JP4721864B2 - Gas shutoff jig, water removal device removal method using this, and joint replacement work method - Google Patents

Description

  The present invention relates to a gas blocking jig for closing a perforation formed in a pipe line communicating with a branch hole of a metal material split joint mounted on a pipe, a water removal device removal method using the same, and a joint replacement work Concerning construction method.

  When connecting a supply pipe to this branch pipe, shutting off gas leaking from this branch pipe, providing a bypass pipe in this branch pipe that bypasses this damaged branch pipe, and removing residual water remaining in this branch pipe, Install supply pipes and bypass pipes to the main pipes via joints attached to the main pipes, or attach joints to the main pipes on the upstream side and downstream side of the leaking part, and insert a shut-off jig into these joints. Generally, this branch pipe is cut off, or a water catcher is attached to a branch port provided at the lower part of the joint.

  In order to connect the supply pipe to this branch pipe, as described in Patent Document 1, a split joint is attached to this branch pipe by a no-blow operation, and a transition service cheese equipped with a stopper for service cheese is installed at the branch port of the split joint. Install. And the branch port of a division joint is obstruct | occluded with the stopper for service cheese, a supply pipe is connected to service cheese, transition service cheese is removed from a division joint by a no-blow operation | work, and a plug is attached to service cheese.

  In order to attach a water catcher to this branch pipe, as described in Patent Document 2, a split joint (a joint member in the literature) is attached to the outside of the water reservoir portion of this branch pipe, and the lower split joint is branched. A water catcher is attached to the mouth, and the upper and lower walls of the branch pipe are drilled from the branch port of the upper split joint, and the drill is removed by no blow and a plug is attached to the branch port of the upper split joint. Then, after draining the water in this branch pipe from the branch port of the lower split joint into the water catcher, remove the plug by no blow, insert a stopper in the lower perforated part, remove the water catcher and branch After attaching the plug to the mouth, remove the stopper with no blow and attach the plug to the upper branch port.

JP 2001-82672 A JP-A-9-217887

  Some of the split joints attached to this branch pipe are made of a metal material and galvanized on the surface. When this metal-made split joint is buried in the soil, the galvanization gradually melts and the split joint may corrode, so it is necessary to replace it periodically.

  However, when the split joint is removed from the main pipe, there is currently no means for reliably closing the perforation provided in the main pipe by a simple method, and it cannot be replaced with a new split joint by no blow. Therefore, if a gas shut-off bag is inserted upstream and downstream of the main pipe where the split joint is installed, the split joint that has been corroded by no blow can be replaced. The problem arises that increases.

  When exchanging the water catcher attached to the lower part of the split joint, the upper perforation and lower perforation provided in the pipes communicating with the upper branch hole and the lower branch hole provided above and below the split joint are simultaneously performed. Although it is necessary to close the hole, there is no means for reliably closing these holes by a simple method. Therefore, it is possible to replace the split joint by inserting a gas shut-off bag into the main branch pipe on the upstream side and downstream side of the split joint and cutting the pipe line inside both shut-off backs. Similar to the exchange of joints, there arises a problem that the excavation area increases and the work becomes large and the work cost increases.

  The present invention has been proposed in view of such a problem, and replacement of a split joint and replacement of a water collector attached to the split joint are performed by a simple method with low work cost and no blow. An object of the present invention is to provide a gas shut-off jig that can be used, a water removal device removal work method using the same, and a joint replacement work method.

  In order to solve such a problem, a gas shutoff jig according to the present invention includes a base shaft portion having a protruding portion at a tip portion, and a first elasticity attached to the base shaft portion and abutted against a rear end portion of the protruding portion. , A spacer attached to the base shaft portion and abutted against the rear end portion of the first elastic portion, a second elastic portion attached to the base shaft portion and abutted against the rear end portion of the spacer, and attached to the base shaft portion And a pressure cylinder portion that is pressed against the rear end portion of the second elastic portion to compress and open the first elastic portion and the second elastic portion, and is attached to the base shaft portion so as to be able to advance and retract. And an operation knob for pressing and releasing the distal end to increase the diameter of the first elastic portion and the second elastic portion and release the expansion.

  According to the present invention, the gas shut-off jig includes the base shaft portion, the first elastic portion, the spacer, the second elastic portion, the pressurizing cylinder portion, and the operation knob. The provided upper perforation and lower perforation can be simultaneously closed by the first elastic portion and the second elastic portion. For this reason, it is possible to replace the water catcher attached to the split joint while closing the upper perforation and the lower perforation, and it is possible to replace the water catcher without blowing.

  The operating knob of the present invention is characterized in that it is screwed to the base shaft portion and can be advanced and retracted along the base shaft portion.

  According to this invention, since the operation knob is screwed to the base shaft portion and can advance and retreat along the base shaft portion, when the operation knob is rotated, the operation knob is moved along the base shaft portion according to the rotation amount. Can be made. When the rotation of the operation knob is stopped, the operation knob stops in a state of being locked to the base shaft portion, and movement in the axial direction is restricted. For this reason, the diameter of the first elastic part and the second elastic part can be expanded and canceled by a simple operation, and the expanded state of the first elastic part and the second elastic part can be easily maintained. Can do.

  Further, the first elastic portion of the present invention can communicate with the upper branch hole of the split joint attached to the pipe and can pass through the upper perforation provided in the pipe, and can communicate with the lower branch hole of the split joint. The second elastic part has a size that can be inserted into the upper perforation, and has a size that can be inserted into the lower perforation provided in the conduit.

  According to this invention, the first elastic part has a size that can pass through the upper perforation and can be inserted into the lower perforation, and the second elastic part has a size that can be inserted into the upper perforation. When the first elastic portion of the blocking jig is inserted into the upper perforation from above the first elastic portion, the first elastic portion is inserted into the lower perforation through the upper perforation. At the same time, the second elastic part is inserted into the upper perforation. For this reason, a 1st elastic part and a 2nd elastic part can be simultaneously inserted in each drilling corresponding to these.

  The present invention also provides a pipe joint with a split joint having an upper branch hole and a lower branch hole, and an upper perforation communicated with the upper branch hole and a lower perforation communicated with the lower branch hole. A water removal device removing work method for removing a water removal device from a split joint in which a water removal device for removing water stored in the lower branch hole is attached, wherein the gas shutoff according to any one of claims 1 to 3 is provided. Inserting the no-blow work back equipped with the jig into the upper branch hole of the split joint and inserting the first elastic part of the gas shut-off jig through the upper drilling into the lower drilling by the operation in the no-blow work back A step of inserting the second elastic part of the gas shut-off jig into the upper perforation to expand the diameter of the first elastic part and the second elastic part to close each perforation, and removing the water collector from the lower branch hole A plug is attached to the lower branch hole to close the lower branch hole And degree, remove the gas blocking jig Noburo work in the back, characterized by having a step of closing the upper branch hole by mounting the plug to the upper branch hole.

  According to the present invention, a no-blow work back equipped with a gas shut-off jig is attached to the upper branch hole of the split joint, and the first elastic part of the gas cut-off jig is inserted into the lower perforation in the no-blow work back, Insert the second elastic part of the gas shut-off jig into the upper perforation, expand the diameter of the first elastic part and the second elastic part to close each perforation, remove the water collector from the lower branch hole and remove the lower branch hole And remove the gas blocking jig in the no-blow work back to close the upper branch hole. According to this, since the first elastic part and the second elastic part simultaneously close the upper perforation and the lower perforation, there is no possibility of gas leaking when removing the water catcher from the split joint. For this reason, the removal work of a water catcher can be performed by no blow. In addition, in the exchanging operation of the water catcher, the exchanging operation of the water catcher can be performed only by excavating the periphery of the embedded split joint, so that the work range can be reduced and the work cost can be reduced.

  Further, the present invention provides a split joint mounted on a pipe having a size capable of being inserted into an upper perforation provided in the pipe in communication with the upper branch hole of the split joint. Using a gas shutoff jig provided with an elastic part (for example, the second elastic part 40 in the embodiment) that is compressed and deformed by operation to close the upper perforation, the split joint is replaced with another split joint (for example, the plastic in the embodiment). This is a joint replacement work method for replacement with a material split joint 86), in which a no-blow work back equipped with a gas shutoff jig is installed in the upper branch hole of the split joint and an operation in the no-blow work back Inserting the elastic part of the gas shut-off jig into the upper perforation to close the upper perforation by expanding the elastic part, and removing the split joint from the pipe and attaching another split joint to the pipe And no blow work bar Attach to the upper branch hole of the other split joint, remove the gas shut-off jig from the pipe in the no-blow work back, and plug the upper branch hole of the other split joint to close the upper branch hole. And a process.

  According to the present invention, a no-blow work back equipped with a gas shut-off jig is attached to the upper branch hole of the split joint, and the elastic part of the gas cut-off jig is inserted into the upper perforation within the no-blow work back and expanded. The upper perforation is closed, the split joint is removed from the pipe, the other split joint is attached to the pipe, the no-blow work back is attached to the upper branch hole of the other split joint, and the gas is generated in the no-blow work back. Remove the blocking jig from the pipe and close the upper branch hole of the other split joint. According to this, since the elastic part of the gas shut-off jig is inserted into the upper perforation through the upper branch hole and expanded in diameter to block the upper perforation, the split joint can be connected without being affected by the presence of the jig. Can be removed from the road. For this reason, the replacement work of the split joint becomes easy, and the replacement work can be performed with no blow.

  Another split joint of the present invention is formed of a plastic material.

  According to the present invention, by forming the replacement split joint with a plastic material, it is possible to obtain a split joint that is difficult to corrode, and it is possible to suppress the occurrence of differential water and gas leakage due to the corrosion of the split joint. it can.

  According to the gas shut-off jig according to the present invention, the water removal device removal method and the joint replacement work method using the same, the gas shut-off jig includes the base shaft portion, the first elastic portion, the spacer, the second elastic portion, and the pressurization. It has a cylindrical part and an operation knob, and removes the water catcher attached to the split joint using this gas shut-off jig, and other parts of the split joint using the gas shut-off jig with an elastic part. By exchanging with the split joint, it is possible to replace and remove the split joint attached to the pipe and the water catcher attached to the split joint at low operating cost and by no blow.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a gas shutoff jig according to the present invention, a water removal device removal work method and a joint replacement work method using the same will now be described with reference to FIGS. First, before explaining the gas shut-off jig used for removing the water collector, the split joint into which this jig is inserted will be outlined.

  As shown in FIG. 1 (side view), the split joint 80 has an upper clamp 81 and a lower clamp 82 that are vertically opposed to each other with the pipe line 90 at the center, and these clamps 81 and 82 are fixed to the pipe line 90. Fastening means (not shown) for fastening bolts and nuts. The upper clamp 81 and the lower clamp 82 are formed in a substantially U shape, and an upper branch hole 81a and a lower branch hole 82a pass through each central portion.

  The gas shut-off jig 1 inserted into the split joint 80 configured as described above has a base shaft portion 10 having a protruding portion 11 protruding outward at a tip portion, and is slidably attached to the base shaft portion 10. The first elastic portion 20 that is abutted against the rear end portion of the protruding portion 11, the spacer 30 that is slidably attached to the base shaft portion 10 and is abutted against the rear end portion of the first elastic portion 20, and the base shaft portion 10 A second elastic portion 40 that is slidably attached and abuts against the rear end portion of the spacer 30, and a second elastic portion 40 that is slidably attached to the base shaft portion 10 and abuts against the rear end portion of the second elastic portion 40. A pressure cylinder portion 50 that compresses and releases the first elastic portion 20 and the second elastic portion 40, and a pressure cylinder portion 50 that is attached to the base shaft portion 10 so as to be able to advance and retreat, press the pressure cylinder portion 50 toward the distal end side, and release the pressure. The diameter of the first elastic part 20 and the second elastic part 40 is increased and the diameter is released. Comprising an operation knob 60.

  The protruding portion 11 provided at the distal end portion of the base shaft portion 10 is formed in a conical shape such that the diameter gradually decreases as it advances toward the distal end side, and enters the upper perforation 91 and the lower perforation 92 provided in the conduit 90. The base shaft portion 10 can be easily inserted. The protruding portion 11 is detachably attached to the distal end portion of the base shaft portion 10. Note that the protruding portion 11 may be integrally attached to the base shaft portion 10.

  The first elastic portion 20 is formed of a rubber material and has a cylindrical shape. The base shaft portion 10 is inserted through the internal through hole 21 and is slidable along the axial direction of the base shaft portion 10. The first elastic portion 20 has a larger diameter than the protruding portion 11. In addition, the 1st elastic part 20 may be comprised with the inclined surface which an outer diameter becomes small gradually as it advances to the front end side.

  The spacer 30 is formed of a metal material and has a cylindrical shape. The base shaft portion 10 is inserted into the internal through hole 31 and is slidable along the axial direction of the base shaft portion 10. Flange portions 32, 33 are formed at the front end portion and the rear end portion of the spacer 30. The front flange portion 32 contacts the rear end portion of the first elastic portion 20, and the rear end flange portion 33. Is in contact with the tip of the second elastic portion 40. The axial length of the spacer 30 is such that when the first elastic portion 20 is disposed in the lower perforation 92, the second elastic portion 40 is positioned in the upper perforation 91. The spacer 30 has a length corresponding to the outer diameter φD of the pipe line 90. For this reason, by preparing the spacer 30 according to the pipe line 90 in advance, the gas blocking jig 1 can be used for pipes having different outer diameters, and the usability of the gas blocking jig 1 can be improved. .

  The second elastic portion 40 is formed of a rubber material and has a cylindrical shape. The base shaft portion 10 is inserted into the internal through hole 41 and is slidable along the axial direction of the base shaft portion 10. The side surface 42 of the second elastic portion 40 is inclined so that the outer diameter gradually decreases as it advances toward the distal end side. The outer diameter of the side surface 42 is formed such that the front end portion is smaller than the inner diameter of the upper perforation 91 and the outer shape of the rear end portion is larger than the inner diameter of the upper perforation 91. For this reason, when the second elastic portion 40 is inserted into the upper perforation 91, any part of the side surface 42 hits the upper perforation 91, and when the second elastic portion 40 expands in this state, the second elastic portion 40 is elastically deformed and the upper perforations 91 can be easily closed.

  The pressurizing cylinder portion 50 is formed of a metal material and has a cylindrical shape. The base shaft portion 10 is inserted into the internal through-hole 51 and is slidable along the axial direction of the base shaft portion 10. A flange portion 52 is formed at the distal end portion of the pressure cylinder portion 50, and this flange portion 52 contacts the rear end surface of the second elastic portion 40. The flange portion 52 has a larger area than the rear end portion of the second elastic portion 40 and can contact the entire rear end portion of the second elastic portion 40. The outer diameter of the flange portion 52 is smaller than the inner diameter of the upper branch hole 81 a of the split joint 80 and larger than the inner diameter of the upper perforation 91. For this reason, the pressurization cylinder part 50 is movable in the upper branch hole 81a. The axial length of the pressure cylinder portion 50 is such that the rear end portion of the pressure cylinder portion 50 is above the upper end of the upper branch hole 81a of the split joint 80 when the second elastic portion 40 is inserted into the upper perforation 91. The length that extends to the position. That is, the gas cutoff jig 1 can be inserted into and removed from the split joint 80.

  The operation knob 60 is formed in a disc shape, and is screwed to the rear end side of the base shaft portion 10 so as to advance and retreat along the axial direction of the base shaft portion 10. For this reason, when the operation knob 60 is rotated to one side and moved to the tip side, the pressure cylinder portion 50 moves downward, the second elastic portion 40 is compressed, and the spacer 30 moves downward. The first elastic part 20 is compressed.

  Next, the water removal device removal work method for removing the water removal device 70 attached to the lower part of the split joint 80 attached to the pipe line 90 using the gas blocking jig 1 will be described. First, as shown in FIG. 2A (partial cross-sectional view), a no-blow work back 72 equipped with a gas shut-off jig 1 is attached to the upper branch hole 81a of the split joint 80, and within the no-blow work back 72 The plug 73 attached to the upper branch hole 81a is removed.

  Then, as shown in FIG. 2B (partial sectional view), the first elastic portion 20 of the gas blocking jig 1 is inserted into the lower perforation 92 through the upper perforation 91 in the no-blow work back 72, The second elastic part 40 of the gas cutoff jig 1 is inserted into the upper perforation 91. Then, the operation knob 60 is rotated to compress and expand the diameter of the first elastic portion 20 and the second elastic portion 40 to close the perforations 91 and 92.

  Then, as shown in FIG. 3C (partial sectional view), the water collector 70 is removed from the lower branch hole 82a, and a plug 74 is attached to the lower branch hole 82a to close the lower branch hole 82a. Then, as shown in FIG. 3D (partial sectional view), the gas blocking jig 1 is removed from the upper branch hole 81a in the no-blow work back 72, and a plug 73 is attached to the upper branch hole 81a to attach the upper branch hole. 81a is closed, the no-blow work back 72 is removed from the upper branch hole 81a, and the water removal device removal work is completed.

  As described above, since the gas cutoff jig 1 can simultaneously close the upper perforation 91 and the lower perforation 92 by the first elastic portion 20 and the second elastic portion 40, when removing the water collector 70 from the split joint 80. There is no risk of gas leaking out. For this reason, the removal work of the water collector 70 can be performed by no blow. Further, in the replacement work of the water catcher 70, since the object of the work is only the split joint 80 and the water catcher 70 attached thereto, the excavator around the buried split joint 80 is simply excavated. Exchange work can be performed, the work range can be reduced, and the work cost can be reduced. Since the gas shutoff jig 1 can be inserted into and removed from the split joint 80 as described above, the split joint 80 is connected to the pipe line 90 in a state where the upper perforation 91 and the lower perforation 92 are closed by the gas shutoff jig 1. And a new split joint 80 can be attached to the pipe line 90 by no blow.

  Further, since the operation knob 60 is screwed to the base shaft portion 10 and can advance and retreat along the base shaft portion 10, the operation knob 60 can be moved according to the rotation amount of the operation knob 60, and the operation knob 60 can be rotated. When the movement is stopped, the operation knob 60 stops in a state of being locked to the base shaft portion 10, and the movement in the axial direction is restricted. For this reason, the diameter of the first elastic part 20 and the second elastic part 40 can be expanded and released by a simple operation, and the expanded state of the first elastic part 20 and the second elastic part 40 can be easily achieved. It can be maintained, and it is possible to reliably prevent the gas from leaking during the water removal device removal work.

  In addition, as shown in FIG. 4 (partial sectional view), the gas shut-off jig 1 described above is a split attached to provide a split joint 85 or a branch pipe (not shown) attached for gas shut-off. A gas shut-off jig (hereinafter referred to as “single shut-off jig 3”) capable of closing the upper perforation 91 provided in the pipe line 90 by being inserted into the joint 85 ′ can be used.

  This single blocking jig 3 has a columnar contact member 63 extending in the lateral direction attached to the distal end portion of the base shaft portion 10, and a spacer 30 disposed at the rear end portion of the contact member 63. The protrusion 11 of the gas shut-off jig 1 shown in FIG. 1 is replaced with a contact member 63, and the first elastic part 20 is removed. Other parts are the same as those of the gas shut-off jig 1 described above. It is. The contact member 63 is an elastic member formed of a rubber material or the like. In addition, about another component, the code | symbol corresponding to the gas interruption | blocking jig | tool 1 is attached | subjected, and description is abbreviate | omitted.

  A joint replacement work method in the case where the metal material split joints 85 and 85 ′ mounted on the pipe line 90 are replaced with plastic material split joints using the single blocking jig 3 will be described. First, as shown in FIG. 5 (a) (partial cross-sectional view), a no-blow work back 72 equipped with a single shut-off jig 3 is mounted in the upper branch holes 85a of the split joints 85 and 85 ′, and the no-blow work back is installed. The plug 73 attached to the upper branch hole 85a in 72 is removed. Then, as shown in FIG. 5B (partial sectional view), the second elastic portion 40 of the single blocking jig 3 is inserted into the upper perforation 91 in the no-blow work back 72, and the operation knob 60 is rotated. Thus, the diameter of the second elastic portion 40 is increased by the pressing operation of the pressure cylinder portion 50 to close the upper perforation 91.

  Then, as shown in FIG. 6C (partial sectional view), the no-blow work back 72 is removed from the upper branch hole 85a, the split joints 85 and 85 ′ are removed from the pipe line 90, and the pipe line 90 is made of a plastic material. A split joint 86 is attached. Then, as shown in FIG. 6D (partial sectional view), the no-blow work back 72 is mounted in the upper branch hole 86a of the plastic joint split joint 86, and the single blocking jig 3 is mounted in the no-blow work back 72. The pipe 90 is removed and a plug 73 is attached to the upper branch hole 86a of the plastic material split joint 86 to close the branch port 86a, and the no-blow work back 72 is removed from the upper branch hole 86a to replace the split joint. Finish the work.

  Thus, the single blocking jig 3 can be inserted into and removed from the split joints 85, 85 ′, 86, and the second elastic portion 40 passes through the upper branch holes 85a of the split joints 85, 85 ′ and the upper perforations 91. Since the upper perforation 91 is inserted and expanded to close the upper perforation 91, the split joints 85 and 85 ′ can be removed from the pipe line 90 without being affected by the presence of the jig. For this reason, the split joints 85, 85 ′ made of a metal material can be easily replaced with the split joint 86 made of a plastic material, and the replacement work can be performed without blowing. Since only the split joints 85 and 85 ′ are to be replaced, the split joints 85 and 85 ′ can be replaced simply by excavating around the embedded split joints 85 and 85 ′, and the work range is reduced. Working costs can be reduced.

The side view of the gas cutoff jig | tool concerning one embodiment of this invention is shown. The partial cross section for demonstrating the water removal device removal work method which removes the water removal device attached to the division | segmentation joint by this gas interruption | blocking jig is shown. The partial cross section figure for demonstrating the water removal device removal work method which removes the water removal device attached to the division | segmentation joint by the gas interruption | blocking jig | tool is shown. The side view of the single interruption | blocking jig | tool concerning other embodiment of this invention is shown. The fragmentary sectional view for demonstrating the joint replacement | exchange work method of replacing | exchanging a split joint with another split joint with a single interruption | blocking jig | tool is shown. The fragmentary sectional view for demonstrating the joint replacement | exchange work method of replacing | exchanging a split joint with another split joint with a single interruption | blocking jig | tool is shown.

Explanation of symbols

1 Gas cutoff jig 3 Single cutoff jig (Gas cutoff jig)
DESCRIPTION OF SYMBOLS 10 Base part 11 Protrusion part 20 1st elastic part 30 Spacer 40 2nd elastic part (elastic part)
50 Pressure cylinder 60 Operation knob 70 Water removal device 72 No blow work back 73, 74 Plug 80, 85, 85 ′ Split joint 81a, 85a, 85a ′, 86a Upper branch hole 82a Lower branch hole 86 Split joint (other split joints) Joint)
90 Pipeline 91 Upper drilling 92 Lower drilling

Claims (4)

A base shaft portion having a protrusion at a tip portion; a first elastic portion attached to the base shaft portion and abutted against a rear end portion of the protrusion portion; and a rear end of the first elastic portion attached to the base shaft portion A spacer that is abutted against the part, a second elastic part that is attached to the base shaft part and abuts against the rear end part of the spacer, and a spacer that is attached to the base axis part and abuts against the rear end part of the second elastic part A pressure cylinder portion that compresses and opens the first elastic portion and the second elastic portion, and is attached to the base shaft portion so as to be able to advance and retreat, and presses the pressure cylinder portion toward the distal end side and releases the pressure. An operation knob for expanding and releasing the diameter of the first elastic portion and the second elastic portion ,
The operation knob is screwed to the base shaft portion and can advance and retreat along the base shaft portion.
The first elastic portion communicates with the upper branch hole of the split joint attached to the pipe and can pass through the upper perforation provided in the pipe, and communicates with the lower branch hole of the split joint. A gas blocking jig having a size that can be inserted into a lower perforation provided in the conduit, and wherein the second elastic portion has a size that can be inserted into the upper perforation . A split joint having an upper branch hole and a lower branch hole is attached to the pipe, and an upper perforation communicating with the upper branch hole and a lower perforation communicating with the lower branch hole are provided in the pipe and stored in the pipe A water removal device removal work method for removing the water removal device from the split joint attached to the lower branch hole with a water removal device that removes the water to be removed,
  Attaching a no-blow work back equipped with the gas shut-off jig according to claim 1 to the upper branch hole of the split joint;
  The first elastic part of the gas blocking jig is inserted into the lower drilling through the upper drilling by the operation in the no-blow work back, and the second elastic part of the gas blocking jig is inserted into the upper drilling. Inserting the inside and expanding the diameter of the first elastic part and the second elastic part to close each of the perforations;
  Removing the water catcher from the lower branch hole, and attaching a plug to the lower branch hole to close the lower branch hole;
  A water removal device removing work method comprising a step of removing the gas blocking jig in the no-blow work back and mounting a plug on the upper branch hole to close the upper branch hole.   A joint replacement work method for replacing a split joint mounted on a pipe line with another split joint using the gas shutoff jig according to claim 1,
  Mounting a no-blow work back equipped with the gas shut-off jig inside the upper branch hole of the split joint;
  Inserting the second elastic part of the gas shut-off jig into the upper perforation by the operation in the no-blow work back to enlarge the diameter of the second elastic part and closing the upper perforation;
  Removing the split joint from the pipe, and attaching another split joint to the pipe;
  The no-blow work back is attached to the upper branch hole of the other split joint, the gas shut-off jig is removed from the pipe line in the no-blow work back, and a plug is inserted into the upper branch hole of the other split joint. A joint replacement work method comprising: mounting and closing the upper branch hole.   The joint replacement work method according to claim 3, wherein the other split joint is formed of a plastic material.

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