JP7264700B2 - Pipe joint with loose flange and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a loose flanged pipe joint and a manufacturing method thereof, and more particularly to a loose flanged pipe joint for connecting, for example, a polyethylene pipe and a different type of pipe, and a manufacturing method thereof.

An example of this type of conventional loose flanged pipe joint is disclosed in Patent Document 1. Patent Literature 1 discloses a polyethylene resin short pipe (joint main body) having a flange (collar portion) integrally provided at one end and a seal ring mounting groove provided on the flange end face. A fastening flange (loose flange) is attached to the outer surface of the polyethylene resin short pipe, and by fastening the fastening flange and the flange portion of the dissimilar pipe in a state where the fastening flange is engaged with the flange, the polyethylene resin short pipe and the heterogeneous pipe are connected. On the other hand, a polyethylene resin pipe is connected to the other end of the polyethylene resin short pipe using an electrofusion socket (EF socket).

Here, when a heterogeneous pipe such as a steel pipe is connected to a joint body made of polyethylene, the joint body and the heterogeneous pipe have different wall thicknesses, so even if they have the same nominal diameter, they have different outer diameters. Moreover, the difference in outer diameter increases as the nominal diameter of the pipeline increases. For this reason, when the nominal diameter of the pipe becomes large, the loose flange and the flange portion of the dissimilar pipe do not match, and a situation arises in which they cannot be directly fastened.

Therefore, conventionally, in a pipeline with a small nominal diameter, the loose flange and the flange portion of a different type of pipe are directly fastened as in the technique of Patent Document 1, while in a pipeline with a large nominal diameter (for example, 350 mm or more), As shown in FIG. 8, a loose flanged pipe joint 1 and a dissimilar pipe 2 are connected by interposing a metal conversion flange short pipe 3 having flanges 4 at both ends.

JP 2004-169797 A

However, if a conversion flange short pipe is used to connect a pipe joint with a loose flange and a pipe of a different type, the member cost is increased by the additional need for the conversion flange short pipe. 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.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a novel loose flanged pipe joint and method of manufacturing the same.

Another object of the present invention is to provide a loose flanged pipe joint and a method of manufacturing the same, which can properly connect a polyethylene pipe and a heterogeneous pipe without using a conversion flange short pipe.

A first invention is a pipe joint with a loose flange for connecting a polyethylene pipe and a steel pipe, the body having a first connection end connected to the polyethylene pipe and a second connection end connected to the steel pipe . and an annular flange integrally formed on the outer surface of the second connection end side of the body, and a state fitted to the body and engaged with the flange The body is formed between the first pipe portion formed on the first connection end side and the first pipe portion and the flange portion, and the polyethylene pipe a second pipe portion having a smaller diameter than the outer diameter; the loose flange has an inner diameter smaller than the outer diameter of the polyethylene pipe and is fitted to the second pipe portion; has an inner diameter greater than or equal to the inner diameter of the second pipe and less than the outer diameter, and the inner surface of the connection portion between the first pipe and the second pipe has a diameter from the first pipe to the second pipe. A loose flanged pipe joint with a tapered surface that becomes smaller .

In a first invention, a loose flanged pipe joint is a pipe joint for connecting a polyethylene pipe and a steel pipe , and includes a joint body and a loose flange. The joint main body is made of polyethylene and includes a trunk portion and an annular collar portion integrally formed with the trunk portion. Also, the body portion has a first pipe portion and a second pipe portion having a smaller diameter than the outer diameter of the polyethylene pipe. The loose flange has an inner diameter smaller than the outer diameter of the polyethylene pipe and is fitted onto the second pipe portion. Also, the inner diameter of the first pipe portion is set to be greater than or equal to the inner diameter of the second pipe portion and less than the outer diameter. Furthermore, the inner surface of the connection portion between the first pipe portion and the second pipe portion is a tapered surface that decreases in diameter from the first pipe portion toward the second pipe portion.

Thus, by forming the second pipe portion having a smaller diameter than the outer diameter of the polyethylene pipe in the trunk portion of the joint body and mounting the loose flange on this second pipe portion, the inner diameter of the loose flange can be reduced. At the same time, the outer diameter of the flange can be reduced. Therefore, even in a pipeline with a large nominal diameter, the bolt holes of the loose flange can be formed at the same positions as the bolt holes of the flange of the steel pipe , so that the loose flange and the flange of the steel pipe can be directly fastened. Become.

According to the first invention, the bolt holes of the loose flange can be formed at the same positions as the bolt holes of the flange portion of the steel pipe. can connect to

A second invention is according to the first invention, and a tapered surface whose diameter increases toward the second connection end is formed on the inner surface of the end portion on the second connection end side of the body portion.

A third invention is according to the second invention, wherein the inner diameter of the second connecting end is larger than the inner diameter of the polyethylene pipe.

According to the second and third inventions, even if the diameter-reduced second pipe portion is formed in the trunk portion, the step between the inner surface of the trunk portion of the joint body and the inner surface of the steel pipe can be reduced or eliminated. , the fluid in the pipeline can flow smoothly.

A fourth invention is according to the second or third invention, 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 greater than the wall thickness of the polyethylene pipe. be.

According to the fourth invention, even if the tapered surface is formed on the inner surface of the body portion, the strength of the proximal end portion of the flange portion can be ensured.

A fifth invention is according to any one of the second to fourth inventions, wherein the second connection end is connected to the steel pipe with a butterfly valve for steel pipe interposed therebetween, and the tapered surface is connected to the butterfly valve for the body portion. is formed so as to avoid interference of the valve body.

According to the fifth invention, even if the butterfly valve is arranged between the loose flanged pipe joint and the steel pipe, it is possible to prevent the operation of the valve element of the butterfly valve from being hindered.
A sixth invention is according to any one of the first to fifth inventions, and the loose flanged pipe joint is used for connecting a polyethylene pipe and a steel pipe having a nominal diameter of 200 mm or more and 700 mm or less.

A seventh invention is a method for manufacturing a loose flanged pipe joint for connecting a polyethylene pipe and a steel pipe, comprising: (A) a large-diameter portion having the same outer diameter and inner diameter as the polyethylene pipe and a large-diameter portion The inner diameter of the large-diameter portion is equal to or greater than the inner diameter of the small-diameter portion and less than the outer diameter of the small-diameter portion, and the inner surface of the connection portion between the large-diameter portion and the small-diameter portion extends from the large-diameter portion. A polyethylene reducer with a tapered surface that tapers toward the small diameter portion , and a polyethylene that has the same outer and inner diameters as the small diameter portion and is integrally formed with an annular flange on the outer surface of one end. and a loose flange having an inner diameter that is smaller than the outer diameter of the large-diameter portion and larger than the outer diameter of the small-diameter portion, and (B) the loose flange is attached to the small-diameter portion of the reducer or the short pipe with the collar. is a method for manufacturing a loose flanged pipe joint, wherein the small diameter portion of the reducer and the other end portion of the flanged short pipe are butt-fused to each other.

According to the seventh invention, the loose flanged pipe joint according to the first invention can be manufactured.

According to the present invention, the bolt holes of the loose flange can be formed at the same positions as the bolt holes of the flange portion of the dissimilar pipe. can connect to

The above object, other objects, features and advantages of the present invention will become more apparent from the detailed description of embodiments given below with reference to the drawings.

1 is a front view showing how a polyethylene pipe and a different type of pipe are connected using a loose flanged pipe joint according to an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view showing how the loose flanged pipe joint of FIG. 1 is used to connect a polyethylene pipe and a pipe of a different kind. FIG. 2 is a front view showing the loose flanged pipe joint of FIG. 1; FIG. 2 is a cross-sectional view showing the loose flanged pipe joint of FIG. 1; FIG. 2 is a cross-sectional view showing how the loose flanged pipe joint of FIG. 1 and a different type of pipe are connected with a butterfly valve interposed therebetween. It is an illustration figure which shows an example of the manufacturing method of a pipe joint with a loose flange. It is a partial enlarged sectional view showing a modification of the end by the side of the 2nd connection end of the body part. FIG. 4 is a front view showing a state in which a conventional loose flanged pipe joint and a different type of pipe are connected using a conversion flange short pipe.

1 and 2, a loose flanged pipe joint 10 (hereinafter simply referred to as "pipe joint 10") according to one embodiment of the present invention is fitted to a joint main body 12 and its body portion 20. It is provided with a loose flange 14, which is used to connect different types of pipes such as polyethylene pipes and steel pipes.

Pipes 100 to which the pipe joint 10 is applied are various pressure pipes (also called internal pressure pipes) such as industrial water pipes, fire fighting water pipes, cooling water pipes, well water pipes, agricultural water pipes, and air pipes. , the pipe joint 10 is suitably used for a pressure pipe line 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 with a nominal diameter of 400 mm and a steel pipe 104 will be described. In this example, the polyethylene tube 102 has an outer diameter of 450 mm and an inner diameter of 364 mm. On the other hand, the steel pipe 104 has an outer diameter of 406 mm and an inner diameter of 396 mm. An annular flange portion 106 conforming to the JIS 10K flange standard is integrally provided at one end of the steel pipe 104 (the connection portion with the pipe joint 10). However, the flange portion 106 may conform to other flange standards.

As shown in FIGS. 3 and 4, the pipe joint 10 includes a joint body 12 made of polyethylene resin such as high-density polyethylene, and a loose flange 14 made of metal such as stainless steel.

The joint main body 12 includes a cylindrical body portion 20 that forms 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. As shown in FIG. An annular collar portion 22 projecting radially outward is integrally formed on the outer surface of the end portion of the body portion 20 on the side of the second connecting end 20b. Furthermore, a gasket mounting groove 24, which is an annular groove having a rectangular cross section, is formed in the end face of the collar portion 22 (or the second connecting end 20b of the body portion 20). A gasket 26 such as an O-ring (see FIG. 2) 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, and is formed in the shape of an annular plate. The loose flange 14 has an outer diameter larger than the outer diameter of the flange portion 22 of the joint body 12, and has a plurality of bolt holes 28 arranged at predetermined intervals in the circumferential direction in a portion protruding outward from the flange portion 22. have.

In such a pipe joint 10, the first connection end 20a of the body portion 20 is connected to the polyethylene pipe 102 using an EF socket (electrofusion socket) 110, as shown in FIGS. On the other hand, the second connection end 20b of the body portion 20 fastens the loose flange 14 and the flange portion 106 of the steel pipe 104 using the bolts 112 and nuts 114 while the loose flange 14 is engaged with the collar portion 22. Thus, it is connected to the steel pipe 104 .

Here, in conventional pipe joints with loose flanges, when the nominal diameter of the pipe becomes large, the positions of the bolt holes in the loose flange and the positions of the bolt holes in the flange portion of the dissimilar pipe do not match. There was a situation in which it was not possible to directly fasten the flange portion of the pipe. This problem was dealt with by using a conversion flange short pipe made of metal (see FIG. 8). However, the use of the conversion flange short pipe has the problem of increased material costs and work load.

Therefore, in this embodiment, a structure is adopted in which a diameter-reduced portion (second pipe portion 32) is provided in the body portion 20 of the joint main body 12, and the loose flange 14 is fitted onto the diameter-reduced portion. By forming the bolt holes 28 at the same positions as the bolt holes 108 of the flange portion 106 of the steel pipe 104, the loose flange 14 and the flange portion 106 of the steel pipe 104 can be directly fastened. A specific description will be given below.

As shown in FIGS. 3 and 4, the body portion 20 of the joint main body 12 is formed between a first pipe portion 30 formed on the first connection end 20a side and between the first pipe portion 30 and the flange portion 22. and a second tube portion 32 to be connected. 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 110 . In this example, the outer diameter of the first tube portion 30 is 450 mm and its inner diameter is 364 mm. On the other hand, the second pipe portion 32 has a diameter smaller 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 tube portion 32 is 400 mm and its inner diameter is 324 mm. 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 toward the second pipe portion 32 . The loose flange 14 is fitted onto the second pipe portion 32 of the body portion 20 .

Further, in this embodiment, the outer diameter of the collar portion 22 of the joint body 12 is the same as or slightly smaller than the diameter of the circle connecting the innermost sides of the plurality of bolt holes 108 formed in the flange portion 106 of the steel pipe 104. set. In other words, the flange portion 22 is formed to have a size that does not interfere with the bolt hole 108 of the steel pipe 104 . Furthermore, the inner diameter of the loose flange 14 is set smaller than the outer diameter of the polyethylene pipe 102 . If the outer diameter of the flange portion 22 is reduced, the engagement area between the flange portion 22 and the loose flange 14 is reduced. can be done. 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 fitted onto the second pipe portion 32 having a reduced diameter. be. In this embodiment, the outer diameter of the collar portion 22 is 482 mm. The loose flange 14 has an inner diameter of 425 mm and an outer diameter of 560 mm. A plurality of bolt holes 28 are formed at the same positions as the bolt holes 108 of the flange portion 106 of the steel pipe 104 in the portion of the loose flange 14 that protrudes outward beyond the collar portion 22 .

Furthermore, in this embodiment, a tapered surface 38 that increases in diameter toward the second connection end 20b is formed on the inner surface of the end portion of the body portion 20 on the side of the second connection end 20b. The tapered surface 38 is composed of a first tapered surface 38a with a large inclination angle formed on the first connection end 20a side and a second tapered surface 38b with a small inclination angle formed on the second connection end 20b side. It has a two-step tapered surface. The inner diameter of the second connecting end 20 b , 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 substantially the same as the inner diameter of the steel pipe 104 . By forming such a tapered surface 38, the step between the inner surface of the body portion 20 and the inner surface of the steel pipe 104 caused by forming the second pipe portion 32 can be reduced or eliminated. The fluid inside can flow smoothly.

Also, the distance D of the shortest distance portion 40 where the distance between the tapered surface 38 and the outer surface of the body portion 20 is the shortest is set to be equal to or greater than the 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 side of the second connection end 20b are determined so that the strength of the proximal end portion of the collar portion 22 is ensured even when the tapered surface 38 is formed.

Furthermore, in this embodiment, as shown in FIG. 5, by forming a tapered surface 38 on the inner surface of the end portion of the body portion 20, even if the butterfly valve 120 is arranged between the pipe joint 10 and the steel pipe 104, This prevents the operation of the valve body 122 from being hindered. That is, when the steel pipe 104 is connected to the second connection end 20b of the body portion 20 with the butterfly valve 120 for the steel pipe 104 (for different types of pipes) interposed therebetween, interference of the valve body 122 of the butterfly valve 120 with the body portion 20 is avoided. A tapered surface 38 is formed so as to

The butterfly valve 120 is a wafer-shaped butterfly valve, and controls fluid by rotating a disk-shaped valve element 122 within a short cylindrical valve box 124 . Further, when the butterfly valve 120 is provided in the pipeline 100, the flange 22 and the valve box 124 of the butterfly valve 120 are sandwiched between the loose flange 14 and the flange 106 of the steel pipe 104. A nut 114 is used to fasten the loose flange 14 and the flange portion 106 .

Here, the tapered surface 38 is mainly formed by cutting. is a one-step tapered surface, the tapered surface 38 can be shaped along the side edge of the valve body 122 . As a result, the size of the body portion 20 to be cut can be reduced, so that the thickness of the body portion 20 can be ensured and the time required for cutting can be reduced. However, the tapered surface 38 may be formed during molding instead of cutting.

Next, 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. 6A, a reducer 50, a short pipe 52 with a flange, and a loose flange 54, which are members for manufacturing the pipe joint 10, are prepared.

At this time, as the reducer 50, one made of 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 smaller diameter than the large-diameter portion 50a is prepared. . As the flanged short pipe 52, a short pipe main body 52a having the same outer diameter and inner diameter as those of 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 one made of high-density polyethylene that has been sealed. A tapered surface 52c that increases in diameter toward one end is formed on the inner surface of one end of the short pipe main 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. 6B, the loose flange 54 is externally fitted to the short pipe main 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. FIG. In this state, as shown in FIG. 6(C), the end face of the small diameter portion 50b of the reducer 50 and the end face of the short pipe main body 52a of the short pipe 52 with flange are butt-fused together. As a result, the pipe joint 10 having the second pipe portion 32 with a reduced diameter and the loose flange 14 fitted onto the second pipe portion 32 is manufactured. A bead 56 is formed in the butt fused portion (second tube portion 32), but this bead 56 may be left as it is or may be removed by cutting.

As described above, according to this embodiment, the body portion 20 of the joint main body 12 is formed with the second pipe portion 32 having a reduced diameter, and the loose flange 14 is fitted onto the second pipe portion 32. Therefore, the positions of the bolt holes 28 of the loose flange 14 can be made the same as the positions of the bolt holes 108 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 (heterogeneous pipe) can be appropriately connected without using a conversion flange short pipe. Therefore, compared with the case of using a conversion flange short pipe, it is possible to reduce the member cost, the construction time, and the work load of the construction worker.

In the above-described embodiment, the tapered surface 38 formed on the inner surface of the end portion of the body portion 20 on the side of the second connection end 20b is a two-step tapered surface, but the shape of the tapered surface 38 is not limited to this. Can be changed. For example, as shown in FIG. 7(A), the tapered surface 38 can be a tapered surface having an arcuate cross section, or as shown in FIG. 7(B), the tapered surface 38 can be a one-step tapered surface. can also Also, the tapered surface 38 is not necessarily formed, and the corner between the second connecting end 20b and the inner surface of the body portion 20 may be left as it is, as shown in FIG. 7(C).

In the above-described embodiment, the first connecting end 20a of the body portion 20 was connected to the polyethylene pipe 102 using the EF socket 110, but the shape of the first connecting end 20a side of the body portion 20 (that is, the first The shape of the pipe portion 30) can be changed as appropriate. For example, the first connecting end 20a of the above-described embodiment may be pre-butt-fused with an EF socket so that it can be connected to the polyethylene tube 102 without using the EF socket 110. FIG. In other words, the first connection end of the pipe fitting 10 may be an EF socket. Also, the first tube portion 30 itself of the above-described embodiment can be replaced with an EF receptacle. That is, the EF socket may constitute the first tube, and the first tube need not necessarily have the same outer and inner diameters as the polyethylene tube 102 .

It should be noted that the specific numerical values such as the dimensions and the specific shapes given above are merely examples, and can be appropriately changed according to the needs such as the specifications of the product.

DESCRIPTION OF SYMBOLS 10 ... Pipe joint with a loose flange 12 ... Joint main 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 (heterogeneous pipe)
106 ... Flange portion 120 ... Butterfly valve

Claims (7)

A pipe joint with a loose flange for connecting a polyethylene pipe and a steel pipe ,
a body portion having a first connection end connected to the polyethylene pipe and a second connection end connected to the steel pipe ; a polyethylene joint body including an annular flange, and a loose flange that is externally fitted to the body and fastened to the flange of the steel pipe in a state of engagement with the flange,
The body portion is
a first pipe portion formed on the first connection end side;
a second pipe portion formed between the first pipe portion and the flange portion and having a smaller diameter than the outer diameter of the polyethylene pipe;
The loose flange has an inner diameter smaller than the outer diameter of the polyethylene pipe and is fitted to the second pipe portion,
The inner diameter of the first tube portion is greater than or equal to the inner diameter of the second tube portion and less than the outer diameter,
A pipe joint with a loose flange, wherein an inner surface of a connection portion between the first pipe portion and the second pipe portion is a tapered surface that decreases in diameter from the first pipe portion toward the second pipe portion. 2. The pipe joint with a loose flange according to claim 1, wherein a tapered surface that increases in diameter toward the second connection end is formed on the inner end surface of the body portion on the second connection end side. 3. The loose flanged pipe joint according to claim 2, wherein the inner diameter of said second connecting end is larger than the inner diameter of said polyethylene pipe. 4. The loose flanged pipe according to claim 2 or 3, 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. fittings. The second connection end is connected to the steel pipe with a butterfly valve for the steel pipe interposed therebetween,
The pipe joint with a loose flange according to any one of claims 2 to 4, wherein the tapered surface is formed so as to avoid interference of the body of the butterfly valve with the body. The loose flanged pipe joint according to any one of claims 1 to 5, wherein the loose flanged pipe joint is used for connecting the polyethylene pipe and the steel pipe having a nominal diameter of 200 mm or more and 700 mm or less. A method for manufacturing a pipe joint with a loose flange for connecting a polyethylene pipe and a steel pipe , comprising:
(A) has a large-diameter portion having the same outer diameter and inner diameter as the polyethylene pipe and a small-diameter portion smaller in diameter than the large-diameter portion, and the inner diameter of the large-diameter portion is equal to or greater than the inner diameter of the small-diameter portion; a reducer made of polyethylene having a size smaller than an outer diameter, and an inner surface of a connection portion between the large diameter portion and the small diameter portion forming a tapered surface that decreases in diameter from the large diameter portion toward the small diameter portion; , a short tube made of polyethylene having the same outer diameter and inner diameter as the small-diameter portion and integrally formed with an annular flange on the outer surface of one end; Prepare a loose flange having an inner diameter larger than the outer diameter of the small diameter portion,
(B) Loose fitting, in which the small-diameter portion of the reducer and the other end of the short flanged pipe are butt-fused while the loose flange is fitted onto the small-diameter portion of the reducer or the short flanged pipe. A method for manufacturing a flanged pipe joint.

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