JP7072485B2 - Insulated joint structure - Google Patents

Description

The present invention relates to an insulated joint structure in which fluid pipes made of dissimilar metal materials are connected to each other in an insulated state.

A fluid pipe is configured by sequentially connecting the ends of a plurality of fluid pipes in a sealed state, and these fluid pipes have the structural strength, earthquake resistance, and weather resistance required at each pipe position. Alternatively, pipes made of various materials are applied depending on the cost and the like. In such a fluid pipeline, when the fluid pipes connected to each other adjacent to each other are different metal pipes such as stainless steel pipe and ductile cast iron pipe, they are different from each other via in-pipe fluid such as water. Due to the potential difference between metals, so-called galvanic corrosion occurs in the electrical contact parts connected between the ends of the metal pipe, and the corroded area increases over time, and there is a risk that leakage will occur from the connections between these ends. was there.

Conventionally, in order to prevent corrosion caused by such a potential difference between dissimilar metals, for example, the surface of a push ring axially engaged with the outer surface of an insertion tube made of a metal material is coated with an insulating member. A part of the inner surface of the receiving tube made of a dissimilar metal material is similarly coated with an insulating member, so that the insertion tube and the receiving tube are fitted to each other via a sealing material. There is a structure in which the push ring and the receiving tube are fastened while avoiding electrical contact at the connecting portion (see, for example, Patent Document 1).

JP-A-2015-143524 (Page 7, Fig. 2)

However, in Patent Document 1, when an external force such as an earthquake or unequal subsidence occurs in a state where the insertion tube and the receiving tube are connected as described above, these tubes are connected to each other. As a result of the behavior of tilting and sliding with respect to the shaft, the insertion tube and the push ring or locking member engaged with the insertion tube and the receiving tube are between exposed parts of the metal material that do not require insulation under normal connection conditions. There is a problem that the metal material is exposed due to contact or peeling or biting of the coating layer of the insulating member due to the above-mentioned behavior, and dissimilar metals come into contact with each other at this exposed portion. In particular, in the case of a large-diameter pipe, the displacement amount of the pipe is large even at a slight inclination angle, and the bending moment acting on the pipe line is also large, so that there is a tendency that the possibility of dissimilar metals coming into contact with each other increases.

The present invention has been made focusing on such problems, and provides an insulated joint structure capable of maintaining the insulating function between dissimilar metal materials even when an unexpected external force such as an earthquake or uneven settlement occurs. The purpose is to do.

In order to solve the above problems, the insulated joint structure of the present invention is used.
A receiving pipe portion made of a metal material and having a flange extending in the outer radial direction at the opening end portion and a metal material different from the receiving pipe portion are inserted into the inside of the receiving pipe portion. An insertion tube portion having an insertion port, a seal member that seals between the socket tube portion and the insertion tube portion, a push ring that presses the seal member, the socket tube portion, and the insertion tube portion. An insulated joint structure including at least a fastening member for fastening the portions.
The insertion tube portion has a flange portion formed integrally with the insertion portion and extended in the outer radial direction, and the push ring is a flange portion of the receiving tube portion and the insertion tube portion. The back surface of the push ring is supported by the flange portion of the insertion tube portion while being interposed between the flange portion in an insulated state, and the fastening member is the flange portion of the receiving tube portion. It is characterized in that it is inserted in an insulated state so as to span the flange portion of the insertion tube portion.
According to this feature, the flange portion integrally formed with the insertion portion of the insertion pipe portion inserted into the socket pipe portion is fastened to the flange portion of the socket pipe portion by the fastening member, so that an earthquake occurs. Even if an unexpected external force such as unequal subsidence occurs, the insertion tube portion is not bent, and the socket tube portion and the insertion tube portion are integrated without causing relative movement, and both of these tubes are integrated. While maintaining a high insulation state of the portion, the seal member can be stably pressed by the push ring supported by the flange portion, and the sealed state of both pipe portions can be maintained.

The fastening member is characterized in that it is inserted through the push ring in an insulated state.
According to this feature, the receiving pipe portion, the insertion pipe portion, and the push ring interposed therein can be integrated in a state of being positioned by the fastening member.

The back surface of the push ring is characterized in that it is in surface contact with the flange portion of the insertion tube portion.
According to this feature, the direction of the push ring that presses the seal member can be positioned by the flange portion.

The front surface of the push ring is characterized in that it is in surface contact with the flange portion of the receiving tube portion.
According to this feature, the direction in which the insertion tube portion, the push ring and the reception tube portion are connected to each other can be positioned.

The push ring is characterized by having a pressing portion that projects toward the inside of the receiving tube portion and presses the sealing member.
According to this feature, the sealing property of the sealing member can be enhanced by pressing the sealing member arranged between the receiving tube portion and the insertion tube portion toward the inside of the receiving tube portion.

It is characterized in that a telescopic joint having at least elasticity is formed at the other end of the receiving pipe portion or the insertion pipe portion.
According to this feature, the expansion / contraction function of the fluid pipeline is ensured by the expansion joint configured at the other end of one of them while exerting the insulation function without moving the receiving pipe portion and the insertion pipe portion relative to each other. can do.

It is a schematic diagram which shows the fluid conduit to which the insulation joint structure in Example 1 was applied. It is a side sectional view which shows the insulation joint structure. It is a side sectional view which shows the state which the push ring and the seal member are externally fitted to the insertion tube part. It is a side sectional view which shows the state which the insertion tube part is fastened to the receiving tube part by the fastening member. It is a side sectional view which shows the state which the fastening of the insertion tube portion and the receiving tube portion is completed. (A) is a rear view of the insertion tube portion, and (b) is also a partial cross-sectional side view. (A) is a rear view of the push ring, (b) is a sectional view taken along the line XX of (a), and (c) is a sectional view taken along the line YY of (a). It is a side sectional view which shows the insulation joint structure which applied the push ring which concerns on the 1st modification. It is a side sectional view which shows the insulation joint structure which applied the push ring which concerns on the 2nd modification. It is a side sectional view which shows the insulation joint structure which applied the insulation film layer which concerns on the modification.

A mode for carrying out the insulated joint structure according to the present invention will be described below based on examples.

The insulated joint structure according to the first embodiment will be described with reference to FIGS. 1 to 10. First, reference numeral 1 in FIG. 1 is an insulated joint structure according to the present invention. Further, in this embodiment, the insertion direction of the insertion tube portion will be described as the front direction (front surface).

As shown in FIG. 1, the fluid pipeline 100 of the present embodiment is configured by connecting a plurality of fluid pipes in a sealed manner in order to allow clean water to flow as an internal fluid thereof, and is configured in the flow path. It is buried in the ground along the line, and fluid pipes are sequentially arranged along the ground and over rivers. The fluid pipeline 100 is a stretchable or flexible pipe in which, for example, a stainless steel or steel pipe bridge portion 100a erected so as to cross a river and a ductile cast iron buried portion 100c embedded and extended in the ground are formed. It is connected via a connecting portion 100b made of stainless steel or steel, and due to such a telescopic or flexible pipe 101, an unexpected external force such as a temperature change or an earthquake applied to the pipe bridge portion 100a and the connecting portion 100b. It is designed to absorb external forces that cause relative movement such as expansion and contraction due to bending and twisting.

In this embodiment, the fluid pipeline 100 is a relatively large diameter pipe, but the fluid pipeline 100 is not limited to this and may be a small diameter pipe. Further, the fluid in the fluid pipeline 100 is clean water, but the fluid flowing inside the fluid pipeline is not necessarily limited to clean water, for example, agricultural water, industrial water, sewage, etc., as well as gas, gas, and liquid. It may be a liquid mixture. Furthermore, the fluid pipeline to which the insulated joint structure according to the present invention is applied is not necessarily limited to the one composed of a pipe bridge portion, a connecting portion and a buried portion.

The insulating joint structure 1 in the present embodiment is electrically insulated when the buried portion 100c is laid with respect to the connecting portion 100b supported by the rigid body 12 such as the concrete abutment which is the abutment of the pipe bridge portion described above. It is a structure that is intervened in the state. In this embodiment, an embodiment used when connecting the receiving pipe portion 2 connected to the end portion of the buried portion 100c and the insertion pipe portion 3 welded to the end portion of the connecting portion 100b will be described. .. As shown in FIG. 2, the insulated joint structure 1 is mainly composed of a receiving pipe portion 2, an insertion pipe portion 3, a sealing member 4, a push ring 5, and a fastening member 6.

Next, the receiving pipe portion 2, the insertion pipe portion 3, the sealing member 4, the push ring 5, and the fastening member 6 constituting the insulating joint structure 1 will be described. As shown in FIG. 2, the receiving tube portion 2 is arranged on one end side of the telescopic flexible tube 20 in this embodiment, and the fluid tube portion 2p, the receiving portion 2a, and the receiving portion 2a are arranged. It is mainly composed of a flange portion 2b extending in the outer radial direction at the opening end portion of the above.

More specifically, as shown in FIG. 3, the receiving tube portion 2 is connected to the inner peripheral edge of the flange end surface 2c, and is connected to the inner peripheral edge of the recess 2d and the recess 2d formed inward in the pipe axis direction, and is connected to the recess 2d. It is provided with an inner cylinder portion 2e having a smaller diameter and extending inward in the pipe axis direction, and an inner protrusion portion 2g connected to an annular end surface 2f formed at the inner end of the inner cylinder portion 2e and protruding in the inner diameter direction. Further, the flange portion 2b is provided with a plurality of bolt holes 2h penetrating parallel to the pipe axis direction along the circumferential direction, and the bolts 7 constituting the fastening member 6 are inserted into these bolt holes 2h. It has become like.

The receiving tube portion 2 of this embodiment is made of ductile cast iron, and the surface thereof is only subjected to normal rust prevention treatment by painting or the like, and the surface of the receiving tube portion 2 is specially insulated. Is not applied. However, the present invention is not limited to this, and the surface of the receiving tube portion 2 may be insulated.

Further, as shown in FIG. 2, the other end side of the telescopic flexible pipe 20 is formed as a flexible pipe side case 31 constituting the telescopic flexible pipe joint 30 which is the telescopic joint of the present embodiment. Explaining the telescopic flexible pipe joint 30, the flexible pipe side case 31 and the seat 32 formed at the other end of the telescopic flexible pipe 20 are bayonet claws 31a formed at the end of the flexible pipe side case 31. And the bayonet claw 32a formed on the seat 32 engages the bayonet. Further, a spherical member 34 having a spherical outer surface is arranged between the flexible tube side case 31 and the insertion tube 41 constituting the embedded portion 100c, and the flexible tube side case 31 is provided by the seal member 35. The space between the spherical member 34 and the spherical member 34 is sealed, and the space between the spherical member 34 and the insertion tube 41 is sealed by the sealing member 36. Further, a groove 41a is provided on the outer periphery of the tip side of the insertion tube 41, and the groove 41a is for preventing detachment while allowing a certain expansion and contraction between the flexible tube side case 31 and the insertion tube 41. , The locking member 42 is provided. Further, a dust cover 33 and a dust ring 37 are provided so that impurities and the like do not enter the telescopic flexible pipe joint 30.

By providing such a telescopic flexible pipe joint 30, the insertion pipe 41 can be formed inside the flexible pipe side case 31 while maintaining the sealing property between the flexible pipe side case 31 and the insertion pipe 41. Since it can be moved in the axial direction and can be rotated by the spherical member 34, it can be expanded and contracted without relatively moving the receiving pipe portion 2 and the insertion pipe portion 3 in the insulating joint structure 1 described later. Despite being regulated, the telescopic flexible pipe joint 30 can provide a telescopic function and a flexible function in the pipeline.

In this embodiment, the telescopic flexible pipe joint 30 is provided at the opposite end of the receiving pipe portion 2, but the present invention is not limited to this, for example, at the opposite end of the insertion pipe portion 3. A telescopic flexible pipe joint may be provided. Further, the joint is not necessarily limited to a telescopic flexible pipe joint, and may be a telescopic pipe joint having at least a telescopic function.

Next, the insertion tube portion 3 will be described with reference to FIGS. 3 and 6. The insertion tube portion 3 is a straight tubular member, has an opening end portion at one end in the tube axis direction, and extends linearly along the tube axis direction so as to be inserted into the socket portion 2a of the socket tube portion 2. The inserted insertion portion 3a, the flange portion 3b protruding in the outer radial direction at the base end side of the insertion portion 3a in the pipe axis direction, and the insertion portion 3a connected to the insertion portion 3a and opposite in the pipe axis direction to the flange portion 3b. It mainly includes a fluid tube portion 3p extending to the side.

Further, the front surface 3c of the flange portion 3b facing the receiving portion 2a side is formed in a flat surface shape extending in a direction substantially orthogonal to the pipe axis, and penetrates the front surface 3c and the back surface 3d of the flange portion 3b. A plurality of bolt holes 3h are formed along the circumferential direction. Further, the other end portion 3r (see FIG. 6) connected to the fluid pipe portion 3p in the pipe axis direction is hermetically connected to the end portion of the connection portion 100b by welding in this embodiment.

In the insertion pipe portion 3 of this embodiment, the tubular member constituting the insertion portion 3a and the fluid pipe portion 3p and the flange portion 3b are integrated by welding, and the back surface of the flange portion 3b is formed by this welding material. A thick portion 3g having a wall thickness is formed in the radial direction and the pipe axis direction at the inner peripheral base portion of 3d. Further, the thickness of the insertion portion 3a in the radial direction is thicker than the thickness of the other end portion 3r side of the fluid pipe portion 3p, which enhances the rigidity of the insertion portion 3a.

The insertion tube portion 3 is a dissimilar metal to the receiving tube portion 2, and is made of a metal such as steel or stainless steel, and the entire surface thereof is subjected to normal rust prevention treatment. Further, in the insertion tube portion 3, a nylon coat is applied to the entire surface of the fluid tube portion 3p except for the insertion portion 3a, the flange portion 3b, the inner peripheral portion of the bolt hole 3h, and the other end portion 3r side. That is, the insulating coating layer C is formed. The insulating treatment is not limited to the nylon coat, and may be a coating on the surface by applying, dipping, spraying or the like an insulating material made of another material such as rubber lining, plastic coating, epoxy resin powder coating and the like. Furthermore, the insertion tube portion 3 may be formed at one end or both ends of a straight tubular or curved fluid tube, or may be formed at one end or both ends of a connecting member such as a fluid valve connected to the conduit. May be done.

Next, the push wheel 5 will be described with reference to FIGS. 3 and 7. The push ring 5 of this embodiment is integrally formed of ductile cast iron like the receiving pipe portion 2, or is composed of an annular member formed separately in the circumferential direction and the pipe axial direction. It is preferable that the metal material constituting the push ring 5 is the same metal as the receiving tube portion 2 as in the present embodiment among the receiving tube portion 2 and the insertion tube portion 3 which are different metals from each other. Further, the push ring 5 is connected to the inner peripheral surface thereof and protrudes in an annular shape in one direction in the pipe axis direction, and as described later, the push ring 5 is connected to a protruding portion 5a as a pressing portion for pressing the seal member 4 and a pipe connected to the outer diameter side of the protruding portion 5a. It mainly includes a front surface 5c extending in a flat surface shape in a direction substantially orthogonal to the axis, and a back surface 5d extending in a flat surface shape in a direction substantially orthogonal to the pipe axis on the opposite side of the projecting portion 5a and the front surface 5c. Further, the front end of the protruding portion 5a in the pipe axis direction is provided with a tapered surface 5b that gradually extends forward toward the outer diameter side, and further, a bolt hole 5h penetrating the front surface 5c and the back surface 5d is provided along the circumferential direction. It has more than one. The inner diameter of the push ring 5 is formed to be slightly larger than the outer diameter of the insertion portion 3a of the insertion tube portion 3, that is, the push ring 5 can be loosely fitted to the outer periphery of the insertion portion 3a.

Further, in this embodiment, the entire surface of the push ring 5 including the protruding portion 5a, the front surface 5c, the back surface 5d, and the inner peripheral portion of the bolt hole 5h of the push ring 5 is subjected to an insulation treatment by applying a nylon coat, that is, an insulating coating layer. D is formed. The insulating treatment is not limited to the nylon coat, and may be a coating on the surface by applying, dipping, spraying or the like an insulating material made of another material such as rubber lining, plastic coating, epoxy resin powder coating and the like. As described above, the push ring 5 is subjected to an insulating treatment that insulates both the receiving tube portion 2 and the insertion tube portion 3 that sandwich the push ring 5 as described later.

Next, the seal member 4 will be described. As shown in FIG. 3, the sealing member 4 is made of a resin material such as elastic rubber, and forms an annular shape having an inner diameter slightly smaller than the outer diameter of the insertion portion 3a of the insertion tube portion 3. are doing. The seal member 4 has a valve portion 4a having a substantially circular cross-sectional view at its front end in a natural state, and a pressed surface 4b at its rear end that faces substantially parallel to the tapered surface 5b of the protruding portion 5a of the push ring 5. , It is stored in a compressed state in the space surrounded by the protruding portion 5a of the push ring, the outer peripheral surface of the insertion portion 3a, the inner cylinder portion 2e of the receiving portion 2a, and the annular end surface 2f, and the receiving tube portion 2 and the insertion tube portion. Seal between 3 and 3.

The procedure for assembling the insulated joint structure 1 including the receiving pipe portion 2, the insertion pipe portion 3, the sealing member 4, and the push ring 5 will be described. As shown in FIG. 3, first, the surfaces of the receiving tube portion 2, the insertion tube portion 3, the seal member 4 and the push ring 5 are cleaned, and the push ring 5 and the seal member 4 are attached to the insertion portion of the insertion tube portion 3. It is fitted to 3a. At this time, it is preferable to apply a lubricant to the outer surface of the insertion portion 3a and the inner surface of the inner cylinder portion 2e of the receiving portion 2a, if necessary.

Subsequently, as shown in FIG. 4, the work bolt constituting the temporary fastening member 16 is formed in the bolt hole 3h of the insertion tube portion 3, the bolt hole 5h of the push ring 5, and the bolt hole 2h of the receiving tube portion 2. By inserting the 17 and fastening the nut 18 screwed to the working bolt 17, the insertion tube portion 3 is inserted into the receiving tube portion 2. It is preferable that the working bolt 17 has a relatively long shaft length and is a T-head bolt as in the present embodiment because it is easy to perform fastening work. First, in the initial set state, the pressed surface 4b of the seal member 4 is arranged so as to be pressed by the protruding portion 5a of the push ring 5 which is supported by surface contact with the front surface 3c of the flange portion 3b of the insertion tube portion 3. Then, by tightening the work bolt 17 and the nut 18, the receiving pipe portion 2 and the insertion pipe portion 3 are gradually pulled toward the pipe axis, and as shown in FIG. 5, the sealing member 4 is It is pushed between the inner cylinder portion 2e of the receiving pipe portion 2 and the outer peripheral surface of the insertion portion 3a, and the valve portion 4a of the seal member 4 is mainly compressed.

In this way, since the back surface 5d of the push ring 5 is in surface contact with the flange portion 3b of the insertion tube portion 3, the direction of the push ring 5 that presses the seal member 4 can be positioned by the flange portion 3b. Further, there is no gap between the back surface 5d of the push ring 5 and the flange portion 3b of the insertion tube portion 3, and there is no sliding during tightening by the temporary fastening member 16, so that the insulating coating layer is peeled off. Can be avoided.

Further, at this time, the protruding portion 5a of the push ring 5 is arranged so as to project toward the inside of the recess 2d of the receiving pipe portion 2, and thus between the receiving pipe portion 2 and the insertion pipe portion 3. By evenly pressing the seal member 4 arranged on the inside of the receiving tube portion 2 toward the inside of the receiving tube portion 2, the gap between the inner peripheral surface of the receiving tube portion 2 and the outer peripheral surface of the insertion tube portion 3 is made evenly in the circumferential direction. Therefore, the sealing property of the sealing member 4 can be improved, and when an external force such as bending acts on the pipeline due to the uneven fitting between the protruding portion 5a of the push ring 5 and the concave portion 2d of the receiving pipe portion 2. However, it can strongly counter this external force.

Next, a plurality of working bolts 17 and nuts 18 arranged along the circumferential direction are sequentially tightened, and the front surface 5c and the back surface 5d of the push ring 5 are the flange end surface 2c of the receiving tube portion 2 and the insertion tube. It is sandwiched by the front surface 3c of the flange portion 3b of the portion 3 in a surface contact state, and is pulled by the sealing member 4 until the receiving pipe portion 2 and the insertion pipe portion 3 are in a sealed state. At the time of this tightening, the temporary fastening member 16, the back surface 3d of the flange portion 3b, the front surface 5c of the push ring 5, the flange portion end surface 2c of the receiving pipe portion 2, the flange portion 2b, etc. are slid to slide the insulating coating layer and the rust preventive treatment. The temporary fastening member 16 is replaced with the insulating member 6 which will be described later, and since the push ring 5 and the receiving pipe portion 2 are made of the same material, the insulating performance of the insulating joint structure 1 is affected. Does not affect.

Further, in this way, the front surface 5c of the push ring 5 is in surface contact with the flange end surface 2c of the receiving tube portion 2, so that the insertion tube portion 3, the pushing ring 5, and the receiving tube portion 2 are connected to each other. The direction can be positioned.

After the work bolts 17 and nuts 18 have pulled the receiving pipe portion 2 and the insertion pipe portion 3 together, the working bolts 17 and nuts 18 are sequentially removed, and new fastening members 6 are sequentially fastened in place of these. do. As shown in FIG. 5, the fastening member 6 is composed of a bolt 7, a nut 8, and a pair of insulating washers 9 inserted into the shaft portion of the bolt 7, and the bolt 7 is arranged in the axial direction thereof. It is inserted into the bolt hole 2h of the flange portion 2b of the receiving tube portion 2, the bolt hole 5h of the push ring 5, and the bolt hole 3h of the flange portion 3b of the insertion tube portion 3. By doing so, the receiving pipe portion 2, the insertion pipe portion 3, and the push ring 5 interposed therein can be integrated in a state of being positioned by the fastening member 6.

Further, the insulating washer 9 is composed of a metal ring 9b in contact with the inner end faces of the bolt 7 and the nut 8, and a resin ring 9a having an insulating property in contact with the flange portion 2b and the flange portion 3b sandwiched between the fastening members 6. The fastening member 6 is fastened in a state of avoiding electrical contact with the receiving tube portion 2 and the insertion tube portion 3 to be fastened. The insulating washer 9 may be provided with resin rings 9a on both sides of the metal ring 9b, or may use bolts, nuts, or other accessory parts for promoting insulation.

Tightening management of the plurality of bolts 7 and nuts 8 constituting the fastening member 6 is performed by using a jig such as a torque wrench as necessary, taking care not to make the fastening unbalanced in the circumferential direction. It is desirable to tighten evenly (for example, in the case of a bolt with a nominal diameter of M20, 100 Nm). In the insulated joint structure 1 of the first embodiment, when the push ring 5 comes into contact with the flange end surface 2c of the receiving pipe portion 2 and the front surface 3c of the flange portion 3b of the insertion pipe portion 3, the tightening torque suddenly increases. Therefore, it is possible to easily determine the completion of tightening by the feeling of tightening without performing tightening by normal torque management.

Further, as described above, after the drawing of the receiving pipe portion 2 and the insertion pipe portion 3 is completed by the working bolt 17 and the nut 18, the bolt 7 and the nut 8 which are the new fastening members 6 are tightened. When the bolt 7 and the nut 8 are fastened, an attractive load such as sliding contact with the receiving pipe portion 2 and the insertion pipe portion 3 is not applied. Therefore, since the fastening member 6 can be fastened as a new product without causing small scratches due to sliding contact at the time of fastening, the insulating function can be fully exhibited without impairing the insulating function.

According to the insulated joint structure 1 according to the present invention described above, the insertion tube portion 3 has a flange portion 3b integrally formed with the insertion portion 3a and extended in the outer radial direction, and the push ring 5 has a push ring portion 5. , The flange portion 2b of the receiving tube portion 2 and the flange portion 3b of the insertion tube portion 3 are interposed in an insulated state, and the back surface 5d of the push ring 5 is supported by the flange portion 3b of the insertion tube portion 3. Further, the fastening member 6 is inserted over the flange portion 2b of the receiving tube portion 2 and the flange portion 3b of the insertion tube portion 3 in an insulated state.

By doing so, the flange portion 3b integrally formed with the insertion portion 3a of the insertion tube portion 3 inserted into the socket tube portion 2 is formed by the fastening member 6 to form the flange portion 2b of the socket tube portion 2. Even if an unexpected external force such as an earthquake or unequal subsidence occurs, the insertion tube portion 3 does not bend, and the receiving tube portion 2 and the insertion tube portion 3 are relative to each other. The seal member 4 is stably pressed by the push ring 5 supported by the flange portion 3b while maintaining the high insulation state of both pipe portions by being integrated without causing movement, and the sealed state of both pipe portions is maintained. Can be retained.

Further, in the present embodiment, since the push ring 5 is a member made of the same metal material as the receiving tube portion 2, as described above, the receiving tube portion 2 and the insertion tube portion 3 are interposed via the push ring 5. When, or when an unexpected external force is generated after the piping is completed, for example, the protruding portion 5a of the push ring 5 or a portion in the vicinity thereof and the concave portion 2d of the receiving pipe portion 2 are in sliding contact with each other. Even when the insulating coating layer D of the push ring 5 is peeled off and electrically contacted at the portion, there is no potential difference between the same metals and there is no possibility that galvanic corrosion will occur. On the other hand, the back surface 5d of the push ring 5 and the front surface 3c of the flange portion 3b of the insertion tube portion 3 are in flat surface contact with each other because there is no unevenly engaged portion. There is no risk that the insulating coating layer D will peel off on the back surface 5d of the push ring 5. In addition, since the insulating coating layer C is formed on the entire surface of the insertion tube portion 3 except for the other end portion 3r side, it is between the insertion tube portion 3 and the push ring 5, which are dissimilar metals. The double insulating coating layer C and the insulating coating layer D are present in the above, so that the insulating performance can be maintained high.

Next, a first modification of the push ring constituting the insulated joint structure of the present invention will be described with reference to FIG. It should be noted that the same configuration as that of the above embodiment and overlapping description will be omitted.

The push ring 15 of the first modification has a front surface 15c which is connected to the inner peripheral surface thereof and extends in a flat surface shape in a direction substantially orthogonal to the pipe axis, and a flat surface shape in a direction substantially orthogonal to the pipe axis on the opposite side of the front surface 15c. It mainly has a back surface 15d extended to. Further, a plurality of bolt holes 15h penetrating the front surface 15c and the back surface 15d are provided along the circumferential direction. The inner diameter side of the front surface 15c of the push ring is configured as a pressing portion for pressing the seal member 4.

By doing so, the front surface 15c of the push ring 15 and the flange end surface 2c of the receiving tube portion 2 can be brought into surface contact with each other flatly over the entire surface. When the portion 2 and the insertion tube portion 3 are attracted to each other, or when an unexpected external force is generated after the piping is completed, there is no possibility that the insulating coating layer D of the push ring 15 is peeled off at the portion where the surface abuts.

Next, a second modification of the push ring constituting the insulated joint structure of the present invention will be described with reference to FIG. It should be noted that the same configuration as that of the above embodiment and overlapping description will be omitted.

The push ring 25 of the second modification is a recessed portion 25a that is connected to the inner peripheral surface thereof and is annularly recessed in one direction in the pipe axis direction to press the seal member 4, and the outer diameter of the recessed portion 25a. The front surface 25c which is connected to the side and extends in a flat surface shape in a direction substantially orthogonal to the pipe axis, and the back surface 25d which extends in a flat surface shape in a direction substantially orthogonal to the pipe axis on the opposite side of the recessed portion 25a and the front surface 25c. Mainly prepared for. Further, the front end of the recessed portion 25a in the pipe axis direction is provided with a tapered surface 25b that gradually extends forward toward the outer diameter side, and further, a bolt hole 25h penetrating the front surface 25c and the back surface 25d is provided along the circumferential direction. It has more than one. However, the tapered surface 25b is not limited to the taper, and may be formed on a plane substantially orthogonal to the pipe axis.

By doing so, the rear end side of the seal member 4 can be accommodated in the recessed portion 25a located outside the flange end surface 2c of the receiving pipe portion 2, so that the seal member 4 is excessive. By pressing with an appropriate pressing force instead of, a uniform elastic repulsive force can be generated over the entire surface of the sealing member 4, the sealing property can be exhibited, and the pressing ring 25 can be centered.

Although examples of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these examples, and any changes or additions that do not deviate from the gist of the present invention are included in the present invention. Will be.

For example, in the embodiment, the insulating coating layer C is formed on the entire surface of the fluid pipe portion 3p except for the insertion portion 3a of the insertion pipe portion 3, the flange portion 3b, the inner peripheral portion of the bolt hole 3h, and the other end portion 3r side. However, the present invention is not limited to this, and as shown in FIG. 10, for example, in addition to the insulating coating layer C formed at the above-mentioned location, the outer peripheral surface on the distal end side of the insertion portion 3a and the outer peripheral surface thereof. A further insulating coating layer F may be formed by rubber vulture or adhesion on the outer surface of the insulating coating layer C that covers the tip surface of the insertion tube portion 3 connected to the above. Further, a spacer such as rubber may be installed on the inner peripheral surface of the receiving tube portion 2.

Further, for example, in the above embodiment, the push ring 5 is a member made of the same metal material as the receiving tube portion 2, but the present invention is not limited to this, and the receiving tube portion is not limited to this, as long as the surface thereof has insulating properties. Unlike 2, it may be a member made of the same metal material as the insertion tube portion 3, or it may be a member made of a metal material different from both the receiving tube portion 2 and the insertion tube portion 3, or the push ring can withstand the pinching pressure. As long as it has the obtained structural strength, it may be composed of not only a metal material but also various hard materials and the like.

1 Insulated joint structure 2 Receiving pipe part 2a Receiving part 2b Flange part 2c Flange part end face 2d Recess 3 Insertion pipe part 3a Insertion part 3b Flange part 3c Front side 3d Back side 3g Thick part 4 Sealing member 4a Valve part 4b Pressing surface 5 Push ring 5a Protruding part (pressing part)
5b Tapered surface 5c Front 5d Back 6 Fastening member 7 Bolt 8 Nut 9 Insulated washer 15 Push ring 15c Front (pressing part)
16 Temporary fastening member 20 Telescopic flexible pipe 25 Push ring 25a Concave part (pressing part)
30 Telescopic flexible pipe joint (expandable joint)
100 fluid pipeline

Claims (6)

A receiving pipe portion made of a metal material and having a flange extending in the outer radial direction at the opening end portion and a metal material different from the receiving pipe portion are inserted into the inside of the receiving pipe portion. An insertion tube portion having an insertion port, a seal member that seals between the socket tube portion and the insertion tube portion, a push ring that presses the seal member, the socket tube portion, and the insertion tube portion. An insulated joint structure including at least a fastening member for fastening the portions.
The insertion tube portion has a flange portion formed integrally with the insertion portion and extended in the outer radial direction, and the push ring is a flange portion of the receiving tube portion and the insertion tube portion. The back surface of the push ring is supported by the flange portion of the insertion tube portion while being interposed between the flange portion in an insulated state, and the fastening member is the flange portion of the receiving tube portion. An insulated joint structure characterized by being inserted in an insulated state so as to span the flange portion of the insertion tube portion. The insulated joint structure according to claim 1, wherein the fastening member is inserted into the push ring in an insulated state. The insulated joint structure according to claim 1 or 2, wherein the back surface of the push ring is in surface contact with the flange portion of the insertion tube portion. The insulated joint structure according to any one of claims 1 to 3, wherein the front surface of the push ring is in surface contact with the flange portion of the receiving tube portion. The insulated joint structure according to any one of claims 1 to 4, wherein the push ring has a pressing portion that projects toward the inside of the receiving pipe portion and presses the sealing member. The insulated joint structure according to any one of claims 1 to 5, wherein a telescopic joint having at least elasticity is formed at the other end of the receiving pipe portion or the insertion pipe portion.

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