Fluid shutoff device and fluid shutoff method

Abstract

To provide a fluid shutoff device which can shut off fluid by smoothly inserting a shutoff bag into a fluid supply pipe, and can suppress a malfunction which damages the shutoff bag when withdrawing the shutoff bag from the fluid supply pipe.SOLUTION: There is provided a fluid shutoff device A which has a seal mechanism S inserted into a fluid supply pipe from a branch pipe, and shuts off a flow of a fluid of the fluid supply pipe by an expansion of a shutoff bag 24 of the seal mechanism S in a state in which the seal mechanism S is inserted into the fluid supply pipe. The seal mechanism S is constituted of a flexible and deformable flexible shaft 21, a tip side member 22 at a tip side part of the flexible shaft 21, a base end side member 23 at a base end part of the flexible shaft 21, and the shutoff bag 24 in a position surrounding the flexible shaft 21 between the tip side member 22 and the base end side member 23.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluid blocking device and a fluid blocking method. [Background technology]

[0002] Patent documents 1 and 2 show technologies in which a blocking bag is inserted into the inside of a fluid supply pipe via a branch pipe or the like that branches off from the fluid supply pipe, and the blocking bag is inflated to block the fluid flowing through the fluid supply pipe.

[0003] Patent document 1 describes a fluid blocking device (called the blocking device in the document) that blocks a fluid flowing in a fluid supply pipe (called a piping in the document) such as a water pipe or a gas pipe, in which a blocking bag (called an expansion bag in the document) is inserted into the internal flow path of the fluid supply pipe and the blocking of the fluid is achieved by expanding the blocking bag in this inserted state.

[0004] The device of Patent Document 1 is provided with a gate valve in a flow path that branches off from a fluid supply pipe via a connection flange, and a cylindrical housing of the shutoff device is supported in a position along the branching direction of the flow path relative to the gate valve. This device also includes a guide tube inside the housing, the tip of which reaches the fluid supply pipe when the gate valve is open, and further includes a cylindrical body inside the guide tube that has a blocking bag at its tip and is movable along the guide tube.

[0005] In such a configuration, when blocking the fluid, the check valve is opened, the cylindrical body is operated to insert the blocking bag along the guide tube into the inside of the fluid supply pipe, and the blocking bag is expanded by supplying fluid.

[0006] Like Patent Document 1, Patent Document 2 achieves fluid blocking by inserting a blocking bag into a fluid supply pipe (referred to as a fluid pipe / water pipe in the document) and inflating the blocking bag in this inserted state. However, it differs from Patent Document 1 in that the blocking bag has an inner cylindrical shaft inside, and the blocking bag is attached to the tip of an outer cylindrical shaft arranged coaxially with the inner cylindrical shaft via a bendable bellows-shaped part.

[0007] In Patent Document 2, a cylindrical sealed case body of a fluid cutoff device (called a fluid blocking device in the document) is supported in a position along the branching direction of the flow path relative to the gate valve, and when the fluid is to be blocked, the gate valve is opened and a cylindrical shaft with a blocking bag at its tip is placed inside the sealed case body. After this, the blocking bag is inserted into the fluid supply pipe together with the cylindrical shaft, causing the bellows-shaped portion to bend, so that the position of the blocking bag is aligned with the position of the fluid supply pipe, and in this state, the blocking bag is expanded by supplying fluid to block the fluid supply pipe. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 11-315991 [Patent Document 2] JP 2013-130244 A Summary of the Invention [Problem to be solved by the invention]

[0009] In the configuration of Patent Document 1, a guide tube is used when inserting the occlusion bag into the fluid supply pipe, but even in a situation where this guide tube is used, it is easy to imagine that the occlusion bag will become deformed, and it may be necessary for the occlusion bag to have a certain shape retention property to prevent such deformation.

[0010] Furthermore, with the configuration of Patent Document 1, when the occlusion bag is inserted into the fluid supply pipe, it is conceivable that the tip portion of the occlusion bag in the insertion direction would come into direct contact with the inner surface of the fluid supply pipe, resulting in wear and abrasion.

[0011] In the configuration of Patent Document 2, a cylindrical shaft guide is arranged inside the occlusion bag, which prevents the occlusion bag from being significantly deformed when it is inserted into the fluid supply pipe. However, only the bellows-shaped portion of the outer cylindrical shaft supporting the occlusion bag can be bent. As a result, it was conceivable that the occlusion bag could be damaged by coming into contact with the edge of the branch port when the occlusion bag is pulled out after the occlusion operation.

[0012] Thus, while the device of Patent Document 2 makes it possible to insert the occlusion bag into the fluid supply pipe in the correct posture, it is conceivable that the smooth withdrawal of the occlusion bag may be hindered, leaving room for improvement.

[0013] For these reasons, there is a demand for a fluid blocking device that can smoothly insert an occlusion bag into the inside of a fluid supply pipe to block the fluid, and that can subsequently suppress the inconvenience of damaging the occlusion bag when pulling it out of the fluid supply pipe.

[0014] Furthermore, there is a need for a fluid blocking method that enables blocking of the fluid in a fluid supply pipe using a fluid blocking device configured in this manner. [Means for solving the problem]

[0015] A characteristic configuration of the fluid cutoff device according to the present invention is a fluid cutoff device that has a seal mechanism that is inserted from a branch pipe into the inside of a fluid supply pipe, and cuts off the flow of fluid in the fluid supply pipe by inflating a blocking bag made of an elastic material provided in the seal mechanism while the seal mechanism is inserted into the fluid supply pipe, and the seal mechanism comprises a flexible shaft that can be bent and deformed, a tip side member that is attached to the tip end of the flexible shaft, and a base end member that is attached to the base end of the flexible shaft. Cylindrical a proximal member, the occlusion bag being positioned between the distal member and the proximal member to surround the flexible shaft; , and , The flexible shaft is connected to a base end side of the flexible shaft, and a supply / discharge flow path is formed in a gap between an outer periphery of the operating shaft and an inner periphery of the base end side member to supply / discharge pressurized fluid to / from the occlusion bag. The point is that

[0016] According to this characteristic configuration, when the seal mechanism is inserted from the branch pipe into the fluid supply pipe, both the flexible shaft of the seal mechanism and the occlusion bag can be deformed so as to bend, allowing for smooth insertion. Furthermore, when the seal mechanism is inserted, the tip side member of the seal mechanism comes into contact with the inner surface of the fluid supply pipe, which prevents the occlusion bag from coming into contact with the inner surface of the fluid supply pipe, and does not cause wear or abrasion to the occlusion bag. In this inserted state, pressurized fluid is supplied to the internal space of the occlusion bag to expand the occlusion bag and expand its diameter, thereby occluding the fluid supply pipe. In addition, when the sealing mechanism is pulled out from the fluid supply pipe, both the flexible shaft of the sealing mechanism and the blocking bag bend and deform, so that the blocking bag is not brought into strong contact with the edge of the opening that connects the fluid supply pipe to the branch pipe, and the blocking bag is not damaged. Therefore, a fluid blocking device has been configured that can smoothly insert the blocking bag into the fluid supply pipe to block the fluid, and can subsequently suppress the inconvenience of damaging the blocking bag when pulling it out of the fluid supply pipe.

[0017] This makes it possible to supply pressurized fluid to the internal space of the occlusion bag via the supply and discharge flow paths of the base end member, and to discharge the pressurized fluid from the internal space of the occlusion bag through the supply and discharge flow paths.

[0018] In addition to the above configuration, the main case may accommodate an operating shaft for moving the sealing mechanism along the longitudinal direction of the main case, the operating shaft may include the operating shaft and an operating cylinder having an inner diameter larger than the outer diameter of the operating shaft, a fluid supply and discharge space may be formed between the outer periphery of the operating shaft and the inner periphery of the operating cylinder, and the fluid supply and discharge space may be connected to the supply and discharge flow path.

[0019] In addition to the above configuration, a fixing ring may be provided that is fitted onto the tip of the occlusion bag and threadably connected to the tip side member to fix the tip of the occlusion bag to the tip side member.

[0020] With this, it is possible to fix the tip of the occlusion bag in a state where it is fitted externally to the tip side member by screwing the fixing ring onto the tip ring. In addition, by separating the fixing ring from the tip ring, maintenance and replacement of the occlusion bag can be easily performed.

[0021] In addition to the above configuration, the tip side member may have a conical outer surface that becomes smaller in diameter toward the tip.

[0022] According to this, when the sealing mechanism is inserted into the inside of the fluid supply pipe, the conical outer surface of the tip side member comes into contact with the opening portion that connects the fluid supply pipe to the branch pipe, or the conical outer surface of the tip side member comes into contact with the inner surface of the fluid supply pipe, thereby making it possible to guide the sealing mechanism.

[0023] The characteristic configuration of the fluid cutoff device according to the present invention is a method for cutting off the flow of fluid in a fluid supply pipe by inserting a seal mechanism of the fluid cutoff device from a branch pipe into the inside of the fluid supply pipe and expanding a blocking bag made of an elastic material provided in the seal mechanism, the seal mechanism having a tip side member on the tip side of a flexible shaft that can be bent and deformed, and a base side Cylindrical a proximal side member, an occlusion bag in a region surrounding the flexible shaft between the distal side member and the proximal side member, and a pressurized fluid is supplied to the occlusion bag to expand the occlusion bag beyond an outer diameter of the distal side member, the fluid cutoff device includes a cylindrical main case that accommodates the tip side member and the base side member so as to be freely movable in a longitudinal direction, the main case accommodates an actuating shaft that is connected to the base end side of the flexible shaft to transmit force to the seal mechanism, and a supply / discharge flow path that supplies / discharges pressurized fluid to / from the occlusion bag is formed in a gap between an outer periphery of the actuating shaft and an inner periphery of the base side member, a drilling step of forming a branch hole in a portion of the fluid supply pipe that communicates with the branch pipe in a state where the branch pipe is attached to the fluid supply pipe; The force of the actuating shaft is transmitted to the flexible shaft to feed the tip member along the longitudinal direction of the main case. an inserting step of inserting the sealing mechanism into the fluid supply pipe; From the supply and exhaust flow path a bag expansion process in which pressurized fluid is supplied to the internal space of the occlusion bag to expand the occlusion bag, thereby bringing the outer surface of the occlusion bag into close contact with the inner surface of the fluid supply pipe.

[0024] According to this characteristic configuration, in the drilling process, a branch hole communicating with the branch pipe attached to the fluid supply pipe is formed, and in the insertion process, the sealing mechanism is inserted to a position where the base end member of the sealing mechanism is not inserted from the branch hole into the inside of the fluid supply pipe, and in the bag expansion process, pressurized fluid is supplied to the internal space of the occlusion bag, causing the occlusion bag to expand and expand, thereby adhering to the inner surface of the fluid supply pipe and achieving occlusion. In particular, during the insertion process, the base-end member is in a position where it is not inserted into the inside of the fluid supply pipe from the branch hole, so that the inconvenience of a load acting in the bending direction on the member connected from the base-end member to the inside of the branch pipe (the area opposite the occlusion bag) during insertion can be suppressed, and the task of removing the occlusion bag from the branch hole after discharging the pressurized fluid from the occlusion bag can be easily performed. Thus, a fluid blocking method has been constructed that allows for blocking of the fluid in a fluid supply pipe using a fluid blocking device. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a cross-sectional view of a fluid cutoff device. [Diagram 2] 4 is an enlarged cross-sectional view of a distal end member and a proximal end member of the fluid blocking device. FIG. [Diagram 3] FIG. 4 is a cross-sectional view showing a fluid cutoff device attached to a branch pipe. [Figure 4] FIG. 1 is a cross-sectional view of a water pipe with a branch pipe attached thereto. [Diagram 5] 13 is a cross-sectional view of the branch pipe with the drilling unit attached thereto. FIG. [Figure 6] 1 is a cross-sectional view of a state in which a sealing mechanism is inserted inside a water pipe. [Figure 7] FIG. 13 is a cross-sectional view of an occlusion bag inflated inside a water pipe. [Figure 8] FIG. 11 is a cross-sectional view showing a state in which the branch pipe is sealed with a sealing plate. [Figure 9] FIG. 11 is a cross-sectional view of a state in which a sealing mechanism is inserted inside a water pipe in another embodiment (a). [Figure 10] FIG. 11 is a cross-sectional view of a sealing mechanism of another embodiment (b). [Figure 11] 10B is a cross-sectional view of the sealing mechanism when being inserted into a water pipe in another embodiment. FIG. [Figure 12] 13B is a cross-sectional view of a sealing mechanism inserted into a water pipe in another embodiment. FIG. [Figure 13] FIG. 11B is a cross-sectional view of the inflatable bag inflated inside a water pipe in another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Basic configuration] Figures 1 to 3 show a fluid blocking device A that blocks water (an example of a fluid) flowing in a water pipe 1 (a fluid supply pipe) by inserting a sealing mechanism S into the outer end of a branch pipe 2 branching off from a water pipe 1 as an example of a fluid supply pipe.

[0027] The fluid cut-off device A cuts off the water flowing in the water pipe 1 at any position, making it possible to perform replacement or maintenance work on the water pipe 1 downstream of the cut-off position, or to create a new branch flow path in the downstream water pipe 1 or install a new opening and closing valve, etc.

[0028] As shown in Fig. 3, a water pipe 1 is provided with a branch pipe 2 at a position communicating with a branch hole 1A formed in the water pipe 1. The branch pipe 2 is attached together with a holder 3 near the upstream side of the position where the water flow needs to be blocked. The branch pipe 2 is formed integrally with the holder 3 which is crimped in a form that embraces the outer surface of the water pipe 1, and a flange portion 4 is formed integrally with the outer end of the branch pipe 2.

[0029] The branch pipe 2 is equipped with a gate valve 5, and this gate valve 5 allows the branch pipe 2 to be opened and closed by a valve body 5A that operates in a direction perpendicular to the pipeline of the branch pipe 2. The flange portion 4 allows the attachment of a drilling machine B as shown in Figure 5 or a fluid cut-off device A as shown in Figure 3, and a completely closed state is maintained by attaching a disk-shaped sealing plate 6 as shown in Figure 8.

[0030] [Fluid cutoff device] 1 to 3, the fluid cutoff device A includes a main case 10 formed of a cylindrical member, a sealing mechanism S housed inside the main case 10 so as to be movable in a direction along the longitudinal direction of the main case 10, and an operating shaft T for moving the sealing mechanism S. In addition, the drawings show the center of a linear flexible shaft 21 of the sealing mechanism S as an axis Y. The main case 10 is formed of a metal pipe such as a steel pipe or a stainless steel pipe.

[0031] The flexible shaft 21 is, for example, one having a structure in which a spring wire is formed into a spiral shape, or a structure in which a wire bundle of multiple spring wires is covered with a resin tube, and is capable of transmitting pressure without buckling when pressure is applied in the longitudinal direction, and of flexing flexibly when a force is applied in the bending direction.

[0032] [Fluid cutoff device: main case] The main case 10 has a connecting flange 11 integrally formed at the end on the connecting side (lower side in Figs. 1 and 3). A cylindrical seal body 12 is housed inside the end on the outer end side (upper side in Figs. 1 and 3) of the main case 10, and an operating shaft T is arranged to pass through this cylindrical seal body 12. The upper end of the main case 10 is also provided with a supply and exhaust part 13 consisting of a pipe that communicates with the internal space of the main case 10. This supply and exhaust part 13 allows air to flow in and out of the internal space of the main case 10 when the seal mechanism S moves inside the main case 10. It is also used to check whether the gate valve 5 has been shut off.

[0033] [Fluid shutoff device: sealing mechanism] The sealing mechanism S has a flexible shaft 21 that can be flexibly deformed, with a tip side member 22 attached to the tip of the flexible shaft 21, a base side member 23 attached to the base end of the flexible shaft 21, and a blocking bag 24 positioned to surround the flexible shaft 21 between the tip side member 22 and the base side member 23.

[0034] 2, the tip side member 22 is composed of a tip guide body 22a that is connected to the tip of the flexible shaft 21, and a cylindrical tip side holding body 22b that is integrated by being screwed onto the base end side of the tip guide body 22a. The tip guide body 22a has a conical outer surface 22t that becomes smaller in diameter toward the tip, and is integrated by being screwed onto a male threaded portion of the tip side holding body 22b, which is formed on the tip guide body 22a.

[0035] In particular, sealing is improved by interposing a seal tape at the screw joint between the tip guide body 22a and the tip side holder 22b. Also, when pressurized air (one example of a pressurized fluid) is supplied to the blocking bag 24, a seal member made of rubber or resin may be fitted or filled inside the tip side holder 22b to prevent air from leaking from the boundary between the tip guide body 22a and the tip side holder 22b.

[0036] The base end side member 23 is composed of a cylindrical base end guide body 23a disposed outside the rear end of the flexible shaft 21, and a cylindrical base end side retaining body 23b which is screwed into the base end guide body 23a to form an integrated body. The base end guide body 23a is a cylindrical body with an outer diameter slightly smaller than the inner diameter of the main case 10, and has a through hole centered on the axis Y. The base end guide body 23a is integrated with the base end side retaining body 23b by screwing a male screw portion of the base end guide body 23a into a female screw portion formed along the inner circumference of the through hole. In particular, the sealing performance is improved by interposing a seal tape at the screwed portion between the base end guide body 23a and the base end side retaining body 23b.

[0037] The blocking bag 24 is made of synthetic rubber, such as ethylene propylene diene rubber (EPDM), which is flexible and elastically deformable, or a resin material, which is flexible and elastically deformable, molded into a tube shape. The blocking bag 24 has thick-walled portions 24b formed at both ends of the tubular bag body 24a to prevent it from slipping out. As a result, the outer diameter of the thick-walled portions 24b of the blocking bag 24 is larger than the outer diameter of the bag body 24a.

[0038] In this sealing mechanism S, the female threaded portion of the fixing ring 25 is screwed into the male threaded portion of the tip side holder 22b, whereby the fixing ring 25 holds the thick wall portion 24b on the tip side of the occlusion bag 24 in a form in which it is pressed against the tip side member 22. Similarly, the female threaded portion of the fixing ring 25 is screwed into the male threaded portion of the base side holder 23b, whereby the fixing ring 25 holds the thick wall portion 24b on the base side of the occlusion bag 24 in a form in which it is pressed against the base side member 23.

[0039] The distal end retainer 22b and the proximal end retainer 23b have a common structure. The fixing ring 25 screwed to the distal end retainer 22b and the fixing ring 25 screwed to the proximal end retainer 23b have a common structure. The fixing ring 25 is generally cylindrical, and has a cylindrical portion that is in close contact with the outer periphery of the thick portion 24b of the blocking bag 24, and has an opening portion that surrounds the outer periphery of the bag body 24a at the end opposite to the female thread portion of the fixing ring 25. The inner diameter of the opening portion is smaller than the inner diameter of the cylindrical portion. A cap member 26, which will be described later, is disposed on the inner periphery of the opening portion to prevent the blocking bag 24 from coming off.

[0040] Furthermore, a cap member 26 is provided to prevent the occlusion bag 24 from falling out at the opening of the fixing ring 25. This cap member 26 is shaped to be fitted into the area continuing from the opening of the fixing ring 25 to the cylindrical portion, and prevents the occlusion bag 24 from falling out by contacting the boundary between the thick portion 24b of the occlusion bag 24 and the bag body 24a. The cap member 26 is provided at the opening of the fixing ring 25 on both the tip end side and the base end side.

[0041] As shown in Figure 2, when viewed in a direction perpendicular to the axis Y, the tip of the flexible shaft 21 is provided with an O-ring 28 on the inner circumference of the tip side retainer 22b, and an O-ring cap 29 supporting the O-ring 28 is provided in the area extending from the inner circumference of the tip side retainer 22b to the inner circumference of the thick portion 24b of the occlusion bag 24.

[0042] In a similar manner, an O-ring 28 is provided on the inner circumference of the base end retaining body 23b, and an O-ring cap 29 that supports the O-ring 28 is provided in the area extending from the inner circumference of the base end retaining body 23b to the inner circumference of the thick portion 24b of the occlusion bag 24.

[0043] In this manner, by providing the O-ring 28, the O-ring cap 29, etc., leakage of fluid when pressurized air (an example of a pressurized fluid) is supplied to the occlusion bag 24 is suppressed.

[0044] This sealing mechanism S functions to expand the diameter of the occlusion bag 24 by supplying the pressurized air (pressurized fluid) supplied to the fluid supply and discharge space 33 of the operating shaft T into the inside of the occlusion bag 24, and therefore a supply and discharge flow path U that enables the supply and discharge of pressurized air is formed inside the base end guide body 23a and inside the base end side retaining body 23b.

[0045] In particular, in this sealing mechanism S, when pressurized air is not supplied to the internal space of the occlusion bag 24, the dimensional relationship is set so that, when viewed in the direction along the axis Y, the outer surface of the bag body 24a is located inward from the outer periphery of the tip guide body 22a, as shown in Figures 1 to 3.

[0046] 2, the actuation shaft 31 of the operating shaft T is inserted into the through hole of the base-end guide body 23a, and a gap is formed between the outer periphery of this actuation shaft 31 and the inner periphery of the through hole of the base-end guide body 23a. In addition, the base end portion of the flexible shaft 21 is inserted into the central hole of the base-end holding body 23b, and a gap is formed between the outer periphery of the base end of the flexible shaft 21 and the inner periphery of the central hole of the base-end holding body 23b. In this way, the base-end side member 23 has a supply / discharge flow path U that supplies and discharges pressurized air to and from the occlusion bag 24 by the two gaps mentioned above.

[0047] [Fluid cutoff device: operating shaft] 1 to 3, the operating shaft T includes an actuating shaft 31 connected to the base end of the flexible shaft 21, and an actuating cylinder 32 that is screwed into the base end guide body 23a with an inner diameter larger than the outer diameter of the actuating shaft 31. In particular, between the outer periphery of the actuating shaft 31 and the inner periphery of the actuating cylinder 32, a fluid supply / discharge space 33 is formed inside the actuating cylinder 32, through which pressurized air (pressurized vertical opening) can be supplied and discharged.

[0048] The actuating cylinder 32 is disposed so as to be inserted into a hole in the cylindrical seal body 12 at the upper end of the main case 10. The tip end (the lower end in FIG. 1) of the actuating cylinder 32 is screwed into the end of the base end guide body 23a, thereby integrating them. The operating shaft T is formed with a pressurized air supply / discharge part 34 that enables the supply and discharge of pressurized air from the outside to the actuating cylinder 32.

[0049] [Cutting off fluid] By configuring it in this manner, as shown in Figure 7, the sealing mechanism S of the fluid blocking device A is inserted into the inside of the water pipe 1 (fluid supply pipe) through the branch hole 1A, pressurized air is supplied to the sealing mechanism S, and the blocking bag 24 of this sealing mechanism S is expanded and brought into close contact with the inner surface of the water pipe 1, thereby blocking the water flowing through the water pipe 1.

[0050] When blocking the flow of water in this manner, it is necessary to provide a branch pipe 2 in the water pipe 1 near the position where blocking is to be performed, and to form a branch hole 1A in the water pipe 1 so as to communicate with the branch pipe 2. One example of the steps up to blocking the flow of water will be described as the "construction procedure" with reference to Figures 4 to 8.

[0051] [Construction procedure] This construction procedure is a specific example of a fluid blocking method, and the following steps are performed in this order: (1) a branch pipe installation step shown in FIG. 4; (2) a drilling step shown in FIG. 5; (3) a sealing mechanism insertion step shown in FIG. 6; (4) a bag expansion step shown in FIG. 7; and (5) a fluid blocking device removal step shown in FIG. 8.

[0052] (1) In the branch pipe installation process, a branch pipe 2 is installed together with a holder 3 to a water pipe 1 near the position where the water flow is to be blocked, as shown in Fig. 4. The combination of the holder 3 and the branch pipe 2 is called a split T-shaped pipe, and the branch pipe 2 is equipped with a gate valve 5 in advance. The holder 3 is formed in a cylindrical shape that is split so as to sandwich the outer circumference of the water pipe 1.

[0053] In particular, the holder 3 with which the branch pipe 2 is integrally formed is referred to as the first holder 3a, and the simple semi-cylindrical holder 3 is referred to as the second holder 3b. For this configuration, after a sealant is provided on the outer periphery of the water pipe 1, the outer periphery of the sealant is surrounded by the first holder 3a and the second holder 3b, and the first holder 3a and the second holder 3b are fixed to the outer periphery of the water pipe 1 by tightening bolts (not shown) so as to draw them together.

[0054] Next, in the (2) drilling step, a drilling machine B is attached to the flange portion 4 of the branch pipe 2 as shown in Fig. 5. This drilling machine B has a main body case 36 and is equipped with a connecting flange portion 37 that is connected to the flange portion 4.

[0055] The drilling machine B has a drilling unit equipped with a cutter 39 at the tip of a cutter shaft 38 through which the branch pipe 2 can be inserted. The cutter shaft 38 is supported so as to be freely retractable relative to a main body case 36, and the main body case 36 incorporates an electric motor (not shown) for rotating the cutter shaft 38.

[0056] As a result, drilling is performed by moving the cutter shaft 38 in a direction in which it comes into contact with the water pipe 1 while driving the cutter shaft 38 to rotate, and a branch hole 1A is formed in the water pipe 1. After this drilling, the cutter shaft 38 is moved in the opposite direction to finish the drilling process.

[0057] After the drilling process is completed, the branch pipe 2 is closed by the valve body 5A of the gate valve 5, and then the drilling machine B is removed.

[0058] (3) In the sealing mechanism insertion process, as shown in Fig. 6, the fluid cutoff device A is attached to the branch pipe 2 by connecting the connecting flange 11 of the fluid cutoff device A to the flange portion 4 of the branch pipe 2. With the fluid cutoff device A attached in this manner, the valve body 5A of the gate valve 5 is opened, and the sealing mechanism S is inserted into the water pipe 1 so as to pass through the branch hole 1A by operating the operating shaft T.

[0059] When inserting the sealing mechanism S, when the conical outer surface 22t on the outer periphery of the tip guide body 22a of the tip side member 22 comes into contact with the inner surface of the water pipe 1, the tip side member 22 is moved smoothly along the inner surface of the water pipe 1, and if the pressure of the water flow inside the water pipe 1 acts as a result of this movement, the flexible shaft 21 bends flexibly due to this pressure, achieving smooth insertion.

[0060] Incidentally, the fluid-cutting device A is assumed to enable the sealing mechanism S to be inserted and removed by manual operation of the operating shaft T, but it may also be configured to enable the sealing mechanism S to be inserted and removed by the driving force of an electric motor, for example.

[0061] Furthermore, during this insertion, the outer diameter of the blocking bag 24 is smaller than the outer diameter of the tip side member 22, which prevents the outer surface of the blocking bag 24 from coming into contact with the inner surface of the branch hole 1A, and the blocking bag 24 is not damaged or subjected to strong resistance during insertion.

[0062] In particular, when inserting the sealing mechanism S in this manner, the insertion amount is controlled so that the base end side member 23 of the sealing mechanism S does not enter the inside of the water pipe 1 through the branch hole 1A, as shown in Fig. 6. This makes it possible to suppress the inconvenience of a load acting in the bending direction on the members constituting the operating shaft T in the outer end side section (the area opposite the occlusion bag 24) connected to the base end side member 23 during insertion, and subsequently makes it easy to remove the occlusion bag 24 from the branch hole 1A.

[0063] (4) In the bag expansion process, as shown in Fig. 7, pressurized air is supplied to the pressurized air supply and discharge unit 34, and this pressurized air is supplied from the fluid supply and discharge space 33 through the supply and discharge flow path U to the internal space of the occluding bag 24, expanding the occluding bag 24. This expansion causes the occluding bag 24 to expand in diameter, and the outer surface comes into close contact with the inner surface of the water pipe 1. Note that a flow path for supplying air compressed by a compressor (not shown) is connected to the pressurized air supply and discharge unit 34, and pressurized air (pressurized fluid) is supplied and discharged by manually operating a valve or other operation.

[0064] By blocking the flow of water inside the water pipe 1 in this way, it becomes possible to perform replacement or maintenance work on the water pipe 1 downstream of the blocking position, or to form a new branch flow path downstream or install a new opening / closing valve, etc.

[0065] This blocks the water flowing through the water pipe 1. In addition, when pressurized air is supplied in this manner, the O-ring 28, O-ring cap 29, etc. housed inside the tip side member 22 suppress the problem of pressurized air leaking from the screwed portion of the tip side member 22, etc.

[0066] Thereafter, when the blocking bag 24 is to be pulled out, air is discharged from the internal space of the blocking bag 24 via the fluid supply and drainage space 33 and the supply and drainage flow path U, causing the blocking bag 24 to be contracted, and the pulling out operation is performed. This changes the amount of bending of the flexible shaft 21, and allows for smooth pulling out due to the flexible bending of the flexible shaft 21.

[0067] (5) In the fluid cut-off device removal process, as shown in FIG. 8 , after the pressurized air is discharged from the blocking bag 24 and the operating shaft T is pulled out, the valve body 5A of the gate valve 5 is blocked, the connecting flange 11 of the fluid cut-off device A is separated from the flange portion 4 of the branch pipe 2, and a sealing plate 6 is attached to the flange portion 4 of the branch pipe 2 to block the outer end of the branch pipe 2.

[0068] [Effects of the embodiment] With this configuration, when the blocking bag 24 is inserted into the water pipe 1 (fluid supply pipe) from the branch hole 1A, the blocking bag 24 flexes flexibly together with the flexible shaft 21, making it possible to align the position of the tip of the blocking bag 24 with the position of the water pipe 1 without forcing the blocking bag 24 into strong contact with the opening edge of the branch hole 1A.

[0069] Furthermore, when inserting the sealing mechanism S, the base end member 23 of the sealing mechanism S does not enter the interior of the water pipe 1 through the branch hole 1A, which prevents the inconvenience of a load acting in the bending direction on the members constituting the operating shaft T at the outer end portion (the area opposite the blocking bag 24) connected to the base end member 23 during insertion, and subsequently, the blocking bag 24 can be easily removed from the branch hole 1A.

[0070] Furthermore, since the outer surface of the tip guide body 22a of the tip side member 22 is formed with a conical outer surface 22t, the sealing mechanism S can be inserted smoothly, and since the outer diameter of the blocking bag 24 when pressurized air is not supplied is smaller than the outer diameter of the tip side member 22, the outer surface of the blocking bag 24 is not damaged during insertion.

[0071] The sealing mechanism S allows the blocking bag 24 to flex flexibly together with the flexible shaft 21, so that even if the water pipe 1 (fluid supply pipe) is non-linear, such as having a bent shape, the outer surface of the blocking bag 24 can be brought into close contact with the inner surface of the water pipe 1 to stop the flow of water (fluid).

[0072] When using the fluid blocking device A configured in this manner to block the water (fluid) flowing in a water pipe 1 (fluid supply pipe), a method for stopping the flow of water can be realized and the required work can be performed even in a water pipe 1 that does not have a branch hole 1A by performing multiple steps in sequence.

[0073] In the seal mechanism S, the tip guide body 22a and the tip retaining body 22b of the tip side member 22 are screwed together, and a fixing ring 25 is screwed onto the tip side retaining body 22b. Similarly, the base end guide body 23a and the base end retaining body 23b of the base end member 23 are screwed together, and the fixing ring 25 is screwed onto the base end retaining body 23b. Therefore, it can be easily disassembled by releasing these screws. Due to this structure, the seal mechanism S can be easily disassembled for maintenance, and parts can also be easily replaced.

[0074] [Another embodiment] The present invention may be configured as follows other than the above-described embodiment (common numbers and symbols as in the embodiment are used to designate components having the same functions as in the embodiment).

[0075] 9, when the sealing mechanism S is inserted into the water pipe 1 (fluid supply pipe) from the branch hole 1A, the insertion amount is set so that a part of the base end side member 23 enters the inside of the water pipe 1. Even when the insertion amount is set in this way, by supplying pressurized air (pressurized fluid) to the internal space of the blocking bag 24 of the sealing mechanism S, it is possible to stop the flow of water (fluid) in the water pipe 1 by expanding the blocking bag 24, as in the embodiment described above.

[0076] In this alternative embodiment (a), the insertion amount of the sealing mechanism S is not limited to the amount shown in FIG. 9, and the sealing mechanism S may be inserted into the water pipe 1 beyond the amount shown in FIG.

[0077] 10, a fluid cutoff device A is configured by providing a sealing mechanism S at the tip of a cylindrical member 41 via a cylindrical and bendable bellows 42. The sealing mechanism S has a hollow cylindrical member 54 that communicates with the bellows 42. The center of the hollow cylindrical member 54 is referred to as an axis Y.

[0078] In the fluid blocking device A of this alternative embodiment (b), as shown in FIG. 10, the sealing mechanism S has a pair of upper annular members 50A, a pair of lower annular members 50B, a hollow tubular member 54, a tip plate 55, and an expansion bag 60 (an example of a blocking bag) arranged between the upper annular member 50A and the lower annular member 50B.

[0079] The pair of upper annular members 50A is composed of a first disk-shaped member 50Aa and a first watertight fitting 50Ab connected to the first disk-shaped member 50Aa with a plurality of (eight in this embodiment) clamp bolts 52 such as hexagon socket bolts. The pair of lower annular members 50B is composed of a second disk-shaped member 50Ba and a second watertight fitting 50Bb connected to the second disk-shaped member 50Ba with a plurality of (eight in this embodiment) clamp bolts 53, 55a.

[0080] In this embodiment (b), the first water stop fitting 50Ab and the second water stop fitting 50Bb have a divided structure that is relatively movable by screwing together the pull bolt 52 and / or the pull bolts 53, 55a.

[0081] 10, the first disk-shaped member 50Aa is integrally formed with a base 56a having an upstream end face (lower face when viewed in the direction shown in FIG. 10) formed in a concave shape, and an extension portion 56b extending from the base 56a to the downstream side (upper side). The base 56a has a plurality of (eight in this embodiment) through holes 56a1 formed at equal intervals in the circumferential direction in an annular portion adjacent to the extension portion 56b, into which the clamping bolts 52 are inserted.

[0082] A male thread 56b1 is formed on the outer circumferential surface of the downstream end (upper end when viewed in the direction shown in FIG. 10) of the extending portion 56b, and a female thread of the bellows 42 is screwed into this male thread 56b1, thereby connecting the first disk-shaped member 50Aa and the bellows 42. In addition, a seal groove 56b2 in which an O-ring sb is attached is formed upstream (lower) of the male thread 56b1 on the outer circumferential surface of the downstream end (upper end) of the extending portion 56b, and a tapered surface 56b5 that compresses the O-ring sh is formed downstream (upper) of the male thread 56b1.

[0083] A female screw portion 56b3 is formed on the inner peripheral surface of the upstream end (lower end when viewed in the direction shown in FIG. 10) of the extension portion 56b, and is screwed into a male screw portion 54a formed on the outer peripheral surface of the downstream end (upper end) of the hollow cylindrical member 54 arranged coaxially with the axis Y, thereby connecting the first disk-shaped member 50Aa and the hollow cylindrical member 54. A seal groove 56b4 in which an O-ring sc is attached is formed on the inner peripheral surface of the upstream end (lower end) of the extension portion 56b downstream (upper) of the female screw portion 56b3. When the first disk-shaped member 50Aa and the hollow cylindrical member 54 are connected, the O-ring sc comes into contact with a tapered surface 54a1 formed on the downstream end (upper end) of the male screw portion 54a of the hollow cylindrical member 54 and is compressed.

[0084] The first water-stop fitting 50Ab is formed in a cup shape, and is integral with a disk base 57a and a cylindrical portion 57b extending from the outermost side of the disk base 57a to the upstream side (lower side). The disk base 57a has an insertion hole 57a1 through which the hollow tubular member 54 is inserted, and a first step portion 57a2 is formed on the outermost side with which one end of the expansion bag 60 (an example of a blocking bag) engages. A seal groove 57a3 in which an O-ring sd is fitted is formed on the outer periphery side adjacent to the insertion hole 57a1 of the disk base 57a, and a plurality of (eight in this embodiment) female screw holes 57a4 into which the draw bolt 52 is screwed are formed at equal intervals in the circumferential direction on the further outer periphery side of this seal groove 57a3. The cylindrical portion 57b is adjacent to the outside of the second water-stop fitting 50Bb, and serves as an outer cylinder into which the second water-stop fitting 50Bb is inserted.

[0085] The downstream end surface (upper surface when viewed in the direction shown in FIG. 10) of the second disk-shaped member 50Ba is formed in a concave shape. The second disk-shaped member 50Ba has an insertion hole 58a formed in the center thereof through which the hollow tubular member 54 is inserted, and a plurality of (eight in this embodiment) through holes 58b into which the clamping bolts 53, 55a, such as hexagon socket bolts, are inserted are formed at equal intervals in the circumferential direction on the outer circumferential side of the insertion hole 58a. The inner circumferential surface of the insertion hole 58a has a seal groove 58a1 into which an O-ring sj ​​is fitted, and a locking recess 58a2 into which the hollow tubular member 54 is locked, formed upstream (lower) of the seal groove 58a1.

[0086] The second water-stopping fitting 50Bb has an insertion hole 59a formed through the center, into which the hollow tubular member 54 is inserted, and a second step 59b is formed on the outermost side, into which the other end of the inflatable bag 60 engages. A seal groove 59c into which an O-ring sf is attached is formed on the outer periphery side adjacent to the insertion hole 59a, and a plurality of (eight in this embodiment) female screw holes 59d into which the draw bolts 53, 55a are screwed are formed at equal intervals in the circumferential direction on the further outer periphery side of this seal groove 59c. The second water-stopping fitting 50Bb is adjacent to the inside of the cylindrical portion 57b of the first water-stopping fitting 50Ab, and serves as an inner cylinder into which the cylindrical portion 57b is inserted.

[0087] A pair of upper annular members 50A and a pair of lower annular members 50B are fitted onto the hollow tubular member 54. A plurality of through holes are formed near the axial center of the hollow tubular member 54 as a fluid inlet 51 communicating with a fluid introduction space V for inflating the inflatable bag 60. The hollow tubular member 54 is also formed at one end with a male threaded portion 54a that screws into a female threaded portion 56b3 formed on the extension portion 56b of the first disk-shaped member 50Aa, and at the other end with an annular protruding portion 54b that engages with a locking recess 58a2 formed on the second disk-shaped member 50Ba.

[0088] The hollow tubular member 54 is inserted into the first water-stopping fitting 50Ab and the pair of lower annular members 50B to engage the annular protrusion 54b and the locking recess 58a2, and then screwed into the first disk-shaped member 50Aa, thereby positioning the first disk-shaped member 50Aa and the second disk-shaped member 50Ba. In addition, the hollow tubular member 54 is prevented from falling off by the tip plate 55 fixed to the second disk-shaped member 50Ba by a plurality of (four in this embodiment) draw bolts 55a such as hexagon socket head bolts.

[0089] In the tip plate 55, a plurality of (four in this embodiment) through holes 55c for accommodating the heads of the clamp bolts 53 and a plurality of (four in this embodiment) through holes (not shown) into which the male threads of the clamp bolts 55a are inserted are arranged alternately in the circumferential direction. In addition, in the downstream end face (upper face) of the tip plate 55, a seal groove 55d in which an O-ring sg is attached is formed between the insertion hole portion 55b and the through hole 55c.

[0090] The expansion bag 60 is made of a synthetic rubber having excellent durability, such as ethylene propylene diene rubber (EPDM), and has an expansion portion 63 that is connected to a first clamped portion 61 clamped by the upper annular member 50A and a second clamped portion 62 clamped by the lower annular member 50B, and expands when air flows in from the fluid inlet portion 51.

[0091] The first clamped portion 61 is bent inward from the expanding portion 63 to have an L-shaped cross section, and similarly, the second clamped portion 62 is bent inward from the expanding portion 63 to have an L-shaped cross section. By engaging the first clamped portion 61 with the first step portion 57a2 of the first water-stopping fitting 50Ab and engaging the second clamped portion 62 with the second step portion 59b of the second water-stopping fitting 50Bb, one end of the expanding bag 60 is supported by the first water-stopping fitting 50Ab and the other end of the expanding bag 60 is supported by the second water-stopping fitting 50Bb. The expanding portion 63 has a bent and deformed shape in its natural state, and becomes an upright shape by further tightening the pull bolt 52 and / or the pull bolts 53, 55a to separate the first water-stopping fitting 50Ab and the second water-stopping fitting 50Bb.

[0092] 10, the first clamped portion 61 of the inflatable bag 60 is engaged with the first stepped portion 57a2 of the first water-stopping fitting 50Ab, and the second clamped portion 62 is engaged with the second stepped portion 59b of the second water-stopping fitting 50Bb, the hollow tubular member 54 is attached to the inside of the pair of upper annular members 50A and the pair of lower annular members 50B, and temporarily fastened with the clamp bolt 52 and the clamp bolts 53, 55a. In this state, the first water-stopping fitting 50Ab and the second water-stopping fitting 50Bb are close to each other, and the inflatable portion 63 is bent and deformed. Further, by further tightening the clamp bolt 52 and the clamp bolts 53, 55a, the first water-stopping fitting 50Ab comes into contact with the first disk-shaped member 50Aa and the second water-stopping fitting 50Bb comes into contact with the second disk-shaped member 50Ba, and the first water-stopping fitting 50Ab and the second water-stopping fitting 50Bb are separated from each other. As a result, a tensile force acts on the expanding portion 63, causing the expanding portion 63 to assume an upright shape. With this configuration, the sealed space surrounded by the hollow tubular member 54, the first water-stopping fitting 50Ab, and the second water-stopping fitting 50Bb becomes the fluid introduction space V.

[0093] As shown in Fig. 13, the inflation section 63 receives fluid pressure due to air introduced into the fluid introduction space V through the fluid inlet section 51 and inflates radially outward. In addition, if the first water-stopping fitting 50Ab and the second water-stopping fitting 50Bb are separated from each other while the inflation bag 60 is supported, and tension is applied to the inflation bag 60, it is possible to prevent deformation of the inflation bag 60 before inflation. As a result, when the inflation bag 60 is inflated by introducing air from the fluid inlet section 51, it is possible to inflate the inflation bag 60 evenly. The expansion rate and strength of the inflation section 63 are designed according to the structure and inner diameter of the water pipe 1.

[0094] [Cutting off fluid] 11 to 13 show an outline of the procedure for blocking water (one example of a fluid) flowing in a water pipe 1 (fluid supply pipe) by inserting a sealing mechanism S of a fluid cutoff device A of another embodiment (b) into the water pipe 1 through a branch hole 1A formed in the water pipe 1. Although these figures do not show the branch pipe 2 and gate valve 5 shown in the embodiment, the branch pipe 2, gate valve 5, etc. are used as in the embodiment.

[0095] [Construction procedure] The construction procedure shown in Figures 11 to 13 is a specific example of a fluid cutoff method using the fluid cutoff device A of another embodiment (b). That is, as shown in Figure 11, the seal mechanism S of the fluid cutoff device A is inserted into the water pipe 1 from the branch hole 1A. When inserted in this manner, the bellows 42 is curved as shown in Figure 12 due to the action of water pressure or the pressure acting on the bellows 42 during insertion, and the axis Y of the seal mechanism S changes its posture to be along the longitudinal direction of the water pipe 1.

[0096] 13, by supplying pressurized air to the tubular member 41, the pressurized air flows into the hollow tubular member 54, is supplied to the fluid introducing space V via the fluid inlet portion 51 of the hollow tubular member 54, and is further supplied to the inner surface side of the expansion bag 60. As a result, the expansion bag 60 expands and comes into close contact with the inner surface of the water pipe 1, thereby blocking the water flowing through the water pipe 1.

[0097] In the construction procedure of this alternative embodiment (b), although not shown in the drawings, a branch pipe 2 is formed in the water pipe 1 in the same manner as in the procedure described in the embodiment (see branch pipe 2 in FIG. 4), and a branch hole 1A is formed in the water pipe 1 in the drilling process (see FIG. 5), after which a sealing mechanism S is inserted into the inside of the water pipe 1 from the branch pipe 2.

[0098] The fluid blocking device A of this alternative embodiment (b) is capable of applying tension to the expansion bag 60 to prevent deformation, and is also capable of evenly inflating the expansion bag 60, so that the expansion bag 60 can be smoothly inserted into the interior of the water pipe 1 from the branch hole 1A, and the expansion bag 60 can be brought into good, intimate contact with the inner surface of the water pipe 1.

[0099] (c) In the sealing mechanism S described in the embodiment, the length of the flexible shaft 21 is set so as to reach a region on the side of the operating shaft T beyond the region where the occlusion bag 24 is disposed.

[0100] In the configuration of this alternative embodiment (c), a flexibly deformable tube or the like is arranged in the region of the flexible shaft 21 extending from the base-end member 23 to the operating shaft T, thereby forming a space through which pressurized air (pressurized fluid) flows, and bending is possible in the region extending beyond the base-end member 23 in the direction of the operating shaft T.

[0101] This makes it possible, for example as in another embodiment (a), when inserting the portion including the base-end member 23 together with the occlusion bag 24 into the inside of the water pipe 1 from the branch hole 1A, to easily flex the area closer to the operating shaft T than the base-end member 23, thereby achieving even smoother insertion.

[0102] (d) The structure of the distal end side member 22 and the structure of the proximal end side member 23 are not limited to the structure described in the embodiment (the structure shown in FIG. 2), and any structure can be adopted.

[0103] As one example, it is possible to support the distal end of the occlusion bag 24 on the distal guide body 22a by screwing the fixing ring 25 onto the distal guide body 22a without using the distal retaining body 22b of the distal member 22. Similarly, it is possible to support the proximal side of the occlusion bag 24 on the proximal guide body 23a by screwing the fixing ring 25 onto the proximal guide body 23a without using the proximal retaining body 23b of the proximal member 23.

[0104] The sealing mechanism S requires sealing to prevent leakage of pressurized air when pressurized air is supplied to inflate the occlusion bag 24, and even if it is configured as in alternative embodiment (d), it will be installed in an area that requires a seal ring, packing, etc. to achieve a seal.

[0105] (e) The pressurized fluid is not limited to air, and it is possible to use liquids such as water, oil, etc. In order to configure in this way, it is also possible to provide a device that pressurizes and supplies a liquid fluid.

[0106] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided that no contradiction arises. Furthermore, the embodiments disclosed in this specification are merely examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0107] The present invention can be used in a fluid blocking device and a fluid blocking method. [Explanation of symbols]

[0108] 1 Water pipe (fluid supply pipe) 2 Branch Pipe 21 Flexible shaft 22 Tip side member 22t exterior 23 Base end member 24 Occlusion Bag 25 Fixing ring 60 Inflatable Bag (Closure Bag) A Fluid shutoff device S sealing mechanism U Supply / discharge channel

Claims

1. 1. A fluid cutoff device having a seal mechanism that is inserted from a branch pipe into a fluid supply pipe, the seal mechanism being inserted into the fluid supply pipe and configured to cut off a flow of fluid in the fluid supply pipe by inflating an occlusion bag made of an elastic material provided in the seal mechanism, the device comprising: the sealing mechanism includes a flexible shaft capable of bending and deforming, a tip side member attached to a tip end of the flexible shaft, a cylindrical base side member disposed at a base end of the flexible shaft, and the occlusion bag disposed at a position surrounding the flexible shaft between the tip side member and the base side member, a cylindrical main case that accommodates the tip side member and the base side member so as to be freely movable in a longitudinal direction, the main case accommodating an actuating shaft that transmits force to the seal mechanism by being connected to a base end side of the flexible shaft; A fluid cutoff device in which a supply / drain passage for supplying / draining pressurized fluid to / from the occlusion bag is formed in the gap between the outer periphery of the actuating shaft and the inner periphery of the base end member.

2. A fluid blocking device as described in claim 1, wherein the main case accommodates an operating shaft for moving the sealing mechanism along the longitudinal direction of the main case, the operating shaft comprises the operating shaft and an operating cylinder having an inner diameter larger than the outer diameter of the operating shaft, a fluid supply and discharge space is formed between the outer periphery of the operating shaft and the inner periphery of the operating cylinder, and the fluid supply and discharge space is connected to the supply and discharge flow path.

3. 3. The fluid cutoff device according to claim 1, further comprising a fixing ring that is fitted onto the tip of the occlusion bag and threadably connected to the tip member to fix the tip of the occlusion bag to the tip member.

4. 4. The fluid cutoff device according to claim 1, wherein the tip side member has a conical outer surface whose diameter decreases toward the tip.

5. A method for blocking fluid flow in a fluid supply pipe by inserting a seal mechanism of a fluid blocking device from a branch pipe into the inside of the fluid supply pipe and expanding a blocking bag made of an elastic material provided in the seal mechanism, comprising: the sealing mechanism includes a tip side member at the tip end of a flexible shaft that is capable of bending and deforming, and a cylindrical base side member at the base end, the occlusion bag is provided in a region surrounding the flexible shaft between the tip side member and the base side member, and the occlusion bag is expanded in diameter beyond the outer diameter of the tip side member by supplying pressurized fluid to the occlusion bag, the fluid cutoff device includes a cylindrical main case that accommodates the tip side member and the base side member so as to be freely movable in a longitudinal direction, the main case accommodates an actuating shaft that is connected to the base end side of the flexible shaft to transmit force to the seal mechanism, and a supply / discharge flow path that supplies / discharges pressurized fluid to / from the occlusion bag is formed in a gap between an outer periphery of the actuating shaft and an inner periphery of the base side member, a drilling step of forming a branch hole in a portion of the fluid supply pipe that communicates with the branch pipe in a state where the branch pipe is attached to the fluid supply pipe; an insertion step of feeding the tip side member along a longitudinal direction of the main case by transmitting a force of the actuating shaft to the flexible shaft, and inserting the seal mechanism into the fluid supply pipe; a bag expansion process in which pressurized fluid is supplied from the supply and discharge flow path to the internal space of the occlusion bag, thereby expanding the occlusion bag and causing the outer surface of the occlusion bag to adhere to the inner surface of the fluid supply pipe.

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