JP2020173016A - Pipe joint with loose flange - Google Patents

Abstract

To provide a pipe joint with a loose flange that can be properly connected with a different kind of pipes while sandwiching a butterfly valve for the different kind of pipes therebetween.SOLUTION: A pipe joint 10 is a pipe joint for connecting a different kind of pipes such as a polyethylene pipe 102 and a steel pipe 104 with a butterfly valve 108, includes a polyethylene pipe joint 12 and a loose flange 14. The joint body is equipped with a body portion 20 and a collar portion 22 formed at one end portion thereof. On an inner surface of one end portion of the body portion, a tapered surface 38 increasing a diameter toward one end is formed so as to avoid an interference of the valve body 112 of the butterfly valve with respect to the body portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to loose flanged pipe joints, and more particularly to loose flanged pipe joints that connect polyethylene pipes with different types of pipes and butterfly valves for different types of pipes.

Patent Document 1 discloses an example of a conventional pipe joint with a loose flange of this type. Patent Document 1 discloses a polyethylene resin short pipe (joint body) in which a flange (flange portion) is integrally provided at one end and a seal ring mounting groove is provided on the flange end surface. A fastening flange (loose flange) is attached to the outer surface of this polyethylene resin short pipe, and the fastening flange and the flange portion of a different type of pipe are fastened with the fastening flange engaged with the flange to form a polyethylene resin short pipe. And a different type of pipe are connected. On the other hand, a polyethylene resin pipe is connected to the other end of the polyethylene resin short pipe by using an electric fusion socket.

Japanese Unexamined Patent Publication No. 2012-41954

I want to connect not only different types of pipes such as steel pipes directly to one end of the joint body (second connection end of the fuselage) of a loose flanged pipe joint, but also to connect to different types of pipes with a butterfly valve for different types of pipes in between. There is a request. However, the inner diameters of the body of the polyethylene joint body and the different types of pipes such as steel pipes are different even if they have the same nominal diameter. Therefore, when a butterfly valve for a different type of pipe designed according to the inner diameter of a different type of pipe is connected to a pipe joint with a loose flange, the valve body of the butterfly valve hits the body of the pipe joint with a loose flange, and the butterfly valve The function may be impaired.

In such a case, conventionally, it has been necessary to further interpose a metal conversion flange short pipe having flanges at both ends between the loose flanged pipe joint and the butterfly valve. However, when the conversion flange short tube is used, the member cost is increased by the amount that the conversion flange short tube is separately required. In addition, the number of flange connection points is increased to two, and the conversion flange short pipe may reach 100 kg depending on the nominal diameter, which imposes a heavy work load on the installer.

Therefore, the main object of the present invention is to provide a novel, loose flanged fitting.

Another object of the present invention is to provide a loose flanged pipe joint that can be appropriately connected to a dissimilar pipe with a butterfly valve for the dissimilar pipe in between.

The first invention is a pipe joint with a loose flange for connecting a polyethylene pipe and a butterfly valve for a different type of pipe and a different type of pipe, with a first connection end connected to the polyethylene pipe and a butterfly valve sandwiched between them. A polyethylene joint body including a body portion having a second connection end connected to a different type of pipe and an annular flange portion integrally formed on the outer surface of the end portion on the second connection end side of the body portion. A loose flange that is externally fitted to the body and fastened to the flange of a different type of pipe while engaged with the flange is provided, and the inner surface of the end of the body on the second connection end side has a second connection end. A tapered surface having a larger diameter toward the body is formed, and the tapered surface is a pipe joint with a loose flange formed so as to avoid interference of the valve body of the butterfly valve with the body portion.

In the first invention, a pipe joint with a loose flange is a pipe joint for connecting a polyethylene pipe and a different type pipe such as a steel pipe and a butterfly valve for a different type pipe, and includes a joint body and a loose flange. The joint body is made of polyethylene and is integrated with a fuselage portion having a first connection end connected to a polyethylene pipe and a second connection end connected to a different type of pipe with a butterfly valve in between. It is provided with an annular collar formed in. Then, on the inner surface of the end portion of the body portion on the second connection end side, a tapered surface having a larger diameter toward the second connection end is formed so as to avoid interference of the valve body of the butterfly valve with the body portion. ..

According to the first invention, since a tapered surface is formed on the inner surface of the end portion of the fuselage portion on the second connection end side to avoid interference between the fuselage portion and the valve body of the butterfly valve, the function of the butterfly valve is enhanced by the body portion. It can be prevented from being hindered. Therefore, different types of pipes can be appropriately connected with a butterfly valve sandwiched between the second connection ends of the body portion.

The second invention is dependent on the first invention, and the distance of the shortest distance portion where the distance between the tapered surface and the outer surface of the body portion is the shortest is set to be larger than the wall thickness of the polyethylene pipe.

According to the second invention, the strength of the base end portion of the collar portion can be ensured even if the tapered surface is formed on the inner surface of the body portion.

According to the present invention, since a tapered surface is formed on the inner surface of the end portion of the body portion on the second connection end side to avoid interference between the body portion and the valve body of the butterfly valve, the function of the butterfly valve is hindered by the body portion. Can be prevented. Therefore, different types of pipes can be appropriately connected with a butterfly valve sandwiched between the second connection ends of the body portion.

The above-mentioned object, other object, feature and advantage of the present invention will become more apparent from the detailed description of the examples described below with reference to the drawings.

It is sectional drawing which shows the state which connected the polyethylene pipe and the butterfly valve for a different kind pipe and a different kind pipe by using the pipe joint with a loose flange which is one Example of this invention. It is a front view which shows the pipe joint with a loose flange of FIG. It is sectional drawing which shows the pipe joint with a loose flange of FIG. It is explanatory drawing which shows an example of the manufacturing method of the pipe joint with a loose flange. It is sectional drawing which shows the state which connected the polyethylene pipe and the butterfly valve for a different kind pipe and a different kind pipe by using the pipe joint with a loose flange which is another Example of this invention. It is a side view which shows the 2nd connection end side of the loose flanged pipe joint of FIG. It is a side view which shows the 2nd connection end side of the pipe joint with a loose flange which is still another Example of this invention.

With reference to FIG. 1, the loose flanged pipe joint 10 (hereinafter, simply referred to as “pipe joint 10”) according to an embodiment of the present invention is loosely fitted to the joint body 12 and its body portion 20. It is provided with a flange 14 and is used for connecting a polyethylene pipe and a different type of pipe such as a steel pipe. As will be described in detail later, the second connection end 20b of the body portion 20 of the pipe joint 10 is connected to the different type pipe with a butterfly valve for the different type pipe sandwiched between them.

The pipeline 100 to which the pipe joint 10 is applied is various pressure pipelines (also referred to as internal pressure pipes) such as industrial water pipes, fire extinguishing water pipes, cooling water pipes, well water supply pipes, agricultural water pipes, and air pipes. , The pipe joint 10 is preferably used for a pressure pipe having a relatively large nominal diameter (for example, 200 to 700 mm).

In this embodiment, a pipe joint 10 for connecting a polyethylene pipe 102 having a nominal diameter of 400 mm, a steel pipe 104, and a butterfly valve 108 for a steel pipe will be illustrated and described. In this embodiment, the polyethylene pipe 102 has an outer diameter of 450 mm and an inner diameter of 364 mm. On the other hand, the outer diameter of the steel pipe 104 is 406 mm, and the inner diameter thereof is 396 mm. Further, an annular flange portion 106 according to the flange standard of JIS 10K is integrally provided at one end portion (connection portion with the pipe joint 10) of the steel pipe 104. However, the flange portion 106 may conform to other flange standards.

Further, the butterfly valve 108 is a wafer-shaped butterfly valve, and the fluid is controlled by the rotation of the disk-shaped valve body 112 in the short cylindrical valve box 110. In this embodiment, the valve body 112 has an outer diameter of 394 mm.

Hereinafter, the configuration of the pipe joint 10 will be described. As shown in FIGS. 2 and 3, the pipe joint 10 includes a joint body 12 formed of a polyethylene resin such as high-density polyethylene, and a loose flange 14 formed of a metal such as stainless steel.

The joint body 12 includes a cylindrical body portion 20 that forms a part of the pipeline 100. The body portion 20 has a first connection end 20a connected to the polyethylene pipe 102 and a second connection end 20b connected to the steel pipe 104. Further, an annular collar portion 22 projecting outward in the radial direction is integrally formed on the outer surface of the end portion of the body portion 20 on the second connection end 20b side. Further, a gasket mounting groove 24, which is an annular groove having a rectangular cross section, is formed on the end surface of the flange portion 22 (or the second connection end 20b of the body portion 20). A gasket 26 (see FIG. 1) such as an O-ring is mounted in the gasket mounting groove 24.

The loose flange 14 is a member that is loosely fitted to the body portion 20 of the joint body 12 in a loosely fitted state, and is formed in the shape of an annular plate. In this embodiment, the loose flanges 14 have an outer diameter larger than the outer diameter of the flange portion 22 of the joint body 12, and are arranged at predetermined intervals in the circumferential direction at a portion protruding outward from the flange portion 22. It has a bolt hole 28 of.

In such a pipe joint 10, as shown in FIG. 1, the first connection end 20a of the body portion 20 is connected to the polyethylene pipe 102 by using an EF socket (electric fusion socket) 120. On the other hand, the second connection end 20b of the body portion 20 is connected to the steel pipe 104 and the butterfly valve 108 by using the loose flange 14. At this time, the loose flange 14 is engaged with the flange portion 22, and the bolt portion 22 and the valve box 110 of the butterfly valve 108 are sandwiched between the loose flange 14 and the flange portion 106 of the steel pipe 104. The loose flange 14 and the flange portion 106 of the steel pipe 104 are fastened using the 122 and the nut 124.

Here, in a conventional pipe joint with a loose flange, when a butterfly valve for a different type of pipe is directly connected to the second connection end of the body portion, the valve body of the butterfly valve hits the body portion and the function of the butterfly valve is impaired. There was a case that it ended up. Further, in a conventional pipe joint with a loose flange, when the nominal diameter of the pipeline becomes large (for example, 350 mm or more), the position of the bolt hole of the loose flange and the position of the bolt hole of the flange portion of the different type of pipe match. In some cases, the loose flange and the flange of a different type of pipe could not be directly fastened. Such a problem can be dealt with by separately using a metal conversion flange short tube, but using the conversion flange short tube has a problem that the member cost and the work load increase.

Therefore, in this embodiment, even if the butterfly valve 108 is arranged between the pipe joint 10 and the steel pipe 104 by forming the tapered surface 38 on the inner surface of the end portion 20b side of the second connection end 20b of the body portion 20, the butterfly valve 108 may be arranged. The operation of the valve body 112 is not hindered. Further, a reduced diameter portion (second pipe portion 32) is provided in the body portion 20, and a structure is adopted in which the loose flange 14 is externally fitted to the reduced diameter portion, and the bolt hole 28 of the loose flange 14 is formed into the flange portion of the steel pipe 104. By forming it at the same position as the bolt hole (not shown) of 106, the loose flange 14 and the flange portion 106 of the steel pipe 104 can be directly fastened. Hereinafter, a specific description will be given.

As shown in FIGS. 2 and 3, the body portion 20 of the joint body 12 is formed between the first pipe portion 30 formed on the first connection end 20a side, the first pipe portion 30, and the collar portion 22. The second pipe portion 32 to be formed is included. The first pipe portion 30 has the same outer diameter and inner diameter as the polyethylene pipe 102, and the inner surface of the first pipe portion 30 and the inner surface of the polyethylene pipe 102 are smoothly connected via the EF socket 120. In this embodiment, the outer diameter of the first pipe portion 30 is 450 mm, and the inner diameter thereof is 364 mm. On the other hand, the second pipe portion 32 has a smaller diameter than the outer diameter of the polyethylene pipe 102, and has an outer diameter and an inner diameter smaller than those of the polyethylene pipe 102 (and the first pipe portion 30). In this embodiment, the outer diameter of the second pipe portion 32 is 400 mm, and the inner diameter thereof is 324 mm. Further, the first pipe portion 30 and the second pipe portion 32 are connected by a tapered pipe portion 34 whose diameter gradually decreases from the first pipe portion 30 to the second pipe portion 32. The loose flange 14 is externally fitted to the second pipe portion 32 of such a body portion 20.

Further, in this embodiment, the outer diameter of the flange portion 22 of the joint body 12 is set to be the same as or slightly smaller than the diameter of the circle connecting the innermost ends of the plurality of bolt holes formed in the flange portion 106 of the steel pipe 104. Will be done. That is, the flange portion 22 is formed to have a size that does not interfere with the bolt holes of the steel pipe 104. Further, the inner diameter of the loose flange 14 is set to be smaller than the outer diameter of the polyethylene pipe 102. If only the outer diameter of the flange portion 22 is reduced, the engaging area between the flange portion 22 and the loose flange 14 will be reduced, but by reducing the inner diameter of the loose flange 14, this engaging area is secured. be able to. It should be noted that the inner diameter of the loose flange 14 can be made smaller than the outer diameter of the polyethylene pipe 102 by adopting a structure in which the loose flange 14 is externally fitted to the reduced diameter second pipe portion 32. is there. In this embodiment, the outer diameter of the collar portion 22 is 482 mm. The inner diameter of the loose flange 14 is 425 mm, and the outer diameter thereof is 560 mm. A plurality of bolt holes 28 are formed at the same positions as the bolt holes of the flange portion 106 of the steel pipe 104 in the portion of the loose flange 14 that protrudes outward from the flange portion 22.

Further, in this embodiment, a tapered surface 38 having a diameter larger toward the second connection end 20b is formed on the inner surface of the end portion of the body portion 20 on the second connection end 20b side. When the steel pipe 104 is connected to the second connection end 20b of the body portion 20 with the butterfly valve 108 for the steel pipe 104 (for different types of pipes) sandwiched between the tapered surface 38, the valve body 112 of the butterfly valve 108 with respect to the body portion 20. It is formed to avoid the interference of.

Specifically, the tapered surface 38 includes a first tapered surface 38a having a large inclination angle formed on the first connection end 20a side and a second tapered surface 38b having a small inclination angle formed on the second connection end 20b side. It is a two-step tapered surface composed of. Further, the inner diameter of the second connection end 20b, that is, the diameter of the maximum diameter portion of the tapered surface 38 is larger than the inner diameter of the polyethylene pipe 102 and is substantially the same as the inner diameter of the steel pipe 104.

Here, the tapered surface 38 is mainly formed by cutting, but by setting the tapered surface 38 as a two-step tapered surface of the first tapered surface 38a and the second tapered surface 38b as described above, the tapered surface 38 The tapered surface 38 can be shaped along the side edge of the valve body 112, as compared with the case where is a one-step tapered surface. As a result, the size of the body portion 20 to be cut can be reduced, so that the wall thickness of the body portion 20 can be secured and the labor of cutting can be reduced. However, the tapered surface 38 may be formed by molding instead of cutting.

Further, the distance D of the shortest distance portion 40, which is the shortest distance between the tapered surface 38 and the outer surface of the body portion 20, is set to a size equal to or larger than the wall thickness of the polyethylene pipe 102 (and the first pipe portion 30). That is, the shape and dimensions of the end portion of the body portion 20 on the second connection end 20b side are determined so that the strength of the base end portion of the flange portion 22 is secured even if the tapered surface 38 is formed.

By forming such a tapered surface 38, it is possible to prevent the operation of the valve body 112 of the butterfly valve 108 from being hindered, and the inner surface of the body portion 20 and the steel pipe generated by forming the second pipe portion 32. The step with the inner surface of the 104 can be reduced or eliminated, and the fluid in the pipeline 100 can flow smoothly.

Subsequently, an example of a method for manufacturing the pipe joint 10 will be described. When manufacturing the pipe joint 10, first, as shown in FIG. 4A, a reducer 50, a short pipe with a flange 52, and a loose flange 54, which are members for manufacturing the pipe joint 10, are prepared.

At this time, the reducer 50 is prepared of a high-density polyethylene having a large diameter portion 50a having the same outer diameter and inner diameter as the polyethylene pipe 102 and a small diameter portion 50b having a diameter smaller than that of the large diameter portion 50a. .. Further, as the short pipe 52 with a flange, a short pipe main body 52a having the same outer diameter and inner diameter as the small diameter portion 50b of the reducer 50 and an annular flange portion 52b are integrally formed on the outer surface of one end of the short pipe main body 52a. Prepare the one made of high-density polyethylene. A tapered surface 52c having a larger diameter toward one end is formed on the inner surface of one end of the short pipe body 52a by cutting or the like. Further, as the loose flange 54, a metal one having an inner diameter smaller than the outer diameter of the large diameter portion 50a of the reducer 50 and larger than the outer diameter of the small diameter portion 50b is prepared.

Next, as shown in FIG. 4B, the loose flange 54 is externally fitted to the short pipe body 52a of the short pipe 52 with a flange. However, the loose flange 54 may be externally fitted to the small diameter portion 50b of the reducer 50. Then, in this state, as shown in FIG. 4C, the end face of the small diameter portion 50b of the reducer 50 and the end face of the short pipe body 52a of the short pipe 52 with a flange are abutted and butt fused. As a result, a pipe joint 10 having a reduced diameter second pipe portion 32 and having a loose flange 14 externally fitted to the second pipe portion 32 is manufactured. A bead 56 is formed in the butt fusion portion (second pipe portion 32), and the bead 56 may be left as it is or may be removed by cutting.

As described above, according to this embodiment, a tapered surface 38 is formed on the inner surface of the end portion of the body portion 20 on the second connection end 20b side to avoid interference of the valve body 112 of the butterfly valve 108 with the body portion 20. Therefore, the steel pipe 104 (different type pipe) can be appropriately connected with the butterfly valve 108 sandwiched between the second connection end 20b of the body portion 20 without using the conversion flange short pipe. Therefore, the member cost, the construction time, and the work load of the builder can be reduced as compared with the case of using the conversion flange short pipe.

Further, since the second pipe portion 32 having a reduced diameter is formed in the body portion 20 of the joint main body 12 and the loose flange 14 is externally fitted to the second pipe portion 32, the nominal diameter of the pipeline 100 is increased. Even if it is large, the position of the bolt hole 28 of the loose flange 14 can be set to the same position as the position of the bolt hole of the flange portion 106 of the steel pipe 104. As a result, the loose flange 14 and the flange portion 106 of the steel pipe 104 can be directly fastened, so that the polyethylene pipe 102 and the steel pipe 104 can be appropriately connected without using a conversion flange short pipe.

In the above-described embodiment, the tapered surface 38 is a two-step tapered surface, but the shape of the tapered surface 38 can be changed as appropriate. For example, the tapered surface 38 can be a tapered surface having an arcuate cross section along the side edge of the valve body 112, which also has the same effect as the two-step tapered surface.

Further, in the above-described embodiment, the flange portion 22 is provided with a second pipe portion 32 having a reduced diameter in the body portion 20 and a structure in which the loose flange 14 is externally fitted to the second pipe portion 32. The loose flange 14 and the flange portion 106 of the steel pipe 104 can be directly fastened while passing the bolt 122 to the outside in the radial direction, but the present invention is not limited to this.

For example, as in the embodiment shown in FIGS. 5 and 6, the protruding length (radial length) of the flange portion 22 is increased, and a bolt hole 42 for passing the bolt 122 is formed in the flange portion 22. Then, the loose flange 14 and the flange portion 106 of the steel pipe 104 (different type pipe) may be directly fastened. Hereinafter, although the description will be made in detail, the same reference numbers will be assigned to the same parts as those in the above-described embodiment, and the duplicated description will be omitted or simplified.

In the embodiment shown in FIGS. 5 and 6, the joint body 12 is formed on a cylindrical body portion 20 having the same outer diameter and inner diameter as the polyethylene pipe 102 and an end outer surface of the body portion 20 on the second connection end 20b side. It includes a flange portion 22 that is integrally formed. The flange portion 22 has an outer diameter equal to or slightly larger than the outer diameter of the flange portion 106 of the steel pipe 104, and the flange portion 22 is formed with a plurality of bolt holes 42 at the same positions as the bolt holes of the flange portion 106. Will be done. On the other hand, the loose flange 14 is formed in an annular plate shape having an inner diameter larger than the outer diameter of the polyethylene pipe 102 and an outer diameter substantially the same as the outer diameter of the flange portion 22, and is formed on the body portion 20 of the joint body 12. It is externally fitted in a loosely fitted state. The loose flange 14 is also formed with a plurality of bolt holes 28 at the same positions as the bolt holes of the flange portion 106. As a result, even when the nominal diameter of the pipeline 100 is large, the loose flange 14 and the flange portion 106 of the steel pipe 104 can be directly fastened without using the conversion flange short pipe.

Further, a tapered surface 38 having a diameter larger toward the second connection end 20b is formed on the inner surface of the end portion of the body portion 20 on the second connection end 20b side. The tapered surface 38 of this embodiment is a one-step tapered surface, but when the steel pipe 104 is connected to the second connection end 20b of the body portion 20 with the butterfly valve 108 for the steel pipe 104 sandwiched between them, the body portion 20 It is the same as the above-described embodiment that the butterfly valve 108 is formed so as to avoid interference with the valve body 112 of the butterfly valve 108. Further, the distance of the shortest distance portion where the distance between the tapered surface 38 and the outer surface of the body portion 20 is the shortest is set to be larger than the wall thickness of the polyethylene pipe 102. As a result, the steel pipe 104 can be appropriately connected with the butterfly valve 108 sandwiched between the second connection end 20b of the body portion 20 without using the conversion flange short pipe, and the strength of the base end portion of the flange portion 22 can be increased. Can be secured.

When connecting the steel pipe 104 and the butterfly valve 108 to the pipe joint 10, the loose flange 14 is engaged with the flange portion 22, and the flange portion 22 and the butterfly valve 108 are engaged between the loose flange 14 and the flange portion 106 of the steel pipe 104. The valve box 110 is sandwiched between the two. Further, the bolt holes 28 of the loose flange 14, the bolt holes 42 of the flange portion 22, and the bolt holes of the flange portion 106 are aligned. Then, the bolt 122 is inserted into each bolt hole and tightened with the nut 124 to fasten the loose flange 14 and the flange portion 106 of the steel pipe 104.

The pipe joint 10 of the embodiment shown in FIGS. 5 and 6 can be manufactured by using a short pipe having the same outer diameter and inner diameter as the polyethylene pipe 102 instead of the reducer 50 in the manufacturing method shown in FIG. However, in the pipe joint 10 of this embodiment, the joint body 12 is not formed by butt fusion of the short pipe and the short pipe with a flange, but after the entire joint body 12 is integrally molded, the joint body 12 is formed. It can also be manufactured by externally fitting the loose flange 14 to the body portion 20 of the above.

Further, as another embodiment, as shown in FIG. 7, a groove 44 through which the bolt 122 passes is formed on the outer surface of the flange portion 22 of the joint body 12 (that is, a petal-shaped flange portion 22 is formed) to form a loose flange. The position of the bolt hole 28 of the 14 may be the same as the position of the bolt hole of the flange portion 106 of the steel pipe 104 so that the loose flange 14 and the flange portion 106 of the steel pipe 104 can be directly fastened.

Further, in each of the above-described embodiments, the first connection end 20a of the body portion 20 is connected to the polyethylene pipe 102 by using the EF socket 120, but the shape of the body portion 20 on the first connection end 20a side is appropriately changed. It is possible. For example, it is also possible to butt-fuse the EF single socket to the first connection end 20a of the above-described embodiment in advance so that the EF socket 120 can be connected to the polyethylene pipe 102 without using the EF socket 120. In other words, the first connection end provided in the pipe joint 10 may be an EF single receiving port. Further, the first pipe portion 30 itself of the embodiment shown in FIG. 1 can be replaced with the EF socket, and the portion of the body portion 20 of the embodiment shown in FIG. 5 on the side of the first connection end 20a (butt fused). It is also possible to replace the short tube part) with an EF socket.

Further, in each of the above-described embodiments, the steel pipe 104 is connected to the second connection end 20b of the body portion 20 with the butterfly valve 108 for different types of pipes sandwiched between them, but of course, different types of pipes such as the steel pipe 104 are directly connected. You can also do it.

The specific numerical values such as the dimensions and the specific shapes mentioned above are merely examples, and can be appropriately changed as necessary such as product specifications.

10… Loose flanged pipe joint 12… Joint body 14… Loose flange 20… Body part 22… Flange part 30… First pipe part 32… Second pipe part 38… Tapered surface 102… Polyethylene pipe 104… Steel pipe (different type pipe)
106 ... Flange 108 ... Butterfly valve 112 ... Valve body

Claims (2)

A pipe joint with a loose flange for connecting a polyethylene pipe and a heterogeneous pipe and a butterfly valve for the dissimilar pipe.
A body portion having a first connection end connected to the polyethylene pipe and a second connection end connected to the different type pipe with the butterfly valve sandwiched between them, and an end of the body portion on the second connection end side. A polyethylene joint body having an annular flange portion integrally formed on the outer surface of the portion, and an outer fitting to the body portion, and fastened to the flange portion of the dissimilar pipe in a state of being engaged with the flange portion. With a loose flange
A tapered surface having a diameter larger toward the second connection end is formed on the inner surface of the end portion of the body portion on the second connection end side.
The tapered surface is a pipe joint with a loose flange, which is formed so as to avoid interference of the valve body of the butterfly valve with the body portion. The pipe joint with a loose flange according to claim 1, wherein the distance of the shortest distance portion where the distance between the tapered surface and the outer surface of the body portion is the shortest is set to a size equal to or larger than the wall thickness of the polyethylene pipe.

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