JP2000039087A - Flange part joining structure for existing pipeline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flange part joining structure for an existing pipeline, having a structure capable of completely eliminating inconvenience such as gas leakage by reliably preventing flange parts from being separated from each other at joining parts, capable of improving economy by reducing the use of resin in order to eliminate the inconvenience, and capable of preventing workability in relation to a member interposed in a pipeline from being deteriorated. SOLUTION: In a flange part connecting structure such as a valve 2 to be interposed between existing pipelines 1, 1' is provided with a pair of patches 3 faced to each other along the laying directions of the existing pipelines 1, 1' and arranged outside flange parts 1A, 1A', and connecting rods 4 having the extending ends perforating through the patches 3. The flange parts 1A, 1A' are pinched by fastening the connecting rods 4 from the outside of the patches 3 so that the facing distance may not be changed, and high strength resin 6 is filled in a state where the flange parts 1A, 1A' and patches 3 are embedded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flange joint structure for an existing pipeline, and more particularly, to preventing gas from leaking from a flange portion of a valve or the like interposed in an existing pipeline such as a gas pipe. The present invention relates to a flange joint structure which can be prevented from occurring.

[0002]

2. Description of the Related Art Various valves and the like are interposed in an existing pipeline such as a gas pipeline. In many cases, these valves and the like are bolted in a state where a sealing packing material is disposed on the flange surface when joining the flanges formed at the open ends of the existing pipeline.

[0003] Such a flange joint portion interposed in an existing pipeline may cause the packing material to age due to aging, vibration of a vehicle passing over the pipeline (road), earthquake, or the like, resulting in the flange joint. There is a concern that bolts and nuts may be loosened or the bolts may break, resulting in a leakage accident from the flange joint.

As a countermeasure against this, conventionally, a structure in which a seal is reinforced so as to surround an abutted flange joint portion and surround the outer periphery thereof with an annular ring (for example, see Japanese Patent Application Laid-Open No.
No. 15188) or a structure in which a sealing material such as resin is filled in a cover frame surrounding a flange joint (for example, JP-A-57-76396, JP-A-57-11).
No. 6992).

[0005]

In mounting the above-mentioned flange joint, there are two methods for detecting a gas leak which is expected to occur later and a method for repairing the gas leak. You also need to take this into account.

[0006] Further, in mounting the flange joint, in consideration of the earthquake resistance after the construction, a portion around the bolt and nut of the flange is repaired with high strength to increase rigidity, and a portion of the flange joint is high. It is necessary to improve the airtightness by repairing the elasticity and to take measures so that the reinforcing means does not adversely affect the valve body.

In response to such a demand, a structure has been proposed in which a coating layer using resin is provided so as to bury the exposed portions of the bolts and nuts provided in the flange joint portion, thereby increasing the rigidity around the bolts and nuts. (For example, Japanese Patent Application No. 7-251425 related to the earlier application of the present applicant).

However, in a structure having a resin coating layer,
The following problems were found:

FIG. 7 shows a case where the pipes are connected via a shutoff valve or the like.
Side flange portions 30A, 30B are connected by fastening with a flange portion 33A on the pipeline 33 side by bolts 31 and nuts 32, and the flange portions 30A, 30B
A resin coating layer 34 is provided in a state where B, bolts 31 and nuts 32 are embedded.

When the pipe is pulled in the direction shown by the reference numeral F by an external force at the time of an earthquake or the like with respect to such a flange joint portion, the flange portions 30A, 30B and 33A become the reference characters F
When a displacement occurs due to being dragged in the direction shown by the arrow, deformation occurs in a direction in which the flange portions 30A, 30B and 33A separate.

When the flanges 30A, 30B and 33A are dragged, the flanges 30A, 30B and 33
In the case of A, the resin coating layer 34 around the outside is pushed from the inside in conjunction with the spread of the base outward. For this reason, the resin coating layer 34 has a flange portion 30A,
At the extended position of 30B, the load from the inside increases, the load tends to act in the direction in which the outer surface expands, and in the worst case, a crack is generated, and gas may leak from the crack.

On the other hand, the external force acting on the flange portions 30A and 30B may act not only in the direction indicated by the reference numeral F but also in the opposite direction (the direction indicated by the reference numeral F 'in FIG. 7). In this case, the external force in the direction indicated by the reference symbol F 'acts toward the center of the shut-off valve 30, and the shut-off valve 30 may be compressed and deformed. Moreover, when the external force in that direction disappears, the flange portion 30 that has been compressed until then is removed.
The flange portions 30A, 30B may be separated from each other due to the inertial force when the A, 30B returns to the original shape, and the gas may leak from the joint surface as in the direction of the above-described reference F.

The flange portions 30A, 30B and 33A whose periphery is covered with a resin coating layer 34 are
As described above, when the joint surface is expanded or cracked by an external force (force in the direction indicated by the symbol F), there is a possibility that the gas leaking from the inside of the pipeline will be filled. Moreover, in order to prevent such gas leakage, it is conceivable to increase the filling amount of the resin used as the coating layer. However, if the filling amount is increased, the economic cost increases, and economical gas leakage prevention is prevented. You can not plan.

Further, as described above, when filling the resin at the connection portion between the shutoff valve 30 and the pipeline 33, for example, the shutoff valve 30 is disposed in a valve pit formed by excavating the ground. In this case, the valve pit may be filled with resin. In this case, the maintenance opening formed in the shut-off valve 30 is closed by the resin. For this reason, when performing maintenance of the valve, extra work such as peeling off the resin is required.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the conventional flange joint structure, the object of the present invention is to surely prevent the flange portions from peeling off at the joint portion and completely eliminate problems such as gas leakage. In addition to reducing the amount of resin used to solve this problem, the economical efficiency has been improved, and the flange joint structure has a structure that does not impair the workability of the members interposed in the pipeline. To provide.

[0016]

In order to achieve this object, the invention according to claim 1 is directed to a construction in which the existing pipeline is laid in a flange joint structure of a valve or the like interposed in an existing pipeline. A pair of backing plates facing each other and arranged outside the flange portion, and a connecting rod having an end in the extension direction penetrated through the backing plate, and the connecting rod at least outside the backing plate. The flange portions are sandwiched by bolting so that the distance between the flange portions does not change, and a high-strength resin is filled with the flange portions and the backing plate embedded therein.

According to a second aspect of the present invention, in the joint structure for a flange portion of an existing pipeline according to the first aspect, the connecting rod is
It is characterized in that the fastening plate is fastened on both side surfaces in the thickness direction.

According to a third aspect of the present invention, in the flange joint structure for an existing pipeline according to the first aspect, a stretch is provided between the contact plates so as to surround the outer periphery between the contact plates. A fiber having high tensile strength and resin impregnating property is provided, and the fiber surrounds the outer periphery of the high-strength resin.

According to a fourth aspect of the present invention, in the structure for joining a flange portion of an existing pipeline according to the first aspect, the flange portion is covered with a tape member around the periphery thereof and sealed with the tape member. In addition, a pipe material having an opening at one end thereof and an opening at the other end open to the atmosphere is erected.

According to a fifth aspect of the present invention, there is provided a flange joint structure for connecting an existing pipeline and a valve in a valve pit formed in the existing pipeline buried underground, Inside, a pair of backing plates facing each other along the direction of laying of the existing pipeline and disposed outside the flange portion are provided, and a connecting rod inserted between the backing plates is provided with a thickness of the backing plate. After fastening on both sides in the direction, the fiber is stretched between the backing plates, and a space including at least the opposed flanges inside is formed by a mold, and the high-strength resin is formed on the mold. It is characterized by filling.

According to a sixth aspect of the present invention, in the structure for joining a flange portion of an existing pipeline according to any one of the first to fifth aspects, the surface of the flange portion is polished before filling the high-strength resin. It is characterized by that.

According to a seventh aspect of the present invention, in the joint structure for flanges of an existing pipeline according to the fifth aspect, the maintenance opening provided in the upper part of the valve is provided with the opening position of the high-strength resin. It is characterized in that a raising member for raising the height to a position higher than the filling height is mounted.

[0023]

According to the first and second aspects of the present invention, the position of the backing plate is maintained by tightening the outer side corresponding to one side in the thickness direction and the both sides in the thickness direction of the backing plate in contact with the flange portion. Since it can be performed, even when an external force along the laying direction of the existing pipeline acts, the joined state of the flange portion can be held firmly. Thereby, since the joints do not separate from each other, leakage of fluid from the joints can be prevented.

According to the third aspect of the present invention, there is provided a fiber having high tensile strength and resin impregnating property which is stretched between the backing plates so as to surround the outer periphery thereof. Since the outer periphery of the resin is surrounded, the fibers can be used as a reinforcing material for increasing the bending rigidity and the tensile rigidity of the high-strength resin.

According to the fourth aspect of the present invention, the periphery of the flange portion is covered with a tape member to seal the joint, and gas leaking from the joint in the sealed space flows into the pipe, so that the pipe material is sealed. By closing the opening, gas leakage can be prevented. Further, by press-fitting the resin from the opening of the pipe material, it is possible to repair a leaked portion of the flange portion.

According to the fifth aspect of the present invention, the high-strength resin filling space for the flange portion in the valve pit where the joint between the valve and the existing pipeline is located can be formed by the mold. The filling amount of the strength resin can be suppressed to a necessary minimum for a portion where gas leakage or the like occurs.

According to the sixth aspect of the present invention, since the surface of the flange portion is polished and coated by filling with a high-strength resin, the adhesion between the resin and the flange surface is improved, and the sealing with the resin is good. Can be done.

According to the seventh aspect of the present invention, since the maintenance opening of the valve is made higher than the filling position of the high-strength resin by the raising member, even if the flange portion is sealed with the resin, the maintenance opening is provided. Maintenance work of the valve can be performed from the outside without closing the opening.

[0029]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a schematic diagram showing a flange joint structure according to an embodiment of the present invention.
Reference numeral 1 'denotes an existing pipeline buried in the ground, and a shutoff valve 2 is connected to the existing pipelines 1 and 1' in the middle of the installation direction.

The existing pipelines 1 and 1 'and the shut-off valve 2 are integrally connected with the flanges 1A and 1A' on the existing pipeline side and the flange 2A on the shut-off valve 2 side, respectively.

Although not shown, such a connecting portion is located in a space formed by a valve pit formed in the ground, and a maintenance opening formed above the shutoff valve 2 is provided with a valve. It can be opened and closed from the top of the pit. The valve pit is usually closed by a cover member (not shown).

Among the flange portions 1A, 1A 'and 2A, a patch plate 3 is arranged outside the flange portions 1A and 1A' of the existing pipelines 1 and 1 '. In a state of straddling, they are opposed to each other along the laying direction of the existing pipelines 1 and 1 'and are connected to each other.

That is, as shown in FIG.
It is bisected in the circumferential direction, and the flange 1 of the existing pipeline 1, 1 '
A, 1A 'is constituted by a ring-shaped member which can be brought into contact with each other, and a connecting portion 3A which is in contact with each other is formed at the dividing position, and a plurality of connecting rod insertion holes 3B are formed along the circumferential direction.

The backing plate 3 is inserted into the existing pipelines 1 and 1 'by fastening the connecting portion 3A in the circumferential direction, and a surface closer to the center of the existing pipeline than the connecting rod insertion hole 3B is provided. Road 1,
1 'can be in contact with the flange portions 1A, 1A'.

In FIG. 1, the connecting rod insertion hole 3B of the backing plate 3
, The end of the connecting rod 4 is inserted therethrough.

The connecting rod 4 has a bolt head at one end in the axial direction, and is formed of a bolt formed with a screw over the entire area in the axial direction. The nut 4A is tightened on the surface. For this reason, the backing plate 3 is positioned by being brought into contact with the outside of the flange portions 1A and 1A ', and both side surfaces in the thickness direction are sandwiched between the bolt head, the nut 4A and the nut 4A, and the existing pipe The abutment plate 3 is held immovable with respect to an axial external force acting on 1, 1 '.

Since the present embodiment has the above configuration,
When the existing pipelines 1 and 1 'and the shutoff valve 2 are connected in the valve pit, the flanges 1A and 1A on the existing pipelines 1 and 1' side are connected.
A patch plate 3 is arranged outside A ′, and after connecting rods 4 are inserted through these patch plates 3, both side surfaces in the thickness direction of the patch plate 3 are tightened by the bolt head, the nut 4A, and the nut 4A to be clamped. Is done.

When the fastening operation of the connecting rod 4 is performed, the movement of the existing pipelines 1 and 1 'in the laying direction is restricted in a state where the contact plates 3 are in contact with the outer surfaces of the flange portions 1A and 1A'. Therefore, even when an external force along the laying direction, that is, an external force in the directions indicated by reference symbols F and F ′ in FIG. 7 is applied, the state in which the degree of adhesion between the flange portions 1A, 1A ′ and 2A is increased. Can be maintained.

In this state, the fibers 5 are arranged around the outer periphery of the backing plate 3, as shown in FIG.

The fiber 5 is a band-shaped member woven in a plain weave or net shape using a material having high tensile strength and resin impregnating property. It is wound and stretched. FIG.
In the figure, the state in which the fiber 5 is wound is indicated by a two-dot chain line. As a material used for the fiber 5, carbon fiber, glass fiber, or the like is used.

The fibers 5 are provided on the backing plate 3 on which the fibers 5 are stretched.
It is located on the outer surface of the high-strength resin 6 that fills the internal space therebetween, and is used as a reinforcing material for increasing the bending rigidity and the tensile rigidity of the high-strength resin.

As the high-strength resin 6, an epoxy resin, an unsaturated polyester resin, a vinyl ester resin or a urethane resin having high hardness is used.
Filling is performed to obtain a state in which A ′ and 2A are embedded.

When the high-strength resin 6 is filled, the surfaces of the flange portions 1A, 1A 'and 2A are polished by sandblasting or the like. Thereby, the high-strength resin 6
This prevents the occurrence of adhesion failure due to the presence of foreign matter or the like between the flange and the surface of the flange portion.

According to the embodiment described above, before the high-strength resin 6 is filled, the backing plates 3 are connected to each other by the flange portions 1A, 1A.
A is positioned in a state in which it is in contact with the outside of A ′, and this state is maintained by tightening both side surfaces in the thickness direction of the backing plate 3 so that the side of the shut-off valve 2 that is in contact with the flange portions 1A and 1A ′ The adhesion to the flange portion 2A is enhanced, and the peel strength between the flange portions 1A, 1A 'and the flange portion 2A is increased.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, the gas leaked from the joint between the flanges 1A, 1A 'and 2A is caused to flow into the pipe 7. 1 and 2 in FIG.
The same components as those shown in FIG.

In FIG. 3, the outer periphery of the joint between the flanges 1A and 1A 'of the existing pipelines 1 and 1' and the flange 2A of the shut-off valve 2 is wound around the joint including the area including the joint. Provided tape member T is provided. Tape member T
Is sealed from the outside of the joint portion of the flange portion, and one end of the pipe member 7 is communicated with the sealed space.

The other end of the tube 7 communicates with the atmosphere, and when leaking from the joint in the sealed space, the gas flows into the tube 7.

Since the present embodiment has the above configuration,
As in the embodiment shown in FIG. 1, after the high-strength resin 6 is filled in the internal space between the caul plates 3, gas leaks from the junction between the existing pipelines 1, 1 'and the shut-off valve 2. Since the joint is hermetically sealed by the tape member T, the gas does not leak into the high-strength resin 6 and flows into the tube 7 whose one end communicates with the sealed space. Therefore, if necessary, the leaked gas can be released to the atmosphere,
Further, gas leakage can be prevented by closing the opening on the atmosphere side of the tube material. Furthermore, the leaking part can be repaired by press-fitting the sealing material from the opening on the atmosphere side of the pipe member 7.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, the existing pipelines 1 and 1 'and the shutoff valve 2
It is characterized in that the filling amount of the high-strength resin in the valve pit where the connecting portion with the resin is located is reduced. In FIG. 4, the same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals. As for the fiber 5, only the reference numerals are shown as in FIG.

In FIG. 4, the flanges 1A and 1A 'of the existing pipelines 1 and 1' and the flange 2A of the shutoff valve 2 are arranged in a valve pit B formed by excavating the ground.

In the valve pit B, the flange portions 1A, 1
A space including a portion where A 'and 2A are fastened is formed by a mold 8 having a resin filling space therein.

The facing distance (L1) of the formwork 8 is smaller than the width (L) of the valve pit B because it is a minimum distance including the flange portions 1A, 1A 'and 2A.

The mold frame 8 is formed of a box having one surface, in this embodiment, a surface facing the bottom in the valve pit B, and a side located on the open surface having a valve pit B. It is fixed at the bottom of. A filling opening 8A is formed in the side wall of the mold frame 8, and a filling pipe (not shown) is connected to the opening 8A so that the high-strength resin 6 is filled. In addition, although not shown in the formwork 8,
The air vent portion in the filling space at the time of filling is formed at a position where the high-strength resin 6 to be filled does not flow out.

Since the present embodiment has the above configuration,
The space formed by the mold 8 is filled with the high-strength resin 6 from the filling opening 8A. The high-strength resin 6 filled in the resin filling space flows to the positions of the flanges 1A, 1A 'and 2A on both sides of the filling opening 8A, and can seal the joint of the flanges. . The high-strength resin 6 filled in the mold 8 is in a state of enclosing the fibers 5 stretched between the caul plates 3, but between the upper surface of the mold 8 and the outer peripheral surface of the caul plate 3. By reducing the distance and the distance between the bottom of the valve pit B and the outer peripheral surface of the backing plate 3, the fibers 5 can be located near the surface layer of the high-strength resin 6. Thereby, the fiber 5 can exhibit rigidity before the high-strength resin 6 is deformed by the bending force or the tensile force acting on the high-strength resin 6.

According to such a configuration, the space formed by the mold 8 is minimized to the flange portions 1A, 1A 'and 2
Since the amount of the high-strength resin 6 that can seal A can be filled, the amount of the high-strength resin 6 used can be reduced as compared with the case where the entire area in the valve pit B is filled.

Next, still another embodiment of the present invention will be described with reference to FIG.

The present embodiment is characterized in that the maintenance opening of the shut-off valve 2 filled with the high-strength resin has the same configuration as that provided at a position higher than the space filled with the high-strength resin. In FIG. 5, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals.

In FIG. 5, a raising member 10 is mounted on a maintenance opening provided above the shut-off valve 2.

As shown in FIG. 6B, the raising member 10 has a through-hole communicating with the maintenance opening 2B of the shut-off valve 2, and is usually attached to the maintenance opening 2B of the shut-off valve 2. The lid member 11 to be attached can be attached to one end of the through hole, and the height (H) of the through hole in the penetrating direction is the height of the backing plate 3 shown in FIG. 1 or the mold shown in FIG. The mounting position of the lid member 11 is set at a position higher than the filling height of the high-strength resin 6 corresponding to the upper surface of the frame 8. That is, as shown in FIG. 6A, the cover member 11 which is normally attached to the maintenance opening 2B of the shutoff valve 2 is used.
Are raised as shown in FIG. 6 (B).

Since the present embodiment has the above configuration,
The raising plate 10 having a through-hole capable of communicating with the outside above the filling height of the high-strength resin 6 corresponding to the upper surface of the backing plate 3 shown in FIG. 1 or the formwork 8 shown in FIG.
Since the high-strength resin 6 is filled and the flange portions 1A, 1A ', and 2A are sealed, the maintenance and inspection work of the shut-off valve 2 is performed above the high-strength resin 6 because the high-strength resin 6 is filled. Can be. Thus, even after the flange portions 1A, 1A 'and 2A are sealed with the high-strength resin 6, the maintenance work of the shut-off valve 2 becomes possible without the need to remove the resin.

[0064]

As is apparent from the above description, according to the first and second aspects of the present invention, the outer side and the both sides in the thickness direction corresponding to one side in the thickness direction of the backing plate abutted on the flange portion. By performing the tightening, the position of the backing plate can be maintained, so that the joined state of the flange portion can be firmly held even when an external force is applied along the existing pipe line laying direction. Thus, since the joints do not separate from each other, it is possible to prevent leakage of fluid from the joints.

According to the third aspect of the present invention, there is provided a fiber having high tensile strength and resin impregnating property which is stretched between the backing plates so as to surround the outer periphery thereof. Since the outer periphery of the high-strength resin is surrounded, the above-mentioned fiber can be used as a reinforcing material for increasing the bending rigidity and the tensile rigidity of the high-strength resin. This prevents the high-strength resin from being broken by an external force, so that it is possible to more effectively prevent the fluid such as gas from leaking by sealing the joint with the high-strength resin.

According to the fourth aspect of the present invention, the periphery of the flange is covered with the tape member to seal the joint,
Since the gas leaked from the joint in the sealed space flows into the pipe, gas leakage can be prevented by closing the opening of the pipe. Further, by press-fitting the resin from the opening of the pipe material, it is possible to repair a leaked portion of the flange portion.

According to the fifth aspect of the invention, the high-strength resin filling space for the flange portion in the valve pit where the joint between the valve and the existing pipeline is located can be formed by the mold. In addition, the filling amount of the high-strength resin can be suppressed to a minimum necessary for a portion where gas leakage or the like occurs, and the cost for preventing fluid leakage at the joint can be reduced.

According to the sixth aspect of the present invention, since the surface of the flange portion is polished and then covered by filling with a high-strength resin, the adhesion between the resin and the flange surface is improved, and the resin is sealed. Can be performed well. This makes it possible to effectively prevent leakage of fluid due to poor adhesion at the joint.

According to the seventh aspect of the present invention, since the maintenance opening of the valve is higher than the filling position of the high-strength resin by the raising member, even when the flange portion is sealed with the resin. Maintenance work of the valve can be performed from the outside without closing the maintenance opening. This allows
Even when the high-strength resin at the joint is prevented from leaking fluid due to filling, it is possible not to hinder maintenance work such as external valve operation.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a bonding structure according to an embodiment of the present invention.

FIG. 2 is a perspective view for explaining a configuration of a backing plate used in the joining structure shown in FIG.

FIG. 3 is a schematic diagram for explaining a joint structure according to another embodiment of the present invention.

FIG. 4 is a schematic diagram for explaining a bonding structure according to another embodiment of the present invention.

FIG. 5 is a schematic view for explaining a joint structure according to still another embodiment of the present invention.

6 is a view for explaining a mounting structure of a lid member provided on a shutoff valve in the joint structure shown in FIG. 5,
(A) shows a conventional structure, and (B) shows a structure using a raising member used in the joining structure shown in FIG. 5.

FIG. 7 is a schematic view for explaining a conventional flange joint structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 'Existing pipe line 1A, 1A' Flange part 2 Shutoff valve which is one of the valves 2A Flange part 3 Backing plate 4 Connecting rod 5 Fiber 6 High strength resin 7 Tube material 8 Formwork 9 Vent pipe 10 Lifting member T Tape member B Valve pit L Width of valve pit L1 Spacing between molds

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Teruaki Fujimaki 3-9-1, Namiki 3-chome, Kanazawa-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor Kazuyoshi Takeuchi 3-183-3 Daikan, Yamato-shi, Kanagawa Prefecture F-term in the Technology Development Center (reference) 3H016 AE00

Claims (7)

[Claims] 1. A flange joint structure for a valve or the like interposed in a system of an existing pipeline, comprising: a pair of abutments opposed to each other along a direction in which the existing pipeline is laid and disposed outside the flange. A plate, and a connecting rod having an end in the extension direction penetrated through the backing plate, and by bolting the connecting rod at least outside the backing plate, the facing distance between the flange portions does not change. A high-strength resin is filled in a state where the high-strength resin is sandwiched and the flange portion and the backing plate are embedded therein. 2. The flange of an existing pipeline according to claim 1, wherein the connecting rods are fastened on both sides in the thickness direction of the backing plate. Part joining structure. 3. The high-strength resin and resin stretched between the patch plates so as to surround the outer periphery thereof between the patch plates. A flange joint structure for an existing pipeline, wherein fibers having impregnation properties are provided, and the fibers surround the outer periphery of the high-strength resin. 4. The flange joint structure for an existing pipeline according to claim 1, wherein the flange portion is covered with a tape member around the periphery thereof, and the flange joint portion sealed with the tape member has an opening at one end thereof. And a pipe member having an opening at the other end open to the atmosphere. 5. A flange joint structure used for connecting an existing pipeline and a valve in a valve pit formed in an existing pipeline buried underground, wherein the existing pipe is installed in the valve pit. A pair of caul plates are provided facing each other along the direction in which the road is laid, and arranged outside the flange portion, and the connecting rods inserted between the caul plates are fastened on both sides in the thickness direction of the caul plate. Above, the fibers are stretched between the backing plates, a space including at least the opposed flanges inside is formed by a mold, and the mold is filled with the high-strength resin. Flange joint structure of existing pipeline. 6. The flange joint structure for an existing pipeline according to claim 1, wherein a surface of the flange is polished before filling the high-strength resin. Flange joint structure of existing pipeline. 7. The flange joint structure for an existing pipeline according to claim 5, wherein the maintenance opening provided at an upper portion of the valve has a position higher than a filling height of the high-strength resin. A flange joining structure for an existing pipeline, wherein a raising member for raising the height is mounted.