Removal member of closing member and working fluid device used in the same

Abstract

To provide a removal method of a closing member which enables safe removal of the closing member in a state that flow is not interrupted, and to provide a working fluid device used in the removal method of the closing member.SOLUTION: A method of removing a closing member 51 from a fluid pipe 1 in a state that flow is not interrupted, includes: an installation step in which actuators 110 of a working fluid device 90 including a working fluid circuit 100 for removing the closing member 51 are installed in the closing member 51 so as to make a pair in a radial direction of the closing member 51; a delivery step in which working fluid is branched and delivered from a pump 120 of the working fluid device 90 to the respective actuators 110 and the returned working fluid is delivered from the respective actuators 110 and joined; a restriction step in which the returned working fluid delivered from the respective actuators 110 and joined in the delivery step is restricted by fluid control means 150; a closing step in which an upstream side in the fluid pipe 1 is closed in a state that the returned working fluid delivered from the respective actuators 110 and joined is restricted by the fluid control means 150; and a removal step in which the closing member 51 is removed.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a method for removing a blocking member attached to a fluid pipe in an uninterrupted flow state, and to a hydraulic fluid device used therein. [Background technology]

[0002] When fluid pipes constituting an existing pipeline through which water, gas, etc. flow deteriorate with age or a new branch is formed, a part of the existing fluid pipe may be replaced with a new fluid pipe. In such a case, a commonly used method is to install two flow control valves spaced apart in the axial direction of the existing fluid pipe, block the flow of fluid in a specified section of the fluid pipe with the valve body of each flow control valve, and bypass the specified section to communicate with each other using a bypass pipe, and replace part of the specified section with a new fluid pipe without stopping the flow of fluid in the fluid pipe using the bypass pipe.

[0003] Also, assuming that a bypass pipe is attached in the uninterrupted flow construction method, a fluid pipe having a neck that branches off and extends from a pipeline section through which a fluid flows is also known. In normal use conditions where the bypass pipe is not used, the end of the neck is blocked by a blocking member, and in conditions where the bypass pipe is attached, the end of the neck is opened by removing the blocking member, making it possible to attach a switchgear that is placed between the bypass pipe and the end of the neck. A method is known that allows such a blocking member to be removed in an uninterrupted flow state.

[0004] For example, the method of removing the occluding member in Patent Document 1 involves attaching a valve device to the center of the neck in the pipe axial direction, extracting the occluding member in the extraction direction to a predetermined position, closing the neck with the valve device, and then removing the occluding member. More specifically, the predetermined position is a position where the valve body of the valve device can be advanced and retreated to a position where it is located when the neck is closed, and where the sealing member of the occluding member can be pressed against the inner circumferential surface of the neck on the side of the extraction direction of the occluding member from that position to seal the gap between the occluding member and the neck. In this way, the flow path of the neck can be closed by the sealing member and the valve device, so that the occluding member can be removed from the neck while the flow is uninterrupted. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-132270 A (pages 6 to 8, Figure 6) Summary of the Invention [Problem to be solved by the invention]

[0006] In the method for removing a blocking member of Patent Document 1, a slider jig consisting of a bolt and a nut is used to remove the blocking member from the neck. More specifically, the blocking member is pushed in the removal direction by the fluid pressure in the fluid pipe, and the removal of the blocking member is restricted by the slider jig, while the nut is moved relatively in the direction away from the bolt to remove the blocking member.

[0007] On the other hand, when the fluid pipe and the blocking member have a large diameter, the sealing member that seals between the fluid pipe and the blocking member increases its resistance to removal over time, making it difficult to remove the blocking member using a slider tool. Therefore, there has been a demand for removing the blocking member using a hydraulic or other hydraulic fluid device. The hydraulic fluid circuit of such a hydraulic fluid device is mainly composed of an actuator, a pump for delivering the hydraulic fluid, and a tank for storing the hydraulic fluid, and the hydraulic pressure of the hydraulic fluid can be used to remove the blocking member.

[0008] However, when the fluid in the fluid pipe exerts a force on the actuator, causing the rod and the cylinder to move relative to each other, the pressure of the working fluid being sent out in the actuator is increased, and the returning working fluid may be sent out from the actuator in addition to the working fluid sent out from the pump to the actuator. As a result, the actuator may operate in the direction of removing the blocking member, and the blocking member may move in the direction of removal, which may cause unexpected situations such as leakage of the fluid in the fluid pipe or sudden removal of the blocking member. For this reason, it has been difficult to put into practical use the removal of the blocking member using a working fluid device.

[0009] The present invention has been made in response to these problems, and has an object to provide a method for removing a blocking member that allows the blocking member to be safely removed without interrupting flow, and a working fluid device used therein. [Means for solving the problem]

[0010] In order to solve the above problems, the method for removing a blocking member of the present invention comprises the steps of: 1. A method for removing an obstruction from a fluid conduit without interrupting flow, comprising: an installation step of installing an actuator of a hydraulic fluid device having a hydraulic fluid circuit for removing the closing member on the closing member; a pumping step of pumping a working fluid from a pump of the working fluid device to the actuator in a direction in which the closing member is removed, and pumping a return working fluid from the actuator; a regulating step in which, when a fluid pressure in the fluid pipe exerts a force on the actuator in the sending step, a return working fluid sent out from the actuator is regulated by a fluid control means; a blocking step of blocking an upstream side of the fluid pipe while the return working fluid discharged from the actuator is regulated by the fluid control means; and a removal step of removing the blocking member. According to this feature, when the pump starts to send out the working fluid to the actuator, the actuator is able to send out the returning working fluid, the actuator is actuated to remove the obstructing member, and when the fluid in the fluid pipe exerts a force on the actuator, the returning working fluid sent out from the actuator is regulated by the fluid control means, so that unintended actuation of the actuator can be prevented, and the obstructing member can be safely removed.

[0011] In the regulating process, the sealing force between the blocking member and the fluid pipe is lost, so that the return working fluid sent out from the actuator is regulated by the fluid control means in response to the internal fluid pressure in the fluid pipe exerted on the actuator. According to this feature, not only can the fluid control means stably regulate the return working fluid discharged from the actuator, but also the control can be easily performed.

[0012] In the sending step, the return working fluid sent from the actuator passes through the fluid control means. According to this feature, the configuration of the working fluid circuit can be simplified.

[0013] The supply of the working fluid from the pump is stopped in a state where the return of the working fluid from the actuator is regulated by the fluid control means. According to this feature, the position of the blocking member can be reliably maintained.

[0014] The working fluid device of the present invention comprises: A hydraulic fluid device for removing a blocking member from a fluid pipe without interrupting flow, comprising: a hydraulic fluid circuit including a pump for delivering hydraulic fluid, an actuator operated by the hydraulic fluid, a tank for storing the hydraulic fluid, and a fluid control means capable of regulating the movement of the hydraulic fluid from the actuator to the tank; The fluid control means is characterized in that it opens and closes in response to changes in fluid pressure of the working fluid between the actuator and the fluid control means. According to this feature, when the working fluid is started to be sent from the pump to the actuator, the actuator can send out the returning working fluid, the actuator can be operated to remove the obstructing member, and even if the fluid pressure of the returning working fluid sent out from the actuator changes when the fluid in the fluid pipe exerts a force on the actuator, this is regulated by the fluid control means, so that unintended operation of the actuator can be prevented. This allows the obstructing member to be safely removed.

[0015] The fluid control means is characterized in that it is a counterbalance valve. According to this feature, the working fluid device can be constructed simply. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2A is a plan view, partly in section, showing a pipe body in an installed state in the embodiment, and FIG. 2B is a side view, partly in section, of the same pipe body. [Diagram 2] FIG. 2 is a perspective view of the neck with the closure member attached; [Diagram 3] FIG. 4 is a perspective view showing a state in which a valve device is attached to a neck portion. [Figure 4] FIG. 13 is a perspective view showing a state in which an actuator is attached to a closing member. [Diagram 5] FIG. 5 is a partially cross-sectional plan view of FIG. [Figure 6] FIG. 2 is a plan view of the working fluid circuit. [Figure 7] FIG. 2 is a schematic diagram showing a working fluid circuit. [Figure 8] 13 is a perspective view showing a state in which removal of the blocking member can begin. FIG. [Figure 9] 13 is a partially sectional plan view showing a state in which the closing member has been pulled out to a predetermined position. FIG. [Figure 10] FIG. 4 is a cross-sectional perspective view showing a state in which the neck portion is closed by the valve device. [Figure 11] 13 is a partially cross-sectional plan view showing a state in which the blocking member has been removed from the neck portion. FIG. [Figure 12]FIG. 12 is a partially cross-sectional side view of FIG. [Figure 13] FIG. 13 is a perspective view showing a state in which insertion of the opening and closing device can be started. [Figure 14] FIG. 4 is a perspective view showing a state in which the opening and closing device is inserted to a predetermined position. [Figure 15] FIG. 4 is a perspective view showing a state in which the opening and closing device is inserted into the neck portion. [Figure 16] FIG. 2 is a perspective view showing a state in which the opening / closing device is attached to the neck portion and the valve device is removed. [Figure 17] 1A is a front view with a partial cross section showing the state before the on-off valve body is inserted into another neck portion using the valve insertion device, FIG. 1B is a front view with a partial cross section showing the state after the on-off valve body has been inserted into another neck portion using the valve insertion device, and FIG. 1C is a front view with a partial cross section showing the state after the on-off valve body has been attached to another neck portion. [Figure 18] 4 is a plan view, partially in section, showing a state in which an on-off valve and a bypass pipe are attached to a fluid pipe. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of an embodiment of a method for removing a blocking member according to the present invention and a hydraulic fluid device used therein. EXAMPLES

[0018] A method for removing a closing member according to an embodiment and a working fluid device used therein will be described with reference to FIGS.

[0019] The fluid pipe 1 of this embodiment is a relatively large-diameter ductile cast iron pipe buried underground. The fluid pipe 1 according to the present invention may be made of other metals such as cast iron and steel, or concrete, vinyl chloride, polyethylene, polyolefin, etc. Furthermore, the inner circumferential surface of the fluid pipe may be coated with an epoxy resin layer, mortar, plating, etc., or an appropriate material may be coated on the inner circumferential surface of the fluid pipe by powder coating. In this embodiment, the fluid in the fluid pipe 1 is not limited to the drinking water of this embodiment, but may be, for example, industrial water, agricultural water, sewage, gas, or a gas-liquid mixture of gas and liquid. In addition, the right side of the paper in Figs. 1 and 18 will be described as the upstream side of the fluid pipe 1.

[0020] As shown in FIG. 1, the fluid pipe 1 of this embodiment has an inlet 2, 3 at both the upstream and downstream ends. The inlet 2, 3 are connected to the receiving ports 6, 7 of the fluid pipes 4, 5 that constitute a fluid pipeline buried in the ground in a substantially horizontal direction. The fluid pipe 1 of this embodiment has a pipeline 8 through which the fluid flows, a neck 41 that protrudes in a direction different from the axis of the pipeline 8 and branches horizontally, and a neck 11 that protrudes in a direction different from the axis of the pipeline 8 and branches vertically at a position slightly downstream of the neck 41. In a normal state in which the fluid pipe 1 is laid, the open end 13 of the neck 11 is closed by a plug 21, and the open end 43 of the neck 41 is closed by a plug 51. The necks 11, 41 of this embodiment have a relatively large diameter (in this embodiment, the neck 11 has a diameter of 300 mm, and the neck 41 has a diameter of 200 mm).

[0021] As described later, the fluid pipe 1 of this embodiment has an on-off valve 84 and a bypass pipe 85 attached to the neck 41 to ensure a detour path for the fluid (see Fig. 18), allowing the fluid to continue flowing through the detour path while allowing work to be done on the fluid pipes 4, 5 downstream of the fluid pipe 1, making the fluid pipe 1 suitable for work under uninterrupted flow conditions. Furthermore, the neck 11 is designed so that a gate valve body 190 (see Fig. 17), described later, for separating the pipeline portion 8 can be detached.

[0022] Next, the necks 11, 41 and the plugs 21, 51 (blocking members) will be described. The necks 11, 41 and the plugs 21, 51 in Fig. 1 have different cross-sectional shapes, but are identical in configuration, so the configuration of the neck 41 and the plug 51 will be mainly described. As shown in Fig. 1, the pipe line portion 8 is formed with a cylindrical neck 41 so as to surround a hole 42 formed in the pipe line portion 8, and the neck 41 has an open end 43 communicating with the hole 42, a flange 47 connected to the open end 43, and an opening 44 to which a working valve 76 as a valve device described later can be attached. The cross-sectional shape of the neck 41 in Fig. 1 is approximately circular, but it may be approximately elliptical like the neck 11 in Fig. 1, approximately oval, approximately rectangular, or the like.

[0023] A flange 54 of the plug 51 is detachably fixed to the flange 47 by bolts and nuts 49. A packing (not shown) may be inserted between the flange 47 and the plug 51 to improve the sealing performance. The plug 51 has a cylindrical portion 51a inserted along the inner circumference of the neck 41, and has sealing members 52 and 53 fitted into an annular groove on the outer circumference of the cylindrical portion 51a and held at a predetermined distance in the axial direction of the cylindrical portion 51a. When the plug 51 is fixed to the flange 47, the sealing member 52 contacts the inner peripheral surface 45 on the pipe 8 side from the opening 44, sealing the gap between the neck 41 and the plug 51, and preventing the fluid in the pipe 8 from leaking from the open end 43 and the opening 44. Similarly, when the plug 51 is fixed to the flange 47, the sealing member 53 contacts the inner surface 46 on the open end 43 side of the opening 44, sealing the gap between the neck 41 and the plug 51, thereby preventing the fluid in the pipeline section 8 from leaking from the open end 43.

[0024] In this way, the plug 51 has the function of simultaneously sealing the opening 44 and the open end 43. As the sealing member, a round rubber packing with a circular cross section, a rubber packing with a substantially C-shape or square cross section, or a rubber packing with a lip can be used. Note that a lining type sealing member may be used instead of a fitting type sealing member.

[0025] The sealing members 52, 53 are slidable in the axial direction of the neck 41 on the inner circumferential surface 45 on the side of the pipe 8 of the neck 41 and the inner circumferential surface 46 on the side of the open end 43. In FIG. 1(a), the bolts and nuts 49 are removed, and the plug 51 is pulled out from the flange 47 using the hydraulic fluid device 90 described later. When the sealing member 52 reaches the position of the opening 44, the side of the sealing member 52 facing the opening 44 is no longer in close contact with the inner circumferential surface of the neck 41, so that the sealing member 52 temporarily loses its sealing function. However, when the sealing member 52 is located at the opening 44, the sealing member 53 is in contact with the inner circumferential surface 46 on the side of the open end 43 of the neck 41 to seal the gap between the neck 41 and the plug 51, so that leakage of the fluid in the pipe 8 from the open end 43 is still prevented. When the plug 51 is further removed, the plug 51 moves further away from the flange 47, and the sealing member 52 comes into contact with the inner circumferential surface 46 of the neck 41 on the open end 43 side, thereby sealing the gap between the neck 41 and the plug 51. In other words, leakage of the fluid in the pipeline portion 8 from the open end 43 is always prevented.

[0026] In this way, the plug 51 is provided with the sealing members 52, 53 on the outer peripheral surface of the tubular portion 51a, which are slidable on the inner peripheral surface of the neck 41 in the axial direction of the neck 41, so that the plug 51 can be moved in the axial direction of the neck 41 while maintaining a sealed state. In addition, when the plug 51 is fixed to the flange 47, the dimension from the upper end of the sealing member 53 to the open end 43 is set to be larger than the dimension between the sealing members 52 and 53 provided on the plug 51. Therefore, when the plug 51 is removed while moving away from the flange 47, at least one of the sealing members 52 and 53 can always be in contact with the inner peripheral surface 46 on the open end 43 side at the same time, so that even if the opening 44 is present in the neck 41, the plug 51 can reliably maintain a sealed state regardless of its insertion position.

[0027] 10, the inner circumferential surface of the neck 41 connected to the opening 44 of the neck 41 is provided with a seat 48 against which a valve element 83 of an operating valve 76 (valve device) attached to the opening 44 abuts. As will be described later, when the valve element 83 of the operating valve 76 attached to the opening 44 is moved to close the neck 41, the valve element 83 abuts against the seat 48 formed on the inner circumferential surface of the neck 41, thereby reliably closing the neck 41. The neck 11 and the plug 21 have the same functions and performance as the neck 41 and the plug 51.

[0028] 2, a cover 56 is fixed to the neck 41 by a screw at the opening 44 of the neck 41 to prevent the intrusion of foreign matter. A sealing member may be provided on the side of the cover 56 facing the opening 44, thereby making it possible to seal the gap between the cover 56 and the opening 44.

[0029] Next, the procedure for installing the bypass pipe 85 and the gate valve body 190 in an uninterrupted flow state will be described. When performing the work in an uninterrupted flow state, the first step is to remove the cover 56 from the opening 44 of the neck 41, with reference to Fig. 2.

[0030] Next, as shown in Fig. 3, the working valve body 77 is attached to the opening 44 of the neck 41 (see Fig. 2), and the bolts and nuts are tightened to a specified torque to attach the working valve body 77 and the retainer 78 to the neck 41. In this way, the working valve 76 is attached to the opening 44.

[0031] Next, as shown in Figs. 4 and 5, the hydraulic fluid device 90 (see Fig. 5) is attached to the flange 47 (see Fig. 5) of the neck 41 and the flange 54 (see Fig. 5) formed on the outer periphery of the plug 51. The hydraulic fluid device 90 is mainly composed of first holders 91 and 92 to which two hydraulic actuators 110 are fixed, second holders 93 (see Fig. 10) and 94 fixed to the first holders 91 and 92 by bolts and nuts, and a hydraulic circuit 100 (hydraulic fluid circuit) (see Figs. 6 and 7) including the two hydraulic actuators 110. Note that, among the holders 91 to 94, the holders on the support side attached to the flange 47 of the neck 41 may be referred to as the first holder on the support side 91 and the second holder on the support side 93, and the holders on the moving side attached to the flange 54 side of the plug 51 may be referred to as the first holder on the support side 92 and the second holder on the moving side 94.

[0032] A tip of a rod 112 (see FIG. 5) of each actuator 110 is fixed to the first holder 91 on the support side, and a tip of a cylinder 111 of each actuator 110 is fixed to the first holder 92 on the moving side. The two actuators 110 are fixed to the first holders 91, 92 so as to face each other in the radial direction of the plug 51 (the left-right direction in this embodiment).

[0033] These first holders 91, 92 are fitted onto the outer diameter side ends of the upper sides of the flanges 47, 54 in this embodiment.

[0034] In addition, in this embodiment, the second holders 93, 94 are fitted onto the outer diameter side end portions of the lower sides of the flanges 47, 54. After the first holders 91, 92 are fitted onto the outer diameter side end portions of the flanges 47, 54, respectively, the second holders 93, 94 are fitted onto the outer diameter side end portions of the flanges 47, 54, respectively, while being disposed radially opposite the first holders 91, 92, and the first holder 91 and the second holder 93 are assembled with screws or the like, and the first holder 93 and the second holder 94 are similarly assembled. This allows the two actuators 110 to be attached to the neck portion 41 and the plug 51.

[0035] Here, the hydraulic circuit 100 of the hydraulic fluid device 90 will be described. As shown in Figures 6 and 7, the hydraulic circuit 100 is mainly composed of two actuators 110L, 110R, a pump 120 that delivers hydraulic fluid such as petroleum-based hydraulic oil, a tank 130 that stores the hydraulic fluid, a switching valve 140, a fluid control means 150, and a plurality of rubber tubes 162, 166, 167, 168, 170, 171 (working fluid pipes). As described above, since each tube is made of rubber, it is easy to handle when mounting the actuators 110L, 110R, and the piping configuration is simple and good.

[0036] As shown in FIG. 7, the actuators 110L, 110R are mainly composed of a cylinder 111, a rod 112 inserted into the cylinder 111 and movable in the axial direction, and a piston 113 fixed to the end of the rod 112 and movable in the axial direction while in sliding contact with the inner surface of the cylinder 111.

[0037] The inside of the cylinder 111 is hermetically partitioned into a head chamber 114 and a rod chamber 115 by a piston 113. The side of the cylinder 111 where the rod 112 is disposed is the rod chamber 115, and the opposite side is the head chamber 114.

[0038] 6, the cylinder 111 is provided with a nipple 116 that can communicate with the head chamber 114 and a nipple 117 that can communicate with the rod chamber 115, and is configured to be detachable from the connectors of the tubes. When the connectors of the tubes are detached, the nipples 116, 117 close valves (not shown), preventing the working fluid from leaking from the chambers 114, 115. On the other hand, when the connectors are connected, the valves are open, allowing the working fluid to flow in and out of the chambers 114, 115. This is the same for the connectors of the tubes and the nipples of the pump 120, the switching valve 140, etc. to which the connectors are connected.

[0039] Next, a detailed description will be given of the configuration of the hydraulic circuit 100. In this embodiment, the pump 120 is a manual type, and serves to send out the working fluid from the tank 130 to the main line 160. Note that the pump is not limited to a manual type, and may be a motor type or an engine type, or may be modified as appropriate.

[0040] As shown in FIG. 7, the working fluid delivered from the pump 120 passes through a main line 160 and flows into the switching valve 140 .

[0041] The switching valve 140 is a 6-port, 3-position open center type, and is manual in this embodiment. When the switching valve 140 is in the neutral position, the main line 160 is connected to the tank 130 through a tank side line 161. The switching valve 140 is not limited to the manual type, and may be a switch type or a remote control type, or may be modified as appropriate.

[0042] When the switching valve 140 is in the pull-side position A, it communicates with the main line 160 to the rod chamber 115 and also communicates with the head chamber 114 to the tank-side line 161. When the switching valve 140 is in the push-side position B, it communicates with the main line 160 to the head chamber 114 and also communicates with the rod chamber 115 to the tank-side line 161.

[0043] Here, the connection between the switching valve 140 and each of the actuators 110L, 110R will be described in detail. The switching valve 140 and the head chambers 114 of each of the actuators 110L, 110R are connected by a third head chamber side tube 162, a branch 163, shutoff valves 164, 165, and tubes 166, 167. The first head chamber side tube 166 connected to the first head chamber side shutoff valve 164 is connected to the nipple 116 (see FIG. 6) of the first actuator 110L, and the second head chamber side tube 167 connected to the second head chamber side shutoff valve 165 is connected to the nipple 116 (see FIG. 6) of the second actuator 110R.

[0044] In addition, the tubes 166, 167 are branched from the switching valve 140 by the branch 163 and connected in parallel. Furthermore, the tubes 166, 167 are the same type of tubes and have approximately the same axial length. As a result, the outgoing working fluid flowing from the pump 120 into the branch 163 is distributed approximately equally to the actuators 110L, 110R within the branch 163, so that the actuators 110L, 110R can be operated with the same expansion and contraction amount. The return working fluid flowing from the actuators 110L, 110R into the branch 163 joins together within the branch 163 and flows out into the tank 130.

[0045] On the other hand, the switching valve 140 and the rod chamber 115 of each actuator 110L, 110R are connected by a third rod chamber side tube 168, the fluid control means 150, a high pressure tee 169, and tubes 170, 171. The first rod chamber side tube 170 is connected to the nipple 117 (see FIG. 6) of the first actuator 110L, and the second rod chamber side tube 171 is connected to the nipple 117 (see FIG. 6) of the second actuator 110R.

[0046] The fluid control means 150 includes a main flow path 151 that can communicate with the third rod chamber side tube 168 and the high pressure tee 169, a check valve 152 provided in the middle of the main flow path 151, and a relief valve 153 that can be opened and closed according to the working fluid pressure of the working fluid on the high pressure tee 169 side of the check valve 152 in the main flow path 151. Note that it is preferable to apply a counterbalance valve as the fluid control means 150.

[0047] The check valve 152 is open to the forward working fluid moving through the main flow path 151 from the third rod chamber side tube 168 toward the high pressure tee 169, while being closed to the forward working fluid moving from the high pressure tee 169 toward the third rod chamber side tube 168.

[0048] The relief valve 153 opens at a predetermined pressure or higher, and when opened, causes the working fluid to flow from the high pressure tee 169 side of the main flow path 151 relative to the check valve 152 to the third rod chamber side tube 168 relative to the check valve 152 in the main flow path 151. In addition, the relief valve 153 is capable of adjusting the fluid pressure at which it can be released by an adjusting means (not shown), and therefore can be adjusted according to the internal fluid pressure in the fluid pipe 1.

[0049] Moreover, the tubes 170, 171 are connected in parallel to the fluid control means 150 by the high-pressure tee 169. Furthermore, the tubes 170, 171 are the same type of tubes, and have approximately the same axial length. As a result, the outgoing working fluid that flows into the high-pressure tee 169 from the pump 120 is distributed approximately equally to each actuator 110 within the high-pressure tee 169, so that each actuator 110L, 110R can be operated with the same amount of expansion and contraction. The return working fluid that flows into the high-pressure tee 169 from each actuator 110 joins together within the high-pressure tee 169 and flows out into the tank 130.

[0050] Returning to the explanation of the procedure for installing the bypass pipe 85 and the gate valve body 190 in an uninterrupted flow state, after switching the switching valve 140 of the hydraulic circuit 100 to the push side position B, all of the bolts and nuts 49 (see Figs. 4 and 5) attached to the flange 47 of the neck 41 and the flange 54 of the plug 51 are removed as shown in Fig. 8. Here, in this embodiment, the neck 41 and the plug 51 have relatively large diameters, and the sealing members 52, 53 (see Fig. 5) of the plug 51 are fixed to the inner circumferential surface of the neck 41 due to aging, so that the plug 51 cannot be removed by the internal fluid pressure in the fluid pipe 1 alone.

[0051] Even if the plug 51 can be removed only by the fluid pressure in the pipe, the plug 51 can be maintained in the current closed position by the working fluid device 90. More specifically, by adjusting the pressure value at which the relief valve 153 is opened by the adjustment means to a pressure higher than the fluid pressure in the fluid pipe 1, even if the fluid pressure in the fluid pipe 1 acts on the cylinder 111 of the actuator 110 through the plug 51 and the cylinder 111 tries to move away from the rod 112, increasing the working fluid pressure in the rod chamber 115, the movement of the returning working fluid from the rod chamber 115 is restricted by the fluid control means 150, so that the plug 51 can be maintained in the current closed position.

[0052] 8, anti-withdrawal bolts 95 and nuts 96 are attached to two of the bolt holes from which the bolts and nuts 49 were removed. A stopper 98 is attached to the withdrawal direction side of the plug 51 of a stopper attachment rod 97 that is fixed to the support-side first holder 91 and inserted so as to be movable relatively to the moving-side first holder 92. The position of the anti-withdrawal nut 96 is then adjusted so that it is approximately in line with the edge of the stopper 98 on the neck 41 side.

[0053] Next, referring to Fig. 7, the pump 120 of the hydraulic fluid device 90 is operated. At this time, the switching valve 140 is switched to the push side position B as described above. As a result, the hydraulic fluid sent out from the pump 120 passes through the switching valve 140, the third head chamber side tube 162, the branch 163, the shutoff valves 164 and 165, and the tubes 166 and 167, and flows into the head chamber 114 of each actuator 110, increasing the hydraulic fluid pressure in the head chamber 114. As a result, the piston 113 tries to move toward the rod chamber 115, and the hydraulic fluid pressure between the rod chamber 115 and the relief valve 153 in the fluid control means 150 is increased.

[0054] When the working fluid pressure upstream of the relief valve 153 reaches or exceeds a pressure at which the relief valve 153 can be opened, the relief valve 153 is opened, and the returning working fluid passes from each rod chamber 115 through the tubes 170, 171, the high-pressure tee 169, the relief valve 153, the third rod chamber side tube 168, and the switching valve 140 and is discharged to the tank 130, and the rod 112 is extended, so that the cylinder 111 moves in the direction away from the piston 113 and the rod 112, that is, in the direction in which the plug 51 is removed. This moves the plug 51 in the removal direction via the moving side holders 92, 94.

[0055] In addition, since the working fluid is an incompressible oil, when the relief valve 153 is opened and the working fluid passes through, the working fluid pressure on the upstream side of the relief valve 153 also falls immediately below a pressure sufficient to open the relief valve 153, and the valve element of the relief valve 153 moves in the closing direction by the biasing means of the relief valve 153. Meanwhile, the pressure for opening the relief valve 153 increases again by the working fluid successively delivered from the manual pump 120.

[0056] In this way, by continuously repeating the process of reducing the pressure of the working fluid by passing it through the relief valve 153 and then increasing the pressure of the working fluid by the manual pump 120, the plug 51 is removed to a predetermined position just before or when the movable first holder 92 abuts against the stopper 98, as shown in Figure 9. At this predetermined position, the sealing member 52 is in close contact with the inner circumferential surface 46 of the neck 41, as described above, and the gap between the neck 41 and the plug 51 is sealed.

[0057] In addition, between the start of removal of plug 51 and the time it is moved to a specified position, sealing members 52, 53 may be peeled off from their adhered state to the inner surface of neck 11 as plug 51 moves, reducing the sealing force, or sealing member 52 may reach the position of opening 44, reducing the sealing force.

[0058] In such a case, the force acting to move the cylinder 111 in the direction away from the rod 112 and the piston 113 due to the fluid pressure in the fluid pipe 1 relatively increases, and the working fluid pressure upstream of the relief valve 153 may increase, but the pressure sufficient to open the relief valve 153 is set to a pressure higher than the fluid pressure in the fluid pipe 1, so the relief valve 153 remains closed. As a result, the return working fluid sent out from the rod chamber 115 is regulated by the relief valve 153, so that it is possible to prevent the rod 112 from unintentionally moving in the direction away from the rod 112 and the piston 113.

[0059] Furthermore, the force acting to move the cylinder 111 in the direction away from the rod 112 and the piston 113 due to the fluid pressure in the fluid pipe 1 relatively increases, and the working fluid pressure upstream of the relief valve 153 increases, so that the working fluid pressure upstream of the relief valve 153 and the working fluid pressure in the head chamber 114 also relatively increase compared to when removal of the plug 51 began. This reduces the number of operations of the pump 120 until the working fluid pressure of the working fluid required to open the relief valve 153 is reached.

[0060] Once plug 51 has been removed to a predetermined position, as shown in Figure 10, operating shaft 80 of working valve 76 is rotated to bring valve body 83 into contact with seat 48 and close neck 41. Until neck 41 is closed by working valve 76, leakage of fluid within fluid pipe 1 is prevented by sealing member 52 as described above.

[0061] Furthermore, as described above, even if the force acting on the cylinder 111 due to the fluid pressure inside the fluid pipe 1 to move it away from the rod 112 and the piston 113 changes, the position of the plug 51 can be maintained, so that leakage of the fluid inside the fluid pipe 1 can be stably prevented until the neck 41 is closed by the operating valve 76.

[0062] 11 and 12, the position of the anti-withdrawal nuts 96 is adjusted relative to each anti-withdrawal bolt 95 until the plug 51 can be removed, each stopper 98 is removed from the stopper mounting rod 97, and the entire plug 51 is removed from the neck 41 while the neck 41 is closed using the hydraulic fluid device 90. Finally, the support side holders 91, 93 are removed from the flange 47 of the neck 41, and the plug 51 is removed.

[0063] As described above, at the start of pump 120 sending out the working fluid to actuator 110, the returning working fluid can be sent from actuator 110, actuator 110 can be operated to remove plug 51, and when the fluid in fluid pipe 1 exerts a force on actuator 110, the returning working fluid sent out from actuator 110 is regulated by fluid control means 150, so that unintended operation of actuator 110 can be prevented. This allows plug 51 to be safely removed.

[0064] In addition, since the fluid control means 150 controls the opening and closing of the relief valve 153 in accordance with the working fluid pressure upstream of the relief valve 153, not only can the fluid control means 150 stably regulate the return working fluid sent out from the actuator 110, but the control can also be made easier, compared to a configuration in which, for example, the working fluid pressure in the rod chamber 115 is measured and a valve provided between the actuator 110 and the tank 130 is opened and closed as desired.

[0065] In addition, the relief valve 153 is opened in response to the working fluid pressure on the upstream side of the relief valve 153, whereby the returning working fluid delivered from the actuator 110 passes through the fluid control means 150 and is discharged to the tank 130, so that it is possible to omit a circuit separate from the fluid control means for discharging the returning working fluid delivered from the actuator 110 to the tank 130. In other words, the configuration of the hydraulic circuit 100 can be simplified.

[0066] Furthermore, when the working valve 76 is operated, for example, the pump 120 is not operated and the delivery of the forward working fluid is stopped, so that the relief valve 153 is reliably maintained in a closed state, and the position of the plug 51 can be reliably maintained.

[0067] As described above, the cylinder 111 moves relative to the rod 112 and the piston 113 only while the relief valve 153 is open, and therefore the distance of movement is substantially the same as when removal of the plug 51 was started. In other words, even if the force acting to move the cylinder 111 away from the rod 112 and the piston 113 due to the fluid pressure in the fluid pipe 1 changes, the distance that the plug 51 moves in response to one opening of the relief valve 153 can be kept substantially constant.

[0068] In addition, since the two actuators 110 are attached to the flange 47 of the neck 41 and the flange 54 of the plug 51 via the retainers 91-94, when the cylinder 111 moves in the direction away from the rod 112 and the piston 113, the stress generated by the force of the cylinder 111 moving the plug 51 acts as a reaction force on the neck 41 via the rod 112.

[0069] In contrast, for example, when the cylinder 111 is fixed to the plug body 51 and the rod 112 is attached to a base material other than the fluid pipe 1, when a force is applied to the plug body 51 in the removal direction, a force in the same direction is also applied to the fluid pipe 1.

[0070] For these reasons, by fixing two actuators 110 to the plug 51 and the fluid pipe 1 as in this embodiment, not only is energy efficiency improved, but the load generated at the connection part between the fluid pipe 1 and other fluid pipes can be reduced. Also, since there is no need to separately provide a base material for supporting the stress of the actuators 110, or a restricting means for restricting the movement of the fluid pipe 1 in the direction in which the plug 51 is removed, the space required to remove the plug 51 can be narrowed.

[0071] In addition, since the two actuators 110L, 110R are fixed to the holders 91-94 so as to be equally spaced in the circumferential direction of the plug 51, the plug 51 can be removed along the axial direction of the neck 41. This makes it possible to prevent the plug 51 from tilting relative to the axial direction of the neck 41, which would increase resistance to removal. Furthermore, if a difference in stroke occurs between the operations of the actuators 110, this can be adjusted by operating the shutoff valves 164, 165.

[0072] In addition, since the forward working fluid delivered from the pump 120 is distributed approximately equally to each actuator 110 as described above, the output, stroke, and operation timing of each actuator 110 can be made approximately uniform. This makes it possible to more suitably remove the plug 51 while preventing it from tilting relative to the axial direction of the neck 41.

[0073] In addition, the length of each of the first rod chamber side tube 170 and the second rod chamber side tube 171 between each actuator 110 and the fluid control means 150 is shorter than the length of the third rod chamber side tube 168 between the switching valve 140 and the fluid control means 150, and since they are the same type of tube, their inner diameter and outer diameter are approximately the same. That is, the fluid control means 150 is positioned closer to each actuator 110 than the switching valve 140, and the volume of each of the tubes 170, 171 is smaller than the volume of the third rod chamber side tube 168. Therefore, when the working fluid pressure on the upstream side of the relief valve 153 becomes high, the amount of expansion of the tubes 170, 171 can be relatively reduced. This makes it possible to more stably prevent unintended relative movement between the cylinder 111 and the rod 112.

[0074] Furthermore, since fluid control means 150 for regulating the return working fluid discharged from actuator 110 is composed of a single counterbalance valve, the configuration of fluid control means 150 can be made more compact than a configuration in which a working fluid pipe having a check valve that functions in the same manner as check valve 152 and a working fluid pipe having a relief valve that functions in the same manner as relief valve 153 are separately provided between switching valve 140 and actuator 110.

[0075] In addition, the area S1 of the pressure receiving surface of the piston 113 facing the head chamber 114 is larger than the area S2 of the pressure receiving surface of the piston 113 facing the rod chamber 115 by the cross-sectional area S3 of the rod 112 (S1=S2+S3). H1 Pressing force F multiplied by area S1 H1 (F H1 =P H1 ×S1) occurs. Accordingly, in the rod chamber 115, a pressing force F H1 The increased pressure P is calculated by dividing by the area S2. H2 (P H2 =F H1 Therefore, the working fluid pressure on the upstream side of the relief valve 153 can be increased efficiently.

[0076] In addition, since the area S2 of the pressure-receiving surface of the piston 113 facing the rod chamber 115 is smaller than the area S1 of the pressure-receiving surface facing the head chamber 114 (S1>S2), when the fluid in the fluid pipe 1 exerts a force on the actuator 110, the working fluid pressure is less likely to be increased in the rod chamber 115 than in the head chamber 114. This makes it possible to reduce the effect of the fluid pressure in the fluid pipe 1 compared to when the head chamber 114 is located upstream of the relief valve 153.

[0077] Next, the installation of the on-off valve 84 (on-off device) to the neck 41 using the working fluid device 90 will be described. The on-off valve 84 has a cylindrical portion 84a that is substantially the same as the cylindrical portion 51a of the plug 51, and two sealing members are attached to this cylindrical portion 84a, similar to the sealing members 52, 53 of the plug 51, so that the neck 41 can be closed in the same way as the plug 51. In the following explanation, explanations that are substantially the same as the method of removing the plug 51 will be omitted.

[0078] 13, the movable side holders 92, 94 are removed from the plug 51 and fixed to the flange of the on-off valve 84, and the support side holders 91, 93 are attached to the flange 47 of the neck 41. At this time, the on-off valve 84 is in a closed state.

[0079] Next, after switching the switching valve 140 of the hydraulic circuit 100 to the retract side position A, the anti-withdrawal bolt 95 and nut 96 are attached again, and the stopper 98 is attached to the insertion direction side of the stopper mounting rod 97 toward the opening / closing valve 84.

[0080] Next, referring to Fig. 7, the pump 120 of the hydraulic fluid device 90 is operated. As a result, the hydraulic fluid sent out from the pump 120 passes through the switching valve 140, the third rod chamber side tube 168, the check valve 152 of the fluid control means 150, the high pressure tee 169, and the tubes 170 and 171, and flows into the rod chamber 115 of each actuator 110, increasing the hydraulic fluid pressure in the rod chamber 115. As a result, the piston 113 moves to the head chamber 114 side, and the returning hydraulic fluid passes from each head chamber 114 through the switching valve 140, the tubes 166 and 167, the shutoff valves 164 and 165, the branch 163, the third head chamber side tube 162, and the switching valve 140, and is discharged to the tank 130. That is, the cylinder 111 moves toward the piston 113 and rod 112, i.e., in the insertion direction of the on-off valve 84, and moves the on-off valve 84 in the insertion direction via the moving retainers 92, 94, inserting the tubular portion of the on-off valve 84 into the neck portion 41.

[0081] When the on-off valve 84 is inserted, even if the force acting on the fluid pressure in the fluid pipe 1 to move the cylinder 111 in the direction away from the rod 112 and the piston 113 changes and the working fluid pressure in the rod chamber 115 increases, the forward working fluid delivered from the pump 120 can flow into the rod chamber 115, while the backflow to the pump 120 side is restricted by the check valve of the pump 120, preventing the cylinder 111 from moving in the direction away from the rod 112 and the piston 113. Note that the check valve for preventing backflow to the pump 120 side may be located downstream of the fluid control means 150.

[0082] Next, as shown in Figure 14, when the opening / closing valve 84 is inserted to a predetermined position just before or when the first holders 91, 92 abut against the stopper 98, the operating shaft 80 of the working valve 76 is rotated to store the valve body 83 within the working valve main body 77 (see Figure 12), and the neck portion 41 is opened.

[0083] Furthermore, even if the fluid pressure in the fluid pipe 1 acts on the opening / closing valve 84 due to the opening of the neck 41, the cylinder 111 is prevented from moving away from the rod 112 and the piston 113, as described above, so that leakage of the fluid in the fluid pipe 1 can be prevented.

[0084] Next, as shown in FIG. 15, each stopper 98 is removed, each of the fall-out prevention bolts 95 and nuts 96 (see FIG. 10) is tightened until it contacts the branch side flange of the on-off valve 84, and the entire cylindrical part of the on-off valve 84 is inserted using the working fluid device 90. Then, each of the fall-out prevention bolts 95 and nuts 96 is removed, and the flange 47 of the neck part 41 and the flange of the on-off valve 84 are fixed using all of the bolts and nuts 49. Finally, as shown in FIG. 16, the working valve 76 is removed from the opening 44 of the neck part 41, and the opening 44 is closed with the cover 56. After that, the bypass pipe 85 is fixed to the on-off valve 84 using bolts and nuts (see FIG. 18).

[0085] Next, a procedure for attaching the gate valve body 190 for separating the pipeline section 8 to the neck 11 using the valve insertion device 200 will be described. The plug 21 attached to the neck 11 is removed by removing the backup ring 26 (see FIG. 1) that blocks the opening 14 from the neck 11, and then installing an operating valve to the opening 14, and then removing the plug 21 in the same procedure as for removing the plug 51, using a working fluid device attached with a retainer formed so as to be engageable with the flange 17 of the neck 11 and the flange of the plug 21.

[0086] As shown in Figure 17(a), the moving frame 202 is fixed to the flange 191 of the gate valve body 190 using a retaining member 203 and a bolt 204. Next, the sealing member 194 provided on the housing 192 of the gate valve body 190 is inserted into the upper inner circumferential surface 16 of the neck 11 to seal the gap between the housing 192 and the neck 11. Furthermore, the fixed frame 201 is fixed to the flange 17 of the neck 11 by an engaging member 205. Since the moving frame 202 is supported by the fixed frame 201 via a jack bolt 207, the gate valve body 190 is held so as not to move even if the pressure of the fluid in the pipeline portion 8 acts on the gate valve body 190.

[0087] Next, the valve element 83 of the working valve attached to the neck 11 is stored inside the working valve body 77, and the jack bolt 207 is rotated to insert the gate valve body 190 into the neck 11 (see FIG. 17(b)). Finally, the flange 17 of the neck 11 and the flange 191 of the gate valve body 190 are fastened and fixed with the bolts and nuts 19, and the valve insertion device 200 is removed (see FIG. 17(c)).

[0088] In this way, the installation of the gate valve body 190 to the neck 11, the installation of the on-off valve 84 to the neck 41, and the installation of the bypass pipe 85 are completed, as shown in Figure 18. When replacing the fluid pipes 4, 5, the on-off valve 84 attached to the neck 41 is opened on both the upstream and downstream sides to allow fluid to flow through the bypass pipe 85, and the upstream and downstream gate valve bodies 190 provided in the pipeline section 8 are closed. This makes it possible to carry out work on the fluid pipes 4, 5 sandwiched between the two gate valve bodies 190 without interrupting the flow.

[0089] When the construction work under the uninterrupted flow condition is completed and the fluid pipe 1 is returned to the laid state in which it is installed for a long period of time, first, the gate valve body 190 of the pipeline section 8 is pulled up and housed in the housing 192 to open the pipeline section 8 and allow the fluid to flow through the downstream fluid pipes 4, 5. Next, the on-off valve 84 attached to the neck section 41 is closed, the bypass pipe 85 for detouring is removed, and the on-off valve 84 is removed from the neck section 41 using the working fluid device 90 in the same procedure as the method for removing the plug 51. Then, the open end 43 of the neck section 41 is closed with the plug 51 using the working fluid device 90 in the same procedure as the method for attaching the on-off valve 84, and the flange 47 of the neck section 41 and the flange 54 of the plug 51 are fixed using the bolts and nuts 49.

[0090] After the gate valve body 190 is fixed by attaching the valve insertion device 200, the bolts and nuts 19 tightening the gate valve body 190 and the flange 17 of the neck 11 are removed (see FIG. 17(b)). Next, the gate valve body 190 is raised to a position where the sealing member 194 of the gate valve body 190 is in contact with the upper inner circumferential surface 16 of the neck 11 and the valve body of the working valve can be closed, and then the valve body of the working valve is inserted into the neck 11 to close the neck 11. Finally, the gate valve body 190 and the valve insertion device 200 are removed, and the open end 13 of the neck 11 is blocked by the plug 21 using the working fluid device 90 in the same procedure as the installation method of the on-off valve 84, and the flange 17 of the neck 11 and the flange of the plug 21 are fixed using the bolts and nuts 19. The opening 14 is also blocked by the backup ring 26.

[0091] 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.

[0092] For example, in the above embodiment, the working fluid circuit of the working fluid device has been described as being a hydraulic circuit equipped with a hydraulic actuator, but this is not limited to this and may be a pneumatic circuit equipped with a pneumatic actuator, or may be modified as appropriate.

[0093] In addition, in the above embodiment, the actuator is described as being attached to the fluid tube and the stopper, but this is not limited to this and, although not specifically shown, the actuator may be fixed to the stopper and a substrate having rigidity other than the fluid tube.

[0094] In the above embodiment, the actuator is described as having a cylinder attached to the plug and a rod attached to the fluid pipe, but this is not limited to this, and the cylinder may be attached to the fluid pipe and the rod may be attached to the plug.

[0095] In addition, in the above embodiment, the same working fluid device is used for both removing the plug body and installing the on-off valve, but this is not limited to this, and different working fluid devices may be used for removing the plug body and installing the on-off valve, a slider jig may be used to install the on-off valve, or other modifications may be made as appropriate.

[0096] In the above embodiment, the actuator is described as a double-acting type in which the actuator is switched between extending and retracting by a switching valve, but the present invention is not limited to this and may be a single-acting type. Even if the actuator is a single-acting type, unintended actuator operation can be prevented by regulating the return working fluid by a fluid control means.

[0097] In addition, in the above embodiment, the working fluid pipe is described as being made of rubber, but this is not limited to this and may be made of metal or resin, and is not limited to being made of rubber.

[0098] In the above embodiment, the fluid control means is described as a counterbalance valve, but this is not limited to this, and the actuator may be connected to the pump side by an actuating fluid pipe having a check valve, and the actuator may be connected to the tank side by an actuating fluid pipe having a relief valve, and other configurations may be used, and may be modified as appropriate.

[0099] In addition, in the above embodiment, the passage of the return working fluid is controlled using a relief valve that can be opened and closed in response to the working fluid pressure upstream of the relief valve, but this is not limited to this, and the relief valve may be one that can be opened and closed in response to the working fluid pressure between the actuator and the pump, or a valve that can be opened at will by the operator of the working valve, or may be modified as appropriate.

[0100] In the above embodiment, the plug 51 for blocking the neck 41 of the fluid pipe 1 is shown as a blocking member that is the target of the removal method according to the present invention, but the present invention is not limited thereto, and for example, even if a valve body capable of opening and closing the inside of the neck 41 is provided, such as the on-off valve 84 attached to the neck 41 instead of the plug 51 in the present embodiment, it may be removed by using the working fluid device 90 with the valve body in a blocked state after use, i.e., the on-off valve 84 is included in the blocking member that is the target of the removal method according to the present invention. Furthermore, for example, although not shown in particular, a valve device provided with a valve body that opens and closes the inside of the fluid pipe by sealing the inner surface of the pipe may be removed by using the working fluid device 90 with the valve body in an open state, i.e., such a valve device is included in the blocking member that is the target of the removal method according to the present invention. [Explanation of symbols]

[0101] 1 Fluid tube 8 Pipe section 41 Neck 51 Plug (obstructing member) 52,53 Sealing member 76 Working valve (valve gear) 84 On-off valve (on-off device) 85 Bypass pipe 90 Hydraulic Fluid Device 100 Hydraulic circuit (working fluid circuit) 110 Actuator 111 Cylinder 112 Rod 120 Pump 130 Tank 140 Switching valve 150 Fluid control means 166,167 Tube (working fluid tube) 170,171 Tube (working fluid tube)

Claims

1. 1. A method for removing an obstruction from a fluid conduit without interrupting flow, comprising: an installation step of installing a pair of actuators of a working fluid device including a working fluid circuit for removing the closing member on the closing member in a radial direction of the closing member; a sending step of branching and sending out the working fluid from a pump of the working fluid device to each of the actuators in a direction in which the blocking member is removed, and sending out returning working fluid from each of the actuators and joining the flow of the working fluid; a regulating step in which the returning working fluids sent from the respective actuators and joined together in the sending step are regulated by a fluid control means; a closing step of closing an upstream side of the fluid pipe in a state in which the returning working fluids sent from the respective actuators and joined together are regulated by the fluid control means; a removal step of removing the blocking member.

2. The method for removing a blocking member as described in claim 1, characterized in that in the regulating process, the sealing force between the blocking member and the fluid pipe is lost, so that the return working fluid sent out from each of the actuators and joining together is regulated by the fluid control means against the internal fluid pressure in the fluid pipe acting on the actuator.

3. 3. The method for removing a blocking member according to claim 1, wherein in the sending step, the returning working fluids sent from the respective actuators and joined together pass through the fluid control means.

4. A method for removing a blocking member as claimed in any one of claims 1 to 3, characterized in that the supply of working fluid from the pump is stopped in a state in which the returning working fluid discharged from each of the actuators and joined together is regulated by the fluid control means.

5. A hydraulic fluid device for removing a blocking member from a fluid pipe without interrupting flow, comprising: a working fluid circuit including a pump for delivering working fluid, a pair of actuators arranged in a radial direction of the closing member and operated by the working fluid, a tank for storing the working fluid, a junction where return working fluids delivered from the actuators join together, and a fluid control means capable of regulating the movement of the working fluid from the junction to the tank, A hydraulic fluid device used for removing a blocking member, characterized in that the fluid control means is capable of opening and closing in response to a change in fluid pressure of the hydraulic fluid between the actuator and the fluid control means.

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