JP4988428B2 - Conductive integrated structure of metal pipes - Google Patents

Description

  The present invention relates to a conduction-integrated structure of a metal pipe embedded in the ground.

When metal buried pipes such as gas pipes, water pipes, and various cable pipes are installed in the vicinity of the railway track, the current flowing through the rail leaks into the ground, and the leakage current (so-called Stray current) often causes galvanic corrosion in those buried tubes.
For example, as shown in FIG. 7, after the leakage current flows from the rail R through the underground into the buried pipe 1, it flows out again toward the rail R on the ground near the substation S of the railway. As a result, severe corrosion occurs locally in the outflow portion C.

Therefore, in order to prevent such electric corrosion, a method is known in which a rubber ring is used for a metal pipe joint part to electrically insulate adjacent pipes so that no stray current flows along the pipe line. Yes.
In addition, a method for preventing current from flowing into the buried pipe from the outside by providing an insulating layer on the surface of the buried pipe or by providing a conductive layer for releasing current to others has been proposed (for example, Patent Document 1).

On the other hand, as a method for preventing such electrolytic corrosion or actively preventing piping, there are electrolytic corrosion methods such as selective drainage method, forced drainage method, external power source method, and galvanic anode method. However, in order to carry out these anticorrosion measures, it is necessary to consolidate the pipelines. Furthermore, the pipes need to be integrated in the same way when performing potential management in order to perform anticorrosion management of the pipes based on the potential of the pipes.
JP 2000-120923 A

  In recent years, there are an increasing number of cases in which the joint portion of the buried pipe adopts a seismic tube joint structure that allows a large amount of axial expansion and contraction and bending so that the pipe body is not damaged due to ground fluctuation during an earthquake or the like.

  However, if the pipes are connected to each other via a conducting wire in order to electrically integrate the pipeline, when the pipes move across the joint, the conducting wire cannot follow the movement and breaks. May end up.

  Once a conducting wire or the like loses the conduction function between the pipes, the restoration of the conduction function must be found by finding the damaged part by fluctuations in the potential of the pipe, excavation, etc., and restoring it with a new conductive member. However, these operations are very difficult and in some cases impossible.

  Then, this invention makes it a subject to prevent the electroconductive member which conduct | electrically_connects a tubular body from being damaged in the case of expansion-contraction and bending of a joint part.

In order to solve the above-described problems, the present invention provides a portion that can be expanded and contracted in a conductive member that conducts the tubes.
In this way, the conductive member can expand and contract following the movement of the tubular body when the tubular bodies expand and contract and bend at the joint. For this reason, damage to the conductive member can be prevented.

In addition, a cover that separates the conductive member from the surrounding ground or filler is provided so that the conductive member does not adhere to the surrounding ground or sheath in the pipe when the tube is embedded.
In this case, the conductive member is not fixed by the surrounding filler, the ground, or the like when the tube is embedded, and its movement is not easily restricted. For this reason, it is easy to move following the movement at the time of expansion / contraction and bending of the tubular bodies, and the breakage of the conductive member can be more reliably prevented.

  In this invention, since the conductive member that conducts the pipes does not break during the expansion and contraction and bending of the pipes, the conduction state between the pipes is maintained even when there is ground fluctuation during an earthquake or the like. Will come to be.

As an embodiment of the above means, the metal pipes are connected to each other through a joint part and buried in the ground, and the contacts provided on both pipes sandwiching the joint part are connected by a conductive member, It is possible to adopt a configuration in which a conductive portion is provided between both pipes and a movable portion is provided on the conductive member to allow expansion and contraction in accordance with a change in the distance between the contact points.
Here, examples of the metal pipe include a ductile cast iron pipe, a cast iron pipe, a steel pipe, and a stainless steel pipe.
When the pipes expand and contract or bend at the joint, the distance between the contacts connecting the conductive members changes, but the conductive member expands and contracts at the movable part to follow the movement of the pipes as the distance changes. can do. For this reason, damage to the conductive member can be prevented.

  In addition, the conductive member is disposed outside the tubular body, and the entire length of the conductive member is covered with a protective member, and the conductive member is electrically connected to the protective member when the tubular body is buried in the ground. The structure which made the sex member movable in the length direction can be employ | adopted.

For example, when the pipe body is laid in the sheath pipe via a filler, the conductive member other than the movable part is sheathed if the conductive member is disposed outside the pipe body. It is considered that the movement is restrained by a filler such as air milk filled between the tubes and the expansion and contraction becomes dull. Further, even when the pipe body is directly embedded in the soil of the ground without going through the sheath pipe, it is considered that the conductive member comes into contact with the surrounding ground and its movement is restricted.
Therefore, if the protective member that covers the conductive member is provided as described above, it is possible to prevent the conductive member from being restrained by the filler or the ground.

  If the conductive member is a conductive wire and the movable part is formed by providing a slack in a part of the conductive wire, the movable part can allow expansion and contraction due to the slack. Can be simplified.

  When the conductive member is a conductor, the protective member provided in a portion other than the movable portion can be a resin protective tube that can accommodate the conductor therein.

Further, if the protective member provided in the movable part of the conductive member has a gap that allows expansion and contraction of the movable part therein, the movable part can appropriately move in the gap when the movable part expands and contracts. Because it can, the expansion and contraction is not hindered.
Thus, if the movable member is covered with the protective member, when the protective member moves relative to the surrounding filler as the joint portion expands and contracts, the protective member or the surrounding filler, or both, The voids can be secured by deformation or crushing.

Moreover, the protective member provided in the movable part of the said electroconductive member can be made into the foaming resin molding which closely_contact | adheres to the circumference | surroundings of the said movable part.
If the movable part is covered with the protective member made of the foamed resin molded body in this way, as in the case described above, when the protective member moves relative to the surrounding filler as the joint part expands and contracts, the protective member or The surrounding fillers or both can be appropriately deformed or crushed to secure the voids. Further, since the foamed resin molded body is in close contact with the periphery of the movable part, the movable part is firmly held by the foamed resin molded body in a normal state where the tube does not expand and contract.

  A first embodiment will be described with reference to FIGS. 1 to 3. In this embodiment, in the NS type joint that is normally used as the joint portion 2 of the pipe bodies 1 and 1 that are ductile cast iron pipes, leakage between the pipe bodies 1 and 1 is caused by conducting between the pipe bodies 1 and 1. It employs a conduction-integrated structure that guides current along the pipe line direction.

  As shown in FIG. 1, the joint portion 2 is configured such that the insertion port 3 of the tube body 1 is fitted into the receiving port 4 of the adjacent tube body 1, and the outer peripheral surface of the distal end portion of the insertion port 3. Further, the insertion port protrusion 3a is formed integrally with the entire circumference. Further, on the inner peripheral surface of the receiving port 4, a rubber ring groove 5 a for storing a sealing rubber ring 5 slidably contacting the outer peripheral surface of the insertion port 3 and a lock ring groove for storing a lock ring 6 with centering rubber. 6a is formed.

In the sheath pipe P buried in the ground, the tubular body 1 is sequentially joined by inserting the insertion port 3 of the tubular body 1 into the receiving port 4 of the preceding tubular body 1, and the joined tubular body 1. , 1... Are pushed into the sheath pipe P, and the pipeline is laid.
A saddle member 9 is fitted to the outer periphery of the insertion port 3 slightly in the rear, and a bolt shaft 8a perpendicular to the tube axis is inserted into the flange portion 9a of the saddle member 9 so that the bolt shaft 8a is rotatable. A propulsion roller 8 is provided. For this reason, the frictional resistance with the sheath P at the time of pushing in the tubular body 1 is reduced, and the pushing force required for propulsion is reduced.
Further, after the propulsion is completed, the gap between the tube body 1 and the sheath tube P is filled with the filler G.

When a large pulling force acts on the joint portion 2 due to an earthquake or the like in the pipeline laid in this way, the insertion port 3 and the receiving port 4 move in a direction in which the insertion port 3 is pulled out in the tube axis direction. At this time, engagement of the lock ring 6 and the insertion port protrusion 3a prevents the insertion port 3 from deviating from the receiving port 4 (see FIG. 1A).
Moreover, when a big pushing force acts on the joint part 2, the insertion port 3 and the receiving port 4 move to the direction pushed in to a pipe-axis direction. At this time, the movement of the insertion port 3 is allowed until the tip of the insertion port 3 comes into contact with the back end 4a of the receiving port 4 (see FIG. 1B).

Further, the insertion port 3 is provided with a flange 7 protruding outward from the saddle member 9, and a propulsive force transmission made of foamed polystyrene or the like is provided between the flange 7 and the end surface 4 b of the receiving port 4. A member M is provided.
The propulsive force transmitting member M plays a role of transmitting propulsive force to the end face 4b of the receiving port 4 when the tube body 1 is pushed into the sheath pipe P, and after the completion of construction, the joint portion 2 as described above. Is pressed and elastically deformed by receiving a compressive force equal to or lower than the elastic limit stress, and when a compressive force higher than that is applied, it is plastically deformed to correspond to the movement of the joint portion 2. .

A metal fixing base 13 is fixed to the outer peripheral surface of the tubular body 1 by welding on both tubular bodies 1 and 1 sandwiching the joint portion 2. The fixed base 13 and the tube 1 are electrically connected with the contact surface as a contact a. Bolts 11 are screwed into the fixing base 13, and the bolts 11 and the fixing base 13 make contact between the bolts 11 and the metal portion of the tube body 1, so that the contact portions are contact points a and a. 1 and the bolt 11 are conducted, and the fixing base 13 is conducted to the tube body 1 through the bolt 11.
Crimp terminals 11 a, 11 a provided at both ends of a conducting wire (conducting member) 12 are fixed to the fixing bases 13, 13 by bolts 11, 11, and the joint portion 2 is sandwiched via one conducting wire 12. The tube bodies 1 and 1 are electrically connected to each other (see FIGS. 2A and 2B).

The conducting wire 12 is accommodated in a resin protective tube (protecting member) 22 of the cable 10, and the conducting wire 12 is movable in the length direction in the protective tube 22. The cable 10 is disposed along the outer peripheral surface of the tube body 1, and passes through a gap between the propulsion roller 8 and the outer peripheral surface of the tube body 1 in a portion where the saddle member 9 is provided. Has been.
In addition, since the arrangement | positioning route of the cable 10 can be set freely, the outer peripheral side of the saddle member 9 is used as the arrangement | positioning route of the said cable 10 in the position (circumferential position) where the propulsion roller 8 does not intervene, for example. Good.

Further, the conducting wire 12 is provided with a movable portion 20 that allows expansion and contraction of the entire length of the cable 10 in accordance with a change in the distance between the contacts a and a due to expansion and contraction of the joint portion 2 or bending.
The movable portion 20 is provided at one end of the conducting wire 12 and is formed by providing a slack in the conducting wire 12 in the vicinity of the connecting portion to the crimp terminal 11a, as shown on the left side of FIG. The If slack is provided in this way, if a tensile force (see arrow A in the figure) acts on the lead wire 12, the lead wire 12 moves in a direction in which the slack is removed, and the lead wire 12 is pushed in the pushing direction. When force (see arrow B in the figure) acts, the lead wire 12 moves in a direction in which the slack increases.

  Further, the tubular body 1 is provided with a protective member 21 that covers the entire circumference of the movable portion 20. The protection member 21 is formed of a foamed polystyrene molded body.

If the tubular body 1 moves in the direction of arrow C from the state shown in FIG. 3A to the state shown in FIG. 3B, the movable part 20 is moved by the space created by the deformation and collapse of the protective member 21. It extends along the moving direction.
Similarly, when the tube 1 moves from the state shown in FIG. 3C in the direction of arrow D in FIG. 3D, the movable portion 20 contracts along the moving direction.

The resin protective tube 22 is desirably provided in a range that does not reach the movable portion 20. This is because if the periphery of the conductive wire 12 of the movable portion 20 is covered with the resin protective tube 22, the expansion and contraction of the movable portion 20 is somewhat restricted. Therefore, in this embodiment, the resin protective tube 22 is provided up to the portion where the conducting wire 12 enters the protective member 21, and the connecting portion between the protective member 21 and the resin protective tube 22 has a sealing material or the like. Thus, a measure is taken to prevent the filler G and the like from entering the interior.
However, when the resin protective tube 22 is a material having great flexibility and does not hinder the expansion and contraction movement of the movable portion 20, the resin protective tube 22 can be provided over the entire length of the conducting wire 12. It is.

  Further, in this embodiment, the protective member 21 is added to the end portion of the conducting wire 12 on the side where the movable portion 20 shown on the left side in FIG. 2B is provided, and the side where the movable portion 20 shown on the right side is not provided. Is also provided at the end of the conducting wire 12. By doing in this way, the effect which protects the fixing stand 13, the volt | bolt 11, the crimp terminal 11a, etc. from corrosion can also be anticipated.

It should be noted that the movable parts 20 may be provided at both ends of the conducting wire 12, respectively. If movable parts are provided at both ends of the conducting wire 12, it is possible to cope with expansion and contraction of the larger joint part 2.
In addition, it can be said that the amount of expansion and contraction that can be accommodated by the movable portion 20 is desirably set to be greater than the expected change in distance between the contacts a and a.

  When the pipe body 1 having such a conductive integrated structure is laid in the sheath pipe P by propulsion, the insertion opening 3 of the pipe body 1 is inserted into the receiving opening 4 of the preceding pipe body 1 for connection. After that, the conductive wire 12 may be connected to each of the tubular bodies 1 and 1 in a state where the connected joint portion 2 is located in or near the starting stand. This is because if the joint portion 2 enters deeply into the sheath pipe P, connection work becomes difficult if the gap between the sheath pipe P and the tubular body 1 is small.

At the time of this connection, a foamed polystyrene molded body as the protective member 21 is integrated in advance around the conductor 12 including the movable portion 20 (the state shown in FIG. 2A). It is convenient to cut out only the part facing the bolt 11 head. This is because, after the bolt 11 is inserted from the notch and screwed into the fixing base 13, the notched portion of the foamed polystyrene is filled with the same kind of material, so that the whole can be easily covered with the protective member 21.
In addition, the said movable part 20 can respond | correspond not only the expansion-contraction and bending of the joint part 2 at the time of an earthquake etc. but the expansion-contraction and bending which arise in the joint part 2 when propelling the pipe body 1 in the sheath P.

  A second embodiment will be described with reference to FIGS. In this embodiment, a conductive integrated structure is adopted in the S-shaped joint.

  The structure of the joint portion 2 is the same as in the case of the NS joint described above. The insertion port 3 is engaged with the lock ring 6 provided on the receiving port 4 side by the insertion port projection 3a provided on the outer peripheral surface of the tube 1. By doing so, the insertion port 3 is prevented from coming off from the receiving port 4 (see FIG. 4).

A taper portion 4c that gradually increases in diameter as it approaches the end surface 4b is provided on the inner surface of the receiving port 4, and a number of screw holes 14 are provided in the end surface 4b along the circumferential direction.
In a state where the insertion port 3 is inserted into the receiving port 4, a rubber ring 15 as a sealing material is inserted between the tapered portion 4 c and the outer peripheral surface of the insertion port 3. The rubber ring 15 is formed in a shape along the inner surface of the receiving port 4. After the rubber ring 15 is inserted between the receiving port 4 and the insertion port 3, a push ring 18 is arranged at the rear part via the split ring 16. .

  A bolt 17 is inserted into the pusher wheel 18 and the bolt 17 is screwed into the screw hole 14. A nut 17 a is attached to the bolt 17 on the rear side of the push ring 18. When the nut 17 a is tightened, the push ring 18 is pushed forward, and the rubber ring 15 is tapered through the split ring 16. It is pushed into the gap between the portion 4 c and the outer peripheral surface of the insertion port 3.

A saddle member 9 is fitted to the outer periphery of the insertion port 3 slightly in the rear, and a bolt shaft 8a perpendicular to the tube axis is inserted into the flange portion 9a of the saddle member 9 so that the bolt shaft 8a is rotatable. A propulsion roller 8 is provided.
Further, a flange 7 protruding outward is provided integrally with the saddle member 9 at the insertion port 3, and a propulsive force transmission member made of foamed polystyrene or the like is provided between the flange 7 and the rear end of the bolt 17. M is provided. Further, a protective ring that abuts against the rear end of the bolt 17 is provided in front of the propulsive force transmission member M in the propulsion direction.
The functions of the propulsive force transmission member M, the propulsion roller 8 and the like are the same as those of the NS type joint of the first embodiment, and thus description thereof is omitted.

  The configuration of the cable 10 is the same as that of the first embodiment. However, as shown in FIG. 4, the conductive wire (conductive member) 12 is continuously formed along the connection body of the tube bodies 1 connected by a large number of joint portions 2. A metal fixing base 13 shown in FIG. 5 is attached to the tube body 1 so that the conducting wire 12 and the tube body 1 are electrically connected.

  The fixing base 13 has a T-shaped cross section including an outer portion 13 a extending in the tube axis direction along the outer peripheral surface of the tube body 1, and an insertion portion 13 b extending from the outer portion 13 a in the inner diameter direction and in close contact with the push ring 18. The bolt 17 is inserted into the hole 13c formed in the insertion portion 13b, and a contact portion between the bolt 17 and the screw hole 14 provided in the end surface 4b of the receiving port 4 is used as a contact a. 13 is electrically connected to the tube 1.

Further, the movable portion 20 is provided in the middle between the adjacent joint portions 2 and 2, that is, in the middle between the contact points a and a, and is formed by providing a slack in the conducting wire 12 as shown in FIG. Is done. Further, the protective member 21 that covers the movable portion 20 is provided. The structure of the protective member 21 is a foamed polystyrene molded body as in the first embodiment. The action when the joint portion 2 expands and contracts is the same as that of the first embodiment except that the protective member 21 does not have terminals such as the fixing base 13, the bolt 11, and the crimp terminal 11a. The description is omitted.
In FIG. 6, two conducting wires 12 are provided in parallel, and the number of conducting wires 12 arranged in this way is arbitrary in any embodiment.

In each of the above-described embodiments, the pipe body 1 is laid in the sheath pipe P via the filler G. However, the present invention is not limited to this embodiment. For example, the pipe body 1 is not inside the sheath pipe P without the filler G. A mode of laying in the case is also conceivable. When the pipe body 1 is laid without using the filler G, a space is interposed around the pipe body 1, and thus the protective member 21 that covers the movable portion 20 may be omitted.
Moreover, also in the aspect which embeds the pipe body 1 directly in the ground, each said conduction | electrical_connection integrated structure is employable.

  In each of the above embodiments, the protective member 21 is a foamed polystyrene molded body, but as the protective member 21, a foamed resin molded body made of another material can be adopted.

Further, the protection member 21 is configured by a member that partitions a space between the secured space and the outside while securing a predetermined space around the movable portion 20 such as a box-shaped member that covers the periphery of the movable portion 20. May be. If the space around the movable part 20 is secured so that the filler G or the like does not flow into the space around the movable part 20, the free movement of the movable part 20 can be secured.
In the aspect which employ | adopted the box-shaped protection member 21, when the joint part 2 expands | contracts, the movable part 20 is a pipe body similarly to the case where the protection member 21 which consists of the said polystyrene foam molded object is employ | adopted (refer FIG. 3). Any one that expands and contracts along the moving direction of 1 and can secure a gap with the surrounding filler G so that the movement of the movable portion 20 is not restrained by the filler G.
For example, a mode in which a protective member 21 made of resin in a box shape is fixed to the outer surface of the tube body 1 by bonding or the like is conceivable.

Moreover, as a structure of the movable part 20, in addition to the structure in which the conducting wire 12 is slackened, a method in which the conducting wire 12 is formed in a spring shape to be stretchable, a pair of sliding members is provided on a part of the conducting wire 12, The structure of the movable part 20 that can be expanded and contracted by sliding between the sliding members, a long hole is provided in the crimp terminal 11a of the conductive wire 12, and the bolt 11 is inserted into the long hole so that the end of the conductive wire 12 is A configuration that is movable with respect to the fixed base 13 can be employed.
In each of the above embodiments, a conductive wire is used as the conductive member. However, a conductive member other than the conductive wire, for example, a metal plate that is long in the tube axis direction may be used. Furthermore, if there is no problem in the use of the pipe line, the conductive member 12 can be disposed along the inner surface of the pipe body 1.

Example 1 is shown, (a) is a partially cut front view showing a state in which the joint portion is pulled, and (b) is a state in which the joint portion is pushed in. Example 1 is shown, (a) is a front view showing a state where a conductive member is attached to a tubular body, (b) is a plan view thereof. Action diagram of FIG. Partial cut front view of Example 2 Example 2 is shown, (a) is a plan view showing a state where a conductive member is attached to a tubular body, (b) is a front view thereof. Detailed view of movable part of embodiment 2 Explanatory diagram showing the mechanism of electrolytic corrosion

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tube 2 Joint part 3 Insertion slot 4 Receptacle 5 Seal rubber ring 6 Lock ring 7 Flange 8 Propulsion roller 9 Saddle member 10 Cable 11 Bolt 11a Crimp terminal 12 Conductive wire (conductive member)
13 fixed base 13a outer side part 13b insertion part 20 movable part 21 protective member 22 protective pipe a contact G filling material P sheath pipe

Claims (3)

Metal pipes 1 and 1 are connected to each other via a joint 2 and buried in the ground, and a conductive member is provided between the contacts a and a provided on both pipes 1 and 1 sandwiching the joint 2. It connects at 12 to conduct between said two pipe members 1 and 1, to the conductive member 12, the contact a, only setting the movable section 20 to permit expansion and contraction along with the change in the distance between a, the conductive member 12 is disposed outside the tubular body 1, and the entire length of the conductive member 12 is covered with protective members 21 and 22, and when the tubular body 1 is buried in the ground, the protective members 21 and 22 The conductive member 12 is moved in the length direction at the portions other than the movable portion 20 and the movable portion 20 with respect to the protective members 21 and 22 with the conductive member 12 and the surrounding filler or ground separated. and freely, the conductive member 12 are conductors, the movable portion 20, the Provided slack is formed in a part of the lines, that the conductive member protecting member 22 provided in a portion other than the movable portion 20 of 12 is a resin protective tube capable of accommodating the conductor therein conducting integrated structure of the metal pipe you characterized. Metal pipes 1 and 1 are connected to each other via a joint 2 and buried in the ground, and a conductive member is provided between the contacts a and a provided on both pipes 1 and 1 sandwiching the joint 2. It connects at 12 to conduct between said two pipe members 1 and 1, to the conductive member 12, the contact a, only setting the movable section 20 to permit expansion and contraction along with the change in the distance between a, the conductive member 12 is disposed on the outside of the tubular body 1, and the entire length of the conductive member 12 is covered with protective members 21 and 22, and when the tubular body 1 is buried in the ground, the protective members 21 and 22 to freely move the conductive member 12 in the longitudinal direction for it, the protection member 21 provided on the movable portion 20 of the conductive member 12 is a foam resin molded article in close contact with the periphery of the movable portion 20 conducting integrated structure of the metal pipe you characterized. Protecting member 21 provided on the movable portion 20 of the conductive member 12, conductive one of the metal pipe according to claim 1, characterized in that it has a gap to allow expansion and contraction of the movable portion 20 in its interior Body structure.

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