Replacement method for fluid pipe

Abstract

To provide a replacement method for a fluid pipe capable of replacing an existing fluid pipe with a newly constructed fluid pipe without causing the existing fluid pipe to remain in a connected state to a casing.SOLUTION: A method is for replacing an existing fluid pipe 2 with a newly constructed fluid pipe 2A by using a flow control device 1 including a seal material 20 serving as a first seal part for sealing a portion between division surfaces of an upper casing 3a and a lower casing 3b, a seal material 30, 30A serving as a second seal part extended in the circumferential direction on an inner peripheral surface of a connection opening 6c of a casing 3, and a gate valve 4. The method includes processes of: disposing the annular seal material 30A formed separately from the seal material 20 on the inner peripheral surface of the connection opening 6c on a shutoff side shut off from pipe internal fluid by using the gate valve 4 in the casing 3; and inserting the newly constructed fluid pipe 2A into the connection opening 6c on the shutoff side in the casing 3 and connecting the newly constructed fluid pipe 2A to the casing 3 in a sealed manner by causing the seal material 20 and the seal material 30A to come into close contact with each other.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a fluid pipe replacement method in which a flow control device is installed at a predetermined location of an existing fluid pipe and the existing fluid pipe is replaced with a new fluid pipe. [Background technology]

[0002] Conventionally, a flow control device has been installed on the primary side (upstream side) and secondary side (downstream side) of a specified area of ​​an existing fluid pipe, comprising a housing that is hermetically attached along the fluid pipe and a fluid control device that is inserted into the cut point of the fluid pipe inside the housing.The fluid control device blocks fluids such as water and gas from entering the specified area, allowing the existing fluid pipe in the specified area to be removed and replaced with a new fluid pipe.

[0003] One method of replacing fluid pipes using this type of flow control device involves, for example, connecting flow control devices installed on the primary and secondary sides of a specified area with a bypass pipe, then using the flow control device to block the fluid from entering the specified area and change the flow path to the bypass pipe side, cutting the existing fluid pipe in the specified area with a cutting device, and connecting a new fluid pipe to the cut section to replace the fluid pipe in the specified area (see, for example, Patent Document 1).

[0004] Furthermore, the housing of the flow control device described in Patent Document 1 above has upper and lower split housings that are split along the axis of the fluid pipe, and one of the split housings is provided with a semicircular arc-shaped sealant along the inner surface of the connection opening of the fluid pipe, while the other split housing is provided with a sealant that is an integrated unit of a semicircular arc-shaped seal portion that is arranged along the inner surface of the connection opening of the fluid pipe and a seal portion that extends along the axis of the fluid pipe, and by fitting these split housings together around the fluid pipe and fastening them with bolts and nuts, the upper and lower split housings are attached to the fluid pipe in a sealed manner via these sealant materials. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-119559 A (pages 5-6, figures 1-5) Summary of the Invention [Problem to be solved by the invention]

[0006] In the flow control device described in Patent Document 1, after removing the existing pipeline in a specified area, a new pipeline is constructed by connecting a new fluid pipe to the existing fluid pipe that remains connected to the housing.

[0007] In this case, the existing fluid pipe with a cut surface remains in the housing, so it is desirable to remove the remaining existing fluid pipe from the housing and insert and connect a new fluid pipe into the connecting opening. However, because the semicircular arc-shaped seal member provided in the connecting opening of one divided housing and the semicircular arc-shaped seal portion constituting the seal member provided in the other divided housing are composed of separate members, when inserting the new fluid pipe into the connecting opening, the divided end faces of these seal members may shift in the pipe axial direction or protrude toward the inner diameter and come into contact with the fluid pipe, causing damage and resulting in leakage. Therefore, there is a problem in that the existing fluid pipe cannot be replaced with a new fluid pipe.

[0008] The present invention has been made in response to such problems, and aims to provide a fluid pipe replacement method that can replace an existing fluid pipe with a new fluid pipe without leaving the existing fluid pipe connected to the housing. [Means for solving the problem]

[0009] In order to solve the above problems, the fluid pipe replacement method of the present invention includes: A fluid pipe replacement method for replacing an existing fluid pipe with a new fluid pipe using a flow control device including: a housing that is attached to an existing fluid pipe and is made up of a plurality of divided housings that can be divided along a pipe axis; a first seal portion that seals between divided surfaces of the divided housings; a second seal portion that extends circumferentially on an inner peripheral surface of a connection opening of the housing; and a flow control device that is installed at a cut point of the existing fluid pipe within the housing, a step of disposing the second seal portion, which is formed in an annular shape separately from the first seal portion, on an inner circumferential surface of a connection opening on a cut-off side that is cut off from the fluid in the pipe by the fluid control in the housing, or on an outer circumferential surface of a newly installed fluid pipe; The method is characterized by comprising a step of inserting a new fluid pipe into the connection opening on the blocking side of the housing, and sealingly connecting the new fluid pipe to the housing by tight contact between the first seal portion and the second seal portion. According to this feature, because the second seal portion is annular, even if a new fluid pipe is inserted from the outside into the connection opening on the cut-off side that has been cut off from the fluid inside the pipe by the fluid control device, the second seal portion can be easily brought into tight contact with the first seal portion, and there is no risk of leakage.Therefore, the existing disconnected fluid pipe can be replaced with a new fluid pipe without leaving it in the housing.

[0010] After the fluid control device is installed in the housing, the method includes a step of removing the existing fluid pipe remaining in the connection opening on the blocking side and the seal portion that seals the existing fluid pipe and the housing. According to this feature, it is possible to connect a newly installed fluid pipe to the housing by pulling out and removing the existing fluid pipe remaining in the housing and the seal portion that seals this fluid pipe to the housing.

[0011] When the new fluid pipe is inserted, the second seal portion formed in an endless annular shape is fitted onto the new fluid pipe. According to this feature, the use of the endless annular second seal portion makes it possible to improve the sealing performance.

[0012] The first seal portion has a contact portion that is pressed against the divided surfaces of the divided housings and bulges radially inward to come into close contact with the second seal portion. According to this feature, the contact portion of the first seal portion bulges radially inward and comes into close contact with the second seal portion, thereby enabling the first seal portion and the second seal portion to exhibit high sealing performance.

[0013] At least one of the divided housings is characterized by including a guide portion that guides the contact portion of the first seal portion so that it bulges radially inward. According to this feature, the contact portion of the first seal portion can be effectively elastically deformed toward the second seal portion, so that these seal portions can be reliably brought into close contact with each other. [Brief explanation of the drawings]

[0014] [Figure 1] (a) is a schematic plan view showing a flow control device according to an embodiment of the present invention installed in an existing fluid pipe, (b) is a schematic plan view showing the existing fluid pipe after being cut, and (c) is a schematic plan view showing the new fluid pipe after being replaced. [Figure 2] 1A is a partially cutaway front view showing the flow restrictor, and FIG. 1B is a partially cutaway right side view. [Figure 3] 1A is a plan view showing the lower housing, and FIG. 1B is a cross-sectional view taken along the line AA in FIG. [Figure 4] 1A is a bottom view showing the upper housing, and FIG. 1B is a cross-sectional view taken along the line BB of FIG. [Figure 5] (a) is a plan view showing the first seal portion, (b) is a front view, (c) is a side view showing the second seal portion having a cut portion, (d) is a side view showing the second seal portion without a cut portion, and (e) is a CC cross-sectional view of (c). [Figure 6] 1A is a plan view showing a state in which the first seal portion and the second seal portion are arranged in the lower housing, and FIG. 1B is a left side view of FIG. 1A. [Figure 7] 1(a) is a plan view showing an existing fluid pipe with a second seal portion annularly installed, and FIG. 1(b) is a side view. [Figure 8] (a) is a plan view showing the state in which the lower housing, the first seal portion, and the second seal portion have been installed on an existing fluid pipe, (b) is a side view, (c) is an enlarged cross-sectional view showing the abutment portion of the first seal portion and the second seal portion in their natural state, and (d) is an enlarged, partially broken, plan view showing the abutment portion of the first seal portion and the second seal portion after elastic deformation. [Figure 9]1A is a schematic front view showing the process of cutting an existing fluid pipe, and FIG. 1B is a schematic front view showing the process of inserting a gate valve into the cut portion of the housing. [Figure 10] FIG. 2 is a partially cutaway front view showing a flow restrictor device in which a gate valve is installed. [Figure 11] 10 is a partially cutaway front view showing a state in which the existing fluid pipe and the second seal portion have been pulled out from the connection opening of the housing. FIG. [Figure 12] 1A is a plan view showing the procedure for removing an existing fluid pipe from a connection opening of a housing, and FIG. 1B is an enlarged view of a main part of FIG. [Figure 13] 10 is a partially cutaway front view showing a state in which a second seal portion is attached to a connection opening of a housing and a new fluid pipe is inserted. FIG. [Figure 14] 10(a) is a plan view showing the procedure for attaching a second seal portion to a connection opening of a housing and inserting a new fluid pipe, and FIG. 10(b) is an enlarged view of the main part of FIG. [Figure 15] FIG. 10 is a partially cutaway front view showing a state in which a new fluid pipe is connected to a connection opening of the housing. [Figure 16] (a) is an enlarged plan view showing the contact portion of the elastically deformed first seal portion, (b) is an enlarged, partially cutaway plan view showing the state in which the second seal portion is pressed against the contact portion of the elastically deformed first seal portion, and (c) is a DD cross-sectional view of (a). [Figure 17] FIG. 10 is a partially cutaway front view showing a state before a new fluid pipe and a second seal portion are connected to a connection opening of a housing according to a modified example of the present invention. [Figure 18] FIG. 10 is a partially cutaway front view showing a state in which a new fluid pipe and a second seal portion are connected to a connection opening of a housing according to a modified example of the present invention. [Figure 19] (a) is an enlarged plan view showing the abutment portion of the first seal portion in its natural state as a modified example, (b) is an enlarged plan view showing the abutment portion of the first seal portion that has been elastically deformed, and (c) is an enlarged plan view showing the state in which the second seal portion is pressed against the abutment portion of the first seal portion that has been elastically deformed. [Figure 20] 10 is a partially cutaway front view showing a state in which a newly installed small-diameter fluid pipe is connected to a connection opening of a housing according to a modified example of the present invention. FIG. [Example]

[0015] A method for replacing a fluid pipe according to an embodiment of the present invention will be described with reference to Figures 1 to 16. In the following description, the near side of Figure 2(a) will be referred to as the front side of the flow restrictor, the rear side as the rear, the left side as the left side, and the right side as the right side.

[0016] As shown in FIG. 1, for example, when removing or repairing a fluid pipe 2 in a specific area W in a flow path consisting of an existing fluid pipe 2, first, as shown in FIG. 1(a), housings 3, 3 of flow control devices 1, 1 according to an embodiment of the present invention are attached to the pipe section on the primary side (upstream side) of the specific area W and the pipe section on the secondary side (downstream side) of the specific area W. Next, as shown in FIG. 1(b), the fluid pipe 2 inside each housing 3, 3 is cut without interrupting the flow of water. Then, gate valves 4, 4 (see FIG. 2(a)), which will be described later, are inserted into the cut portions of the fluid pipe 2 inside each housing 3, 3 to stop the water flow, thereby cutting off the water supply to the specific area W as shown in FIG. 1(c).

[0017] After that, a drainage device (not shown) or the like is installed in the existing fluid pipe 2 in the specific area W, and the fluid in the fluid pipe 2 in the specific area W is discharged to the outside, and then work can be done to replace the existing fluid pipe 2 in the specific area W with a new fluid pipe using the construction method described below.

[0018] In this embodiment, the fluid in the fluid pipe 2 is tap water. However, it may be, for example, industrial water, agricultural water, sewage, or other liquids other than water, or it may be gas or a gas-liquid mixture. The fluid pipe 2 is a ductile cast iron pipe formed into a straight pipe with a generally circular cross section. In this embodiment, the fluid pipe 2 is disposed generally horizontally. The fluid pipe according to the present invention may also be made of other metals, such as cast iron or steel, or concrete, polyvinyl chloride, polyethylene, or polyolefin. Furthermore, the inner surface of the fluid pipe may be coated with an epoxy resin layer, mortar, plating, or the like, or may be powder coated with an appropriate material.

[0019] 2(a) and 2(b), the flow control device 1,1 is mainly composed of a housing 3 that hermetically fits over a predetermined portion of the fluid pipe 2, and a gate valve 4 that acts as a fluid regulator and is inserted into the housing 3 and can open and close the flow path. Note that since the flow control devices 1,1 are configured in the same way, the following will only describe the flow control device 1 installed on the upstream side of the specific area W, and will omit a description of the flow control device 1 installed on the secondary side of the specific area W.

[0020] [Case] As shown in Figures 2(a) and (b), the housing 3 is made of ductile cast iron and is mainly composed of a main body 5 formed in a substantially cylindrical shape with an open top, side body portions 6a and 6b formed in a substantially cylindrical shape that protrude from the left and right sides of the main body 5 in left and right directions perpendicular to the central axis of the main body 5 and are capable of covering the fluid pipe 2, and a bottom portion 7 that closes the lower opening of the main body 5.

[0021] 2(a) and 2(b), in this embodiment, the housing 3 is a split T-shaped pipe consisting of an upper housing 3a and a lower housing 3b, and has a split structure divided into two, upper and lower, along the central axis of the side body portions 6a, 6b. The lower housing 3b and the upper housing 3a are fastened together with fastening members, bolts and nuts N1, to hermetically attach the housing 3 so as to cover a predetermined portion of the fluid pipe 2 from above and below. The ends of the side body portions 6a, 6b in the pipe axis direction are hermetically fitted over the housing 3, and the housing 3 is fixed to the fluid pipe 2 by anti-detachment fittings 8, 8. The anti-detachment fittings 8, 8 have a split structure divided into two, upper and lower, along the pipe axis of the fluid pipe 2, and are attached to a predetermined portion of the fluid pipe 2 by fastening the upper and lower divided members 8a, 8b together with fastening members, bolts and nuts N2.

[0022] [Lower housing] As shown in Figures 2(a) and 2(b) and 3(a) and 3(b), the lower housing 3b is made up of a main body 5 and the lower halves of side body sections 6a and 6b, and is capable of covering the lower part of the fluid pipe 2. The lower part of the main body 5 is formed in a generally cylindrical shape with an open top and a closed bottom 7 at the bottom, and the lower parts of the side body sections 6a and 6b are formed in a generally semicircular arc shape in side view with an open top. Furthermore, flange sections 11b and 11b protruding in the outer diameter direction are provided on the front and rear sides of the upper end of the lower housing 3b, extending in the left-right direction, and the upper surfaces of the flange sections 11b and 11b form a dividing surface with the upper housing 3a.

[0023] 3(a) and 3(b), on the upper surface of each of the front and rear flanges 11b, 11b, there is provided a housing groove 21 (see the cross-hatched area in FIG. 3(a)), which has a generally concave vertical cross section and which houses a sealing material 20 (see FIGS. 5(a) and 5(b)) described later, extending in the left-right direction at a position spaced apart from the outer diameter of the main body 5 and the side body portions 6a, 6b. Furthermore, on the outer diameter side of the housing groove 21 in the flange 11b, there are formed a plurality of bolt insertion holes 22 for bolts and nuts N1 extending in the left-right direction.

[0024] The left-right central portion of accommodation groove 21 is curved to fit along the outer periphery of main body 5, with deformation guide portion 21a extending toward the inner diameter side and opening toward the inner diameter side. The left and right sides of accommodation groove 21 are linearly formed to fit along side body portions 6a, 6b, with deformation guide portions 21b, 21b extending toward the inner diameter side and opening toward the inner diameter side formed at the left and right ends.

[0025] On the front and rear sides of the inner circumferential surface of the main body 5, convex vertical seats 24b, 24b protruding inward are provided with their lower portions extending in the vertical direction, against which the gate valve 4 (described later) comes into sealing contact. In addition, a horizontal seat 24a is provided extending in the front-rear direction between the front and rear vertical seats 24b, 24b on the upper surface of the bottom 7. The deformation guide portion 21a of the accommodation groove 21 is connected to the upper part of the vertical seat 24b.

[0026] As shown in FIGS. 3(a) and 3(b), the inner peripheral surfaces of the side trunk portions 6a and 6b are provided with circumferentially extending storage grooves 31, 31 having a generally concave longitudinal cross section for accommodating sealing materials 30 (see FIG. 5(c)) and 30A (see FIG. 5(d)), which will be described later. The storage grooves 31 are each composed of an inner recess 31a, an outer recess 31b having a smaller lateral dimension than the inner recess 31a, and a protrusion 31c protruding toward the inner diameter between the inner recess 31a and the outer recess 31b. The deformation guide portions 21b of the storage groove 21 are connected to the upper portion of the storage groove 31. As described above, the inner diameter side of the deformation guide portion 21a and the inner diameter side of the deformation guide portions 21b are open in the storage groove 21, and a wall portion 21c is formed in the remaining portions.

[0027] [Upper case] As shown in Figures 2(a) and 2(b) and 4(a) and 4(b), the upper housing 3a is made up of a main body 5 and the upper halves of side body sections 6a and 6b, and is capable of covering the upper part of the fluid pipe 2. The upper part of the main body 5 is formed in a generally cylindrical shape with open top and bottom faces, and the upper parts of the side body sections 6a and 6b are formed in a generally semicircular shape in side view with open bottom faces. Flanges 11a and 11a protruding in the outer diameter direction are provided on the front and rear sides of the lower end of the upper housing 3a, extending in the left-right direction, and the upper surfaces of the flanges 11a and 11a form a dividing surface with the lower housing 3b.

[0028] 4(a) and 4(b), a plurality of bolt insertion holes 22 for bolts and nuts N1 are formed in the left-right direction on the outer diameter side of each of the front and rear flanges 11a. Note that no accommodating groove for a sealing material 20 (described later) is formed on the underside of each of the flanges 11a, but a flat surface is formed that faces the accommodating groove 21 in the up-down direction.

[0029] On the front and rear sides of the inner circumferential surface of the main body 5, the upper parts of convex vertical seat portions 24b, 24b that protrude toward the inner diameter side are extended in the vertical direction, and by connecting to the vertical seat portions 24b, 24b of the lower housing 3b, the check valve 4 described later abuts in a sealing manner.

[0030] 4(a) and 4(b), on the inner peripheral surfaces of the side body portions 6a and 6b, storage grooves 31, 31 having a generally concave vertical cross section are provided extending in the circumferential direction and adapted to accommodate sealing materials 30, 30 (see FIG. 5(c)) and sealing materials 30A, 30A (see FIG. 5(d)), which will be described later. The storage grooves 31, 31 are composed of an inner recess 31a, an outer recess 31b whose left-right dimension is smaller than that of the inner recess 31a, and a protrusion 31c that protrudes radially inward between the inner recess 31a and the outer recess 31b, and are adapted to connect to the storage grooves 31, 31 of the lower housing 3b.

[0031] A convex seat 24c that protrudes inward is provided in an annular shape in the circumferential direction on the upper inner peripheral surface of the main body 5, and is adapted to contact the gate valve 4 (described later) in a sealing manner. The upper ends of the vertical seats 24b, 24b are connected to the front and rear sides of the seat 24c. A flange 5f that protrudes outward is formed in an annular shape at the upper end of the main body 5.

[0032] The upper housing 3a and the lower housing 3b configured in this manner are integrated by fastening them with a plurality of bolts and nuts N1 attached to the bolt insertion holes 22 with the respective flange portions 11a and 11b butted against each other to form the housing 3. In the fastened state, the ends of the accommodating grooves 31 and 31 of the upper housing 3a and the lower housing 3b are connected to form an annular accommodating groove, and the ends of the vertical seats 24b and 24b of the upper housing 3a and the lower housing 3b are connected to form vertical seats 24b and 24b extending in the up-down direction.

[0033] The housing 3 may be divided, for example, in the front-rear direction, or may be divided into a predetermined number of sections, such as three or more. In this embodiment, the lower housing 3b and the upper housing 3a are hermetically joined together with a plurality of fastening members (not shown) made of bolts and nuts, but they may also be joined by welding or other methods. The lower housing 3b and the upper housing 3a that constitute the housing 3 are each integrally molded by casting, but they may also be integrated by welding each of the main body 5 and the side body sections 6a, 6b together, for example. In this embodiment, the housing 3 is made of ductile cast iron, but the material is not limited to this and may be made of other materials, such as steel.

[0034] [Sealing material] As shown in FIGS. 5(a) and 5(b), the sealing material 20 is made of an elastic material such as rubber and extends in the left-right direction. In its natural state, the central portion in the left-right direction is curved to fit along the outer periphery of the main body portion 5, with abutment portions 20a extending toward the inner diameter. The left and right sides of the sealing material 20 are linearly formed to fit along the side body portions 6a and 6b, with abutment portions 20b extending toward the inner diameter at the left and right ends. The abutment portions 20a and 20b are formed in a flat plate shape, while the remaining portions are formed in a generally cylindrical shape. The thickness of the sealing material 20 is greater than the vertical dimension of the accommodation groove 21, so that, when accommodated, the upper portion of the sealing material 20 protrudes above the dividing surface of the flange portion 11b (see FIG. 6(b)).

[0035] As shown in Fig. 5(c), the sealing material 30 is formed in a band shape with ends made of an elastic material such as rubber, and is formed into a ring shape by abutting the ends 30a, 30a together. The sealing material 30 of this embodiment is formed by cutting the sealing material molded into an endless ring shape at one point in the circumferential direction, so that the ends 30a, 30a abut against each other without any gaps. Note that the end 30a of this embodiment has a cutting line configured so that multiple cut surfaces facing in different directions are formed. Furthermore, the cut portions may be provided at multiple points in the circumferential direction.

[0036] As shown in FIG. 5(e), in its natural state, the sealing material 30 is composed of a bulbous bulb portion 30b in cross section and a heel portion 30c that is continuous with the bulb portion 30b and has a hook-like shape in the outer diameter direction. The inner peripheral surface is formed so that its diameter gradually decreases from the heel portion 30c side toward the bulb portion 30b.

[0037] Furthermore, the sealing material 30A described later has a cross-sectional shape substantially similar to that of the sealing material 30 and is formed in a circular ring shape from an elastic material such as rubber, and is configured in an endless shape without end portions 30a like the sealing material 30, as shown in FIG. 5(d).

[0038] As shown in Figures 6(a) and (b), the sealing materials 20, 20 are accommodated in front and rear accommodating grooves 21, 21 formed in the flange portions 11b, 11b of the lower housing 3b, and when the sealing materials 20, 20 are accommodated, the outer diameter side portions of the sealing materials 20, 20, i.e., the portions that do not hinder elastic deformation toward the inner diameter side, are fixed to the wall portions 21c of the accommodating grooves 21, 21 with an adhesive.

[0039] The contact portions 20a of the sealing material 20 are arranged in the central deformation guide portion 21a of the housing grooves 21, and the contact portions 20b of the sealing material 20 are arranged in the left and right deformation guide portions 21b of the housing grooves 21. The central contact portion 20a is arranged so that its inner diameter side end is substantially flush with the inner surface of the longitudinal seat portions 24b of the main body 5, while the left and right contact portions 20b are arranged so that their inner diameter side ends are close to the housing grooves 31 formed on the inner surfaces of the side body portions 6a (see the enlarged view in FIG. 6(a)).

[0040] As shown in Figures 6(a) and (b), the lower half of the sealing material 30 is accommodated in left and right accommodation grooves 31, 31 formed on the inner surfaces of the side trunk portions 6a, 6b of the lower housing 3b. As will be described in Figure 8, the sealing materials 30, 30 are accommodated in the accommodation grooves 31, 31 while being annularly fitted around the outer circumferential surface of the fluid pipe 2. However, Figures 6(a) and (b) show the sealing material 30 accommodated in the accommodation grooves 31 in its natural state, with the fluid pipe 2 not shown. When the sealing material 30 is accommodated, the valve portion 30b of the sealing material 30 is fitted into the inner recess 31a of the accommodation grooves 31, 31, and the heel portion 30c of the sealing material 30 is fitted into the outer recess 31b.

[0041] [Gate valve] As shown in Figure 2(a), the check valve 4 as a fluid control device of the present invention is mainly composed of an inner valve box 143 arranged inside the main body 5 of the housing 3, a valve cover 144 connected integrally to the upper part of the inner valve box 143, a valve element 145 provided inside the inner valve box 143 and the valve cover 144, a valve stem 146 for sliding the valve element 145 between the inner valve box 143 and the valve cover 144, and an operating part 147 connected to the valve stem 146 for opening and closing the valve element 145 from the outside.

[0042] The inner valve box 143 has a plate-shaped partition wall portion 141 arranged so as to separate the flow path inside the main body portion 5, a disk-shaped inner lid portion 142 arranged approximately horizontally above the partition wall portion 141 and closing the top opening of the main body portion 5, and an opening 148 formed by penetrating the partition wall portion 141. A gasket 150 is provided in a groove (not shown) extending from the bottom end face to the side end face of the partition wall portion 141, and a gasket 151 is fitted in a groove (not shown) extending circumferentially on the peripheral end face of the inner lid portion 142. These gaskets 150, 151 are integrally formed so as to be continuous, and extend along the end face of the gate valve 4.

[0043] The upper end of the valve stem 146 is suspended from the top of the valve cover 144 so as to be rotatable about its axis, and a female thread 152 formed on the top of the valve body 145 is screwed into a male thread formed on the outer circumferential surface. Because the rotation of the valve body 145 around the valve stem 146 is restricted, by rotating the valve stem 146 forward or backward via the operating unit 147, the valve body 145 moves vertically between an open position (not shown) where it is housed inside the upper valve cover 144 and opens the opening 148, and a closed position (position shown by the solid line in Figure 2(a)) where it is located inside the lower inner valve body 143 and closes the opening 148.

[0044] [Replacement process for existing fluid pipes] Next, the process of replacing the existing fluid pipe 2 with a new fluid pipe will be described with reference to Figures 7 to 16. Since the flow control devices 1, 1 installed on both sides of the specific area W in the pipe axis direction shown in Figure 1 have substantially the same configuration, only the flow control device 1 on the primary side of the specific area W will be described here, and a description of the replacement process using the flow control device 1 on the secondary side will be omitted.

[0045] First, when installing the flow control device 1 in the fluid pipe 2, as shown in FIGS. 7(a) and 7(b), sealing materials 30, 30 are annularly attached to two locations on the fluid pipe 2. The distance between the sealing materials 30, 30 in the pipe axis direction is adjusted to match the distance between the left and right housing grooves 31, 31 of the lower housing 3b. As shown in FIG. 7(b), the sealing materials 30, 30 are wrapped around the fluid pipe 2 with the ends 30a, 30a spread out to form a roughly upward C-shape, and then the ends 30a, 30a are bonded together with an adhesive or the like to form a ring shape. As described above, the end 30a of the sealing material 30 has multiple cut surfaces facing different directions, which makes it difficult for the ends 30a, 30a to separate, allowing the bonded state to be maintained.

[0046] 8(a) and 8(b), first, the lower housing 3b is placed below the fluid pipe 2, and the accommodating grooves 31, 31 and the sealing materials 30, 30 are aligned. After that, the lower housing 3b is raised and fitted onto the fluid pipe 2 so that the lower halves of the sealing materials 30, 30 fit into the accommodating grooves 31, 31. The sealing material 20 is then accommodated in the accommodating groove 21 of the lower housing 3b. For operational reasons, it is desirable to accommodate the sealing material 20 in the accommodating groove 21 of the lower housing 3b in advance.

[0047] 8(c), the sealing material 20 accommodated in the accommodation groove 21 of the lower housing 3b is disposed close to the outer diameter side of the accommodation groove 21, with a space provided on the inner diameter side to allow elastic deformation. In particular, the left and right side portions of the abutting portion 20b accommodated in the deformation guide portion 21b are close to or in contact with the left and right wall portions 21c of the deformation guide portion 21b, and the end portion on the inner diameter side is located on the outer diameter side of the sealing material 30 accommodated in the accommodation groove 31.

[0048] 8(b), the upper housing 3a is placed above the fluid pipe 2, and the accommodating grooves 31, 31 and the sealing materials 30, 30 are aligned. Then, the upper housing 3a is lowered and fitted onto the fluid pipe 2 so that the upper halves of the sealing materials 30, 30 fit into the accommodating grooves 31, 31. Then, bolts and nuts N1 are inserted into the multiple bolt insertion holes 22 in the flange portion 11a of the upper housing 3a and the flange portion 11b of the lower housing 3b and fastened, thereby integrating the upper housing 3a and the lower housing 3b to form the housing 3.

[0049] 8(d), the contact portions 20a, 20b of the sealing materials 20, 20 arranged on the lower housing 3b are crushed by the dividing surface of the flange portion 11a of the upper housing 3a and elastically deform so as to bulge toward the inner diameter side. The contact portions 20b are guided by the left and right wall portions 21c of the deformation guide portion 21b so as to bulge toward the inner diameter side, so that the inner diameter side end portion of the contact portion 20b extends further toward the inner diameter side than the inner surface of the accommodation groove 31, and the inner diameter side end portion of the contact portion 20b protrudes into the accommodation groove 31. As a result, the sealing materials 20, 20 come into contact with the sealing materials 30, 30 accommodated in the accommodation groove 31, and predetermined portions of the fluid pipe 2 are hermetically covered by the housing 3.

[0050] Furthermore, as described above, the ends 30a, 30a of the sealant 30 are positioned at the top, so the ends 30a, 30a do not come into contact with the front and rear sealants 20, 20, ensuring high sealing performance between the sealants 20, 20 and the sealants 30, 30. Next, the divided members 8a, 8b of the separation prevention fitting 8 are attached to the top and bottom of the side body portions 6a, 6b of the housing 3, respectively (see FIG. 9).

[0051] Next, as shown in Figure 9(a), the gate valve device 50 is hermetically connected to the upper opening of the main body 5. The gate valve device 50 has a cylindrical valve box 50a that penetrates vertically, a valve cover 50b that protrudes to the right from the valve box 50a and is connected to the valve box 50a via a communication port (not shown) formed on the inner peripheral surface, a valve disc 50c that is arranged to be movable in a substantially horizontal direction between the valve box 50a and the valve cover 50b, and a seat (not shown) that serves as a valve seat for receiving the valve disc 50c. A sealing material (not shown) for the valve disc 50c can be tightly fitted to the seat (not shown).

[0052] The valve box 50a is hermetically connected via a sealant (not shown) to the open end (opening) on ​​the upper side of the main body 5. Furthermore, the end of a valve stem (not shown) that is threadedly engaged with the valve element 50c inside the valve lid 50b protrudes from the tip of the valve lid 50b, and an operating handle (not shown) is provided at the end of this valve stem, so that the interior of the housing 3 can be opened and closed by rotating the operating handle to move the valve element 50c between the valve box 50a and the valve lid 50b.

[0053] Next, a cutting device 70 is hermetically connected to the upper open end of the valve box 50a. The cutting device 70 is mainly composed of a mounting flange tube 71, a cutter 72 for cutting the fluid pipe 2, a drive motor 74 for rotating the cutter 72 within the mounting flange tube 71, and an advance / retract mechanism 73 for moving the cutter 72 up and down. The cutter 72 is formed in a cylindrical shape with an outer diameter larger than the outer diameter of the fluid pipe 2, and is composed of a hole saw 72a with a cutting blade along the circumferential direction at its lower end, and a center drill 72b arranged coaxially with a rotation axis 72c of the hole saw 72a and protruding beyond the cutting blade.

[0054] The cutter 72 is arranged so that the central axis of the center drill 72b is concentric with the central axis of the main body 5 of the housing 3, and is inserted into the main body 5 from the upper open end and can advance to a position where it penetrates at least the pipe wall of the fluid pipe 2.

[0055] Next, the drive motor 74 of the cutting device 70 rotates the cutter 72 around the rotation axis 72c, and the advance / retract mechanism 73 moves the cutter 72 downward to cut the fluid pipe 2 without interrupting the flow. At this time, the locking claws that make up the separation prevention fitting 8 lock onto the outer surface of the fluid pipe 2, allowing the fluid pipe 2 to be cut in a stable state.

[0056] When the fluid pipe 2 is cut by the cutter 72, a cut piece (not shown) separated from between the ends 2H, 2T (see FIG. 10) of the fluid pipe 2 is held in the hole saw 72a. Thereafter, the advance / retract mechanism 73 retracts the cutter 72 together with the cut piece (not shown) into the inside of the mounting flange tube 71, and the valve body 50c of the gate valve device 50 is moved toward the valve box 50a, closing the inside of the housing 3.

[0057] Some of the foreign matter such as chips generated by cutting is discharged by water pressure together with the fluid in the pipe from the drain port 13 provided at the bottom of the housing 3, but the remainder gradually sinks due to gravity over time, falling and remaining at the bottom 7 of the housing 3. After the mounting flange cylinder 71 is removed from the valve box 50a and the cutting device 70 is removed, the foreign matter that has accumulated at the bottom 7 of the housing 3 is discharged to the outside by a discharge device (not shown) attached to the valve box 50a.

[0058] Next, a gate valve installation process is performed to install a gate valve 4 as a fluid control valve in the housing 3. As shown in FIG. 9(b), first, with the gate valve device 50 closed, a cylindrical member 90a is hermetically connected to the upper side of the valve box 50a. Next, a hole (not shown) formed in the upper part of the housing 3 is connected to a hole (not shown) formed in the lower part of the cylindrical member 90a with a connecting pipe (not shown), thereby communicating the inside of the housing 3 with the inside of the cylindrical member 90a. The cylindrical member 90a is filled with fluid while air is vented through an air vent valve (not shown) provided at the top of the cylindrical member 90a. After confirming that the air has been vented from the cylindrical member 90a, the air vent valve (not shown) is closed. Next, with the inside of the housing 3 and the inside of the cylindrical member 90a at approximately the same pressure, the valve element 50c is opened, and the drive mechanism 90b of the insertion device 90 is operated to lower the gate valve 4.

[0059] 10, when the lower end of the packing 150 of the partition wall portion 141 of the gate valve 4 enters the housing 3, the front and rear sides are pressed against the vertical seats 24b, 24b (see FIG. 3) and the packing 151 of the inner lid portion 142 is pressed against the inner peripheral surface of the seat portion 24c at approximately the same time. In this way, when the gate valve 4 is installed in a predetermined position, the upper opening of the housing 3 is hermetically closed by the inner lid portion 142 and the partition wall portion 141 separates the ends 2H, 2T of the fluid pipe 2 inside the housing 3, making it possible to stop water leakage.

[0060] After the check valve 4 is installed in the predetermined installation position, multiple fixing pins (not shown) arranged circumferentially around the main body 5 are advanced toward the inner diameter side of the main body 5, and the inner lid portion 142 is engaged with the fixing pins (not shown), thereby restricting the upward movement of the inner lid portion 142 and holding it in the predetermined installation position, thereby preventing the check valve 4 from departing from the housing 3.

[0061] Thereafter, the air vent valve (not shown) provided on the cylindrical member 90a is opened, and it is confirmed that the packings 150, 151 of the gate valve 4 are watertight, and the insertion device 90 and gate valve device 50 are removed from the housing 3. Then, as shown in FIG. 10, the main body lid 149 above the inner lid portion 142 is placed on top of the housing 3, and the flange 5f of the main body portion 5 and the main body lid 149 are fastened together with bolts and nuts N3 as fastening members to form a sealed connection, thereby completing the installation of the gate valve 4. In this way, by installing the gate valve 4 to separate the interior of the housing 3, the fluid is separated into the primary side and secondary side of the gate valve 4, and the flow path is blocked. Note that the dotted area to the left of the gate valve 4 in FIG. 10 indicates the fluid.

[0062] Next, as shown in Figure 11, after the fluid on the secondary side of the check valve 4 is drained to the outside, the upper and lower divided members 8a and 8b of the anti-detachment fitting 8 are separated and removed from the side body 6b on the secondary side of the check valve 4, i.e., the blocking side that is blocked from the fluid in the pipe by the check valve 4, and the piping of the existing fluid pipe 2 to be removed is cut to a length that makes it easy to dismantle and removed one by one.The fluid pipe 2 to be replaced that is inserted into the connection opening 6c of the side body 6b is lifted by a crane or the like and pulled out to the side while maintaining its horizontal and height position, and the sealing material 30 is removed from the accommodating groove portion 31 near the connection opening 6c.

[0063] 12(a), when removing the existing fluid pipe 2 connected to the connection opening 6c, the left ends of long bolts 60, 60 extending in the pipe axis direction are fixed to the front and rear sides of the right ends of the flanges 11a, 11b of the housing 3. Next, nuts 61a, 61b are screwed onto the long bolts 60, 60, and then a press ring 65 having a split structure that splits into two along the pipe axis of the fluid pipe 2 is inserted into insertion holes 62, 62 formed in the press ring 65, and the press ring 65 is positioned a short distance away from the side body 6b of the housing 3.

[0064] Next, the locking claws 64 of the pressure ring 65 are pushed inward by the push bolts 63 to firmly lock them into the pipe wall of the fluid pipe 2 (see Figure 12 (b)), and the front and rear nuts 61a, 61b are rotated using a tool 66 to push the pressure ring 65 away from the housing 3, allowing the fluid pipe 2 to be pulled out from the connection opening 6c.

[0065] Next, as shown in Figure 13, a new endless annular sealing material 30A (see Figure 5(d)), which is different from the sealing material 30 that has already been removed, is inserted through the connection opening 6c of the side body portion 6b from which the existing fluid pipe 2 has been pulled out, and fitted into the housing groove 31. Next, a new fluid pipe 2A, which is different from the pulled-out existing fluid pipe 2, is inserted into the connection opening 6c while being suspended by a crane or the like and maintained at a horizontal and vertical position, and the new fluid pipe 2A is hermetically connected to the housing 3 by the tight contact of the sealing material 20 and the sealing material 30. Note that the new fluid pipe 2A in this embodiment has a large-diameter socket at the end opposite to the end that is inserted into the housing 3.

[0066] More specifically, when inserting and connecting a new fluid pipe 2A into the connection opening 6c, as shown in Figure 14(a), first, the new fluid pipe 2A is inserted into the connection opening 6c until its tip reaches the sealing material 30A, and the press ring 65 is positioned away from the side body portion 6b of the housing 3. As shown in Figure 14(b), the press ring 65 is fitted onto the existing fluid pipe 2 so that the locking claws 64 face in the opposite direction to when the existing fluid pipe 2 is pulled out, and the locking claws 64 are pressed inward by the press bolts 63 of the press ring 65 to firmly lock onto the pipe wall of the fluid pipe 2.

[0067] Next, as shown in Figure 14(a), a lever hoist 68 is hung between the front and rear sides of the right end portions of the flange portions 11a, 11b of the housing 3 and the front and rear sides of the push ring 65, and the operating handle 69 is operated to wind up the chain and pull the push ring 65 toward the housing 3, thereby allowing the fluid pipe 2 to be inserted into the sealing material 30A through the connection opening 6c.

[0068] As shown in Figure 15, after inserting the new fluid pipe 2A into the connection opening 6c on the shut-off side of the housing 3, the upper and lower divided members 8a, 8b are fastened with fastening members, namely bolts and nuts N2, while the anti-detachment fittings 8, 8 are engaged with the end of the side body portion 6b, whereby the fluid pipe 2A is fixed to the housing 3 so that it cannot be detached by the anti-detachment fittings 8, 8.

[0069] Furthermore, when the new fluid pipe 2A is connected to the connection opening 6c on the shutoff side of the housing 3, the new fluid pipe 2A is connected to the housing 3 in a sealed state due to the tight contact between the seal material 20 and the seal material 30A.

[0070] 16(a), when the upper housing 3a is placed above the lower housing 3b and fastened with bolts and nuts N1, the sealing material 20 is pressed by the dividing surface of the flange portion 11a of the upper housing 3a, and elastically deforms to bulge toward the space on the inner diameter side. The contact portion 20b is guided by the left and right side walls of the deformation guide portion 21b to bulge toward the inner diameter side, so that the end on the inner diameter side extends further toward the inner diameter side than the inner surface of the accommodating groove 31, and the end on the inner diameter side of the contact portion 20b protrudes into the accommodating groove 31.

[0071] 13, when the endless annular sealing material 30A is inserted through the connection opening 6c and fitted into the accommodating groove 31, the inner diameter side end of the abutting portion 20b protrudes into the accommodating groove 31. Therefore, when the sealing material 30A is fitted into the accommodating groove 31, the sealing material 30 and the abutting portion 20b are in reliable contact with each other. Also, as shown in FIGS. 16(b) and 16(c), when the new fluid pipe 2A is inserted into the sealing material 30A, the sealing material 30A is pressed toward the outer diameter side, and the abutting portion 20b is pressed against the sealing material 30A so as to push back against the outer diameter side, thereby improving the sealing performance between the sealing material 20A and the sealing material 30A.

[0072] Although not specifically shown, the abutment portion 20a housed in the deformation guide portion 21a, like the abutment portion 20b, is pressed by the dividing surface of the flange portion 11a of the upper housing 3a, and is guided by the left and right side walls of the deformation guide portion 21b to bulge toward the inner diameter, and the end portion on the inner diameter side elastically deforms so as to protrude toward the inner diameter from the inner surface of the vertical seat portion 24b, and is pressed against the gasket 150 of the check valve 4, thereby improving the sealing performance between the sealing material 20 and the gasket 150.

[0073] In this way, by performing the process of connecting a new fluid pipe 2A to the connection opening 6c on the blocking side in the housing 3 in the same way for the secondary side flow control device 1 in the specific area W, all flow paths in the specific area W can be replaced with new fluid pipes.

[0074] [Actions and Effects] As described above, in the fluid pipe replacement method according to the embodiment of the present invention, the housing 3 is attached to the existing fluid pipe 2 and is made up of an upper housing 3a and a lower housing 3b as a plurality of divided housings that can be divided along the pipe axis, the sealing material 20 as a first seal portion that seals between the divided surfaces of the upper housing 3a and the lower housing 3b, the sealing materials 30, 30A as second seal portions that are provided on the inner peripheral surface of the connection opening 6c of the housing 3 in the circumferential direction, and the sealing materials 30, 30A are provided at the cut portion of the existing fluid pipe 2 within the housing 3 (between the ends 2H, 2T). The method replaces an existing fluid pipe 2 with a new fluid pipe 2A using a flow control device 1 equipped with a gate valve 4 as a fluid control device, and includes the steps of: placing a ring-shaped sealing material 30A formed separately from the sealing material 20 on the inner surface of the connection opening 6c on the cut-off side in the housing 3, which is cut off from the fluid in the pipe by the gate valve 4; and inserting the new fluid pipe 2A into the connection opening 6c on the cut-off side in the housing 3, and tightly connecting the new fluid pipe 2A to the housing 3 by the sealing material 20 and the sealing material 30A fitting closely together (see Figures 13 to 16).

[0075] According to this, because the sealing material 30A is annular, even if a new fluid pipe 2A is inserted from the outside into the connection opening 6c on the blocking side that is blocked from the fluid inside the pipe by the check valve 4, the sealing material 30A can be easily brought into tight contact with the sealing material 20, and there is no risk of leakage.Therefore, the disconnected existing fluid pipe 2 can be replaced with the new fluid pipe 2A without leaving it in the housing 3.

[0076] In more detail, because the sealing material 30A is annular, when a new fluid pipe 2A is inserted into the connection opening 6c, unlike conventional sealing materials that are divided into upper and lower parts, the divided ends of the sealing material do not shift in the axial direction of the pipe due to sliding contact with the inserted new fluid pipe 2A, causing leakage.Instead, the sealing material 30A is pressed in the outer diameter direction and is pressed against the abutment portion 20b of the sealing material 20, improving sealing performance.

[0077] Furthermore, since the linear sealing material 20 and the annular sealing material 30 can be constructed separately, the shape of the sealing material does not become complicated, making manufacturing difficult, and only the sealing material 30 used when cutting the fluid pipe 2 can be partially replaced with new sealing material 30A without replacing the sealing material 20 clamped between the upper housing 3a and the lower housing 3b, thereby reducing costs and improving the durability of the sealing material.

[0078] Furthermore, after the check valve 4 is installed in the housing 3, a process is provided for removing the existing fluid pipe 2 remaining in the connection opening 6c on the shut-off side and the sealing material 30 sealing the existing fluid pipe 2 to the housing 3 (see Figures 11 and 12), which makes it possible to connect a newly installed fluid pipe to the housing by pulling out and removing the existing fluid pipe remaining in the housing and the sealing portion sealing the fluid pipe to the housing.

[0079] Furthermore, when inserting a new fluid pipe 2A, an endless annular sealing material 30A is fitted onto the new fluid pipe 2A. In this way, the use of an endless annular sealing material 30A without a cutting portion improves sealing performance.

[0080] Furthermore, the sealing material 20 has a contact portion 20b that is pressed against the dividing surface between the upper housing 3a and the lower housing 3b and bulges toward the inner diameter, thereby coming into close contact with the sealing material 30A. As a result, the contact portion 20b of the sealing material 20 bulges toward the inner diameter and comes into close contact with the sealing material 30A, thereby enabling the sealing material 20 and the sealing material 30A to exhibit high sealing performance.

[0081] Furthermore, of the upper housing 3a and the lower housing 3b, the lower housing 3b is provided with a deformation guide portion 21b that guides the abutment portion 20b of the sealing material 20 to bulge toward the inner diameter side, thereby effectively elastically deforming the abutment portion 20b of the sealing material 20 toward the sealing material 30A, thereby ensuring that the sealing materials 20, 30A are tightly contacted with each other.

[0082] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0083] For example, in the above embodiment, in the process of inserting a new fluid pipe 2A into the connection opening 6c on the shutoff side of the housing 3 and tightly fitting the seal material 20 and the seal material 30A to hermetically connect the new fluid pipe 2A to the housing 3, an embodiment has been described in which the new fluid pipe 2A is inserted with the seal material 30A fitted into the receiving groove 31 formed in the side body portion 6b of the housing 3, but the present invention is not limited to this. As shown in the modified examples shown in Figures 17 to 19, a seal material 130A may be annularly fitted around the outer periphery of the new fluid pipe 2A, and the new fluid pipe 2A may be inserted so that the seal material 20 and the seal material 130A tightly fit to the housing 103. Note that in the following modified examples, the same components and parts as those in the above embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0084] 17, in flow control device 101 as a modified example of the present invention, sealing material 130A is formed in an annular shape from an elastic material such as rubber, and in its natural state is composed of valve portion 30d that bulges out like a bulb in cross section and corner portion 30e that extends radially outward from valve portion 30d, with the outer circumferential surface gradually tapering in diameter from corner portion 30e toward valve portion 30d. Also, housing groove 131 of housing 103 of this modified example has a tapered surface whose diameter gradually increases toward the side ends of side trunk portions 6a, 6b.

[0085] Furthermore, in the above embodiment, the housing 3 was fixed to the newly installed fluid pipe 2A by the anti-detachment fittings 8, 8 engaged with the side body portions 6a, 6b, but in this modified example, as shown in Figure 18, the housing 103 is fixed to the newly installed fluid pipe 2A by pressure rings 165, 165 fastened to the side body portions 6a, 6b with bolts and nuts N5.

[0086] More specifically, the newly installed fluid pipe 2A is inserted into the connection opening 6c, and the pressure ring 165 is fastened to the side body portions 6a and 6b with the bolt and nut N5, and the corner portion 30e of the sealing material 130A is pressed into the connection opening 6c by the pressure ring 165, whereby the sealing material 130A is pressed against the accommodating groove portion 131 to form a seal.

[0087] In addition, as shown in Figure 19(a), in the sealing material 120 as a modified example of the first seal portion, the abutment portion 120b accommodated in the deformation guide portion 121b of the accommodating groove portion 121 elastically deforms until the inner diameter side end is positioned more inner diameter side than the inner surface of the accommodating groove portion 131 when the upper housing 3a is placed on top of the lower housing 3b and fastened with bolts and nuts N1 as shown in Figure 19(b), and the inner diameter side end of the abutment portion 120b protrudes into the accommodating groove portion 131.

[0088] 19(c), by inserting the new fluid pipe 2A together with the sealing material 130A and placing the sealing material 130A in the receiving groove 131, and fastening the pressing ring 165 to the side trunk portions 6a, 6b with bolts and nuts N5, the sealing material 130A is pressed toward the housing 103 by the pressing ring 165, causing the sealing material 130A to bulge outward and press against the abutment portion 120b so as to push it back outward, thereby improving the sealing performance between the sealing material 120 and the sealing material 130A. The modifications shown in FIGS. 17 to 19 also achieve the same functions and effects as the above-described embodiment.

[0089] Furthermore, in the above embodiment, a form in which a fluid pipe 2A having a receiving port is applied as a newly installed fluid pipe is exemplified, but the present invention is not limited to this, and as shown in Figure 20, a fluid pipe 102A or the like having a main pipe portion with an outer diameter smaller than the end portion inserted into the side body portions 6a, 6b may also be connected.

[0090] Furthermore, in the above embodiment, an example has been given of a configuration in which the newly installed fluid pipe 2A is fixed by a locking claw provided inside the detachment prevention fitting 8, but the present invention is not limited to this, and as shown in Fig. 20, a flange 170 that protrudes toward the outer diameter side may be formed on the newly installed fluid pipe 102A, and the flange 170 may be fastened to the housing 3 by the detachment prevention fitting 108. Note that such a flange 170 may also be formed on the newly installed fluid pipe 2A according to the above embodiment.

[0091] Furthermore, in the above embodiment, a housing 3 is attached to an existing fluid pipe 2, the fluid pipe 2 is cut within the housing 3, a check valve 4 is inserted to install a flow control device 1, and the existing fluid pipe 2 remaining in the connection opening 6c on the blocking side of the housing 3 of the installed flow control device 1 is pulled out and a new fluid pipe 2A is inserted. However, the present invention is not limited to this, and as long as it includes at least the steps of placing the second seal portion on the inner surface of the connection opening on the blocking side, and inserting a new fluid pipe into the connection opening and sealingly connecting the new fluid pipe to the housing by tightly fitting the first seal portion and the second seal portion together, it is not necessary to include the step of pulling out the existing fluid pipe from the connection opening.

[0092] Furthermore, in the above embodiment, in the step of inserting a new fluid pipe into the connection opening, the sealing material 30 used to seal the existing fluid pipe 2 is removed, and the new fluid pipe 2A is sealed with a sealing material 30A different from the sealing material 30, but the present invention is not limited to this, and the new fluid pipe 2A may be sealed with the sealing material 30 without removing the sealing material 30 used to seal the existing fluid pipe 2. Furthermore, sealing materials 30A, 130A, etc. may be used to seal the existing fluid pipe 2.

[0093] In the above embodiment, the sealing material 20 is accommodated in the accommodation groove 21 formed in the flange 11b of the lower housing 3b, but the present invention is not limited to this, and the sealing material 20 may be accommodated in an accommodation groove formed in the flange 11a of the upper housing 3a without forming an accommodation groove 21 in the lower housing 3b, or in accommodation grooves formed in both the upper housing 3a and the lower housing 3b. Also, it does not necessarily have to be accommodated in an accommodation groove.

[0094] In addition, in the above embodiment, a form in which a check valve 4 capable of opening and closing a flow path is applied is exemplified as an example of a fluid control device capable of controlling the flow of a fluid, but the present invention is not limited to this, and the fluid control device may be a valve body such as a switching valve or butterfly valve that can open and close a flow path, or a plug (stop valve) that can close a flow path may be applied.

[0095] In addition, in the above embodiment, an example was given of a form in which check valves 4 are installed on both sides of the specific area W to cut off water supply to the specific area W, but the present invention is not limited to this, and the flow control devices 1, 1 on both sides of the specific area W may be connected by a bypass pipe to form a detour flow path, so that the replacement work with a new fluid pipe 2A can be carried out without interrupting the flow.

[0096] In addition, in the above embodiment, an example was given in which the process of cutting the fluid pipe 2 and the process of installing the gate valve 4 as a fluid control valve inside the housing 3 are performed in an uninterrupted flow state, but the cutting process and the installation process may also be performed in an uninterrupted water state. [Explanation of symbols]

[0097] 1 Flow control device 2 Fluid pipes (existing fluid pipes) 2A Fluid Pipe (Newly Installed Fluid Pipe) 2H,2T end 3. Housing 3a Upper housing (split housing) 3b Lower housing (split housing) 4. Gate valve (fluid control) 5 Main fuselage 6a,6b Side body 6c Connection opening 8,108 Anti-detachment fittings 11a, 11b flange portion 20 Sealing material (first sealing part) 20a,20b Contact part 21 Receiving groove 21a, 21b Deformation guide portion (guide portion) 21c wall 30 Sealing material 30A Sealing material (second sealing part) 30a end face 31 Receiving groove 50 Gate valve device 60 long bolt 61a, 61b Nut 65,165 Push ring 68 Lever Hoist 70 Cutting device 90 Insertion Device 101 Flow control device 102A Fluid Pipe (Newly Installed Fluid Pipe) 103 Case 120 Sealing material (first sealing part) 120b Contact part 121b Deformation guide part (guide part) 130A Sealing material (second sealing part) 131 Storage groove 170 Tsuba

Claims

1. A fluid pipe replacement method for replacing an existing fluid pipe with a new fluid pipe using a flow control device including: a housing that is attached to an existing fluid pipe and is made up of a plurality of divided housings that can be divided along a pipe axis; a first seal portion that seals between divided surfaces of the divided housings; a second seal portion that extends circumferentially on an inner peripheral surface of a connection opening of the housing; and a flow control device that is installed at a cut point of the existing fluid pipe within the housing, a step of disposing the second seal portion, which is formed in an annular shape separately from the first seal portion, on an inner circumferential surface of a connection opening on a cut-off side that is cut off from the fluid in the pipe by the fluid control in the housing, or on an outer circumferential surface of a newly installed fluid pipe; a step of inserting a new fluid pipe into the connection opening on the blocking side of the housing, and sealingly connecting the new fluid pipe to the housing by tightly fitting the first seal portion and the second seal portion.

2. 2. The fluid pipe replacement method according to claim 1, further comprising the step of removing the existing fluid pipe remaining in the connection opening on the blocking side and the seal portion sealing the existing fluid pipe and the housing after the fluid control device is installed in the housing.

3. 3. The fluid pipe replacement method according to claim 1, wherein when inserting the new fluid pipe, the second seal portion formed in an endless annular shape is fitted onto the new fluid pipe.

4. The fluid pipe replacement method according to claim 1, characterized in that the first seal portion has an abutment portion that is pressed against the dividing surfaces of each of the divided housings and bulges toward the inner diameter, thereby making close contact with the second seal portion.

5. 5. The fluid pipe replacement method according to claim 4, wherein at least one of the divided housings includes a guide portion that guides the contact portion of the first seal portion so as to bulge radially inward.

Images