Freezing method for continuous flow

Abstract

To provide a flow-uninterrupted construction method for reducing costs by making the nominal diameter of a newly installed piping element smaller than that of an existing piping element after freezing a branch pipe section with an ice plug. [Solution] An existing pipeline has a T-shaped pipe section 1 having a main pipe section 10 and a branch pipe section 11 protruding in the radial direction R of the main pipe section 10, and this is a flow-uninterrupted construction method for replacing an existing piping element 12 installed in the branch pipe section 11 of the T-shaped pipe section 1 with a newly installed piping element N, and includes a freezing process for freezing the fluid L in the branch pipe section 11 while the fluid L is flowing in the main pipe section 10 of the T-shaped pipe section 1, a removal process for removing the existing piping element 12 while the fluid L is frozen, and a process for attaching a new piping element N having a nominal diameter smaller than the nominal diameter of the existing piping element 12 to the branch pipe section 11 while the fluid L is frozen.

Description

[Technical field]

[0001] The present invention relates to a freezing type flow-uninterrupted construction method. [Background technology]

[0002] A known method is to freeze the fluid in the branch pipe of an existing T-pipe using liquid nitrogen or the like, block the flow of the fluid with an ice plug, and then replace the piping element (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP2018-141473A (Figure 3) [Patent Document 2] JP2006-329227A (Summary) [Patent Document 3] JP2007-187204A(Abstract) Summary of the Invention

[0004] In the invention of Patent Document 1, the existing piping elements and the newly installed piping elements have the same nominal diameter, which may be uneconomical.

[0005] Air valves are generally installed at the branch pipes of T-shaped pipes. These air valves are used to release the huge amount of air that fills a long pipe after it has been installed. Therefore, a relatively large air valve is installed. Once the air in the pipeline has been removed and the pipeline is filled with a specified amount of water or oil, the large air valve is no longer necessary, and a small nominal diameter air valve for maintenance is sufficient.

[0006] However, in the method disclosed in Patent Document 1, the existing air valve is replaced with one having the same nominal diameter as the existing one, which is uneconomical.

[0007] In addition, the pipelines that require replacement of the air valve are old, and therefore the distance from the top of the main pipe to the ground is short, and the ceiling height of the valve chest is low. Therefore, when installing the air valve, it is not possible to insert a repair valve due to height restrictions, and the air valve is sometimes installed via a reducer in the branch pipe of the main pipe. In this case, if the newly installed air valve deteriorates, it will be necessary to carry out construction work using the freezing method again.

[0008] On the other hand, Patent Document 3 discloses an adapter flange for reducing the nominal diameter. However, it does not disclose replacing an installed fire hydrant with one having a smaller nominal diameter.

[0009] The object of the present invention is to provide a method of construction without interrupting flow, which reduces the height to the top of the newly installed piping element within the valve chamber by making the nominal diameter of the newly installed piping element smaller than that of the existing piping element after freezing the branch pipe section with an ice plug, thereby enabling the newly installed piping element to fit within the valve chamber while reducing costs.

[0010] The flow-uninterrupting construction method of the present invention is a method for replacing an existing pipeline having a T-shaped pipe section 1 having a main pipe section 10 and a branch pipe section 11 protruding in a radial direction R of the main pipe section 10, an existing piping element 12 installed in the branch pipe section 11 of the T-shaped pipe section 1 with a newly installed piping element N, a freezing step of freezing the fluid L in the branch pipe portion 11 while the fluid L is flowing in the main pipe portion 10 of the T-shaped pipe portion 1; a removal process of removing the existing piping element 12 while the fluid L is frozen; and attaching a new piping element N having a smaller nominal diameter than the nominal diameter of the existing piping element 12 to the branch pipe portion 11 while the fluid L is in a frozen state.

[0011] According to the present invention, the new piping element N having a smaller nominal diameter than the existing piping element 12 is installed, so that the cost is reduced.

[0012] Preferably, a first coupling step is performed in which an adapter A having a lower surface S1 that fits a flange 11F of the branch pipe portion 11 and an upper surface S2 that fits a flange NF of the newly installed piping element N is coupled to the branch pipe portion 11 while the fluid L is in a frozen state; The method further includes a second connecting step of connecting a flange NF of the new piping element N to the upper surface S2 of the adapter A. In this case, by using the adapter A, a standard product can be used as is for the newly installed piping element N, resulting in low costs.

[0013] More preferably, the adapter A is an annular plate-like flange. By using a plate-shaped flange as adapter A, it is easier to fit into the valve chamber compared to using a reducer that is long in the axial direction of the pipe.

[0014] Preferably, the existing piping element 12 is an existing repair valve 121 and an air valve 122, and the newly installed piping element N is a repair valve N1 and an air valve N2 having a smaller nominal diameter than the existing repair valve 121 and air valve 122. In this case, the nominal diameter of the newly installed repair valve and air valve after construction will be smaller, which will reduce costs and make the height to the top of the air valve smaller, making it more compact.

[0015] Preferably, the existing piping element 12 is an existing air valve 122 , and the newly installed piping element N is a repair valve N 1 and an air valve N 2 having a smaller nominal diameter than the existing air valve 122 . In this case, since the nominal diameter of the new installation will be smaller, even if a repair valve is inserted between the air valve and the branch pipe section, the height to the top of the air valve can be kept small and stored within the valve chamber, so the repair valve can be inserted. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a front view showing an example of a piping structure after replacement has been completed using the flow-uninterrupted construction method of the present invention. [Diagram 2] 1A to 1C are a plan view, a cross-sectional view, and a bottom view showing an adapter. [Diagram 3] FIG. [Figure 4] FIG. 2 is a front view showing an example of an existing piping structure. [Diagram 5] FIG. 2 is a front view of the main parts showing the first embodiment of the flow-undisrupted construction method. [Figure 6] FIG. 2 is a front view of the main parts showing the first embodiment of the flow-undisrupted construction method. [Figure 7] FIG. 2 is a front view of the main parts showing the first embodiment of the flow-undisrupted construction method. [Figure 8] FIG. 11 is a front view of the main parts showing a second embodiment of the flow-undisrupted construction method. [Figure 9] FIG. 11 is a front view of the main parts showing a second embodiment of the flow-undisrupted construction method. [Figure 10] FIG. 11 is a front view of the main parts showing a second embodiment of the flow-undisrupted construction method. EXAMPLES

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the drawings. Prior to describing the present method, an existing piping structure and a new piping structure will be described.

[0018] Figure 4 shows the existing piping structure. 4, a T-shaped pipe section 1 of an existing pipeline has a main pipe section 10 and a branch pipe section 11 protruding in a radial direction R of the main pipe section 10. An existing piping element 12 is installed in the branch pipe section 11 of the T-shaped pipe section 1. As will be described below, the existing piping element 12 is removed from the existing pipeline.

[0019] In this example, the existing branch pipe section 11 is composed of a branch section 11B branched off from a main pipe section 10, and a reducer (diameter reduction pipe) 11R flange-joined to this branch section 11B.

[0020] In this example, the existing piping element 12 is composed of an existing repair valve 121 and an air valve 122. The repair valve 121 is flange-connected to the reducer 11R, and the air valve 122 is flange-connected to the repair valve 121.

[0021] 1 to 7 show the first embodiment. Figure 1 shows the piping structure after construction was completed. The existing piping element 12 of FIG. 4 is replaced with the new piping element N of FIG.

[0022] In FIG. 1, the newly installed piping element N is a repair valve N1 and an air valve N2 having a smaller nominal diameter than the existing repair valve 121 and air valve 122 (FIG. 4).

[0023] An adapter A is interposed between the reducer 11R and the newly installed repair valve N1 in Fig. 1. As shown in Fig. 2 and Fig. 3, the adapter A is an annular plate-shaped flange, and has a lower surface S1 in Fig. 2 that fits the flange 11F of the branch pipe section 11 in Fig. 1, and an upper surface S2 in Fig. 2 that fits the flange NF of the newly installed piping element N in Fig. 1.

[0024] This method is a flow-uninterrupted method, and the following steps are carried out while the fluid L continues to flow in the main pipe section 10 of FIG.

[0025] Prior to the formation of the ice plug, a framing process is performed as shown in Fig. 5(a). In the framing process in Fig. 5(a), a form-like frame 3 is attached to the reducer 11R so as to surround the reducer 11R. The frame 3 may be made of polystyrene foam, for example, and the gap between the frame 3 and the reducer 11R may be filled with wet putty.

[0026] 5(b), a refrigerant 4 such as liquid nitrogen is poured into the frame 3 to fill the frame 3 with the refrigerant 4 for freezing. The refrigerant 4 freezes the fluid L in the reducer 11R.

[0027] That is, a freezing step is performed to freeze a part of the fluid L in the branch pipe section 11 while the fluid L is flowing in the main pipe section 10 of Fig. 4. In this example, it is sufficient that the part of the fluid L to be frozen is at least a part of the branch pipe section 11.

[0028] In the frozen state, the old piping element 12 is removed as shown in FIG. 6(a).

[0029] After this removal, as shown in Fig. 6(b), a first coupling process is performed in which the adapter A is coupled to the flange 11F of the reducer 11R while the fluid L is frozen. After this, a second coupling process is performed in which the flange NF of the repair valve N1, which is a part of the newly installed piping element N in Fig. 7, is coupled to the upper surface S2 of the adapter A.

[0030] After that, the air valve N2 is attached on the repair valve N1 in Fig. 7(b). Note that, since the repair valve N1 is closed during this attachment, the frozen state may be released.

[0031] After the replacement, the refrigerant 4 is recovered and the frame 3 is removed.

[0032] In this manner, the existing piping element 12 shown in FIG. 4 is replaced with the new piping element N shown in FIG.

[0033] FIG. 1 and FIGS. 7 to 10 show the second embodiment. Figure 1 shows the piping structure after construction was completed. The existing piping element 12 of FIG. 8 is replaced with the new piping element N of FIG.

[0034] In FIG. 1, the newly installed piping element N is a repair valve N1 and an air valve N2 having a smaller nominal diameter than the existing air valve 122 (FIG. 8).

[0035] An adapter A is interposed between the reducer 11R and the newly installed repair valve N1 in Fig. 1. As shown in Fig. 2 and Fig. 3, the adapter A is an annular plate-shaped flange, and has a lower surface S1 in Fig. 2 that fits the flange 11F of the branch pipe section 11 in Fig. 1, and an upper surface S2 in Fig. 2 that fits the flange NF of the newly installed piping element N in Fig. 1.

[0036] This method is a flow-uninterrupted method, and the following steps are carried out while the fluid L continues to flow in the main pipe section 10 of FIG.

[0037] Prior to the formation of the ice plug, a framing process is performed as shown in Fig. 9(a). In the framing process in Fig. 9(a), a form-like frame 3 is assembled to the reducer 11R so as to surround the reducer 11R. The frame 3 may be made of polystyrene foam, for example, and the gap between the frame 3 and the reducer 11R may be filled with wet putty.

[0038] 9(b), a refrigerant 4 such as liquid nitrogen is poured into the frame 3 to fill the frame 3 with the refrigerant 4 for freezing. The refrigerant 4 freezes the fluid L in the reducer 11R.

[0039] That is, a freezing step is performed to freeze a part of the fluid L in the branch pipe section 11 while the fluid L is flowing in the main pipe section 10 of Fig. 8. In this example, it is sufficient that the part of the fluid L to be frozen is at least a part of the branch pipe section 11.

[0040] In the frozen state, the old piping element 12 is removed as shown in FIG. 10(a).

[0041] After this removal, as shown in Fig. 10(b), a first coupling process is performed in which the adapter A is coupled to the flange 11F of the reducer 11R while the fluid L is frozen. After this, a second coupling process is performed in which the flange NF of the repair valve N1, which is a part of the newly installed piping element N in Fig. 7, is coupled to the upper surface S2 of the adapter A.

[0042] After that, the air valve N2 is attached on the repair valve N1 in Fig. 7(b). Note that, since the repair valve N1 is closed during this attachment, the frozen state may be released.

[0043] After the replacement, the refrigerant 4 is recovered and the frame 3 is removed.

[0044] In this manner, the existing piping element 12 shown in FIG. 8 is replaced with the new piping element N shown in FIG.

[0045] In addition, in the present invention, when installing a new piping element N, the adapter A, the repair valve N1 and the air valve N2 may be pre-assembled together (sub-assembled), and then the sub-assembled new piping element N may be installed to the reducer 11R.

[0046] Also, the location where the ice valve is formed may be the branch portion 11B instead of the reducer 11R. Furthermore, the position of the frame 3 arranged on the reducer 11R may be higher than that of this embodiment.

[0047] Also, the adapter A may have a structure like a reducer in which the inner diameter becomes smaller toward the top.

[0048] Furthermore, prior to the freezing step of FIG. 5(b), the bolts and nuts fastening the reducer and the repair valve 121 may be replaced in advance.

[0049] Furthermore, a tapping screw may be provided in advance on the reducer as a fastening device that engages with the ice valve. [Industrial Applicability]

[0050] The construction method of the present invention can be applied to pipelines for crude oil, etc., in addition to pipelines for water supply. [Explanation of symbols]

[0051] 1: T-shaped pipe section 10: Main pipe section 11: Branch pipe section 11B: Branch section 11R: Reducer 11F, NF: Flange 12: Existing piping element 121: Repair valve 122: Air valve 3: Frame 4: Refrigerant A: Adapter S1: Bottom S2: Top N: New piping element N1: Repair valve N2: Air valve L: Fluid R: Radial direction

Claims

1. A method for replacing an existing pipeline having a T-shaped pipe section 1 having a main pipe section 10 and a branch pipe section 11 protruding in a radial direction R of the main pipe section 10, an existing piping element 12 installed in the branch pipe section 11 of the T-shaped pipe section 1 with a new piping element N, a freezing step of freezing the fluid L in the branch pipe portion 11 while the fluid L is flowing in the main pipe portion 10 of the T-shaped pipe portion 1; a removal process of removing the existing piping element 12 while the fluid L is frozen; and attaching a new piping element N having a smaller nominal diameter than the nominal diameter of the existing piping element 12 to the branch pipe section 11 while the fluid L is frozen. a first coupling step of coupling an adapter A having a lower surface S1 that fits a flange 11F of the branch pipe portion 11 and an upper surface S2 that fits a flange NF of the newly installed piping element N to the branch pipe portion 11 while the fluid L is in a frozen state; This uninterrupted flow construction method further includes a second connecting step of connecting the flange NF of the newly installed piping element N to the upper surface S2 of the adapter A.

2. In claim 1, A flow-uninterrupted construction method in which the adapter A is a circular plate-shaped flange.

3. In claim 2, A flow-uninterrupted construction method in which the existing piping element 12 is an existing repair valve 121 and air valve 122, and the newly installed piping element N is a repair valve N1 and air valve N2 having a smaller nominal diameter than the existing repair valve 121 and air valve 122.

4. In claim 2, The uninterrupted flow construction method, in which the existing piping element 12 is an existing air valve 122, and the newly installed piping element N is a repair valve N1 and an air valve N2 having a smaller nominal diameter than the existing air valve 122.

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