JP7331199B2 - Insulated joint structure - Google Patents

Description

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

Fluid pipes are constructed by successively connecting the ends of a plurality of fluid pipes in a sealed state. Alternatively, pipes made of various materials are applied according to cost and the like. In such fluid conduits, when the fluid conduits that are connected at their ends adjacent to each other are metal conduits of different types, such as a stainless steel pipe and a ductile cast iron pipe, the different types of metal pipes are connected via a fluid in the pipe such as water. Due to the potential difference between the metals, so-called galvanic corrosion occurs at the electrical contacts where the ends of the metal tubes are connected, and the corroded area increases with age, and there is a risk of leakage from the connections between these ends. was there.

Conventionally, in order to prevent corrosion caused by a potential difference between dissimilar metals, the surface of a push ring axially engaged with the outer surface of a spigot tube made of metal is coated with an insulating member. By covering a part of the inner surface of the socket pipe made of a metal material different from that of the socket pipe with an insulating member in the same way, the socket pipe and the socket pipe which are inserted into each other through the sealing material can be separated from each other. There is a structure in which a press ring and a socket pipe are fastened while avoiding electrical contact at the connecting portion (see, for example, Patent Document 1).

JP 2015-143524 A (page 7, FIG. 2)

However, in Patent Document 1, when an external force such as an earthquake or uneven subsidence occurs in a state in which the spigot pipe and the socket pipe are connected as described above, these pipes are connected to each other. As a result of tilting and sliding with respect to the shaft, the spigot pipe, the pressing ring or locking member engaged therewith, and the socket pipe are exposed to each other at the exposed portions of the metal materials that do not require insulation in a normal connection state. There is a problem that the coating layer of the insulating member is peeled off or gnawed due to the contact or the behavior described above, and the metal material is exposed, and the different metals come into contact with each other at the exposed portion. In particular, in the case of a large-diameter pipe, even a slight angle of inclination causes a large amount of displacement of the pipe, and a large bending moment acts on the pipe.

The present invention has been made by paying attention to such problems, and provides an insulating joint structure that can maintain the insulating function between dissimilar metal materials even if an unexpected external force such as an earthquake or uneven subsidence occurs. intended to

In order to solve the above problems, the insulating joint structure of the present invention includes:
A receptacle pipe part made of a metal material and having a flange extending in the outer diameter direction at the open end, and a receptacle pipe part made of a different metal material from the receptacle pipe part and inserted into the receptacle pipe part. A spigot pipe portion having a spigot portion, a seal member for sealing between the socket pipe portion and the spigot pipe portion, a press ring for pressing the seal member, the socket pipe portion and the spigot pipe. An insulation joint structure comprising at least a fastening member that fastens the part,
The spigot pipe portion has a flange portion formed integrally with the spigot portion and extending in the outer diameter direction, and the press ring is formed between the collar portion of the socket pipe portion and the spigot pipe portion. The press ring is interposed in an insulated state between the flange portion and the back surface of the press ring is supported by the flange portion of the insertion pipe portion, and the fastening member is the flange portion of the socket pipe portion. and the flange portion of the spigot pipe portion and are inserted in an insulated state.
According to this feature, since the flange portion integrally formed with the spout portion of the spigot pipe portion to be inserted into the spigot pipe portion is fastened to the flange portion of the spigot pipe portion by the fastening member, Even if an unexpected external force such as uneven subsidence occurs, the spigot pipe part does not bend, and the socket pipe part and the spigot pipe part are integrated without relative movement. While maintaining a highly insulated state between the pipe portions, the press ring supported by the flange portion stably presses the seal member, thereby maintaining the sealed state of both pipe portions.

The fastening member is characterized in that it is inserted through the pressing ring in an insulated state.
According to this feature, the socket pipe portion, the spigot pipe portion, and the push ring interposed therebetween can be integrated while 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 pressing ring is characterized in that it is in surface contact with the collar portion of the socket pipe portion.
According to this feature, it is possible to position the direction in which the insertion tube portion, the pressing ring and the socket tube portion are connected to each other.

The pressing ring is characterized by having a pressing portion that protrudes into the socket pipe portion and presses the sealing member.
According to this feature, by pressing the seal member disposed between the socket pipe portion and the insertion pipe portion toward the inside of the socket pipe portion, the sealing performance of the seal member can be enhanced.

An expansion joint having at least stretchability is formed at the other end of the socket pipe portion or the insertion pipe portion.
According to this feature, while the socket pipe part and the insertion pipe part are not moved relative to each other and the insulation function is exhibited, the expansion joint formed at either of the other ends secures the expansion and contraction function of the fluid pipe line. can do.

FIG. 2 is a schematic diagram showing a fluid pipeline to which the insulating joint structure in Example 1 is applied; It is a sectional side view which shows an insulation joint structure. FIG. 5 is a side cross-sectional view showing a state in which a pressing ring and a seal member are fitted onto the spigot tube portion; FIG. 4 is a side cross-sectional view showing a state in which the spigot pipe portion is fastened to the socket pipe portion by a fastening member; FIG. 4 is a side cross-sectional view showing a state in which fastening of the spigot pipe part and the socket pipe part is completed; (a) is a rear view of the insertion tube portion, and (b) is a partially cross-sectional side view of the same. (a) is a rear view of the push ring, (b) is a cross-sectional view taken along line XX of (a), and (c) is a cross-sectional view taken along line YY of (a). FIG. 11 is a side cross-sectional view showing an insulation joint structure to which a pressing ring according to a first modification is applied; FIG. 11 is a side cross-sectional view showing an insulating joint structure to which a pressing ring according to a second modification is applied; FIG. 11 is a side cross-sectional view showing an insulating joint structure to which an insulating coating layer according to a modification is applied;

A mode for carrying out the insulating joint structure according to the present invention will be described below based on an embodiment.

An insulating joint structure according to a first embodiment will be described with reference to FIGS. 1 to 10. FIG. First, reference numeral 1 in FIG. 1 denotes an insulating joint structure according to the present invention. Also, in this embodiment, the inserting direction of the spigot tube portion will be described as the forward direction (front surface).

As shown in FIG. 1, the fluid conduit 100 of the present embodiment is configured by connecting a plurality of fluid conduits in a sealed manner for circulating clean water as the internal fluid. It is buried in the ground along the line, and the fluid pipes are arranged in order, for example, over the ground or over rivers. The fluid pipeline 100 includes a pipe bridge portion 100a made of stainless steel or steel, for example, constructed over a river, and an embedded portion 100c, made of ductile cast iron, for example, which is buried in the ground and extends. 101 and a connecting portion 100b made of stainless steel or steel. It absorbs an external force that causes relative movement such as expansion and contraction due to bending and twisting.

In this embodiment, the fluid conduit 100 is a relatively large-diameter pipe, but is not limited to this and may be a small-diameter pipe. Although the fluid in the fluid pipe 100 is clean water, the fluid flowing inside the fluid pipe is not necessarily clean water. It may be a liquid mixture. Furthermore, the fluid pipeline to which the insulating joint structure according to the present invention is applied is not necessarily limited to one composed of a pipe bridge portion, a connecting portion, and an embedded portion.

The insulating joint structure 1 in this embodiment is electrically insulated when laying the buried portion 100c with respect to the connection portion 100b supported by a rigid body 12 such as a concrete abutment that serves as an abutment of the pipe bridge portion. It is a structure interposed in the state. In this embodiment, a description will be given of a mode used when connecting the receptacle pipe portion 2 connected to the end portion of the embedded portion 100c and the spigot pipe portion 3 welded to the end portion of the connection portion 100b. . As shown in FIG. 2, the insulating joint structure 1 is mainly composed of a socket pipe portion 2, an insertion pipe portion 3, a seal member 4, a pressing ring 5 and a fastening member 6. As shown in FIG.

Next, the socket pipe portion 2, the spigot pipe portion 3, the seal member 4, the pressing ring 5 and the fastening member 6 that constitute the insulating joint structure 1 will be described. As shown in FIG. 2, the socket pipe portion 2 is disposed on one end side of the expandable flexible tube 20 in this embodiment, and includes a fluid pipe portion 2p, a socket portion 2a, and a socket portion 2a. It is mainly composed of a collar portion 2b extending radially outward from the open end of the .

More specifically, as shown in FIG. 3, the socket pipe portion 2 continues to the inner peripheral edge of the flange end face 2c, and is formed inwardly in the pipe axial direction to form a concave portion 2d. An inner cylindrical portion 2e extending inward in the tube axial direction and having a smaller diameter than the inner cylindrical portion 2e, and an inner protrusion 2g extending inward in the inner diameter direction and connected to an annular end face 2f formed at the innermost end of the inner cylindrical portion 2e are provided. In addition, a plurality of bolt holes 2h are provided in the flange portion 2b along the circumferential direction and penetrate in parallel with the pipe axis direction, and the bolts 7 constituting the fastening member 6 are inserted through these bolt holes 2h. It's like

The socket pipe portion 2 of this embodiment is made of ductile cast iron, and its surface is only subjected to normal rust prevention treatment such as painting. has not been applied. However, it is not limited to this, and the surface of the socket pipe portion 2 may be insulated.

Further, as shown in FIG. 2, the other end side of the expansion/contraction flexible tube 20 is formed as a flexible tube side case 31 constituting an expansion/contraction flexible tube joint 30, which is the expansion joint of this embodiment. The flexible tube side case 31 and the seat 32 formed at the other end of the flexible tube 20 are connected to each other by a bayonet claw 31 a formed at the end of the flexible tube side case 31 . , and a bayonet claw 32 a formed on the seat 32 engages with the bayonet. A spherical member 34 having a spherical outer surface is disposed between the flexible tube side case 31 and the spigot tube 41 forming the embedded portion 100c. and the spherical member 34 are sealed, and the seal member 36 seals the space between the spherical member 34 and the spigot tube 41 . In addition, a groove 41a is provided on the outer periphery of the distal end side of the spigot tube 41, and the groove 41a is provided to prevent detachment while allowing a certain amount of expansion and contraction between the flexible tube side case 31 and the spigot tube 41. , a locking member 42 is provided. Further, a dust cover 33 and a dust ring 37 are provided to prevent contaminants from entering the flexible tube joint 30 .

By providing such an extensible flexible tube joint 30, the flexible tube side case 31 and the spigot tube 41 maintain sealing performance, and the spigot tube 41 is 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 socket pipe portion 2 and the insertion pipe portion 3 in the insulation joint structure 1 described later. In spite of being restricted, the expansion and contraction flexible tube joint 30 allows the conduit to be provided with expansion and contraction and flexibility functions.

In the present embodiment, the elastic flexible tube joint 30 is provided at the opposite end of the socket pipe portion 2, but is not limited to this. A telescoping flexible joint may be provided. Moreover, it is not necessarily limited to an expansion/contraction flexible joint, and may be an expansion/contraction joint having at least an expansion/contraction function.

Next, the insertion tube portion 3 will be described with reference to FIGS. 3 and 6. FIG. The spigot pipe portion 3 is a straight tubular member, has an open end at one end in the pipe axial direction, and extends linearly along the pipe axial direction so as to be insertable into the socket portion 2 a of the socket pipe portion 2 . and a flange portion 3b projecting radially outward from the base end side of the insertion port 3a in the pipe axis direction. It mainly includes a fluid tube portion 3p extending sideways.

A front surface 3c of the flange portion 3b facing the socket portion 2a side is formed in a flat surface shape extending in a direction substantially orthogonal to the pipe axis, and penetrates between the front surface 3c and the rear 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 axial direction is hermetically connected to the end portion of the connecting portion 100b by welding in this embodiment.

In the spigot pipe portion 3 of this embodiment, the tubular members constituting the spigot portion 3a and the fluid pipe portion 3p and the flange portion 3b are integrated by welding. A thick portion 3g that is thick in the radial direction and the pipe axial direction is formed at the inner peripheral base portion of 3d. The radial thickness of the spigot portion 3a is greater than the thickness of the other end portion 3r of the fluid tube portion 3p, thereby increasing the rigidity of the spigot portion 3a.

The spigot pipe portion 3 is made of a metal different from that of the socket pipe portion 2, such as steel or stainless steel. In this embodiment, nylon coating is applied to the entire surface of the fluid pipe portion 3p except for the spigot portion 3a, the flange portion 3b, the inner peripheral portion of the bolt hole 3h, and the other end portion 3r side. , that is, an insulating coating layer C is formed. The insulating treatment is not limited to the nylon coating, and the surface may be coated with an insulating material made of a different material such as rubber lining, plastic coating, epoxy resin powder coating, or the like by coating, dipping, spraying, or the like. Furthermore, the spigot pipe portion 3 may be formed at one end or both ends of a straight or curved fluid pipe, or may be formed at one end or both ends of a connection member such as a fluid valve connected to a pipe line. may be

Next, the push ring 5 will be described with reference to FIGS. 3 and 7. FIG. The push ring 5 of this embodiment is made of ductile cast iron, like the socket pipe portion 2, and is formed integrally, or is formed of an annular member divided in the circumferential direction or the pipe axial direction. The metal material constituting the pressing ring 5 is preferably the same metal as the socket pipe portion 2 as in the present embodiment, among the socket pipe portion 2 and the insertion pipe portion 3 which are different metals. The push ring 5 has a projecting portion 5a as a pressing portion that continues to the inner peripheral surface and protrudes annularly in one axial direction of the pipe and presses the seal member 4 as will be described later. It mainly includes a front surface 5c extending in a flat surface in the direction substantially perpendicular to the axis, and a back surface 5d extending in the shape of a flat surface in the direction substantially perpendicular to the tube axis on the opposite side of the protrusion 5a and the front surface 5c. A tapered surface 5b is provided at the front end of the protruding portion 5a in the tube axial direction, and a tapered surface 5b extending gradually forward toward the outer diameter side is provided. It has multiple. The inner diameter of the push ring 5 is slightly larger than the outer diameter of the spigot portion 3a of the spigot tube portion 3, so that the push ring 5 can be loosely fitted around the outer circumference of the spigot portion 3a.

In this embodiment, the entire surface of the push ring 5, including the projecting portion 5a, the front surface 5c, the rear surface 5d, and the inner circumference of the bolt hole 5h, is subjected to insulation treatment by applying a nylon coat, that is, an insulating coating layer. D is formed. The insulation treatment is not limited to the nylon coating, and the surface may be coated with an insulating material made of a different material such as rubber lining, plastic coating, epoxy resin powder coating, or the like by coating, dipping, spraying, or the like. As described above, the push ring 5 is insulated from both the socket pipe portion 2 and the spigot pipe portion 3 that sandwich the push ring 5 as will be described later.

Next, the sealing member 4 will be explained. As shown in FIG. 3, the sealing member 4 is made of an elastic resin material such as rubber, and has an annular shape with an inner diameter slightly smaller than the outer diameter of the spout portion 3a of the spout tube portion 3. are doing. The seal member 4 has a valve portion 4a having a substantially circular cross-sectional shape in its natural state at its front end, and a pressing surface 4b at its rear end facing the tapered surface 5b of the protruding portion 5a of the push ring 5 substantially in parallel. , the protruding portion 5a of the pressing ring, the outer peripheral surface of the spigot portion 3a, the inner cylindrical portion 2e of the socket portion 2a, and the annular end surface 2f. Seal between 3.

A procedure for assembling the insulating joint structure 1 including the socket pipe portion 2, the spigot pipe portion 3, the seal member 4, and the pressing ring 5 as described above will be described. As shown in FIG. 3, first, the surfaces of the socket tube portion 2, the insertion tube portion 3, the seal member 4, and the pressing ring 5 are cleaned, and the pressing ring 5 and the sealing member 4 are removed from the insertion portion of the insertion tube portion 3. 3a is fitted. At this time, it is preferable to apply a lubricant to the outer surface of the spigot portion 3a, the inner surface of the inner cylindrical portion 2e of the socket portion 2a, and the like, if necessary.

Subsequently, as shown in FIG. 4, working bolts constituting temporary fastening members 16 are inserted into the bolt holes 3h of the spigot pipe portion 3, the bolt holes 5h of the pressing ring 5, and the bolt holes 2h of the socket pipe portion 2. 17 is inserted, and a nut 18 screwed onto the working bolt 17 is tightened to insert the spigot pipe portion 3 into the socket pipe portion 2 . The working bolt 17 preferably has a relatively long axial length and is a T-head bolt as in the present embodiment because it facilitates the 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 projecting portion 5a of the push ring 5 supported in surface contact with the front surface 3c of the flange portion 3b of the spigot pipe portion 3. As shown in FIG. Then, by tightening the working bolt 17 and the nut 18, the socket pipe portion 2 and the insertion pipe portion 3 are gradually drawn in the pipe axial direction, and as shown in FIG. It is pushed between the inner cylindrical portion 2e of the socket pipe portion 2 and the outer peripheral surface of the spigot portion 3a, and mainly the valve portion 4a of the seal member 4 is compressed.

Since the rear 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 determined by the flange portion 3b. In addition, since there is no gap between the back surface 5d of the press ring 5 and the flange portion 3b of the spigot tube portion 3, and there is no sliding between them during tightening by the temporary fastening member 16, the insulating coating layer is peeled off. can be avoided.

At this time, the protruding portion 5a of the pressing ring 5 is arranged so as to protrude into the concave portion 2d of the socket pipe portion 2. The gap between the inner peripheral surface of the socket pipe portion 2 and the outer peripheral surface of the spigot pipe portion 3 is evenly spaced in the circumferential direction by pressing the sealing member 4 arranged in the inside of the socket pipe portion 2 evenly. As a result, the sealing performance of the seal member 4 can be improved, and the projection 5a of the push ring 5 and the recess 2d of the socket pipe portion 2 are unevenly fitted, so that when an external force such as bending acts on the pipe line, However, it can strongly resist this external force.

Next, a plurality of working bolts 17 and nuts 18 arranged along the circumferential direction are sequentially tightened so that the front surface 5c and rear surface 5d of the press ring 5 are aligned with the flange end surface 2c of the socket pipe portion 2 and the spigot pipe. The front surface 3c of the flange portion 3b of the portion 3 is pressed while being in surface contact, and the socket pipe portion 2 and the insertion pipe portion 3 are pulled together by the seal member 4 until they are sealed. During this tightening, the temporary fastening member 16, the rear surface 3d of the flange portion 3b, the front surface 5c of the press ring 5, the flange end surface 2c of the socket pipe portion 2, the flange portion 2b, etc., slide to form an insulating coating layer and an antirust treatment. is affected, the temporary fastening member 16 is replaced with an insulated fastening member 6, which will be described later, and the press ring 5 and the socket pipe portion 2 are made of the same material, so the insulation performance of the insulating joint structure 1 is not affected.

Since the front surface 5c of the push ring 5 is in surface contact with the flange end surface 2c of the socket pipe portion 2, the spigot pipe portion 3, the push ring 5, and the socket pipe portion 2 are connected to each other. direction can be positioned.

After completion of pulling the socket pipe portion 2 and the insertion pipe portion 3 by these working bolts 17 and nuts 18, the working bolts 17 and nuts 18 are sequentially removed, and new fastening members 6 are sequentially fastened in place of them. 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 through the shaft portion of the bolt 7. It is inserted through the bolt hole 2h of the flange 2b of the socket pipe portion 2, the bolt hole 5h of the pressing ring 5, and the bolt hole 3h of the flange portion 3b of the insertion pipe portion 3. By doing so, the socket pipe portion 2 , the spigot pipe portion 3 , and the push ring 5 interposed therebetween can be integrated while being positioned by the fastening member 6 .

The insulating washer 9 is composed of a metal ring 9b that contacts the inner end surfaces of the bolt 7 and the nut 8, and an insulating resin ring 9a that contacts the collar portion 2b and the flange portion 3b sandwiched by the fastening member 6. The fastening member 6 is fastened while avoiding electrical contact with the socket pipe portion 2 and the spigot pipe portion 3 to be fastened. The insulating washer 9 may be provided with a resin ring 9a on both sides of the metal ring 9b, or may be formed using bolts, nuts, or other accessories for promoting insulation.

Tightening management of the plurality of bolts 7 and nuts 8 that make up the fastening member 6 is performed by using a jig such as a torque wrench as necessary, while taking care not to tighten in a circumferential direction. (For example, if the nominal diameter of the bolt is M20, it is desirable to tighten the bolt evenly up to 100 N·m). In addition, in the insulating joint structure 1 of Example 1, when the press ring 5 comes into contact with the flange end surface 2c of the socket pipe portion 2 and the front surface 3c of the flange portion 3b of the spigot pipe portion 3, the tightening torque abruptly increases. Therefore, it is possible to easily judge the completion of tightening by the feeling of tightening without performing tightening by normal torque management.

Further, as described above, after the work bolt 17 and the nut 18 complete the drawing of the socket pipe portion 2 and the insertion pipe portion 3, the bolt 7 and the nut 8, which are new fastening members 6, are tightened. When the bolt 7 and the nut 8 are tightened, a drawing load such as sliding contact with the socket pipe portion 2 and the insertion pipe portion 3 is not applied. Therefore, the fastening member 6 can be fastened as a new one without causing small scratches or the like due to sliding contact when fastening, so that the insulation function can be sufficiently exhibited without impairing the insulation function.

According to the insulating joint structure 1 according to the present invention described above, the spigot pipe portion 3 has the flange portion 3b formed integrally with the spigot portion 3a and extending in the outer diameter direction. , and is interposed between the flange portion 2b of the socket pipe portion 2 and the flange portion 3b of the insertion pipe portion 3 in an insulated state, and the back surface 5d of the pressing ring 5 is supported by the flange portion 3b of the insertion pipe portion 3. Further, the fastening member 6 is inserted across the collar portion 2b of the socket pipe portion 2 and the flange portion 3b of the insertion pipe portion 3 in an insulated state.

By doing so, the flange portion 3b integrally formed with the spigot portion 3a of the spigot pipe portion 3 to be inserted into the spigot pipe portion 2 is moved by the fastening member 6 to the flange portion 2b of the spigot pipe portion 2. Therefore, even if an unexpected external force such as an earthquake or uneven subsidence occurs, the spigot pipe portion 3 will not bend, and the spigot pipe portion 2 and the spigot pipe portion 3 will face each other. The seal member 4 is stably pressed by the press ring 5 supported by the flange portion 3b while the two pipe portions are integrated without movement and a high insulation state is maintained, thereby maintaining the sealed state of the two pipe portions. can hold.

Further, in this embodiment, since the press ring 5 is made of the same metal material as the socket pipe portion 2, the socket pipe portion 2 and the insertion pipe portion 3 are interposed with the push ring 5 as described above. or when an unexpected external force occurs after the completion of piping, for example, the protrusion 5a of the push ring 5 or a portion near it and the recess 2d of the socket pipe portion 2 come into sliding contact. Even if the insulating coating layer D of the press ring 5 peels off at the part and makes electrical contact, there is no potential difference between the same metals and there is no risk of galvanic corrosion. On the other hand, since the rear surface 5d of the push ring 5 and the front surface 3c of the flange portion 3b of the spigot tube portion 3 are in flat surface contact with no unevenly engaged portions, the surfaces are in contact with each other. There is no possibility that the insulating coating layer D will peel off from the rear surface 5d of the push ring 5. As shown in FIG. In addition, since the insulating coating layer C is formed on the entire surface of the insertion tube portion 3 except for the side of the other end portion 3r, the gap between the insertion tube portion 3 and the press ring 5, which are different metals, can be reduced. has a double insulating coating layer C and an insulating coating layer D, so that a high insulating performance can be maintained.

Next, referring to FIG. 8, a first modification of the press ring constituting the insulating joint structure of the present invention will be described. It should be noted that the same configuration as that of the above-described embodiment and redundant description will be omitted.

The push ring 15 of the first modified example has a front surface 15c extending in a flat surface shape in a direction substantially perpendicular to the pipe axis and a flat surface shape in a direction substantially perpendicular to the pipe axis on the opposite side of the front surface 15c. It mainly includes a rear surface 15d extending to the . Further, a plurality of bolt holes 15h extending through the front surface 15c and the rear surface 15d are provided along the circumferential direction. The inner diameter side of the front surface 15c of the press ring is configured as a pressing portion that presses the seal member 4. As shown in FIG.

By doing so, the front surface 15c of the pressing ring 15 and the flange end surface 2c of the socket pipe portion 2 can be brought into flat surface contact over the entire surface. When the portion 2 and the spigot pipe portion 3 are pulled together, or when an unexpected external force occurs after the completion of piping, there is no fear that the insulating coating layer D of the pressing ring 15 will peel off at the portion where the surfaces come into contact.

Next, a second modification of the press ring constituting the insulation 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-described embodiment and redundant description will be omitted.

The pressing ring 25 of the second modification has a recessed portion 25a as a pressing portion that continues to the inner peripheral surface and is annularly recessed on one side in the pipe axis direction and presses the seal member 4, and the outer diameter of the recessed portion 25a. A front surface 25c extending in a flat surface shape in a direction substantially perpendicular to the pipe axis and a rear surface 25d extending in a flat surface shape in the direction substantially perpendicular to the pipe axis on the opposite side of the concave portion 25a and the front surface 25c. Mainly provide The recessed portion 25a has a taper surface 25b extending gradually forward toward the outer diameter at the front end thereof in the tube axial direction. and multiple. However, the tapered surface 25b is not limited to being tapered, and may be formed on a surface substantially perpendicular to the tube 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 face 2c of the socket pipe portion 2, so that the seal member 4 can be excessively moved. However, by pressing with an appropriate pressing force, a uniform elastic repulsive force can be generated over the entire surface of the seal member 4, the sealing performance can be exhibited, and the press ring 25 can be centered.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and any changes or additions within the scope of the present invention are included in the present invention. be

For example, in the embodiment, the insulating coating layer C is applied to the entire surface of the fluid pipe portion 3p except for the spigot portion 3a of the spigot pipe portion 3, the flange portion 3b, the inner peripheral portion of the bolt hole 3h, and the other end portion 3r side. is formed, but not limited to this, for example, as shown in FIG. A further insulating coating layer F may be formed by rubber vulcanization or adhesion on the outer surface of the insulating coating layer C that covers the tip surface of the spigot tube portion 3 that continues to. A spacer made of rubber or the like may be installed on the inner peripheral surface of the socket pipe portion 2 .

Further, for example, in the above-described embodiment, the push ring 5 is a member made of the same metal material as the socket pipe portion 2, but is not limited to this. 2 may be made of the same metal material as the spigot pipe portion 3, or a member made of a metal material different from both the socket pipe portion 2 and the spigot pipe portion 3 may be used. As long as it has sufficient structural strength, it may be made of various hard materials other than metal.

1 Insulated joint structure 2 Socket pipe portion 2a Socket portion 2b Flange portion 2c Flange end surface 2d Recess 3 Insertion pipe portion 3a Insertion portion 3b Flange portion 3c Front surface 3d Back surface 3g Thick portion 4 Sealing member 4a Valve portion 4b Cover Pressing surface 5 Press ring 5a Protruding portion (pressing portion)
5b Tapered surface 5c Front surface 5d Back surface 6 Fastening member 7 Bolt 8 Nut 9 Insulating washer 15 Push ring 15c Front surface (pressing portion)
16 Temporary fastening member 20 Expandable flexible tube 25 Push ring 25a Recessed portion (pressing portion)
30 Expansion joints (expansion joints)
100 fluid line

Claims (6)

A receptacle pipe part made of a metal material and having a flange extending in the outer diameter direction at the open end, and a receptacle pipe part made of a different metal material from the receptacle pipe part and inserted into the receptacle pipe part. A spigot pipe portion having a spigot portion, a seal member for sealing between the socket pipe portion and the spigot pipe portion, a press ring for pressing the seal member, the socket pipe portion and the spigot pipe. An insulating joint structure comprising at least a fastening member that fastens the part in an insulated state,
The spigot pipe portion has a flange portion formed integrally with the spigot portion and extending in the outer diameter direction, and the press ring is formed between the collar portion of the socket pipe portion and the spigot pipe portion. The front surface of the press ring is formed in a flat surface shape and is in surface contact with the flange portion of the socket pipe portion, and the back surface of the press ring is interposed between the flange portion and the flange portion in an insulated state. is an insulating joint structure characterized in that the flange portion of the spigot pipe portion is in surface contact with the flange portion. 2. The insulating joint structure according to claim 1, wherein said fastening member is inserted through said pressing ring in an insulated state. 3. The insulating joint structure according to claim 1, wherein the pressing ring has a pressing portion that protrudes into the socket pipe portion and presses the sealing member. 3. The insulating joint structure according to claim 1, wherein the front surface of the pressing ring is formed in the shape of the flat surface over substantially the entire surface, and has a pressing portion that presses the sealing member. 3. The insulating joint structure according to claim 1 , wherein the front surface of said pressing ring has a concave portion for pressing said seal member on its inner diameter side. 6. The insulating joint structure according to any one of claims 1 to 5, wherein an expansion joint having at least stretchability is formed at the other end of the socket pipe portion or the insertion pipe portion.

Images