JPH0429749B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for energizing a tube, and more particularly, the present invention relates to a method for energizing a tube, and more specifically, passing a wire through a tube made of a conductive material into a tube made of a conductive material, and electrically connecting the tube through the tube wire passing device. The present invention relates to a method for energizing a tube. Such a method of energizing a pipe is necessary in order to ensure corrosion protection by passing an anticorrosive current through a metal pipe buried underground and having an electrically insulating coating layer.
For example, when connecting metal pipes using pipe joints,
Electrical continuity between the metal tubes may be cut off by the sealing material for preventing leakage. Therefore, the anti-corrosion current does not flow through all the tubes, and therefore the tubes to which the anti-corrosion current is not flowing will corrode.
Therefore, in order to establish electrical continuity between pipes connected by pipe fittings, etc., the pipe fittings are exposed by drilling a vertical hole, and the connections are made using a sealing material to prevent electrical insulation. It may be necessary to redo it. Such prior art requires a large amount of manpower and time for drilling vertical holes, and is inferior in workability. An object of the present invention is to provide a method for electrically connecting both sides of an insulated portion of a conductive tube with simple operations. The present invention provides a third wire made of a conductive material that is spirally wound within a tube made of a conductive material, and has a relatively large bending rigidity and torsional rigidity. One end of a second wire that is wound and has a bending stiffness and torsional stiffness smaller than that of the third wire is connected and fixed, and the second wire is spirally wound and made of a conductive material and is fixed to the other end of the second wire. One end of a first wire having bending rigidity and torsional rigidity smaller than that of the second wire is connected and fixed, and a guide member made of a conductive material is connected to the other end of the first wire, and the guide member is connected to the other end of the first wire. A method for energizing a pipe, characterized in that the first wire rod is able to bend due to weight, and the pipe is electrically connected to the pipe by passing the wire through an in-pipe wire threading tool that allows the first wire to bend due to weight. It's a method. FIG. 1 is a sectional view of an embodiment of the present invention. A covered metal pipe 61 as a branch pipe and a covered metal pipe 62 as a supply pipe are buried in the ground 60. The coated metal tubes 61 and 62 are steel tubes coated with an electrically insulating coating layer. The coated metal tube 62 is
3, and a second supply pipe 6 connected to the first supply pipe 64 via a pipe joint 65.
6, and a third supply pipe 68 connected to the second supply pipe 66 via an elbow 67. coated metal tube 6
1 and 62, a galvanic anode 69 such as a magnesium lump is connected to the coated metal pipe 61 as a branch pipe. A corrosion protection current flows through the coated metal tubes 61 and 62 by the current current anode 69, and the steel tubes are protected from corrosion. A fuel fluid such as city gas is transported to the coated metal pipe 61 . This fuel fluid flows from the tee 63 of the coated metal pipe 61 to the first supply pipe 64 and to the pipe joint 6.
5, second supply pipe 66, elbow 67, third supply pipe 6
8, the gas is supplied from a gas meter 72 to a gas fuel device installed in a house 73 via an elbow 70 and a valve in a standpipe 71. FIG. 2 is a sectional view of the vicinity of the pipe joint 65. 1st
The supply pipe 64 and the second supply pipe 66 are connected by a pipe joint 65. In the pipe joint 65, the ends of the first supply pipe 64 and the second supply pipe 66 are partially inserted into both ends of the joint main body 75, and yarns 76 and lead 77 are interposed on the outer periphery of these pipes. is pushed into the tube shaft to achieve airtightness. A first supply pipe 64 and a second supply pipe connected to a pipe joint 65
The outer peripheral surface of each end of the supply pipe 66 is coated with an electrically insulating coating layer, so that the electrical connection between the first supply pipe 64 and the second supply pipe 66 is insufficient. Therefore, no anticorrosion current flows through the first supply pipe 64 and the coated metal pipe 61 as a branch pipe.
Therefore, the second supply pipe 66 and the coated metal pipe 61 are likely to corrode. Therefore, the pipe fitting 1 made of a conductive material according to the present invention is inserted into the coated metal pipe 62 from the vicinity of the gas meter 72.
The inner circumferential surface of the first supply pipe 64 and the inner circumferential surface of the second supply pipe 66 are electrically connected by the intra-tube wire passing tool 1 . The intraductal wire passing tool 1 consists of a longitudinal wire 1a and a guide member 5 fixed to the distal end thereof. Long wire rod 1a
is composed of first to third wire rods as described later, and each wire rod is formed in a coil shape and has flexibility. The longitudinal wire 1a is made of conductive piano wire, and its outer periphery is exposed. The longitudinal wire 1a has elastic properties as described below, and elastically contacts the inner circumferential surfaces of the first supply pipe 64 and the second supply pipe 66, thereby causing the first supply pipe 64 to and the second supply pipe 66 are maintained in electrical continuity via the pipe joint 65. In addition, by twisting the longitudinal wire 1a of the pipe wire threading tool 1 around the axis, the spring wire rod 1a of the pipe wire threading tool 1 comes into contact with the inner circumferential surfaces of the first supply pipe 64 and the second supply pipe 66. The force is increased, and electrical continuity can be further ensured. At this time, in order to prevent the torsional force of the pipe wire threading tool 1 from returning, one end of the pipe wire threading tool 1 on the insertion side (the right side in Fig. 2) is in a state where a twisting force is applied to the pipe wire threading tool 1. It may be fixed as it is to the inner peripheral surface of the standpipe 71 near the gas meter 73. As a fixing means, soldering, attachment using metal fittings 100, etc. can be implemented. During the wiring operation of the pipe fitting 1, when the pipe fitting 1 is inserted into the coated metal pipe 62, as shown in FIG. 3, before time t1, the pipe joint 65 electrically insulates the first supply pipe 64 and the second supply pipe 66, so that the potential of the first supply pipe 64 and the second supply pipe 66 becomes low, for example, -850 mV. There is. When the guiding member 5 of the pipe wire threading device 1 passes through the pipe joint 65 and reaches the first supply pipe 64, that is, after time t1, the first supply pipe 64 and the second supply pipe 66 are connected to the pipe wire threading device 1. When the second supply pipe 66 is electrically connected, the potential of the second supply pipe 66 rises to, for example, -550 mV, and thereby an anticorrosion current flows and the anticorrosion effect is exhibited. In this way, the pipe joint 65 is
By electrically connecting the first supply pipe 64 and the second supply pipe 66 through the metal pipes 61 and 62 to achieve a conductive state between the coated metal pipes 61 and 62 and flowing an anti-corrosion current in a fixed direction, the coated metal pipes 61 and 62 can be prevented from corrosion. Moreover, the coating layer of the coated metal pipes 61 and 62 is damaged, and the outer peripheral surface of the steel pipe is damaged at a location 79 on the ground 60.
Even when they are in contact with each other, the direction of the current between the coated metal tubes 61 and 62 and the current anode 69 does not change, and therefore corrosion of the damaged area 79 can be reliably prevented. FIG. 4 is a side view of the pipe wire passing device 1 according to the present invention. This in-pipe wire passing device 1 has a guiding member 5, a first wire 2, a second wire 3 and 3 wire rods 4 are formed in a row in this order.
The first wire rod 2, the second wire rod 3, and the third wire rod 4 are each made of piano wire or the like, and the piano wire or the like is wound in a spiral shape. Third wire 4
has relatively large bending stiffness K ₃ and torsional stiffness G ₃ , and its longitudinal length l3 is 10 in the natural state.
The length is selected from m to 15 m or longer. An end 3 a of the second wire 3 is fixed to an end 4 a of the third wire 4 . The second wire 3 has a bending stiffness K ₂ and a torsional stiffness G ₂ smaller than the third wire 4 .
The wire diameter of the second wire rod 3 is smaller than the wire diameter of the third wire rod 4, and the diameter thereof is smaller than that of the third wire rod 4, and therefore, the function of improving the wire threading rate of the wire threading tool 1. has. The length l2 of this second wire 3 is selected to be approximately 0.7 m to 1.0 m, for example. An end 2 a of the first wire 2 is fixed to the other end 3 b of the second wire 3 . The first wire rod 2 can be bent by the weight of the guiding member 5, and has a bending rigidity _K1 and a torsional rigidity _G1 smaller than the second wire rod 3. 1st
The wire diameter of the wire rod 2 is smaller than that of the second wire rod 3, and the diameter is smaller than that of the second wire rod 3.
The length l1 of this first wire 2 is selected to be around 7 cm, for example. FIG. 5 is a perspective view of the vicinity of the guide member 5. 1st
The guiding member 5 fixed to the other end 2b of the wire 2 is
It has a square surface 6 when viewed from the free end side (left side in FIG. 5), that is, from the front, and is partially formed into a prismatic shape. The proximal end 7 of the guide member 5 has a tapered shape and is fixed to the other end of the first wire 2 with a hexagonal screw (not shown) or the like. This guiding member 5
is made of a conductive material such as steel, and the length l4 of one piece including the tip end face 6 is selected to be around 11 mm, for example. By applying a rotational force to the third wire 4, the guiding member 5 accumulates stress against torsion in the pipe, and when the load falls below a certain level, it can rotate and vibrate due to the reaction, and can be reused. I can also bear it. Figure 6 shows the first wire 2, the second wire 3, and the third wire 4.
It is a graph showing the relationship between the length direction and the bending rigidity K and torsional rigidity G of the wire rods 2, 3, and 4. Each bending rigidity K 1 , K 2 , of the fixed end portion 4a of the first wire rod 2, the second wire rod 3, and the third wire rod 4 of the wire threading tool 1 to the second wire rod 3, and the other end portion _4b of the third wire rod ₄ , Figure 6 1 for K ₃ and K ₄
As shown by the solid line 8, the relationship of the first equation holds true. K ₁ <K ₂ <K ₃ <K ₄ ...(1) Also, the fixed end portion 4a of the first wire rod 2, the second wire rod 3, and the third wire rod 4 to the second wire rod 3, and the other end portion of the third wire rod 4 Each torsional stiffness G ₁ , G ₂ , G ₃ , G ₄ of 4b is shown in Fig. 6 2.
As shown by the solid line 9, the relationship of the second equation holds true. G ₁ <G ₂ <G ₃ <G ₄ ...(2) The third wire 4 has different quenching of its strands near the fixed end 4a to the second wire 3 and near the other end 4b, As a result, from the end 4a to the other end 4
Bending stiffness K ₃ and torsional stiffness G ₃ as b
are configured to gradually increase, as shown by the solid line 8 in FIG. 6 and the solid line 9 in FIG. 6, respectively. In addition, the bending rigidity of the third wire 4 is K ₃
and the torsional stiffness G ₃ are expressed by the dashed dotted line 10 in FIG.
Two-dot chain line 11 and one-dot chain line 12, 2 in FIG.
As shown by the dashed dotted lines 13, the size may be increased in stages. By configuring the bending rigidity K and the torsional rigidity G to gradually increase from the first wire rod 2 to the other end of the fourth wire rod 3, the wire passage rate of the in-pipe wire passing tool 1 can be increased. can be improved. Referring to FIG. 7, a chi 15 is connected to the upper part of the underground pipe 14. A ground pipe 17 is connected to this chi 15 from a service pipe 16, and gas is supplied to a house 18. A pipe joint 19, an elbow 20, and a valve 21 are interposed between the lead-in pipe 16 and the standpipe 17. According to the in-pipe wire passing tool 1 according to the present invention, the guiding material portion 5 can enter the underground pipe 14 from these standpipes 17 via the lead-in pipe 16. FIG. 8 shows a state in which the pipe wire passing tool 1 enters the chi 15 from the lead-in pipe 16. The first wire rod 2 is bent by the gravity of the guiding member 5, so that the guiding member 5 can easily advance from the chi 15 into the underground pipe 14. When the first wire 2 hangs down due to the gravity of the guiding member 5, the guiding member 5 is rotated and pushed in while rotating the third wire 4 around its axis. It is possible to enter the underground pipe 14 while vibrating. Further, as shown in FIG. 9, the end of the tube 23 is closed with a plug 22.
Even when a branched pipe 24 is connected near the pipe 24, the in-pipe wire passing tool 1 according to the present invention can be inserted into the pipe 23 or the pipe 24 as shown by the arrow 25, and vice versa. 23 can be entered as indicated by arrow 26. The leading end surface 6 of the guiding member 5 is square.
Therefore, the corner portion 6a of the tip end surface is likely to get caught in a step at an elbow, a tee, a pipe joint, or the like. When this corner portion 6a catches on a step inside the tube, it bounces due to the bending steel properties and torsional rigidity of each of the first wire rod 2, second wire rod 3, and third wire rod 4. This allows the guide member 5 to enter the pipe while climbing over the step. Table 1 shows the experimental results of the inventor.

[Table] When the first wire rod 2, the second wire rod 3, and the third wire rod 4 made of the materials shown in Table 1 were used to wire the gas pipe shown in FIG. The tool 1 was able to enter the main pipe 42 from the above ground pipe 28 through the elbows 29 to 39, enter the lead pipes 40 to 50 connected in a zigzag manner, and reach the inside of the main pipe 42 from the chi 41. In this way, when I ran wires inside various gas pipes using the subject pipe wiring tool 1, I found that it was approximately 92~
It was confirmed that the line could be connected with 100% probability, the success rate was extremely high, and the time required to connect the line was relatively short. The in-pipe conduit according to the present invention is capable of passing not only underground gas pipes, but also other pipes installed in building walls or other hidden parts, or even exposed pipes. good. Alternatively, the end portion 4b of the third wire 4 of the intra-tube wire threading tool may be rotated around the axis using, for example, a pistol-shaped tool to feed the intra-tube wire threading tool into the pipe. As another embodiment of the present invention, the first wire 2, the second
The wire rod 3 and the third wire rod 4 are wound inside and outside 2 in opposite directions.
It may be configured by a coil spring having a heavy structure, and the first wire 2, the second wire 3, and the third wire 4
may be made of different materials. As yet another embodiment of the present invention, the galvanic anode 6
One terminal is connected to the coated metal tube 61 instead of 9,
A DC power source whose other terminals are grounded may also be used. Alternatively, the guide member 5 fixed to the tip of the longitudinal wire 1a may be formed of a permanent magnet piece, and the guide member 5 may be attracted to the inner surface of the tube after energization is achieved.
This prevents the electrical connection from being cut off even if the in-pipe wiring tool does not make sufficient contact with the inner surface of the pipe due to long-term use or vibration, thereby increasing the reliability of the wiring function. be enhanced. The present invention is not limited to energization in a pipe joint as in the above-mentioned embodiments, but can be implemented to energize an elbow or other coated metal pipe. As described above, according to the present invention, a wire is passed through a pipe made of a conductive material into a pipe made of a conductive material, and the pipes are electrically connected through the pipe made of a conductive material. This allows an anti-corrosion current to flow through all the tubes. Therefore, corrosion of the pipe can be reliably prevented.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a cross-sectional view of the vicinity of the pipe joint 65, and FIG. Graph showing the relationship, FIG. 4 is a side view of the pipe wire passing device 1 according to the present invention, FIG. 5 is an enlarged perspective view of the vicinity of the guiding member 5, and FIG. Graph showing the relationship between bending stiffness K and torsional stiffness G, seventh
The figure is a piping diagram for explaining the wiring work, FIG. 8 is a sectional view showing the wiring state near the chi 41, FIG. FIG. 10 is a piping diagram of an embodiment of the present invention. 1... In-pipe wire passing tool, 5... Guiding member, 14, 16,
61, 62...tube.

Claims (1)

[Scope of Claims] 1. A third wire made of a conductive material, which is spirally wound in a tube made of a conductive material, and has relatively high bending and torsional rigidity; One end of a second wire that is spirally wound and has lower bending and torsional rigidity than the third wire is connected and fixed, and a spirally wound wire made of a conductive material is attached to the other end of the second wire. One end of the first wire is connected and fixed, and the other end of the first wire is connected to a guide member made of a conductive material, The member is characterized in that the first wire rod is passed through an in-pipe wire passing tool that allows the first wire to bend due to the weight of the member, and the pipes are electrically connected via this in-pipe wire threading tool. How to energize tubes.