d and the protruding portion 12p are provided along the circumferential direction of the pipe axis of the main pipe 11. This makes it more reliable to prevent the main pipe flange 11f and the metal flange 12 from coming apart.

[0041] Furthermore, bolt holes BH are provided in the main pipe flange 11f and the metal flange 12. This allows the ends of the piping members to be bolted together.

[0042] Furthermore, the system includes a sheet packing 20 positioned facing the metal flange 12 of the piping member, and a fastening member 30 for connecting the piping member to other members. In other words, the piping member and other members can be connected via the sheet packing 20 and the fastening member 30.

[0043] Furthermore, with at least one of the mold 100 and the main pipe 11 preheated, the end of the main pipe 11 is inserted between a plurality of outer molds 103 and pressurized toward the metal flange 12, and the mold 100 and the main pipe 11 are cooled to attach the metal flange 12 to the end of the main pipe 11. This makes it possible to attach the metal flange 12 to the end of the resin main pipe 11. Thus, it is possible to manufacture piping components that can be connected to sheet packings 20 and metal pipes.

[0044] (Second Embodiment) Next, the second piping member 210 (piping member) and the second piping structure 2 according to the second embodiment of the present invention will be described. In this second embodiment, the same reference numerals are used for parts that are the same as those in the first embodiment, and their descriptions are omitted. Only the differences will be described. The second piping member 210 according to the second embodiment differs from the first piping member 10 in that, as shown in Figure 10, the main pipe flange 11f and the metal flange 12 do not have bolt holes BH.

[0045] (2nd piping structure 2) Next, a second piping structure 2 equipped with the second piping member 210 described above will be explained. The second piping structure 2 comprises the second piping member 210, a sheet packing 20, a loose flange 50, and a fastening member 30. The loose flange 50 is an annular member equipped with bolt holes BH. The bolt holes BH of the loose flange 50 are provided, for example, at four equally spaced locations around the circumferential direction of the pipe axis of the main pipe 11.

[0046] The loose flange 50 connects the second piping member 210 to another member. The other member is, for example, the second piping member 210. That is, a pair of the above-mentioned second piping members 210 are provided and connected by the loose flange 50 via the sheet packing 20. The other member may be a metal pipe 40 not shown. That is, in the second piping structure 2, the above-mentioned second piping member 210 and the metal pipe 40 not shown may be connected by the loose flange 50 via the sheet packing 20. Hereafter, the other member will be described assuming it is the second piping member 210.

[0047] The loose flanges 50 are provided in pairs at the connection point of the second piping structure 2. Specifically, the loose flanges 50 are positioned on both sides of the main pipe flanges 11f of the second piping members 210 facing each other in the axial direction of the main pipe 11. In this state, the fastening member 30 is tightened as shown in Figure 10. As a result, the two loose flanges 50 sandwich the main pipe flanges 11f of the second piping members 210 facing each other from the outside in the axial direction of the main pipe 11. In this way, the pair of loose flanges 50 fix the second piping members 210 facing each other.

[0048] (Manufacturing method S2 for the second piping member 210) Next, the manufacturing method S2 for the second piping member 210 will be described. The manufacturing method S2 for the second piping member 210 differs from the manufacturing method S1 for the first piping member 10 in that the base mold 101 does not have a projection 108 for forming the bolt hole BH of the main pipe flange 11f.

[0049] As described above, the second piping member 210 according to this embodiment includes a sheet packing 20 positioned facing the metal flange 12 of the second piping member 210, and a loose flange 50 connecting the second piping member 210 to other members. In other words, the second piping member 210 and other members can be connected via the sheet packing 20 and the loose flange 50.

[0050] (Third embodiment) Next, the third piping member 310 (piping member) and the third piping structure 3 according to the third embodiment of the present invention will be described. In this third embodiment, the same reference numerals are used for parts that are the same as those in the first and second embodiments, and their descriptions are omitted. Only the differences will be described.

[0051] The third piping member 310 according to the third embodiment differs from the first piping member 10 and the second piping member 210 in that, as shown in Figure 11, the main pipe flange 11f and the metal flange 12 do not have bolt holes BH, and that it has an inclined portion 11fs. As shown in Figure 11, the inclined portion 11fs is formed integrally with the main pipe flange 11f on the outer circumferential surface of the third piping member 310. The inclined portion 11fs is provided along the circumferential direction of the pipe axis of the main pipe 11. The inclined portion 11fs is provided so that the outer diameter of the third piping member 310 gradually decreases from the main pipe flange 11f provided at the end of the main pipe 11 toward the side of the main pipe 11. The inclined portion 11fs is in contact with the housing 60, which will be described later.

[0052] (Third piping structure 3) Next, the third piping structure 3 equipped with the third piping member 310 described above will be explained. The third piping structure 3 comprises the third piping member 310, a sheet packing 20, a housing 60, and a fastening member 30 (not shown). The housing 60 connects the third piping member 310 to other members. These other members are, for example, the third piping member 310. That is, a pair of the aforementioned third piping members 310 are provided and connected by the housing 60 via a sheet packing 20. The other members may be a metal pipe 40 (not shown) having a sloping portion 11fs similar to that of the third piping member 310. In other words, in the second piping structure 2, the aforementioned third piping member 310 and the metal pipe 40 (not shown) may be connected by the housing 60 via a sheet packing 20. Hereafter, the other members will be described assuming they are the third piping member 310.

[0053] The housing 60 is an arc-shaped member when viewed from the pipe axis direction of the third piping member 310. In this embodiment, the housing 60 is semicircular. A pair of housings 60 are provided at the connection point between the ends of the third piping member 310. The housings 60 are positioned to sandwich the connection point between the ends of the third piping member 310 from the radial outside of the third piping member 310. As a result, as shown in Figure 11, the housings 60 cover the connection point between the ends of the third piping members 310 facing each other from the radial outside of the third piping member 310. The pair of housings 60 are then fixed together by the fastening member 30. As a result, the pair of housings 60 fix the third piping members 310 facing each other together. The housing 60 preferably includes an inclined portion 60s corresponding to the inclined portion 11fs of the third piping member 310, as shown in Figure 11.

[0054] (Manufacturing method S3 for the third piping member 310) Next, the manufacturing method S3 for the third piping member 310 will be described. The manufacturing method S3 for the third piping member 310 differs from the manufacturing method S1 for the first piping member 10 and the manufacturing method S2 for the second piping member 210 in that, as shown in Figure 12, the base mold 101 does not have a projection 108 for forming the bolt hole BH of the main pipe flange 11f, and each outer mold 103 has an inclined shape 103s for forming the inclined portion 11fs of the third piping member 310.

[0055] As described above, the third piping member 310 according to this embodiment includes a sheet packing 20 positioned facing the metal flange 12 of the third piping member 310, and a housing 60 connecting the third piping member 310 to other members. In other words, the third piping member 310 and other members can be connected by the housing 60 via the sheet packing 20.

[0056] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, in the first embodiment, in order to ensure that bolt holes BH are formed in the main pipe flange 11f, each outer mold 103 may have a fitting recess that fits onto the upper part of the projection 108 of the base mold 101. In this case, it is preferable that the projection 108 of the base mold 101 and the fitting recess fit together when the base mold 101 is covered with the outer mold 103.

[0057] The bolt holes BH in the first piping member 10 may be provided by fixing the main pipe flange 11f and the metal flange 12 without providing bolt holes BH, similar to the second piping member 210, and then machining the main pipe flange 11f and the metal flange 12 together using a drill or the like. The base mold 101 and core mold 102 that constitute the mold body 104 may be formed as a single unit.

[0058] Furthermore, without departing from the spirit of the present invention, the components in the above embodiments may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate. [Explanation of Symbols]

[0059] 1 1st piping structure 2 Second piping structure 3 Third piping structure 10. First piping member 11 Main pipes 11d recess 11f Main pipe flange 11fs slope section 11P parting line 12 Metal flanges 12p convex part 20 Sheet packing 30 Fastening members 40 Metal piping 40f Metal pipe flange 50 Loose Flange 60 Housing 60s sloped section 100 molds 101 Base Type 102 Core mold 102a base 102b Core part 103 External shape 103s inclined shape 104 Mold body 107 Main Unit 107a Inner surface 108 Protrusion 210 Second piping member 310 Third piping member B bolt BH bolt hole C Cavity N Nut S10 Flange mounting process S12 Connection process S14 Extraction Process

Claims

1. A resin main pipe equipped with a main pipe flange at its end, An annular metal flange is positioned on the main pipe flange and facing the sheet packing, Equipped with, A recess is provided on the surface of the main pipe flange that faces the metal flange. A piping member wherein the metal flange has a protrusion corresponding to the recess on the surface facing the main pipe flange.

2. The piping member according to claim 1, wherein the recess and the protrusion are provided in the circumferential direction of the pipe axis of the main pipe.

3. The piping member according to claim 1, wherein bolt holes are provided in the main pipe flange and the metal flange.

4. The piping member according to claim 1, wherein the main pipe is made of a polyolefin resin.

5. The piping member according to claim 4, wherein the main pipe contains glass fibers.

6. The piping member according to claim 1, wherein a parting line extending from the axial end of the main pipe is formed on the outer circumferential surface at the end of the main pipe.

7. The piping member according to Claim 1, A sheet packing positioned facing the metal flange of the piping member, A fastening member that connects the aforementioned piping member to other members, A piping structure equipped with this.

8. The piping member according to claim 1, A sheet packing positioned facing the metal flange of the piping member, A loose flange connecting the aforementioned piping member to other members, A piping structure equipped with this.

9. The piping member according to claim 1, A sheet packing positioned facing the metal flange of the piping member, A housing that connects the aforementioned piping member to other members, A piping structure equipped with this.

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