JP2008014389A - Tool for conduit blockage and renewal method of supply pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tool for conduit blockage with a structure simpler than conventional one. <P>SOLUTION: The tool has a blocking member 5 having a pair of elastic spherical members 51a, 51b of a closed cell structure connected at a predetermined interval by a wire 52 which are fit into a first supply pipe 1 from an opposite direction of the flowing direction of gas where the gas flows and a flexible press-in member 6 for pressing the blocking member 5 into the supply pipe 1. Preferably, the elastic spherical members 51a, 51b are made of ethylene propylene rubber (EPDM) or polychloroprene rubber (CR). The press-in member 6 has a rod-like body 61 formed by a soft resin such as polyurethane and a sphere 62 formed by engineering plastic such as polyamide fixed at its distal end. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flow path closing tool used for renewing a supply pipe through which a fluid such as a gas flows, and a supply pipe renewal method using the same.

  In the gas piping, fuel gas such as city gas and natural gas is supplied to customers through a main branch pipe buried in the ground in parallel with the road and a supply pipe branched therefrom. As this branch pipe, cast iron pipe has been used, which has the advantage of being strong against gas pressure and external pressure (earth pressure, etc.) and having high durability, and that can be easily taken out by drilling work. Switching to resin pipes (for example, PE pipes), which have excellent properties and earthquake resistance, is increasing. Switching from a cast iron pipe to a resin pipe is, for example, after shutting off the gas supply to the downstream side of a supply pipe connected to an existing main pipe (cast iron pipe, etc.) and then cutting, disassembling and removing the supply pipe The construction is performed in such a manner that a new supply pipe is connected to the newly established main pipe (PE pipe or the like). However, when this supply pipe replacement work is performed, there is an inconvenience that gas cannot be used by the consumer during the work. In addition, even after completion of the reassignment work, it is necessary to enter the customer's facility and perform a safety check including an ignition test. Therefore, the reassignment work may not be performed as scheduled due to the convenience of the customer.

  Therefore, in order to perform the reassignment work without shutting off the gas supply from the supply pipe to the customer, for example, the live pipe branch shut-off method shown in FIG. 4 (the state of recombination is completed) has been proposed and put into practical use. ing. This shut-off method is a pair of branch ports as in the joint 9a having a pair of branch ports 91a and 92a in the middle of the supply pipe 1b branched from the existing main branch pipe 1a via the joint 90b and connected to the customer 100. A joint 9b having 91b and 92b is mounted, and one of the branch ports (for example, 91a and 92b) is connected by a bypass pipe 110 to ensure supply of gas from the existing main branch pipe 1a to the customer 100. . The existing main branch 1a is connected to a new main branch 1c through a joint 90a. Next, in each joint 9a, 9b, a gas blocking bag (not shown) is inserted into the supply pipe 1a from the branch ports 91b, 92a to block the section AB. At this time, gas is supplied to the customer 100 from the existing main branch pipe 1 a via the bypass pipe 110. Next, the supply pipe in the section AB is cut and removed, and a new supply pipe 1d branched from the new main pipe 1c is connected to the upstream side of the joint 9a on the customer side. Finally, after the gas shut-off bag is removed, the bypass pipe 110 is removed, and the gas supply to the customer 100 is switched from the newly installed main branch pipe 1c.

  According to this live pipe branch cutoff method, a fixed section of the supply pipe is connected with a bypass pipe through a joint, and then the gas in that section is shut off and the supply pipe is cut, and then the supply pipe is newly installed. Since it is connected to the branch pipe, there is an advantage that the renovation work can be performed without stopping the gas supply to the customer and without entering the customer's facility, but it has two branch ports. In addition, a plurality of joints with a special structure are required, and a plurality of (two places) perforations must be made in the supply pipe 1a with respect to one joint, which increases the construction cost.

  Another method has also been proposed in which the replacement work is performed without shutting off the gas supply from the supply pipe to the customer. For example, in Patent Document 1, in order to repair a part of an existing pipeline in a state in which gas supply is ensured, a communication hole that connects the inside and the outside of the existing pipeline is formed at both end portions to be blocked. By inserting a double-type bag connected with a gas shut-off device from these communication holes, connecting the gas shut-off device with a bypass pipe, and introducing inflation air into the bag, It is described that distribution can be blocked.

  Further, in Patent Document 2, in order to repair a part of an existing pipeline with gas supply secured, a communication hole that communicates the inside and the outside of the existing pipeline is formed at both end portions to be blocked. The gas shut-off device is connected through these communication holes and a double bag connected through an air passage having a multi-pipe structure is inserted, and the gas shut-off device is connected by a bypass pipe, and then expanded to the bag. The introduction of air is described. The air passage having a multi-pipe structure has one end facing the first air passage facing the inside of the first air bag, the second air passage facing the inside of the second air bag, and the space located between the two bags. It has 3 air passages. In Patent Document 2, according to this repair method, even if the gas pressure is high and the back cannot be sealed completely, the gas that has entered the space located between the bags is used as the third pressure. It is supposed that it can be discharged to the outside through the air passage.

JP 2001-271983 (pages 3 to 5, FIG. 1, FIG. 2, FIG. 3) JP 2001-50471 A (pages 3 to 4, FIG. 1 and FIG. 2)

  Since the above-described gas shut-off device requires two pairs of air bags, the structure becomes complicated and the cost is increased. Further, according to the repair method described above, since the double-type air bag is configured to be installed on both sides of the repair blocking section, holes for inserting the airbag are drilled on both sides (two places) of the repair section. In addition, since this drilling operation is performed in the pit, the construction man-hour is increased.

  A first object of the present invention is to solve the above-mentioned problems and to provide a flow path closing tool having a simplified structure as compared with the prior art.

  The second object of the present invention is to provide a supply pipe renewal method that solves the above-mentioned problems and can reduce the number of construction steps compared to the conventional art.

  In order to achieve the first object, the flow path closing tool of the present invention is press-fitted into a first supply pipe to which a gas flows and a second supply pipe is connected, with a predetermined interval. And a shielding member having a pair of spherical elastic members having a single cell structure connected by a wire, and a flexible pushing member for pushing the shielding member into the supply pipe.

  In the present invention, the spherical elastic member is preferably made of ethylene-propylene rubber (EPDM) or chloroprene rubber (CR).

  In order to achieve the second object, the supply pipe renewal method according to the present invention is such that the second supply pipe is connected to the first supply pipe, and the first supply pipe upstream of the connecting portion is connected to the first supply pipe. An opening is provided, and a shielding member having a pair of spherical elastic members having a single cell structure connected by a wire through the opening at a predetermined interval is sent into the supply pipe, and a flexible pushing member is provided. After pressing the spherical elastic member and inserting the entire shielding member into the supply pipe, the section of the first supply pipe sandwiched between the spherical elastic members is cut off, and the end of the supply pipe is sealed. It is characterized by that.

  The flow path closing tool of the present invention has a single cell structure in which a gas flows and is press-fitted into a first supply pipe to which a second supply pipe is connected and connected by a wire at a predetermined interval. Since it is composed of a shielding member having a pair of spherical elastic members and a flexible pushing member that pushes the shielding member into the supply pipe, a tool having a greatly simplified structure compared to the prior art, can do. Therefore, according to the present invention, cost reduction of the tool can be achieved.

  In the supply pipe renewal method of the present invention, the second supply pipe is connected to the first supply pipe, and an opening is provided in the supply pipe upstream of the connecting portion. After inserting a shielding member having a pair of spherical elastic members having a single cell structure, the section between the spherical elastic members is cut off and the end of the first supply pipe is simply sealed. It is possible to reliably block the gas flow to the downstream side. Therefore, according to the present invention, the gas supply pipe replacement work can be performed with fewer man-hours than before.

  In particular, in the present invention, since the perforation in the section where the supply pipe is blocked is only required once, the number of man-hours required for the replacement of the gas supply pipe can be greatly reduced as compared with the prior art.

The details of the present invention will be described with reference to the accompanying drawings.
1 is a sectional view of a supply pipe into which a flow path closing tool according to an embodiment of the present invention is inserted, FIG. 2 is a front view of the flow path closing tool, and FIG. 3 is a state in which the supply pipe of FIG. 2 and 3, the same parts as those in FIG. 1 are denoted by the same reference numerals.

  As shown in FIG. 1, a first supply pipe 1 (hereinafter referred to as an existing pipe) that is an existing pipe buried in the ground is branched from this branch pipe (not shown), and gas G flows in the direction of the arrow. ing. A second supply pipe (not shown, hereinafter referred to as a new pipe) newly provided in parallel with the existing pipe 1 has an end portion of the connecting pipe 2 connected through, for example, an EF joint (not shown) at the junction joint 3. The gas G that has flowed from the direction of the arrow can be introduced into the inside through the opening 10 of the existing pipe 1. In the EF joint, a heating wire is embedded in a joint body made of a thermoplastic resin such as polyethylene, and when the heating wire is energized, the inner diameter portion of the joint body and the resin pipe (new pipe or connecting pipe 2) are melted. It is configured so that the resin pipe is connected by being attached.

  The joint 3 has an upper clamp 31 and a lower clamp 32 that are fixed to the existing pipe 1, and a cheese portion 33 that is fixed by being screwed into the upper clamp 31. The upper clamp 31 and the lower clamp 32 are formed by covering the outer surfaces of the main bodies 311 and 321 made of a steel material such as malleable cast iron with linings 312 and 322 made of a resin having corrosion resistance such as vinyl chloride, and the cheese portion. Similarly to these, the outer surface of the main body 331 made of a steel material 33 is coated with a lining 332 made of a resin having corrosion resistance. The cheese portion 33 has a branch portion 34 into which an end portion of the connecting pipe 2 is inserted, and is expanded in diameter by a technique such as bulging after the stiffener 35 is attached to the inner surface of the end portion of the connecting pipe 2. The connecting pipe 2 and the branch part 34 are connected, and sealing is performed by a packing 36 interposed between the connecting pipe 2 and the branch part 34. In order to seal the existing pipe 1 and the merging joint 3, a packing 313 is mounted on the inner peripheral side of the upper clamp 31 so as to surround the opening 10.

  With respect to the gas flow direction, an opening 11 having a diameter smaller than that of the existing pipe 1 can pass through the shielding member 5 constituting the flow path closing tool on the upstream side of the position where the confluence 3 of the existing pipe 1 is connected. A clamp 41 having a main body 41 having a packing 43 and a main body 42 is mounted on the periphery thereof. As shown in FIG. 2, the shielding member 5 inserted into the existing pipe 1 has a wire 52 having such a length that it can be extended to both sides of the opening 11 by a predetermined distance when pulled. Spherical elastic members (hereinafter referred to as sponge balls) 51a and 51b fixed by fixing metal fittings 53a and 53b are provided at both ends. The sponge balls 51a and 51b are formed of a foam having a closed cell structure. The foam is not limited to a single bubble as a whole, and may be a foam in which closed cells and open cells are mixed. In this case, gas leakage (for example, gas leakage when the gas pressure is 20 kPa) is prevented. Therefore, a foam having a water absorption of 5% or less is preferable. As these foams, soft sponges such as NR sponge, IR sponge, CR sponge, EPDM sponge, and silicone sponge can be used. From the viewpoint of gas resistance, EPDM sponge or CR sponge is preferable.

  The pushing member denoted by reference numeral 6 in FIG. 1 has a structure in which a sphere 62 is fixed to the tip of a flexible rod-like body 61. The rod-like body 61 is a round rod-like or prismatic member, and may be hollow or solid. However, in order to be easily bent substantially at right angles as shown in the figure, a soft resin {Shore hardness (D) of 30 to It is preferable to use a tube made of a thermoplastic resin (polyurethane) of about 70 ° or a thermosetting resin (urethane elastomer, etc.)}. The sphere may be any diameter that is smaller than the opening 11 and has a size and mechanical strength sufficient to contact and push the sponge ball 51a or 51b. For example, the diameter is about 2/3 of the sponge ball. Spheres formed of engineering plastics (polyamide or the like) having

  The dimensions of the above portions may be set in accordance with the diameter (nominal diameter) of the existing pipe 1. For example, when the diameter (nominal diameter) of the existing pipe 1 is 32 A, the diameter of the opening 11 is 27.8 mm. And a shielding member 5 in which sponge balls 51a and 51b made of EPDM and having an outer diameter (diameter) of 30 mm are connected by a wire 52 made of a brass wire having a length of 300 mm and a length of 300 mm. Can be used. Further, as the pushing member 6, a rod-like body 61 made of a polyurethane tube, to which a sphere 62 made of nylon having an outer diameter (diameter) of 20 mm is fixed, can be used.

  Next, referring to FIG. 3 as well, the supply pipe connection comprising the following steps 1) to 6) including the operation of blocking the flow of gas inside the existing pipe 1 using the above-mentioned flow path closing tool 5 is performed. Explain the replacement work. 1 and 3 show a state in which pits (not shown) having a size necessary for reconnecting the supply pipes are formed.

1) The junction joint 3 is assembled at a predetermined position of the existing pipe 1 and branched from the end of the connecting pipe 2 attached to the branch section 34 and the newly installed branch pipe to both ends of the electric fusion joint (socket). The end of the new pipe is inserted, and the connecting pipe 2 and the new pipe are fusion bonded by electric fusion.

2) After covering the junction joint 3 with a no-blow bag (not shown) and blocking from the atmosphere, a cutter (not shown) is set in the cheese portion 33 and drilled at a predetermined position of the existing pipe 1 to open the hole 10. Then, the cutter is taken out from the cheese portion 33, and the upper end portion of the cheese portion 33 is sealed with a plug (not shown).

3) A clamp 4 is mounted around the existing pipe 1, a no blow bag (not shown) is put on the clamp 4 and cut off from the atmosphere, and then a cutter (not shown) is set on the clamp 4. After the opening 11 is drilled at a predetermined position, the cutter is taken out from the clamp 4.

4) One sponge ball 51a (or 51b) of the flow path closing tool 5 is inserted into the existing pipe 1 from the opening 11, and then the pushing member 6 is inserted from the opening 11, and the tip (sphere 62) is inserted. By pushing the sponge ball 51a (or 51b) toward the merging joint 3, the sponge ball 51a (or 51b) is compressed, that is, the sponge ball 51a (or 51b) is crushed as shown in FIG. It has a flat shape (vertical cross section is substantially elliptical). Next, the other sponge ball 51 b (or 51 a) is also pushed into the existing pipe 1 toward the upstream side from the opening 11. The pushing length may be set so that the two sponge balls 51 a and 51 b are inserted into the existing pipe 1 and positioned on both sides of the opening 11. Thus, after the sponge balls 51a and 51b are inserted to a predetermined position of the existing pipe 1, the pushing member 6 is pulled out from the existing pipe 1.

5) Since the sponge balls 51a and 51b are kept in close contact with the inner surface of the existing tube 1, the existing tube 1 in the section (L) sandwiched between the sponge balls 51a and 51b is connected to the wire 52 and one sponge ball 51b. Cut and remove.

6) As shown in FIG. 3, after the free end of the wire 52 is fastened to the locking hole 12, it is sealed with a plug 8 at the right end of the supply pipe 1 via a mechanical joint 7 configured as follows. Thus, it becomes possible to supply gas to the consumer on the downstream side of the existing pipe 1 via the junction joint 3.

  The mechanical joint 7 shown in FIG. 3 includes a joint body 71, cap nuts 72a and 72b that are screwed into both ends thereof, packings 73a and 73b, retainers 74a and 74b, and retaining members 75a and 75b that are mounted inside these. I have. The joint main body 71 is formed by coating the outer surface of a main body 711 made of a steel material such as malleable cast iron with a lining 712 made of a resin having corrosion resistance such as vinyl chloride, and the cap nuts 72a and 72b are also made of malleable cast iron or the like. The outer surfaces of the main bodies 721a and 721b made of a steel material are coated with linings 722a and 722b made of a resin having corrosion resistance such as vinyl chloride. The body 711 of the joint body 71 has threaded portions 713a and 713b at both ends, and female threads 723a and 723b are formed on the body 721a of the cap nut 72a and the body 721b of the cap nut 72b, respectively. According to this mechanical joint 7, the joint body 71 to which the cap nuts 72 a and 72 b are attached and the plug 8 is screwed is attached to the end of the existing pipe 1, and the cap nuts 72 a and 72 b are tightened, thereby The ends are sealed.

  The present invention is not limited to the above, and various modifications can be made. For example, by providing a mark (for example, a marking portion) in the center of the wire 52, it is possible to visually confirm that the entire wire 52 has entered the inside of the supply pipe. Moreover, a confluence | merging joint can be set as the structure which integrated the cheese part and the upper clamp.

It is sectional drawing of the supply pipe | tube provided with the tool for flow path obstruction | occlusion concerning embodiment of this invention. It is a front view of the shielding member of FIG. It is sectional drawing which shows the use condition of the shielding member of FIG. It is a piping system diagram which shows the conventional interruption | blocking construction method typically.

Explanation of symbols

1: First supply pipe (existing pipe),
2: Connecting pipe 3: Merge joint, 31: Upper clamp, 311: Main body, 312: Lining, 313: Packing, 32: Lower clamp, 321: Main body, 322: Lining, 33: Cheese part, 331: Main body, 332: Lining, 34: branching part, 35: stiffener, 36: seal 4: clamp, 41, 42: main body, 43: packing 5: shielding member, 51a, 51b: spherical elastic member, 52: wire 6: pushing member, 61: Rod-shaped body, 62: Sphere 7: Mechanical joint, 71: Joint body, 711: Body, 712: Lining, 713a, 713b: Male thread, 72a, 72b: Cap nut, 721a, 721b: Nut body, 722a, 722b: Lining, 723a, 723b: female thread, 73a, 73b: packing, 74a, 74b: retainer, 75a, 7 b: the retaining member 8: Plug

Claims (3)

A shielding member having a pair of spherical elastic members having a single cell structure in which gas flows and is press-fitted into a first supply pipe to which a second supply pipe is connected and connected by a wire at a predetermined interval; A flow path closing tool comprising: a flexible pressing member that presses the shielding member into the first supply pipe. 2. The flow path closing tool according to claim 1, wherein the spherical elastic member is made of ethylene-propylene rubber (EPDM) or chloroprene rubber (CR). A second supply pipe is connected to the first supply pipe, and an opening is provided after shutting off a portion of the first supply pipe on the upstream side of the connection portion from outside air, and a predetermined interval is provided through the opening. A shielding member having a pair of spherical elastic members each having a single cell structure connected by a wire is fed into the first supply pipe, and a pressing member having flexibility is pressed against the spherical elastic member to form the shielding member. Is inserted into the supply pipe, the section of the first supply pipe sandwiched between the spherical elastic members is cut off, and the end of the supply pipe is sealed. .

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