JP4795661B2 - Piping joint structure - Google Patents

Description

  The present invention relates to a pipe joint structure, and particularly to a pipe joint structure in which adjacent pipe members are connected to each other by butt welding.

Conventionally, for example, when stainless steel pipes are connected to each other by butt welding, the welded part is cut off from the air by an inert gas such as helium gas or argon gas in order to prevent oxidation of the welded part on the outer surface side of the pipe. Inert gas welding method is used in which welding is performed, and the inner surface side of the pipe is similarly filled with an inert gas such as helium gas or argon gas in order to prevent oxidation of the welded portion. So-called back sealing has been performed (see, for example, Patent Document 1).
JP-A-62-270281

However, such a conventional method has a problem that a large amount of inert gas is required to back-seal the inside of the pipe, which is uneconomical and expensive.
Also, if the piping path is complicated or the piping length is long, it is difficult to completely seal the back, so the weld located on the inner surface side of the piping is oxidized, resulting in an oxide scale ("NORO"). (Also called).

  The present invention has been made in view of the above circumstances, and provides a pipe joint structure that can be welded without a back seal and can prevent oxidation scale from being generated on the inner surface side of the pipe. For the purpose.

The present invention employs the following means in order to solve the above problems.
In the pipe joint structure according to claim 1, the end of the first pipe and the end of the second pipe disposed adjacent to the first pipe are connected by butt welding, The outer surface of the first pipe material and the outer surface of the second pipe material have a pipe joint structure formed in the same plane, and an inner fitting portion is provided around the end of the first pipe material. The first groove is formed in the circumferential direction on the outer side in the radial direction of the inner fitting portion, and the radius of the inner fitting portion is formed at the end of the second pipe member. An outer fitting portion that is fitted to the outer side in the direction is formed, and a second groove is formed on the end face of the outer fitting portion and in a position facing the first groove in the circumferential direction. The first tube is formed so that its inner diameter gradually decreases toward the end. Together are an outer diameter is formed so as to maintain a constant length, said second tube member, the inner diameter and outer diameter are formed to maintain a constant length In addition, the outer peripheral surface of the inner fitting portion is provided radially outside the inner surface of the end portion of the first pipe member, and the inner fitting portion faces the outer peripheral surface of the inner fitting portion. The peripheral surface is provided on the outer side in the radial direction from the inner surface other than the end portion of the second pipe material .
According to such a pipe joint structure, the first pipe member and the second pipe member are formed by fitting the inner fitting portion of the first pipe member inside the outer fitting portion of the second pipe member. For example, a groove having a substantially V shape in sectional view is formed by one groove and a second groove, and a groove portion formed in a substantially V shape in sectional view from the outer peripheral surface side of these pipe members is formed, for example, They are connected by butt welding by an inert gas welding method.
The inner fitting portion of the first pipe member and the outer fitting portion of the second pipe member are formed by the first groove and the second groove when they are fitted, for example, a cross section The inner peripheral edge of the V-shaped groove is closed (sealed) by the outer peripheral surface of the inner fitting portion, and the outer peripheral surface of the inner fitting portion and the inner peripheral surface of the outer fitting portion There is almost no gap between them.
When welding is performed in this state, it is possible to prevent the inner peripheral end of the welded portion from being exposed in the pipe and to prevent the generation of oxide scale at the inner peripheral end of the welded portion.
That is, according to the pipe joint structure of the present invention, it is possible to eliminate the back seal at the time of welding and to prevent the generation of oxide scale in the pipe.
Since the back seal can be eliminated, it is possible to eliminate the need for a large amount of inert gas conventionally required for performing the back seal, and it is possible to reduce the cost.
In addition, the ability to prevent the generation of oxide scale in the pipe eliminates the need for the flushing and hammering operations conventionally required to remove the oxide scale generated in the pipe, greatly increasing the work period. It can be shortened.
Furthermore, the ability to prevent the generation of oxide scale in the pipes, for example, can reliably prevent accidents such as the oxide scale from entering a bearing such as a power generation turbine installed downstream and damaging the bearing. can do.
Furthermore, since the outer peripheral surfaces of the pipes are formed in the same plane, the appearance can be refreshed, and the appearance can be improved.

The pipe according to claim 2 is connected by the pipe joint structure according to claim 1 .
According to such a pipe, it is possible to weld the connection part between the pipe material and the pipe material constituting the pipe without a back seal, and to prevent the generation of oxide scale on the inner surface side of the connection part. Can do.

  According to the present invention, it is possible to perform welding without a back seal, and it is possible to prevent the generation of oxide scale on the inner surface side of the pipe.

Hereinafter, an example in which an embodiment of a pipe joint structure according to the present invention is applied to a lubricating oil pipe for a power generation turbine (hereinafter referred to as “pipe”) will be described with reference to the drawings.
FIG. 1 is a development view in which a pipe 1 having a pipe joint structure 10 according to this embodiment is developed by cutting along a plane parallel to the extending direction of the pipe 1.
The pipe 1 is configured with a first pipe member 11, a second pipe member (first pipe member) 12, and a third pipe member (second pipe member) 13 as main elements. A pipe joint structure 10 is provided between the pipe material 12 and the third pipe material 13.

The first tubular material 11 is a stainless steel tubular material having a substantially constant thickness throughout and having, for example, V-shaped bevels B formed on the end faces of both ends.
The second tubular material 12 has, for example, a V-shaped groove B formed on the end surface facing the first tubular material 11, and the opposite end (the side facing the third tubular material 13). It is a stainless steel pipe member in which the male part 14 of the pipe joint structure 10 is formed at the end).
The third pipe member 13 is formed with a female portion 15 of the pipe joint structure 10 at an end portion on the side facing the second pipe member 12 and an end surface on the opposite side (on the side facing the first pipe member 11). For example, the end face is a stainless steel tube having a V-shaped groove B formed therein.

FIG. 2 is a cross-sectional view of the second pipe member 12 cut along a plane parallel to the extending direction of the pipe 1.
As shown in FIG. 2, the second pipe member 12 is formed so that its thickness gradually increases from the groove B side to the male part 14 side. That is, the inner diameter of the second pipe member 12 gradually decreases from the groove B side to the male part 14 side, and the outer diameter of the second pipe member 12 extends from the groove B side to the male part 14 side. It is manufactured so as to maintain a length substantially the same as the outer diameter.

The male portion 14 includes an inner fitting portion 14a that protrudes along the inner peripheral surface of the second pipe member 12 from the radially inner end surface, and, for example, a V-shaped groove formed on the radially outer end surface. And a groove portion (first groove) 14b.
The inner fitting portion 14a has a constant thickness over the entire circumferential direction of the second pipe member 12 (for example, t1 = 3.5 mm in the case of stainless steel, and thermal conductivity is higher than stainless steel in the case of carbon steel). This is a member that is thicker than this (for example, about 4 mm to 5 mm) and is an annular member in front view, and on the radially outer side (upper side in the drawing) of the inner fitting portion 14a, there is a female portion. Fifteen outer fitting portions 15a are fitted.

FIG. 3 is a cross-sectional view of the third pipe member 13 cut along a plane parallel to the extending direction of the pipe 1.
As shown in FIG. 3, the third pipe member 13 is formed so that its thickness is substantially constant from the groove B side to the female portion 15 side. That is, the inner diameter and the outer diameter of the third tubular material 13 are formed to have substantially the same length as the inner diameter and the outer diameter of the first tubular material 11.
The female portion 15 includes an outer fitting portion 15a that protrudes along the outer peripheral surface of the third pipe member 13 from an end surface on the outer side in the radial direction, and a V-shaped opening formed on the end surface of the outer fitting portion 15a. And a groove portion (second groove) 15b having a tip.
The outer fitting portion 15a is an annular member that is formed to have a constant thickness (for example, t2 = 6.0 mm) over the entire circumferential direction of the third pipe member 13, and the outer fitting portion 15a. The inner fitting portion 14a of the male portion 14 is fitted on the inner side in the radial direction (lower side in the figure).

The second tube member 12 and the third tube member 13 described above are formed by fitting the inner fitting portion 14a of the second tube member 12 into the inner side of the outer fitting portion 15a of the third tube member 13. The groove 14b and the groove 15b of the female portion 15 form a groove having a substantially V shape in sectional view, and the groove portion formed in the substantially V shape in sectional view is formed on the outer peripheral surface side of the pipe members 12 and 13. To butt welding by an inert gas welding method (see FIG. 1).
When the inner fitting part 14a of the second pipe member 12 and the outer fitting part 15a of the third pipe member 13 are fitted, the groove 14b of the male part 14 and the groove 15b of the female part 15 The inner peripheral end of the groove having a V-shaped cross-sectional view formed by the inner fitting portion 14 is closed (sealed) by the outer peripheral surface of the inner fitting portion 14. There is almost no gap between the inner peripheral surface of the fitting portion 15a.
When welding is performed in this state, it is possible to prevent the inner peripheral end of the welded portion W from being exposed in the pipe and to prevent the generation of oxide scale at the inner peripheral end of the welded portion W.
That is, according to the pipe joint structure 10 according to the present embodiment, the back seal at the time of welding can be eliminated, and the generation of oxide scale in the pipe can be prevented.
Since the back seal can be eliminated, it is possible to eliminate the need for a large amount of inert gas conventionally required for performing the back seal, and it is possible to reduce the cost.
In addition, the ability to prevent the generation of oxide scale in the pipe eliminates the need for the flushing and hammering operations conventionally required to remove the oxide scale generated in the pipe, greatly increasing the work period. It can be shortened.
Furthermore, the ability to prevent the generation of oxide scale in the pipes, for example, can reliably prevent accidents such as the oxide scale from entering a bearing such as a power generation turbine installed downstream and damaging the bearing. can do.
Furthermore, the outer diameters of the first tube member 11, the second tube member 12, and the third tube member 13 are substantially the same, that is, the outer peripheral surface of the pipe 1 is formed in substantially the same plane. Therefore, the appearance can be refreshed and the aesthetics can be improved.

Another embodiment of the pipe joint structure according to the present invention will be described with reference to FIGS.
FIG. 4 is a development view in which the pipe 2 having the pipe joint structure 20 according to the present embodiment is cut along a plane parallel to the extending direction of the pipe 2.
The pipe 2 is configured by using a first pipe member 21, a second pipe member (first pipe member) 22, and a third pipe member (second pipe member) 23 as main elements. A pipe joint structure 20 is provided between the pipe material 22 and the third pipe material 23.

The first tubular material 21 is a stainless steel tubular material having a substantially constant thickness throughout and having, for example, V-shaped bevels B formed on the end faces of both ends.
The second tubular material 22 has, for example, a V-shaped groove B formed on the end surface facing the first tubular material 21, and the opposite end (the side facing the third tubular material 23). It is a stainless steel pipe material in which the male part 24 of the pipe joint structure 20 is formed at the end).
The third pipe member 23 has a female portion 25 of the pipe joint structure 20 formed at an end portion on the side facing the second pipe member 22, and an end surface on the opposite side (on the side facing the first pipe member 21. For example, the end face is a stainless steel tube having a V-shaped groove B formed therein.

FIG. 5 is a cross-sectional view of the second pipe member 22 cut along a plane parallel to the extending direction of the pipe 1.
As shown in FIG. 5, the portions other than the male portion 24 of the second pipe material 22 are formed so that the thickness thereof is substantially constant from the groove B side to the male portion 24 side. That is, the inner diameter and the outer diameter of the second tube material 22 are formed to have substantially the same length as the inner diameter and the outer diameter of the first tube material 21.
On the other hand, the male portion 24 of the second tube material 22 is formed so that the inner diameter thereof is substantially the same as that of the first tube material 21 and the outer diameter thereof is longer than the outer diameter of the first tube material 21. .
The male part 24 has, for example, an inner fitting part 24a that protrudes from the radially inner end face along the inner peripheral surface of the second pipe member 22 and, for example, a V-shaped groove formed on the radially outer end face. And a groove portion (first groove) 24b.
The inner fitting portion 24a is an annular member in a front view formed so as to have a constant thickness (for example, t3 = 5.0 mm) over the entire circumferential direction of the second tubular material 22, and the inner fitting portion 24a. The outer fitting portion 25a of the female portion 25 is fitted to the outer side in the radial direction (upper side in the drawing).

FIG. 6 is a cross-sectional view of the third pipe member 23 cut along a plane that is parallel to the extending direction of the pipe 2.
As shown in FIG. 6, the portion other than the female portion 25 of the third pipe member 23 is formed so that its thickness is substantially constant from the groove B side to the female portion 25 side. That is, the inner diameter and the outer diameter of the third tube material 23 are formed to have substantially the same length as the inner diameter and the outer diameter of the first tube material 21.
On the other hand, the female portion 25 of the third tubular material 23 has an inner diameter that is substantially the same as that of the first tubular material 21, and an outer diameter that is longer than the outer diameter of the first tubular material 21. .
The female portion 25 includes an outer fitting portion 25a that protrudes along the outer peripheral surface of the third pipe member 23 from the end surface on the radially outer side, and a V-shaped opening formed on the end surface of the outer fitting portion 25a. And a groove portion (second groove) 25b having a tip.
The outer fitting portion 25a is an annular member in a front view formed to have a constant thickness (for example, t4 = 7.0 mm) over the entire circumferential direction of the third tube member 23, and the outer fitting portion 25a. The inner fitting portion 24a of the male portion 24 is fitted on the inner side in the radial direction (lower side in the figure).

The second tube material 22 and the third tube material 23 described above are formed by fitting the inner fitting portion 24a of the second tube material 22 into the inner side of the outer fitting portion 25a of the third tube material 23. The groove 24b and the groove 25b of the female portion 25 form a groove having a substantially V shape in a sectional view, and a groove portion formed in a substantially V shape in the sectional view from the outer peripheral surface side of the pipe members 22 and 23. Are connected by butt welding by an inert gas welding method (see FIG. 4).
When the inner fitting part 24a of the second pipe member 22 and the outer fitting part 25a of the third pipe member 23 are fitted, the groove 24b of the male part 24 and the groove 25b of the female part 25 are The inner peripheral end of the groove having a V-shaped cross section formed by the step is closed (sealed) by the outer peripheral surface of the inner fitting portion 24, and the outer peripheral surface of the inner fitting portion 24a and the outer fitting portion 25a. There is almost no gap between the inner peripheral surface of each other.
When welding is performed in this state, it is possible to prevent the inner peripheral end of the welded portion W from being exposed in the pipe and to prevent the generation of oxide scale at the inner peripheral end of the welded portion W.
That is, according to the pipe joint structure 20 according to the present embodiment, the back seal at the time of welding can be eliminated, and the generation of oxide scale in the pipe can be prevented.
Since the back seal can be eliminated, it is possible to eliminate the need for a large amount of inert gas conventionally required for performing the back seal, and it is possible to reduce the cost.
In addition, the ability to prevent the generation of oxide scale in the pipe eliminates the need for the flushing and hammering operations conventionally required to remove the oxide scale generated in the pipe, greatly increasing the work period. It can be shortened.
Furthermore, the ability to prevent the generation of oxide scale in the pipes, for example, can reliably prevent accidents such as the oxide scale from entering a bearing such as a power generation turbine installed downstream and damaging the bearing. can do.
Furthermore, the inner diameters of the first tube member 11, the second tube member 12, and the third tube member 13 are substantially the same, that is, the inner peripheral surface of the pipe 1 is formed in substantially the same plane. Therefore, no matter which direction the fluid flows, impurities such as dust do not accumulate inside the pipe 2, and the fluid flows more smoothly than in the above-described embodiment. Can do.

Another embodiment of the pipe joint structure according to the present invention will be described with reference to FIG.
FIG. 7 is a development view in which the pipe 3 having the pipe joint structure 30 according to the present embodiment is cut along a plane parallel to the extending direction of the pipe 3.
The pipe 3 is configured with a first pipe member 31, a second pipe member (first pipe member) 32, and a third pipe member (second pipe member) 33 as main elements. A pipe joint structure 30 is provided between the pipe material 32 and the third pipe material 33.

The first tubular material 31 is a stainless steel tubular material having a substantially constant thickness throughout and having, for example, V-shaped bevels B formed on the end faces of both ends.
The second tubular material 32 has, for example, a V-shaped groove B formed on the end surface facing the first tubular material 31, and the opposite end (the side facing the third tubular material 33). It is a stainless steel pipe material in which the male part 34 of the pipe joint structure 30 is formed at the end).
The third pipe member 33 is formed with a female portion 35 of the pipe joint structure 30 at the end portion on the side facing the second pipe member 32, and the opposite end surface (on the side facing the first pipe member 31). For example, the end face is a stainless steel tube having a V-shaped groove B formed therein.

  The second pipe member 32 is formed so that its thickness gradually increases from the groove B side to the male part 34 side. That is, the inner diameter of the second pipe member 32 gradually decreases from the groove B side to the male part 34 side, and the outer diameter of the second pipe member 32 extends from the groove B side to the male part 34 side. It is manufactured so as to maintain a length substantially the same as the outer diameter.

The male part 34 has an inner fitting part 34a protruding along the inner peripheral surface of the second pipe member 32 from the radially inner end face, and, for example, a V-shaped groove formed on the radially outer end face. And a groove portion (first groove) 34b.
The inner fitting portion 34a has a constant thickness (for example, t1 = 3.5 mm in the case of stainless steel and higher thermal conductivity than stainless steel in the case of carbon steel) over the entire circumferential direction of the second pipe member 32. It is a member that is formed to have a thickness (for example, about 4 mm to 5 mm) that is thicker than this, and is an annular member in front view, and a female portion is disposed radially outward (upper side in the drawing) of the inner fitting portion 34a. An outer fitting portion 35a of 35 is fitted.
Further, the inner fitting portion 34a is positioned so that the distal end surface thereof is closer to the proximal end side (root side) of the female portion 35 than in the embodiment described with reference to FIGS. The inner fitting portion 34a and the outer fitting portion 35a are provided so as to extend in the direction in which the second pipe member 32 extends so that the overlapping portion between the inner fitting portion 34a and the outer fitting portion 35a increases.

The third pipe member 33 is formed so that its thickness is substantially constant from the groove B side to the female part 35 side. That is, the inner diameter and the outer diameter of the third tubular material 33 are formed to have substantially the same length as the inner diameter and the outer diameter of the first tubular material 31.
The female portion 35 includes an outer fitting portion 35a that protrudes along the outer peripheral surface of the third pipe member 33 from the end surface on the radially outer side, and a V-shaped opening formed on the end surface of the outer fitting portion 35a. And a groove portion (second groove) 35b having a tip.
The outer fitting portion 35a is an annular member formed in a front view and having a constant thickness (for example, t2 = 6.0 mm) over the entire circumferential direction of the third pipe member 33, and the outer fitting portion 35a. The inner fitting portion 34a of the male portion 34 is fitted on the inner side in the radial direction (lower side in the figure).

The second tube member 32 and the third tube member 33 described above are formed by fitting the inner fitting portion 34a of the second tube member 32 into the inner side of the outer fitting portion 35a of the third tube member 33. The groove 34b and the groove 35b of the female portion 35 form a groove having a substantially V shape in sectional view, and the groove portion formed in the substantially V shape in sectional view is formed on the outer peripheral surface side of the pipe members 32 and 33. From butt welding by an inert gas welding method.
When the inner fitting part 34a of the second pipe member 32 and the outer fitting part 35a of the third pipe member 33 are fitted, the groove 34b of the male part 34 and the groove 35b of the female part 35 are The inner peripheral end of the groove having a V-shaped cross-sectional view formed by the outer peripheral surface of the inner fitting portion 34 is sealed (sealed) by the outer peripheral surface of the inner fitting portion 34a. There is almost no gap between the inner peripheral surface of the fitting portion 35a.
When welding is performed in this state, it is possible to prevent the inner peripheral end of the welded portion W from being exposed in the pipe and to prevent the generation of oxide scale at the inner peripheral end of the welded portion W.
That is, according to the pipe joint structure 30 according to the present embodiment, the back seal at the time of welding can be eliminated, and the generation of oxide scale in the pipe can be prevented.
Since the back seal can be eliminated, it is possible to eliminate the need for a large amount of inert gas conventionally required for performing the back seal, and it is possible to reduce the cost.
In addition, the ability to prevent the generation of oxide scale in the pipe eliminates the need for the flushing and hammering operations conventionally required to remove the oxide scale generated in the pipe, greatly increasing the work period. It can be shortened.
Furthermore, the ability to prevent the generation of oxide scale in the pipes, for example, can reliably prevent accidents such as the oxide scale from entering a bearing such as a power generation turbine installed downstream and damaging the bearing. can do.
Furthermore, the outer diameters of the first pipe member 31, the second pipe member 32, and the third pipe member 33 are substantially the same, that is, the outer peripheral surface of the pipe 3 is formed in substantially the same plane. Therefore, the appearance can be refreshed and the aesthetics can be improved.
Furthermore, the distal end surface of the inner fitting portion 34a is positioned closer to the proximal end side (root side) of the female portion 35 than the embodiment described with reference to FIGS. Since the inner fitting portion 34 is formed (so that the overlapping portion between the joining portion 34a and the outer fitting portion 35a increases), the dent between the inner fitting portion 34 and the outer fitting portion 35a is reduced. Thus, impurities such as dust accumulated in the pipe 3 can be reduced.

In the above-described embodiment, the groove B of the first pipe members 11, 21, 31, the groove B of the second tube members 12, 22, 32, and the grooves of the first tube members 11, 21, 31 are included. B and the groove B of the third pipe members 13, 23, 33 are each butt welded by an inert gas welding method with a groove portion formed in a substantially V shape in cross section by the groove B and the groove B. To connect.
However, the present invention is not limited to this, and the first tube members 11, 21, 31 and the second tube members 12, 22, 32, and the first tube members 11, 21, 31 and the third tube member 13. , 23 and 33 can be connected by the above-described pipe joint structures 10, 20 and 30, respectively.

  Further, the present invention is not only applicable for connecting straight pipes (straight pipes) as described above. For example, an elbow pipe 41 as shown in FIG. It is also possible to connect the above-described third pipe member 33, or to connect a T-shaped pipe 51 and the above-described third pipe member 33 as shown in FIG.

Furthermore, when the pipe joint structure 10 shown in FIG. 1 is adopted, it is desirable that the fluid flow direction is the direction indicated by the white arrow in the figure.
As a result, the fluid can flow smoothly along the inner peripheral surface of the pipe 1, and impurities such as dust are prevented from accumulating on the end surface (the right end surface in the drawing) of the inner fitting portion 14a. be able to.

Furthermore, when the inner fitting portions 14a, 24a, and 34a are made of stainless steel, the thicknesses t1 and t3 are preferably set to 3.5 mm or more.
Thereby, it is possible to prevent a burn mark due to welding from being formed on the inner peripheral surface side of the pipes 1, 2, 3.

  Furthermore, the present invention can be applied not only to a stainless steel pipe as described above but also to a pipe made of carbon steel, aluminum, alloy steel, or the like.

  Furthermore, the present invention can be applied not only to the lubricating oil piping for power generation turbines as described above, but also to any piping as necessary, such as control oil piping for fuel generation turbines, fuel oil piping, and gas piping. be able to.

It is the expanded view which cut and expanded the lubricating oil piping for power generation turbines which comprised one Embodiment of the piping joint structure by this invention in the surface parallel to the extension direction of piping. It is sectional drawing which cut | disconnected the 2nd pipe material (1st pipe material) shown in FIG. 1 by the surface parallel to the extension direction of piping. It is sectional drawing which cut | disconnected the 3rd pipe material (2nd pipe material) shown in FIG. 1 by the surface parallel to the extension direction of piping. It is the expanded view which cut and expanded the lubricating oil piping for power generation turbines which comprised other embodiment of the piping joint structure by this invention in the surface parallel to the extension direction of piping. It is sectional drawing which cut | disconnected the 2nd pipe material (1st pipe material) shown in FIG. 4 by the surface parallel to the extension direction of piping. It is sectional drawing which cut the 3rd pipe material (2nd pipe material) shown in FIG. 4 by the surface parallel to the extension direction of piping. It is the expanded view which cut and developed the lubricating oil piping for power generation turbines which comprises another embodiment of the piping joint structure by this invention on the surface parallel to the extension direction of piping. It is sectional drawing for demonstrating the example which applied the pipe joint structure shown in FIG. 7 to connecting an elbow pipe and a straight pipe. FIG. 8 is a cross-sectional view for explaining an example in which the pipe joint structure shown in FIG. 7 is applied to connect a T-shaped pipe and a straight pipe.

1 Piping 2 Piping 3 Piping 10 Piping joint structure 12 Second pipe (first pipe)
13 Third pipe (second pipe)
14 end 14a inner fitting part 14b groove (first groove)
15 end 15a outer fitting part 15b groove (second groove)
20 Piping joint structure 22 Second pipe material (first pipe material)
23 Third pipe (second pipe)
24 end 24a inner fitting part 24b groove (first groove)
25 end 25a outer fitting part 25b groove (second groove)
30 Piping joint structure 32 Second pipe material (first pipe material)
33 Third pipe (second pipe)
34 end 34a inner fitting part 34b groove (first groove)
35 end 35a outer fitting part 35b groove (second groove)
41 Elbow pipe (first pipe material)
51 T-shaped pipe (first pipe material)

Claims (2)

The end of the first pipe and the end of the second pipe disposed adjacent to the first pipe are connected by butt welding, and the outer surface of the first pipe and the second The outer surface of the pipe material is a pipe joint structure formed in the same plane,
An inner fitting portion is formed in the end portion of the first pipe member in the circumferential direction, and a first groove is formed in the circumferential direction on the radially outer side of the inner fitting portion,
An outer fitting portion that is fitted to the outer side of the inner fitting portion in the radial direction is formed at an end portion of the second pipe member. A second groove is formed in the circumferential direction at a position facing the tip,
The first pipe is formed so that its inner diameter gradually decreases toward the end, and its outer diameter is formed to maintain a constant length,
The second pipe material is formed so that the inner diameter and the outer diameter thereof each maintain a constant length,
The outer peripheral surface of the inner fitting portion is provided on the radially outer side than the inner surface of the end portion of the first pipe member, and the inner peripheral surface of the outer fitting portion is opposed to the outer peripheral surface of the inner fitting portion. Is provided on the outer side in the radial direction with respect to the inner surface other than the end portion of the second pipe material. A pipe connected by the pipe joint structure according to claim 1 .

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