JP2015045373A - Renewal method of conduit and conduit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a renewal method of a conduit which can avoid an erroneous operation after construction and complicated maintenance management, and can also suppress a cost, and the conduit.SOLUTION: A new conduit 11 is laid along a zone S1 to be renewed in an existing conduit 1 while holding a fluid flowing state, an upstream side and a downstream side of the new conduit 11 are made to communicate with the existing conduit 1 via communication conduits 15 and 16, and a bypass is formed by arranging changeover valves 31, 32 and 36 at branched parts 21 and 22 in which the communication conduits 15 and 16 are merged with the existing conduit 1, and a branched part 26 in which the communication conduit 16 is merged with the new conduit 11, respectively. After switching a flow passage to the bypass from the existing conduit 1 of the zone S1 to be renewed, the existing conduit 1 of the zone S1 is removed. A connecting port 21c which is connected to the removed existing conduit 1 is covered with a lid, or closely sealed, and after that, a valve body 31A of the changeover valve 31 is removed.

Description

  The present invention relates to a method for updating an existing pipeline through which a fluid flows, and a pipeline updated by the method.

  In the construction of renewing an existing water pipeline (an example of an existing pipeline), it is desirable to use a continuous water construction method that allows construction while maintaining the water flow state in consideration of convenience for users of tap water. Conventionally, as shown in FIG. 13, a branch pipe is connected in the middle of an existing water pipe, the flow path is temporarily switched to a bypass formed by the branch pipe, and the pipe in the section is updated. It was like that. The arrow in the pipeline represents the flow of water.

  Specifically, first, as shown in (a), split T-shaped pipes 81 and 82 are mounted on both sides of the A section sandwiched between the gate valve 87 and the gate valve 88, and the gate valves 81a and 82a are respectively attached thereto. Connect. Next, the pipe line part to which the split T-shaped pipes 81 and 82 are attached is drilled, and the branch pipe line 85 is connected as shown in (b) to form a bypass. After the gate valves 81a and 82a are opened and the gate valves 87 and 88 are closed, and the section A is updated to the new pipe 80A, the gate valves 87 and 88 are opened and the gate valves 81a and 82a are closed, and the branching is performed as shown in (c). Pipe line 85 is removed.

  Also in the B section, as shown in (d), a bypass is formed by connecting the branch pipeline 86 in the manner described above. Subsequently, the gate valves 83a and 84a connected to each of the split T-shaped pipes 83 and 84 are opened, the gate valves 88 and 89 are closed, and the B section is updated to the new pipe line 80B. Thereafter, the gate valves 88 and 89 are opened, the gate valves 83a and 84a are closed, and the branch pipe 86 is removed as shown in FIG. By repeating this process, existing water pipelines can be updated sequentially.

  However, in this method, since the gate valves 81a and 83a are left even after the branch pipe is removed, there is a possibility that the opening and closing of the flow path may be switched due to an erroneous operation, and complicated maintenance management may be required. Patent Documents 1 and 2 propose a method in which a connection port that is connected to a branch pipe line via a gate valve is sealed with an unrestricted water construction method and the gate valve is removed. However, in this method, there is a room for improvement in terms of cost because the number of plug members having a special structure is the same as the number of portions to be sealed.

JP 2010-96241 A JP 2010-117029 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for renewing a pipeline that can avoid malfunctions and complicated maintenance management after construction, and that can reduce costs, and the pipeline. It is in.

  The above object can be achieved by the present invention as described below. That is, in the method for updating a pipeline according to the present invention, a new pipeline is laid along a section to be updated in an existing pipeline while maintaining a state in which a fluid flows, and the new pipeline is connected via a connecting pipeline. The upstream side and the downstream side of the pipe are communicated with the existing pipe line, and are branched into a branch part where the connecting pipe joins the existing pipe and a branch part where the connecting pipe joins the new pipe A switching valve that can selectively close the connection port of the part, and a first step of forming a bypass that bypasses the section to be updated of the existing pipeline, and the switching valve should be operated to update The second step of switching the flow path from the existing pipeline in the section to the bypass, and removing the existing pipeline in the section, and the connection port of the branch portion where the switching valve is closed, the second of Cover or close the connection port connected to the existing pipe line removed in the process, and switch between them. In which and a third step of removing the valve body.

  In this method, the bypass is formed in the first step, and the existing pipeline is removed in the second step. Before removing the existing pipeline, the switching valve provided at the branching section is operated to switch the flow path to the bypass. The new pipeline included in the bypass can configure the updated pipeline, but is not limited thereto. In the third step, the connection port of the branching portion to be covered or tightly closed is previously closed with a switching valve, so that a general-purpose product can be used. According to this method, by removing the valve body from the switching valve, it is possible to avoid malfunction and complicated maintenance management after construction. Moreover, since a general-purpose product can be used for the lid and the sealing plug of the connection port, and the valve body is recovered, the cost can be effectively suppressed.

  In this pipe line updating method, the first step and the second step are repeated to extend the update section toward the downstream side. In the second and subsequent first steps, the immediately preceding first step is performed. The new pipeline laid in the process is extended to the downstream side to form a bypass, and in the second process after the second time, the existing pipeline in the section to be renewed and the upstream branch of the existing pipeline It is preferable to remove the provided switching valve. According to this method, the construction range can be efficiently extended. Nevertheless, since the switching valve provided in the existing pipeline can be collected and reused in the subsequent first process, the cost can be effectively suppressed.

  In this method of updating a pipeline, the switching valve provided at a branching portion where the connecting pipeline joins the new pipeline has a structure in which a valve body is built in a T-shaped tube constituting a part of the new pipeline The connection port to be closed may be switched according to the posture of the valve body with respect to the T-shaped tube. In this case, installation and handling of the switching valve at the branch portion of the new pipeline can be simplified, and workability can be improved.

  In this method of updating a pipeline, the switching valve provided at the branching portion where the connecting pipeline joins the existing pipeline is built in a split T-shaped tube that is externally fitted to the existing pipeline. It may have a structure in which an inner valve box is accommodated, and the connection port to be closed may be switched according to the posture of the valve body with respect to the inner valve box. In this case, the switching valve can be appropriately installed in the existing pipeline, which is useful.

  In this pipe line updating method, it is preferable to reuse the valve body removed in the third step as the valve body of the switching valve provided in the first step thereafter. By reusing the valve bodies in this way, the number of used valve bodies can be reduced and the cost can be suppressed.

  In this method of updating a pipe, a valve body of the switching valve provided at a branch portion where the connecting pipe joins the existing pipe is a pair of pipe cut surfaces formed by full-cut cutting of the existing pipe It is preferable that the pipe cut surface be corroded after the valve body is removed in the third step. Thereby, inconveniences such as occurrence of rust on the cut surface of the pipe can be prevented.

  Further, the pipeline according to the present invention is a new pipeline laid along the update section of the existing pipeline, a communication pipeline that communicates the upstream side and the downstream side of the new pipeline with the existing pipeline, A split T-shaped pipe that is externally fitted to the existing pipe, and a branch that joins the connecting pipe to the new pipe; And a T-shaped tube provided at a branch portion in the middle of the new pipeline and constituting a part of the new pipeline. The split T-shaped tube has an opening portion closed by a lid at the top, and does not incorporate a valve body that can close the connection port of the branch portion, and the branched portion provided with the split T-shaped tube Of these connection ports, the connection ports that are not used for communication between the existing pipeline and the communication pipeline are covered or sealed. The T-shaped tube has an opening closed by a lid at the top, and does not have a built-in valve body that can close the connection port of the branched portion, and the connection of the branched portion provided with the T-shaped tube. Among the ports, a connection port that is not used for communication between the new pipeline and the communication pipeline, or a connection port that branches off from the trunk line of the new pipeline is covered or sealed.

The schematic plan view which shows an example of the procedure which updates a pipe line by this invention The schematic plan view which shows an example of the procedure which updates a pipe line by this invention Horizontal sectional view showing the switching valve on the existing pipeline side AA arrow sectional view of FIG. Horizontal sectional view showing the switching valve on the new pipeline side BB arrow sectional view of FIG. Horizontal cross-sectional view showing the bifurcation with the connection port covered Longitudinal sectional view showing the bifurcation before the anticorrosion treatment Perspective view of corrosion protection body Perspective view of core Longitudinal sectional view showing the bifurcation after the corrosion prevention treatment FIG. 2 is a schematic plan view showing an example of a procedure following the stage [H] in FIG. Schematic showing an example of the procedure for updating an existing water pipeline

  An embodiment of the present invention will be described with reference to the drawings, taking as an example a construction for updating an existing water pipe (an example of an existing pipe) formed by piping a duct pipe made of ductile cast iron. First, a method for updating a pipeline will be schematically described with reference to FIGS. 1 and 2, and then each configuration will be described in detail.

[How to update pipelines]
In FIGS. 1 and 2, the arrows along the pipelines represent the flow of water. The existing pipeline 1, which is a water pipeline, constitutes a main pipeline from the water source or water purification plant to the city area, and [A] is a state before construction. First, while maintaining the water flow state, the new pipeline 11 is laid along the section S1 of the existing pipeline 1 to be updated as shown in [B], and the new pipeline is connected via the connecting pipelines 15 and 16. 11 is connected to the existing pipe line 1, and switching valves 31, 32, and 36 are provided in the branch portions 21, 22, and 26, respectively, to bypass the section S 1 to be updated in the existing pipe line 1. A bypass is formed (corresponding to the first step).

  In the branch portions 21 and 22, the connection pipelines 15 and 16 join the existing pipeline 1, respectively, and in the branch portion 26, the connection pipeline 16 joins the new pipeline 11. The switching valves 31, 32, and 36 are all three-way switching valves that can selectively close the connection port of the branching portion. The valve body 31A of the switching valve 31 indicated by a black fan shape closes the connection port facing the fan-shaped arc. Therefore, in [B], the water flow from the existing pipeline 1 to the connecting pipeline 15 is blocked. The switching valves 32 and 36 and other switching valves to be described later are configured in the same manner.

  Next, as shown in [C], the switching valves 31, 32, and 36 are operated to switch the flow path from the existing pipeline 1 in the section S1 to be updated to the bypass, and the existing pipeline 1 in the section S1 is removed. (Corresponding to the second step). Subsequently, as shown in [D], the connection port 21c of the branch portion 21 connected to the removed existing pipeline 1 out of the connection ports of the branch portions 21, 22, and 26 where the switching valve is closed is applied. Cover or seal and remove the valve body 31A of the switching valve 31 provided at the branch portion 21 as in [E] (corresponding to the third step). In the present embodiment, the cap 10 is attached to the cut end of the tube and the connection port 21c is covered.

  In [D], since the switching valve 31 is closed in advance, the connection port 21c of the branch portion 21 is in a water-stopped state. Therefore, a special structure is not necessary for the member (cap 10 in this embodiment) for covering or sealingly plugging the connection port 21c, and a general-purpose product can be applied. In the branch part 21, since the valve body 31A is removed after the connection port 21c is covered, it is possible to appropriately avoid malfunction and complicated maintenance after construction. Moreover, since a general-purpose product can be applied to the cap 10 and the valve body 31A is recovered, the cost can be effectively suppressed.

  By repeating the bypass formation process (first process) and the existing pipe removal process (second process) as described above and extending the renewal section toward the downstream side, the construction range is efficiently extended. I can do it. At that time, in the first process after the second time, the new pipe laid in the immediately preceding first process is extended downstream to form a bypass, and in the second process after the second time, it should be updated. It is preferable to remove the switching valve provided at the branch portion on the upstream side of the existing pipeline along with the existing pipeline in the section.

  As shown in [E], in the second first step, a bypass that bypasses the section S2 of the existing pipeline 1 to be updated is formed. In this case, the new pipeline 11 laid in the immediately preceding first step is extended downstream. Specifically, the new pipeline 12 is laid along the section S2 to be updated, and the upstream side and the downstream side of the new pipeline 12 are communicated with the existing pipeline 1 via the connection pipelines 16 and 17, Switching valves 32, 33, 36, and 37 are provided at the branch portions 22, 23, 26, and 27, respectively. The communication pipe line 16 and the switching valves 32 and 36 are laid in the immediately preceding first step.

  As shown in [F], in the second process of the second time, together with the existing pipeline 1 in the section S2 to be updated, the switching valve 32 provided in the branch portion 22 on the upstream side of the existing pipeline 1 is removed. To do. Before removing them, the switching valve 33 on the existing pipeline 1 side and the switching valves 36 and 37 on the new pipelines 11 and 12 side are operated to bypass the existing pipeline 1 in the section S2 to be updated. Switch the flow path. The first and second steps after the third time are also basically performed in the same manner.

  As shown in [G], in the first step for the third time, a bypass that bypasses the section S3 of the existing pipeline 1 to be updated is formed. The new pipeline 13 communicates with the existing pipeline 1 via the communication pipelines 17 and 18, and switching valves 33, 32, 37 and 38 are provided at the branch portions 23, 24, 27 and 28, respectively. Moreover, in [G], the connection port of the branch part 26 connected to the removed existing pipeline 1 among the connection ports of the branch parts 23, 26, 27 in which the switching valve was closed at the stage of [F]. 26a is applied, and the valve body 36A of the switching valve 36 provided at the branch portion 26 is removed (corresponding to the third step).

  The valve body removed in the third step can be reused as the valve body of the switching valve provided in the first step thereafter. In the present embodiment, in the stage from [D] to [E], the removed valve body 31A of the switching valve 31 is reused as the valve body of the switching valve 33 provided in the branch portion 23. Further, at the stage from [F] to [G], the removed valve body 36A of the switching valve 36 is reused as the valve body of the switching valve 38 provided in the branch portion 28. By reusing such a valve body, the number of valve bodies required for construction can be reduced, which contributes to cost reduction.

  In the present embodiment, the switching valve 32 that has been removed together with the existing pipe line 1 in the second step in the stage from [E] to [G] is provided in the branching section 24 in the subsequent first step. It is reused as a valve. This is to reuse the valve body 32A together with a split T-shaped tube described later. Similarly to this, the switching valve 33 provided in the branch portion 23 can be reused after being removed. If such a use is utilized, only four valve bodies 31A, 32A, 36A, and 37A are sufficient for construction.

  In the third step, the valve body may be removed in at least one of the switching valve on the existing pipeline side and the switching valve on the new pipeline side, but it is preferable to remove the valve body on both sides as in this embodiment. By reusing them, the number of parts can be greatly reduced. The third step can be performed at any timing after the first step and the second step are completed for the first time. However, when the recovered valve body is reused immediately, the first step and the second step are performed. It is performed at an appropriate timing in the middle of repeating step 2.

  In the stage [H], the first process and the second process for the fourth time are completed, and the construction is completed. This pipe line includes new pipe lines 11 to 14 laid along the renewal section of the existing pipe line 1, and connecting pipe lines 15 and 19 for communicating the upstream side and the downstream side of the new pipe line with the existing pipe line 1. Is provided. In the branch parts 21, 25, and 26 to 29, the valve bodies are removed from the switching valves provided in each of them. Moreover, the connection ports 21c, 25b, and 26a to 28a connected to the removed existing pipeline 1 are covered.

  In the updated pipeline, the valve element is removed from each switching valve, so there is no fear of malfunction, and complicated maintenance management can be eliminated. Moreover, since the shaft member for operating the valve body does not protrude upward, the risk of heavy machinery being caught when the same place is excavated in the future can be reduced. In the case of renewing this pipe line in a later year, the valve body is returned to the required branching part, a switching valve is provided, and the cover of the connection port is released to perform the new pipe line in the same procedure as above. Can be used for laying.

  As will be described later, in the present embodiment, at the branching portion where the connecting pipe joins the existing pipe 1, the valve body of the switching valve is formed of a pair of pipe cut surfaces formed by full cut cutting of the existing pipe 1. Arranged between. Therefore, in the branch portions 21 and 25 remaining after the completion of construction, the pipe cut surface is corroded after the valve body is removed in the third step. For example, in the branching part 21, after removing the valve body 31A in [E], the corrosion prevention body 61 is installed in [F], thereby performing the corrosion prevention treatment.

[Switching valve on the existing pipeline side]
The switching valve provided at the branch portion where the connecting pipeline joins the existing pipeline will be described in detail. Here, the switching valve 31 provided in the branch part 21 is given as an example. The switching valve provided in the other branch parts 22-25 can be fundamentally comprised similarly to this.

  As shown in FIGS. 3 and 4, the switching valve 31 has a structure in which the inner valve box 40 is accommodated in the split T-tube 4 that is externally fitted to the existing pipe line 1. The split T-shaped pipe 4 has a divided structure that can surround the outer peripheral surface of the existing pipe line 1 in a watertight manner, and functions as an outer valve box that houses the inner valve box 40. The inner valve box 40 is formed in a cylindrical shape and incorporates a valve body 31A. In FIG. 4, the inner valve box 40 is drawn not in section but in appearance. The branch portion 21 is formed with a connection port 21a formed in the branch short tube and a pair of connection ports 21b and 21c along the existing pipe line 1, depending on the posture of the valve body 31A with respect to the inner valve box 40. The connection port to be closed is switched.

  The split T-shaped tube 4 having an upper and lower split structure including the upper member 4A and the lower member 4B has its divided surface oriented substantially in the horizontal direction. As shown in FIG. 4, an opening closed by a lid 42 is formed on the upper part of the split T-shaped tube 4. The full cut cutting of the existing pipe line 1 and the insertion / extraction of the valve body 31A incorporated in the inner valve box 40 are performed through this opening. At that time, a work gate valve and a sealing case (see FIG. 8) are connected to the opening of the split T-tube 4 in order to prevent water leakage. The upper end of the rotating shaft 31B of the valve body 31A protrudes from the lid body 42.

  The valve body 31A includes a bottom wall 31C having a fan shape in plan view and a seal wall 31D that can come into contact with the inner surface of the inner valve box 40. The valve body 31A is built in the inner valve box 40 and is rotated via a rotating shaft 31B. It is configured to move freely. In FIG. 3, the valve body 31 </ b> A closes the connection port 21 a, but by rotating this, the sealing position with respect to the inner valve box 40 is switched, and the connection port 21 b and the connection port 21 c can be selectively closed. A packing 41 in contact with the inner surface of the split T-tube 4 is attached to the outer surface of the inner valve box 40.

  When the switching valve 31 is provided in the first step, first, the split T-shaped pipe 4 is attached to the existing pipe line 1 at the location that is the starting point of the bypass. At this time, the branch short pipe that becomes the communication pipe 15 is connected to the split T-shaped pipe 4. Next, a perforation apparatus is connected to the opening of the split T-shaped tube 4 via a work gate valve, and the existing pipe line 1 is cut in the pipe axis direction by full cut cutting. In order to prevent water leakage at the time of cutting, the branch short tube is covered in advance. Then, the inner valve box 40 is accommodated in the split T-shaped tube 4 by a connecting / dismounting jig instead of the punching device, and the opening is closed by the lid 42.

  When removing the valve body 31A in the third step, an attachment / detachment jig is attached to the opening from which the lid 42 has been removed via a work gate valve, and the inner valve box 40 is connected from the split T-shaped tube 4 through the opening. Take out. As described above, the removed valve body 31A is reused as the valve body of the switching valve 33 provided thereafter. In the stage shown in FIG. 1D, only the split T-shaped tube 4 is attached to the portion that becomes the branching portion 23, and after this portion is fully cut, the valve body 31A built in the inner valve box 40 is split. By inserting it into the T-shaped tube 4, a switching valve 33 is provided as shown in FIG.

  With this structure, in the pipe of FIG. 2 [H], the split T-shaped pipes externally fitted to the existing pipe 1 are connected to the branch portions 21 and 25 where the connecting pipes 15 and 19 merge with the existing pipe 1. Is provided. The split T-shaped tube has an opening at the top thereof closed by a lid and does not incorporate a valve body that can close the connection ports of the branch portions 21 and 25. Of the connection ports of the branch portions 21 and 25, the connection ports 21 c and 25 b that are not used for communication between the existing pipeline 1 and the communication pipelines 15 and 19 are covered. If the above-described use of the switching valves 32 and 33 is utilized, only three split T-shaped tubes are sufficient for construction.

[Switching valve on the new pipeline side]
The switching valve provided at the branch portion where the connecting pipe joins the new pipe will be described in detail. Here, the switching valve 36 provided in the branch part 26 is taken as an example. The switching valves provided in the other branch portions 27 to 29 can be basically configured in the same manner.

  As shown in FIGS. 5 and 6, the switching valve 36 has a structure in which a valve body 36 </ b> A is built in the T-shaped tube 5 constituting a part of the new pipeline. The T-shaped tube 5 functions as a valve box that houses the valve body 36A. In FIG. 6, the valve body 36 </ b> A is drawn with an appearance instead of a cross section. In the branch portion 26, a connection port 26a formed in the short branch pipe and a pair of connection ports 26b and 26c along the main line of the new pipe line are formed, and according to the posture of the valve body 36A with respect to the T-shaped tube 5 The connection port to be closed is switched. Although a branched short pipe, which is a separate member, is connected to the T-shaped tube 5, it may have a structure that integrally forms a T-shape instead.

  Unlike the switching valve 31 provided in the existing pipeline 1, the switching valve 36 is configured as a newly installed switching valve for piping. For this reason, it is not necessary to perform full-cut cutting, and the inner surface of the pipe can be subjected to a corrosion prevention treatment in advance, and a simple and compact configuration can be achieved by not providing an inner valve box. In the upper part of the T-shaped tube 5, an opening closed by a lid 52 is formed, and the valve body 36 </ b> A can be taken in and out through this opening. When removing the valve body 36 </ b> A, the above-described working gate valve and sealing case are connected to the opening of the T-shaped tube 5.

  Similar to the valve body 31A, the valve body 36A includes a bottom wall 36C having a fan-like shape in plan view, and a seal wall 36D that can contact the inner surface of the T-tube 5 and is configured to be rotatable via a rotation shaft 36B. Has been. Although the valve body 36A of FIG. 5 closes the connection port 26a, the seal position with respect to the T-shaped tube 5 is switched by rotating this, and the connection port 26b and the connection port 26c can be selectively closed. The removal of the valve body 36A can be performed in the same manner as in the case of the valve body 31A. As shown in FIG. 2G, in the scene where the removed valve body 36A is reused, no special measures are required because the bypass is not passed.

  With this structure, in the pipe shown in FIG. 2 [H], the branch pipe 29 where the connecting pipe 19 joins the new pipe, and the branch pipes 26 to 28 in the middle of the new pipe, The T-shaped tube which comprises a part is provided. And the T-shaped tube has an opening portion closed by a lid at the top, and does not incorporate a valve body that can close the connection ports of the branch portions 26 to 29. Of the connection ports of the branch portions 26 to 29, the connection ports 29 c that are not used for communication between the new pipeline and the communication pipeline 19 and the connection ports 26 a to 28 a that branch from the trunk line of the new pipeline are covered. Yes.

[Cover of connection port]
FIG. 7 is a horizontal sectional view of the branch portion 21 in FIG. A cap 10, also called a mechanical cap, is attached to the cut end of the tube at the tip of the connection port 21 c. When the joint portion of the pipe is released at the distal end side of the connection port 21c, the lid member may be joined using the joint structure. In the branch portions 25 and 29, the connection ports can be covered in the same manner. The connection ports 26a to 28a of the branch portions 26 to 28 are covered with flange lids 20 joined to the end faces of the branch short tubes, respectively. Instead of these, a plug member that closes the inside of the tube may be used, and the connection port may be sealed.

[Corrosion prevention of pipe cut surface]
As described above, in the branch portions 21 and 25, after removing the valve body, the pipe cut surface formed by the full cut cutting is subjected to a corrosion prevention treatment. According to the technique described in Japanese Patent Application No. 2012-053219 (filed on Mar. 9, 2012, unpublished at the time of filing this application) by the present applicants, a pair of pipe cut surfaces can be easily maintained while maintaining a water flow state. Can be corrosion resistant. Hereinafter, this method will be briefly described.

  First, as shown in FIG. 8, a sealed case 72 is connected to the opening of the split T-shaped tube 4 via a work gate valve 71. The work gate valve 71 and the sealing case 72 can also be used when the above-described valve body is removed or reused. The double cylinder 6 built in the sealed case 72 has a nested structure in which the cylindrical core body 62 shown in FIG. 10 is inserted into the cylindrical corrosion-resistant body 61 shown in FIG. Here, the double cylinder 6 is in a temporarily held state in which only the lower end portion of the core body 62 is inserted into the corrosion protection body 61. In FIG. 8, the double cylinder 6 is drawn not by a cross section but by an appearance.

  Next, as shown in FIG. 11, the double cylinder 6 lowered by pushing down the operating rod 73 is accommodated in the split T-shaped tube 4 through the opening. When the double cylinder 6 is disposed between the pair of tube cutting surfaces 30, the corrosion protection body 61 is first positioned, and the core body 62 is inserted into the corrosion protection body 61 by further pressing the operation rod 73 thereafter. The Since the outer diameter of the core body 62 is larger than the inner diameter of the corrosion-resistant body 61, the corrosion-resistant body 61 is expanded by inserting the core body 62. As shown in FIGS. 7 and 11, the expanded corrosion-resistant body 61 is pressed against and closely adhered to the pair of tube cutting surfaces 30 to be subjected to a corrosion-proof treatment.

  An inner plug 63 is provided on the upper part of the double cylinder 6, and the opening of the split T-tube 4 is sealed at the stage of FIG. 11. The anticorrosion body 61 is made of, for example, rubber or synthetic resin, and the core body 62 is made of, for example, ductile cast iron. A plurality of through-holes communicating with the connection port of the branch portion are provided on the sides of the anticorrosive body 61 and the core body 62. When the installation of the double cylinder 6 is completed, the work gate valve 71 and the sealing case 72 are removed, and the lid 42 is attached to the opening of the split T-shaped tube 4 to stabilize the posture of the double cylinder 6.

  In the present embodiment, three through holes are provided on the sides of the anticorrosive body 61 and the core body 62, but the present invention is not limited to this. For example, it is conceivable to provide the through holes only in two directions so as to close the connection port to be covered (the connection port on the right side in FIG. 7). According to such a configuration, it is possible to prevent so-called “dead water” from being generated in the section from the corrosion-resistant body 61 to the cap 10. The water remaining in the section can be discharged through the drain port of the cap 10.

[Other Embodiments]
(1) In the above-described embodiment, the construction is completed at the stage [H] in FIG. 2, and the updated pipelines 11 to 14 included in the bypass are configured for subsequent use. Although the example to provide was shown, it is not limited to this. For example, as shown in FIG. 12, a further new pipeline 9 may be laid and the new pipeline 9 may be used for subsequent use. According to this method, it is possible to lay the updated pipeline on the removed existing pipeline 1.

  In FIG. 12, first, as shown in [I], the anticorrosion body 61 installed in the branch portions 21 and 25 is removed, and valve bodies 31A and 32A are inserted in place of them, and the switching valves 31 and 35 are inserted. Is provided. If the installation of the corrosion protection body 61 is postponed in FIG. 2, the removal work of the corrosion protection body 61 can be omitted. And as shown to [J], the cap 10 which covered the connection ports 21c and 25b is removed, and the new pipeline 9 is newly installed so that they communicate with each other. The procedures [I] and [J] may be reversed.

  Next, as shown in [K], the switching valves 31 and 35 are operated to switch the flow path to the new pipeline 9, and the new pipelines 11 to 14 are removed together with the connecting pipelines 15 and 19. Subsequently, as shown in [L], after attaching the flange lid 20 to the connection ports 21a and 25a and applying the lid, the valve bodies 31A and 32A are removed from the branch portions 21 and 25, and the corrosion protection body 61 is substituted for them. Is installed.

  (2) In the present invention, the switching valve provided at the branch portion in the first step is not limited to the above-described structure. In the above-described embodiment, an example in which a three-way switching valve is used has been shown. However, a switching valve corresponding to a connection port of four or more directions can also be used, and a different valve body or valve box shape may be adopted. I do not care.

  (3) The present invention can be applied to renewal of existing water pipes, but is not limited to this, and can be widely applied to renewal of fluid lines used for fluids other than water, such as gas.

DESCRIPTION OF SYMBOLS 1 Existing pipe line 4 Split T-shaped pipe 5 T-shaped pipe 6 Double cylinder 11-14 New pipe line 15-19 Connection pipe line 21-25 Branch part 26-29 Branch part 21a-21c Connection port 26a-26c Connection port 30 Pipe cut surfaces 31 to 33 Switching valves 31A and 32A Valve bodies 36 to 38 Switching valves 36A and 37A Valve body 40 Inner valve box 42 Cover body 52 Cover body

Claims (7)

While maintaining the fluid flow state, a new pipeline is laid along the section to be renewed of the existing pipeline, and the upstream and downstream sides of the new pipeline are communicated with the existing pipeline via the connecting pipeline. And a switching valve capable of selectively closing a connection port of the branching section between the branching section where the connecting pipe joins the existing pipe and the branching section where the connecting pipe joins the new pipe And forming a bypass that bypasses the section to be updated of the existing pipeline, and
A second step of operating the switching valve to switch the flow path from the existing pipeline in the section to be updated to the bypass, and removing the existing pipeline in the section;
Covering or sealing the connection port connected to the existing pipe line removed in the second step among the connection ports of the branching portion where the switching valve is closed, and removing the valve body of the switching valve And a third step of updating the pipeline. When repeating the first step and the second step and extending the update section toward the downstream side,
In the first step after the second time, the new pipeline laid in the immediately preceding first step is extended downstream to form a bypass,
2. The method for updating a pipeline according to claim 1, wherein, in the second and subsequent second steps, the switching valve provided in the upstream branch portion of the existing pipeline is removed together with the existing pipeline in the section to be updated. .   The switching valve provided at a branch portion where the connecting pipe joins the new pipe has a structure in which a valve body is built in a T-shaped pipe constituting a part of the new pipe, and the T-shaped pipe The method for updating a pipe line according to claim 1 or 2, wherein the connection port to be closed is switched according to the posture of the valve body with respect to the valve.   A structure in which the switching valve provided at a branch portion where the connecting pipe joins the existing pipe accommodates an inner valve box containing a valve body in a split T-tube externally fitted to the existing pipe. The method for updating a pipeline according to any one of claims 1 to 3, wherein a connection port to be closed is switched according to a posture of the valve body with respect to the inner valve box.   The method of updating a pipe line according to any one of claims 1 to 4, wherein the valve body removed in the third step is reused as a valve body of a switching valve provided in the first step thereafter.   The valve body of the switching valve provided at the branch portion where the connecting pipe joins the existing pipe is disposed between a pair of pipe cutting surfaces formed by full-cut cutting of the existing pipe, The pipe line updating method according to any one of claims 1 to 5, wherein the pipe cut surface is corroded after the valve body is removed in a third step. A new pipeline laid along the renewal section of the existing pipeline, a communication pipeline connecting the upstream side and the downstream side of the new pipeline to the existing pipeline, and the communication pipeline in the existing pipeline A split T-shaped pipe that is provided at a junction where the pipes merge and is fitted to the existing pipe, a branch where the connecting pipe joins the new pipe, and a branch that is in the middle of the new pipe And a T-shaped tube constituting a part of the new pipeline,
The split T-shaped tube has an opening portion closed by a lid at the top, and does not incorporate a valve body that can close the connection port of the branch portion, and the branched portion provided with the split T-shaped tube Of these connection ports, the connection ports that are not used for communication between the existing pipeline and the communication pipeline are covered or sealed.
The T-shaped tube has an opening closed by a lid at the top, and does not have a built-in valve body that can close the connection port of the branched portion, and the connection of the branched portion provided with the T-shaped tube. A pipe line in which a connection port that is not used for communication between the new pipe line and the communication pipe line, or a connection port branched from the main line of the new pipe line is covered or sealed.

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