JP2011122692A - Flange connecting structure of duct constitution member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a seal mounting groove simply and easily in a construction site even when the seal mounting groove does not exist in any of annular connecting surfaces of both connecting flanges. <P>SOLUTION: Both connecting flanges 2-3 equipped with smoothly flat annular contacting surfaces 2a-3a, which are formed at ends of both duct constitution members 2-3 and can be contacted flatly in conduit axis direction, are connected and fastened with a fastener 4 in such a condition that an annular gasket 6 is interposed between the annular contacting surfaces 2a-3a, an inner side ring 9, which constructs an inner side circumferential wall surface at a radial inner side of annular seal mounting groove 8 for mounting the gasket 6, and an outer side ring 10, which constructs an outer side circumferential wall surface at a radial outer side of the seal mounting groove 8, are arranged between the annular contacting surfaces 2a-3a of the both connecting flanges 2-3, and a position holding means A, which holds at least one of the inner side ring 9 and an outer side ring 10 at a setting circumferential wall forming position of the seal mounting groove 8, is provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a flange joint structure that flange-joins pipe line components such as fluid pipes (water pipes, etc.) and fluid equipment (gate valves, air valves, etc.) that constitute a fluid piping system.

As a flange joint structure of pipe line components,
(1) As shown in Patent Document 1, both connecting flanges having smooth annular joint surfaces formed at the ends of both pipe-line constituting members and capable of being brought into surface contact with each other from the pipe axial direction A flange joint structure in which an annular sheet-like gasket is interposed between the joint surfaces and tightened and connected with bolts and nuts as fasteners;
(2) As shown in Patent Document 2, both connecting flanges having smooth annular joint surfaces formed at the end portions of both pipe line constituent members and capable of surface contact from the tube axis direction are A flange joint structure that is tightened and connected with bolts and nuts as fasteners in a state where a circular gasket having a circular or semi-circular cross section is interposed in a seal mounting groove formed on the annular joint surface;
Exists.

  In the case of the latter flange joint structure, when the pressure of the fluid flowing in the pipe constituent member acts on the gasket to which the initial contact surface pressure is applied by the fastening operation of the fastener, this fluid pressure is applied to the gasket. Since the surface pressure is increased, a higher self-sealing function (self-sealing action) can be obtained compared to the former flange joint structure.

JP-A-9-13008 JP 2004-19832 A

  However, there are many former flange joint structures in the fluid piping system. For example, in a construction site where a high self-seal function is required, the other flange jointed to the fluid pipe that is one of the pipe line components is provided. When renewing a fluid device that is a pipe component member, if there is no seal mounting groove on either the annular joint surface of the connecting flange on the fluid pipe side or the annular joint surface of the new connecting flange on the fluid device side Needs to cut the seal mounting groove on the annular joint surface of one of the connecting flanges.

  However, it is difficult to cut the seal mounting groove at the construction site, and the seal mounting groove will be cut at a well-equipped factory, resulting in a high construction cost and a long construction period. There is.

  The present invention has been made in view of the above-mentioned actual situation, and the main problem is that even if no seal mounting groove is present on any of the annular joint surfaces of the two connecting flanges, the seal is not provided at the construction site. The object is to provide a flange joint structure for a pipe constituent member that can easily and easily reveal the mounting groove.

A first characteristic configuration according to the present invention is such that both connecting flanges having smooth annular joint surfaces formed at end portions of both pipe constituent members and having a smooth annular joint surface that can be brought into surface contact with each other from the pipe axis direction are the annular joints. It is a flange joint structure of pipeline constituent members that are tightened and connected with a fastener with an annular gasket interposed between the faces,
An inner ring constituting an inner circumferential wall surface on the radially inner side of the annular seal mounting groove for mounting the gasket between the annular joint surfaces of the both connecting flanges, and a radially outer side of the seal mounting groove And a position holding means for holding at least one of the inner ring and the outer ring at a set peripheral wall forming position of the seal mounting groove. .

  According to the above configuration, for example, in a construction site where a high self-seal function is required, the fluid device that is the other pipe constituent member that is flange-joined to the fluid pipe that is the one pipe constituent member is updated. At this time, even if there is no seal mounting groove on any of the annular joint surfaces of both connecting flanges, the inner ring and the outer ring are arranged between the annular joint surfaces of both connecting flanges. An annular seal mounting groove for mounting the gasket can appear between the inner peripheral wall surface configured with the outer peripheral surface and the outer peripheral wall surface configured with the inner peripheral surface of the outer ring.

  In addition, since at least one of the inner ring and the outer ring is held at the setting peripheral wall forming position of the seal mounting groove by the position holding means, when both the rings are held in position, the fastener is tightened. An accurate self-sealing function (self-sealing function) can be obtained by an accurate seal mounting groove from the beginning of operation.

  Even when only one ring is held at the setting peripheral wall forming position of the seal mounting groove by the position holding means, the other ring forms the setting peripheral wall as the gasket is compressed due to the tightening operation of the fastener. Since the position is corrected to the position side, it can be brought close to the expected high self-sealing function (self-sealing action).

  Therefore, at the construction site where a high self-seal function is required, even if there is no seal mounting groove on any of the annular joint surfaces of the two connecting flanges, both the inner and outer rings and the position holding means are used. By simply preparing, the seal mounting groove can be easily and easily revealed at the construction site, and the construction cost can be reduced and the construction period can be shortened compared to cutting the seal mounting groove. Can do.

  According to a second characteristic configuration of the present invention, the inner ring is formed in a ring-shaped metal core material and at least a portion of the core material facing the annular joint surfaces of the two connecting flanges. It is in the point comprised from an elastic seal layer.

  According to the above configuration, using the inner ring constituting the inner peripheral wall surface on the radially inner side of the seal mounting groove, the elastic seal layer formed on the metal core material constituting the inner ring and the both By pressure contact with the annular joint surface of the connecting flange, it is possible to seal hermetically on the radially inner side of the gasket, so that the sealing function can be improved by cooperation with the gasket.

  A third characteristic configuration according to the present invention is that the inner diameter of the outer ring is the same as or substantially the same as the outer diameter of the gasket.

  According to the above configuration, the relative positional relationship between the gasket and the outer ring can be determined or substantially determined from the beginning of the tightening operation of the fastener, facilitating the assembly, and the connection of both the connecting flanges. The contact pressure between the outer ring and the gasket at the time can be increased.

  A fourth characteristic configuration according to the present invention is configured by a first positioning portion formed on the inner ring in a state where the position holding means is in contact with or close to the inner peripheral surface of at least one of the pipe line constituent members. In the point.

  According to the above configuration, when the inner ring is assembled between the joint surfaces of the connecting flanges of the two pipe constituent members, the first positioning portion formed on the inner ring is inserted along the inner peripheral surface of the pipe constituent member. By doing so, it is possible to easily align the shaft cores of the two pipe constituent members and the shaft core of the inner ring, and to suppress the displacement of the inner ring during the fastening and fixing operation of the two connecting flanges. be able to.

  According to a fifth characteristic configuration of the present invention, the position holding means is formed on the outer ring in a state where it is engaged with or close to an annular recess formed on the outer peripheral surface side between the joint surfaces of the two connecting flanges. It is in the point comprised from the 2nd positioning part.

  According to the above configuration, when the outer ring is assembled between the joint surfaces of the connecting flanges of the two pipe constituent members, the second positioning portion formed on the outer ring is connected to the outer peripheral surface side between the joint surfaces of the two connecting flanges. By engaging or approaching the annular recess formed in the opening, it is possible to easily align the shaft cores of the two pipe constituent members and the shaft core of the outer ring, and to fasten and fix both the connecting flanges. It is possible to suppress the displacement of the outer ring during operation.

  According to a sixth feature of the present invention, the position holding means includes an insertion hole for the bolt of the fastener, and is formed on the outer ring in a state where the fastener is positioned and held between both connecting flanges. It is in the point comprised from the made connection part.

  According to the above configuration, when the outer ring is assembled between the joint surfaces of the connecting flanges of the two pipe constituent members, the bolt of the fastener is inserted into the insertion hole of the connecting portion formed in the outer ring, and the outer ring By positioning and holding the connecting portion of the ring between the joint surfaces of both connecting flanges, the shaft cores of the two pipe constituent members and the shaft core of the outer ring can be easily aligned, and both the connecting flanges It is possible to prevent the outer ring from being displaced during the tightening and fixing operation.

Longitudinal side view showing the first embodiment of the flange joint structure of the pipe constituent member of the present invention Enlarged cross-sectional view of the main part before tightening Partial cutaway perspective view of the main part Enlarged sectional view of the main part when tightening and fixing The expanded sectional view of the principal part at the time of the clamping fixation which shows 2nd Embodiment of this invention The expanded sectional view of the principal part at the time of the clamping fixation which shows 3rd Embodiment of this invention The expanded sectional view of the principal part at the time of clamping fixation which shows 4th Embodiment of this invention The expanded sectional view of the principal part at the time of the clamping fixation which shows 5th Embodiment of this invention The expanded sectional view of the principal part at the time of the clamping fixation which shows 6th Embodiment of this invention The expanded sectional view of the principal part at the time of the clamping fixation which shows 7th Embodiment of this invention The top view of the outer side ring which shows 7th Embodiment of this invention The expanded sectional view of the principal part before the fastening fixation which shows 8th Embodiment of this invention The expanded sectional view of the principal part at the time of the clamping fixation which shows 9th Embodiment of this invention The expanded sectional view of the principal part at the time of clamping fixation which shows the modification of 9th Embodiment of this invention

[First Embodiment]
1 to 4 show a flange joint structure in a fluid piping system, and a connecting flange of a branch pipe portion 2 as an upstream side pipe constituting member protruding from a cast iron pipe water pipe 1 which is an example of a fluid pipe. In 2A, the upstream connecting flange 3A of the repair valve 3, which is an example of a fluid device as a downstream pipe constituting member, is in a watertight state by a fastener (fastening means) 4 including a plurality of sets of bolts 4A and nuts 4B. The connection flange 5A of the air valve 5 which is an example of a fluid device is fastened to the downstream connection flange 3B of the repair valve 3 with a plurality of sets of bolts 4A and nuts 4B. The tool 4 is connected so as to be detachable in a watertight state.

  An annular and smooth annular joint surface 2a that can be brought into surface contact from the tube axis direction on the center side of the opposing surfaces of the connection flange 2A of the branch pipe portion 2 and the upstream connection flange 3A of the repair valve 3; 3a is formed, and between the opposing surfaces of the two annular joint surfaces 2a and 3a, an annular gasket having a semi-elliptical cross-sectional shape (in this embodiment, GF type gasket 1 is used) 6 And an annular stepped surface that is recessed to the side away from the opposing surface of the mating coupling flanges 3A, 2A at a portion that is continuous to the radially outer side of the annular joint surfaces 2a, 3a. 2b and 3b are formed, and when the branch pipe portion 2 and the repair valve 3 are tightened and connected, an annular recess 7 that opens radially outward on the outer peripheral surface side between the joint surfaces of the two connecting flanges 2A and 3A. Is formed.

  Insertion holes 2c and 3c for the bolts 4A of the fastener 4 are formed through a plurality of locations in the circumferential direction of the annular step surfaces 2b and 3b of the connecting flanges 2A and 3A.

  Between the joint surfaces of the connecting flange 2A of the branch pipe portion 2 and the upstream connecting flange 3A of the repair valve 3, an inner circumference on the radially inner side of the annular seal mounting groove 8 for mounting the gasket 6 is provided. An inner ring 9 that constitutes a wall surface and an outer ring 10 that constitutes an outer peripheral wall surface on the radially outer side of the seal mounting groove 8 are disposed, and among the inner ring 9 and the outer ring 10, Position holding means A is provided for holding the outer peripheral surface 9a of the inner ring 9 at an inner peripheral wall surface formation setting position that is a setting peripheral wall formation position of the seal mounting groove 8.

  The inner ring 9 is a core material made of an annular metal (for example, stainless steel (SUS), spheroidal graphite cast iron (FCD), general structural rolled steel (SS), etc.) whose cross section is formed in a horizontally long rectangular shape. (Core metal) 9A and an elastic seal layer 9b covering the entire circumference of the core material 9A and capable of sealing the space between the facing surfaces of the connecting flanges 2A and 3A with the annular joint surfaces 2a and 3a in a watertight state. And a covering material 9B made of an elastic material (for example, styrene butadiene rubber (SBR)).

The outer ring 10 is made of an annular metal (for example, stainless steel (SUS), spheroidal graphite cast iron (FCD), general structural rolled steel (SS), etc.) having a transverse cross section formed in a horizontally long rectangular shape, and The inner diameter of the inner peripheral surface is the same as or substantially the same as the outer diameter of the gasket 6.
According to this configuration, the relative positional relationship between the gasket 6 and the outer ring 10 can be determined or substantially determined from the beginning of the tightening operation of the fastener 4, the assembly can be facilitated, and both couplings can be achieved. The contact pressure between the outer ring 10 and the gasket 6 when the flanges 2A and 3A are connected can be increased.

  Of the two corners on the radially outer side of the outer ring 10, the corner located on the downstream side (the repair valve 3 side) has the branch pipe 2 as shown in FIGS. 2 and 4. The connecting flange 2A and the upstream side connecting flange 3A of the repair valve 3 are inserted and operated to the flow path blocking position through a clearance formed within the range of the loosening operation allowance of a fastener (an example of a fastening means) 4 for fixedly connecting the connecting flange 2A. A tapered guide surface 10a for inserting and guiding the thin plate-like partition plate valve of the in-pipe flow path blocking device is formed.

  The thickness of the outer ring 10 was determined by tightening the bolts 4A and nuts 4B with a predetermined torque until both side surfaces in the tube axis direction were pressed against the annular joint surfaces 2a and 3a of the connecting flanges 2A and 3A. At this time, the contact portion between the annular joint surfaces 2a, 3a of the both connecting flanges 2A, 3A and the gasket 6 is configured to have a thickness at which a set contact surface pressure is obtained.

  In this case, the outer ring 10 functions as a gauge block that regulates the facing distance between the annular joint surfaces 2a and 3a of the coupling flanges 2A and 3A to a set interval when the bolt 4A and nut 4B are tightened. The desired high self-sealing function (self-sealing function) can be surely exhibited while simplifying the tightening operation.

  Further, in a state where both side surfaces in the tube axis direction of the outer ring 10 are pressed against the annular joint surfaces 2a and 3a of the connecting flanges 2A and 3A, both elastic seal layers 9b in the covering material 9B of the inner ring 9 are both. Since it is press-contacted to the annular joint surfaces 2a and 3a of the connecting flanges 2A and 3A, a high sealing function can be exhibited by cooperation with the gasket 6.

  When both the connecting flanges 2A and 3A are tightened and fixed in the set connected state, the thickness of the outer ring 10 is made smaller than the facing distance between the annular joint surfaces 2a and 3a of the both connecting flanges 2A and 3A. In this case, the facing distance between the annular joint surfaces 2a and 3a can be made closer to the set interval by press-contacting the inner ring 9 and the annular joint surfaces 2a and 3a of the connecting flanges 2A and 3A. The gap between the opposing surfaces of the outer ring 10 and the upstream connection flange 3A of the repair valve 3 is managed by a clearance gauge, and the pressure contact between the annular joint surfaces 2a, 3a of the connection flanges 2A, 3A and the gasket 6 It is necessary to adjust the contact pressure at the part to the set contact pressure.

  The position holding means A is a cylindrical first protruding integrally formed along the tube axis direction from the covering material 9B of the inner ring 9 in a state in contact with the inner peripheral surface 2d of the branch pipe portion 2. The outer peripheral surface of the first positioning portion 11 is configured by the positioning portion 11, and the outer diameter on the distal end side is smaller than the inner diameter of the branch pipe portion 2, and the outer diameter on the proximal end side is the branch pipe portion. The tapered mounting guide surface 11a is slightly larger than the inner diameter of 2.

  The branch pipe part 2 and the first positioning part 11 are concentrically or substantially the same by contact between the tapered mounting guide surface 11a of the first positioning part 11 and the opening side portion of the inner peripheral surface 2d of the branch pipe part 2. It is configured to align to a core state, in other words, to adjust the position in the radial direction so that the center (axis) of the first positioning portion 11 and the axis of the branch pipe portion 2 coincide with each other. ing.

  In the first embodiment, the outer peripheral surface 11a of the first positioning portion 11 formed integrally with the covering material 9B of the inner ring 9 is formed as a tapered tapered surface having a mounting guide function. You may comprise the outer peripheral surface 11a of 1 positioning part 11 in parallel with the said inner peripheral surface 2d in the state which adjoins to the inner peripheral surface 2d of the said branch pipe part 2. As shown in FIG.

  In the first embodiment, the first positioning portion 11 is formed in a cylindrical shape. However, the first positioning portion 11 is in contact with or close to a plurality of locations in the circumferential direction of the inner peripheral surface 2d of the branch pipe portion 2. You may comprise from a some positioning piece.

  Furthermore, in the said 1st Embodiment, although this invention was applied to the flange joint structure of the connection flange 2A of the said branch pipe part 2 and the upstream connection flange 3A of the repair valve 3, the downstream connection flange 3B of the repair valve 3 is used. The present invention may also be applied to a flange joint structure between the air valve 5 and the connection flange 5A of the air valve 5.

  Furthermore, in the first embodiment, the GF type gasket 1 having a semi-elliptical cross-sectional shape is used as the gasket 6, but an O-ring having a cross-sectional shape formed in a circular shape or the like is used. May be used.

[Second Embodiment]
In the first embodiment described above, the position holding means A is integrated along the tube axis direction from the covering material 9B of the inner ring 9 in a state in contact with or close to the inner peripheral surface 2d of the branch pipe portion 2. As shown in FIG. 5, the position holding means A is in contact with the inner peripheral surface 3d of the repair valve 3 as shown in FIG. You may comprise from the cylindrical 1st positioning part 12 integrally formed by protruding from the coating | coated material 9B along the pipe-axis core direction.

  As with the first positioning portion 11 of the first embodiment, the outer peripheral surface of the first positioning portion 12 has an outer diameter on the distal end side smaller than the inner diameter of the branch pipe portion 2 and an outer diameter on the proximal end side. Is formed on a tapered mounting guide surface 12 a that is slightly larger than the inner diameter of the branch pipe portion 2.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.

  Further, the outer peripheral surface 12a of the first positioning portion 12 may be configured in parallel with the inner peripheral surface 3d in a state of being close to the inner peripheral surface 3d of the repair valve 3, and further, the first positioning portion 12 May be composed of a plurality of positioning pieces that contact or approach a plurality of locations in the circumferential direction of the inner peripheral surface 3d of the repair valve 3.

[Third Embodiment]
As shown in FIG. 6, you may comprise the 1st positioning part 11 of 1st Embodiment, and the 1st positioning part 12 of 2nd Embodiment combining.
That is, the position holding means A is a cylinder formed integrally and projecting along the tube axis direction from the covering material 9B of the inner ring 9 in a state where it is in contact with or close to the inner peripheral surface 2d of the branch pipe portion 2. A cylindrical shape that is integrally projected along the tube axis direction from the covering material 9B of the inner ring 9 in a state in contact with or close to the inner peripheral surface 3d of the repair valve 3 You may comprise from the 1st positioning part 12 of this.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment and 2nd Embodiment, the same number is attached to the same structure location as 1st Embodiment and 2nd Embodiment. The description thereof is omitted.

[Fourth Embodiment]
In the first to third embodiments described above, the inner ring 9 has a sealing function. However, as shown in FIG. 7, the inner ring 9 is made of a metal material (for example, stainless steel (SUS), spherical You may comprise from graphite cast iron (FCD), general structure rolling steel (SS), etc.).

  In addition, as an example of the position holding means A, a cylindrical first positioning formed so as to protrude from the inner ring 9 along the tube axis direction in contact with or close to the inner peripheral surface 2d of the branch pipe portion 2. The portion 11 is also integrally formed from the same metal material as the inner ring 9, and the outer peripheral surface 11 a of the first positioning portion 11 is in close proximity to the inner peripheral surface 2 d of the branch pipe portion 2. It is configured in parallel with 2d.

In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.
Similarly to the fourth embodiment, the inner ring 9 and the first positioning portion 12 in the second embodiment may be integrally formed from the same metal material, and further, the inner ring 9 in the third embodiment. And the first positioning portions 11 and 12 may be integrally formed from the same metal material.

[Fifth Embodiment]
In the flange joint structure shown in FIG. 8, the inner ring 9 includes an annular metal core material (core metal) 9A whose cross section is formed in a horizontally-long rectangular shape, and a gasket 6 side of the core material 9A and a branch. The inner ring 9 is covered with a covering material 9B made of an annular elastic material (for example, styrene butadiene rubber (SBR)) having an L-shaped cross section that covers the connecting flange 2A side of the pipe portion 2. The material 9B is an example of the position holding means A, and is a cylinder that protrudes from the covering material 9B of the inner ring 9 along the tube axis direction in contact with or close to the inner peripheral surface 2d of the branch pipe portion 2. A first positioning portion 11 having a shape is integrally formed.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.

[Sixth Embodiment]
In the flange joint structure shown in FIG. 9, the position holding means A that holds at least one of the inner ring 9 and the outer ring 10 at the set peripheral wall forming position of the seal mounting groove 8 joins the connecting flanges 2A and 3A. A second positioning portion 13 integrally formed in a substantially T-shaped cross section at the radially outer end of the outer ring 10 in a state of being engaged with or close to the annular recess 7 formed in the outer peripheral surface between the surfaces. It is composed of

  The inner positioning surface 13a of the second positioning portion 13 is configured such that both the connecting flanges constituting the annular recess 7 when the inner ring 9 and the outer ring 10 are clamped and fixed between the joint surfaces of the both connecting flanges 2A and 3A. It is comprised so that it may contact | abut or adjoin to the inner side rising peripheral surface in 2A, 3A annular | circular shaped level | step difference surface 2b, 3b.

  In the sixth embodiment, the inner diameter of the inner ring 9 is the same or substantially the same as the diameter of the inner peripheral surface 2d of the branch pipe portion 2 and the diameter of the inner peripheral surface 3d of the repair valve 3. A length (height) h in the tube axis direction of the second positioning portion 13 is configured to be smaller than an opening width (vertical width) H in the tube axis direction of the annular recess 7.

In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.
In the sixth embodiment, the second positioning portion 13 is integrally formed in a substantially T-shaped cross section with respect to the radially outer side end portion of the outer ring 10. The outer ring 10 may be integrally formed in a substantially L-shaped cross section with respect to the radially outer side end portion.
At this time, when the inner ring 9 and the outer ring 10 are clamped and fixed between the joint surfaces of the two connecting flanges 2A and 3A, the inner positioning surface 13a of the second positioning portion 13 is connected to the two connecting flanges 2A and 3A. It will contact or be close to one of the inner rising peripheral surfaces of the annular step surfaces 2b and 3b.

Furthermore, in the sixth embodiment, the inner ring 9 has an inner peripheral surface 2d of the branch pipe portion 2 and an inner peripheral surface 3d of the repair valve 3 as in any of the first to fifth embodiments described above. The first positioning portion 11 that is in contact with or close to at least one of them may be integrally projected along the tube axis direction.
In this case, the position holding means A has a first positioning portion 11 that holds the inner ring 9 at an inner peripheral wall surface formation setting position that is a setting peripheral wall formation position, and the outer ring 10 is formed as a setting peripheral wall of the seal mounting groove 8. It is comprised from the 2nd positioning part 13 hold | maintained in the outer peripheral wall surface formation setting position which is a position.

[Seventh Embodiment]
In the flange joint structure shown in FIG. 10, the position holding means A is provided with an insertion hole 14a for the bolt 4A of the fastener 4 and the annular recess 7 between the connecting flanges 2A and 3A has the fastener 4 of the fastener 4. It is comprised from the connection part 14 integrally formed in the radial direction outer side edge part of the outer side ring 10 in the state hold | maintained with the volt | bolt 4A.

  As shown in FIG. 11A, the connecting portion 14 is viewed from the axial direction of the tube axis, and the connecting flanges 2 </ b> A and 3 </ b> A are inserted through the radially outer end of the outer ring 10. Only a portion corresponding to the holes 2c and 3c is formed in a cross shape or a radial shape protruding outward in the radial direction, or as shown in FIG. 11B, it is integrated over the entire outer peripheral surface of the outer ring 10. It can be configured to be formed in an annular shape.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.

[Eighth Embodiment]
In the flange joint structure shown in FIG. 12, the lower end portion of the inner ring 9 and the lower end portion of the outer ring 10 are connected by a connecting portion 15 with a radial interval corresponding to the set groove width of the seal mounting groove 8. May be configured.

The connecting portion 15 is provided over the entire circumference of the lower end portion of the inner ring 9 and the lower end portion of the outer ring 10, or a plurality of circumferential portions between the lower end portion of the inner ring 9 and the lower end portion of the outer ring 10 are provided. You may disperse | distribute and provide in a location.
Further, the connecting portion 15 is formed integrally with the lower end portion of the inner ring 9 and the lower end portion of the outer ring 10, or is formed separately from the inner ring 9 and the outer ring 10, and screws or the like. It may be attached to the lower end of the inner ring 9 and the lower end of the outer ring 10.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.

[Ninth Embodiment]
When the outer ring 10 is made of spheroidal graphite cast iron (FCD) or general structure rolled steel (SS), the outer ring 10 may corrode with long-term use. As a countermeasure for preventing corrosion of the outer ring 10, as shown in the flange joint structure of FIG. 13, the outer peripheral surface of the outer ring 10 is covered with an annular recess 7 between the two connecting flanges 2 </ b> A and 3 </ b> A in a watertight or close contact state. An anticorrosion cover 16 made of an elastic material (for example, styrene butadiene rubber or urethane rubber) is provided.

  The thickness of the corrosion protection cover 16 is configured to be equal to or greater than the thickness of the outer ring 10, and the diameter (inner diameter) of the inner peripheral surface of the corrosion protection cover 16 is the outer diameter of the outer ring 10. The diameter is the same as or slightly smaller than the diameter.

  The corrosion prevention cover 16 is formed with an insertion hole 16a through which the bolt 4A of the fastener 4 penetrates in a contact or elastic pressure contact state, that is, a diameter equal to or slightly smaller than the mountain diameter of the bolt 4A. The position of the anticorrosion cover 16 in the direction of the tube axis is maintained in the annular recess 7 between the connecting flanges 2A and 3A by the bolt 4A of the fastener 4. This is performed by the frictional resistance between the inner peripheral surface of the insertion hole 16a and the outer peripheral surface of the bolt 4A.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.

  Moreover, you may comprise by screwing the nut which positions the said anticorrosion cover 16 in the pipe-axis core direction in the site | part located in the annular recessed part 7 of the said volt | bolt 4A.

  Furthermore, as shown in FIG. 14, the thickness of at least the inner end side portion 16b of the anticorrosion cover 16 is larger than the thickness of the outer ring 10 and the annular shape of the connecting flange 2A on the branch pipe portion 2 side. You may comprise in the thickness which can cover the outer peripheral surface of the outer side ring 10 in the state which contact | abutted to the level | step difference surface 2b in the state which is watertight or close to it.

  In the embodiment of FIG. 14, only the thickness of the inner end side portion 16b of the corrosion protection cover 16 is configured to be larger than the thickness of other portions, but the thickness of the corrosion protection cover 16 in the entire radial direction is increased. Further, the thickness of the anticorrosion cover 16 may be the same as or substantially the same as the opening width (vertical width) H of the annular recess 7 in the tube axis direction.

  Furthermore, the outer diameter of the anticorrosion cover 16 may be configured not to contact the bolt 4A.

[Other Embodiments]
(1) In each of the above-described embodiments, as the flange joint structure between the pipe line constituent members, a flange joint structure between the connection flange 2A of the branch pipe portion 2 and the upstream connection flange 3A of the repair valve 3 is taken as an example. Although explained, it is not limited to such a flange joint structure between a fluid pipe and a fluid device, but a flange joint structure between fluid devices such as a downstream connection flange 3B of the repair valve 3 and a connection flange 5A of the air valve 5. Alternatively, the technique of the present invention can also be applied to a flange joint structure between fluid pipes.

  (2) As position holding means A for holding at least one of the inner ring 9 and the outer ring 10 at a set peripheral wall forming position of the seal mounting groove 8, an adhesive, a screw, or the like other than the methods described in the above embodiments May be used.

  (3) In each of the above-described embodiments, the inner ring 9 and the outer ring 10 are made of a metal material. However, as long as the inner ring 9 and the outer ring 10 have mechanical strength that is not crushed by the tightening connection force of the two connection flanges 2A and 3A. Alternatively, it may be made of a material other than a metal such as a synthetic resin.

A Position holding means 2 Pipeline component (branch pipe)
2A Connection flange 2a Annular joint surface 3 Pipeline component (repair valve)
3A Connecting flange 3a Annular joint surface 4 Fastener 4A Bolt 6 Gasket 7 Annular recess 8 Seal mounting groove 9 Inner ring 9A Core material 9B Covering material 9b Elastic seal layer 10 Outer ring 11 First positioning part 12 First positioning part 13 Second Positioning part 14 Connecting part 14a Insertion hole

Claims (6)

Both connecting flanges that are formed at the ends of both pipe line constituent members and that have a smooth annular joint surface that can be brought into surface contact with each other from the tube axis direction, have an annular gasket interposed between the annular joint surfaces. It is a flange joint structure of pipeline constituent members that are tightened and connected with a fastener in a state,
An inner ring constituting an inner circumferential wall surface on the radially inner side of the annular seal mounting groove for mounting the gasket between the annular joint surfaces of the both connecting flanges, and a radially outer side of the seal mounting groove And an outer ring that constitutes the outer peripheral wall surface of the pipe, and a pipe structure in which position holding means for holding at least one of the inner ring and the outer ring at a setting peripheral wall forming position of the seal mounting groove is provided. Flange joint structure of members.   The inner ring includes a metal core formed in an annular shape, and an elastic seal layer formed in a portion of the core facing the annular joint surface of both the connecting flanges. Item 2. A flange joint structure for a pipe constituent member according to Item 1.   The flange joint structure of a pipe line component according to claim 1 or 2, wherein an inner diameter of the outer ring is configured to be the same as or substantially the same as an outer diameter of the gasket.   The said position holding means is comprised from the 1st positioning part formed in the said inner ring in the state which contacted or adjoined to the internal peripheral surface of at least one pipe line structural member. The flange joint structure of the pipe line component described in 2.   The said position holding means is comprised from the 2nd positioning part formed in the said outer ring in the state which engages or adjoins to the annular recessed part opened in the outer peripheral surface side between the joint surfaces of the said connection flange. Item 3. A flange joint structure for a pipe constituent member according to any one of items 1 to 3.   The position holding means includes an insertion hole for a bolt of the fastener, and includes a connecting portion formed on the outer ring in a state where the fastener is positioned and held between both connecting flanges. Item 3. A flange joint structure for a pipe constituent member according to any one of items 1 to 3.

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