JP5279578B2 - Pipe branch sealing method and fluid pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for hermetically plugging a tube branch part capable of simply plugging a plug member in a lock state and prevented from being spontaneously unlocked from the lock state when the tube branch part provided on a side surface of a fluid tube is hermetically plugged, a fluid tube capable of being used in the method and a tube branch part hermetically plugging device. <P>SOLUTION: The method for hermetically plugging a tube branch part comprises the inserting process of inserting the plug member 2 including a protuberance 21a around the outer periphery into the tube branch part 1a to make the protuberance 21a pass through an omission part 12 of an engagement wall 11 and the lock process of rotating the plug member 2 to positionally align the protuberance 21a and the engagement wall 11 in the circumferential direction to attain engagement in the axial direction to restrict the movement of the plug member 2 in the axial direction. In the insertion process, the protuberance 21a is inserted into a bayonet groove 14 to receive the protuberance 21a by a forward circumferential wall surface 15, and in the lock process, the plug member 2 is moved backward to receive the protuberance 21a by a rear circumferential wall 16, and the protuberance 21a is disposed between a pair of restraint wall surfaces 17, 18 spaced apart from each other in the circumferential direction. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention includes a tube branch stoppered method for stoppered cylindrical tube branch disposed on the side surface of the fluid tube, relates to a fluid conduit that can be used in the method, the branch pipes which is particularly connected by without suspension of water supply method This is useful when the gate valve is removed together.

  When renewing an existing water pipe (an example of a fluid pipe) that has become obsolete, in consideration of convenience for users of tap water, the state of uninterrupted water is maintained without stopping the pipe upstream. Construction is desired. Therefore, if a branch pipe is connected in the middle of an existing water pipe using the continuous water construction method and the water flow state is maintained by a bypass formed by the branch pipe, the water pipe can be renewed without water interruption. It can be carried out. Such a continuous water construction method is described in Patent Document 1 below, for example.

  FIG. 41 is a schematic diagram illustrating an example of a procedure for updating an existing water pipe. The arrows in the pipeline represent the flow of water. First, a section A in the pipe is targeted, and split T-shaped pipes 81 and 82 are attached to both ends thereof, and a gate valve 83 is connected to each of them (FIG. 41 (a)). Next, after connecting a perforation device (not shown) to each gate valve 83 to perforate the pipe portion surrounded by the split T-shaped pipes 81 and 82, the perforation device is removed from the gate valve 83. Then, the bypass pipe 84 is connected to form a bypass, the gate valve 83 is opened, and the stopper 85 containing the valve body is installed in the main pipe to be closed (FIG. 41 (b)). Thereby, the existing water pipe in A section can be updated to new installation pipe line 8A, maintaining the state of uninterrupted water.

  When the renewal of the water pipe in the A section is completed, the stopper 85 is opened and water is passed through the main pipe. At this stage, the bypass of section A is not necessary, so the branch pipe 84 is removed (FIG. 41 (c)). Subsequently, for the B section, the branch pipe 86 is connected in the same manner as described above to form a bypass, the gate valve 89 is opened, and the stopper 85 is closed (FIG. 41 (d)). At this time, the split T-shaped pipe 87 is attached to a new water pipe in the A section. And the water pipe in B section is updated to the newly installed pipe line 8B, maintaining the state of uninterrupted water, and when it is completed, the branch pipe 86 is removed (FIG. 41 (e)). By repeating this process, existing water pipes can be updated sequentially.

  By the way, in the water pipe renewal construction as described above, the process of removing the branch pipe is complicated, and in particular, in order to remove the gate valves 83 and 89 from the main pipe when removing the branch pipe, the main pipe is not cut off. It is necessary to close the cap while maintaining the water state, and the operation becomes very complicated. Therefore, conventionally, only the branch pipe is removed and the gate valve is left behind, but there is a concern that the gate valve will be caught by a heavy machine when excavating the same place in the future.

  In order to solve these problems, Patent Documents 2 and 3 below are disclosed as methods for removing the branch pipe together with the gate valve. In this method, an annular core is inserted into a perforated portion of an existing pipe, the annular core is expanded and closely locked, and then a stopper is attached by a screwing action or a fitting action via a retaining ring. To do. However, with these methods, the plug body cannot be easily detached from the annular core while maintaining the state of uninterrupted water. Therefore, when connecting the branch pipe to the main pipe again and releasing the sealed plug, Convenience is bad.

  When the bypass is branched from the new pipe as shown in FIG. 41 (d), a split T-shaped pipe having a split structure is not attached to the new pipe and drilled, but a part of the new pipe is integrated in advance. Although it is possible to construct a T-tube having a structure and connect the branch pipe to the pipe branching portion provided on the side surface of the T-tube via a gate valve, the inventions described in the following Patent Documents 2 and 3 In the first place, it is a removal method of the split T-tube, so it cannot be applied in such a case.

  On the other hand, Patent Document 4 below describes an apparatus for inserting and sealing a pair of valve bodies that sandwich a sealing material into a pipe branch portion of a split T-shaped tube. However, in this apparatus, it is necessary to directly operate the valve bodies in order to fix the valve bodies to the pipe branching portion and to fix the valve bodies to each other. Therefore, after sealing the pipe branching part with the sealing material, before fixing the valve body and the sealing material, the gate valve etc. must be removed from the pipe branching part, and the plug member is inserted, fixed and sealed. It is impossible to carry out a series of operations. In addition, since the valve body is fixed by press-contacting a bolt to the inner peripheral surface of the pipe branching portion, it is not allowed to fix the valve body until a lid is attached to the pipe branching portion.

  The present inventor provided on the side surface of an integral structure fluid pipe piped as described above or a split structure fluid pipe mounted on a perforated existing pipe so that the branch pipe can be removed together with the gate valve. In consideration of tightly plugging the cylindrical pipe branching portion, and considering the workability and the stability of the plug member, the projection of the plug member is engaged with the engaging wall of the pipe branching portion and fixed ( (Not yet known at the time of this application).

  However, it is also conceivable that the plug member naturally rotates due to the action of water flow and the like, and the engagement between the protrusion and the engagement wall is arbitrarily disengaged. With such a technique, the lock state of the plug member may be released alone. It has been found. On the other hand, after sealing the pipe branching portion with a plug member, it is possible to cover the plug member by attaching a lid to the opening of the pipe branching portion, but the plug member is unlocked without the operator's knowledge. If the cover is removed, the plug member is suddenly pulled out by water pressure at the same time, which is very dangerous.

  Thus, in the above method, not only can the plug member inserted into the pipe branching portion be simply locked, but the lock state of the plug member is not released alone, and if necessary, the plug member It is important that the locked state can be easily released. In addition, since this sealing work is performed in a state where the inside of the pipe branching portion cannot be seen, it is desirable that the sealing work can be performed by a simple operation of the plug member.

JP 2002-154004 A JP 2002-267086 A JP 2005-106083 A JP-A-63-13997

The present invention has been made in view of the above circumstances, and the purpose of the present invention is to easily lock the plug member when sealing the pipe branching portion provided on the side surface of the fluid pipe, and to independently lock the plug member. An object of the present invention is to provide a tube branching portion sealing method that is not released and that can easily release the locked state of the plug member, and a fluid pipe that can be used in the method.

  The above object can be achieved by the present invention as described below. That is, in the pipe branching portion sealing method according to claim 1 of the present invention, a plug member is inserted into a cylindrical pipe branching portion provided on the side surface of the fluid pipe, and the inner peripheral surface of the pipe branching portion and the plug are inserted. An insertion step of setting a missing portion of the engagement wall provided on one of the outer circumferences of the member to a state in which the protrusion provided on the other has passed, and rotating the plug member so that the protrusion and the engagement wall A locking step for restricting axial movement of the plug member by aligning circumferential positions and engaging in the axial direction, and in the inserting step, the protrusion is fitted into the bayonet groove through the missing portion, and the bayonet groove In the locking step, the plug member is rotated to relatively shift the circumferential position of the protrusion, and the plug member is moved rearward in the insertion direction in the locking step. Is received by the second circumferential wall surface of the bayonet groove, It is intended to place the projection between the pair of regulation walls which are provided at intervals in the direction.

  In the pipe branching portion sealing method of the present invention, the plug member is inserted into the pipe branching portion and rotated to restrict the axial movement of the plug member to be in a locked state, and the pipe branching portion is sealed with the plug member. Can do. Of the inner peripheral surface of the pipe branching portion and the outer periphery of the plug member, one is provided with an engaging wall having a missing portion, and the other is provided with a projection, and by engaging these, the plug member is simple and It is fixed stably. Further, in order to release the hermetic plug by the plug member, it is only necessary to rotate the plug member to shift the circumferential position between the protrusion and the engagement wall, and to pull out the plug member from the pipe branching portion.

  When the engagement wall is provided on the inner peripheral surface of the pipe branching portion and the protrusion is provided on the outer periphery of the plug member, the operation when the plug member is locked and the operation when releasing the lock state are as follows: Details are as follows. First, in the insertion step, the plug member is inserted into the pipe branching portion, and the projection of the plug member passes through the missing portion of the engagement wall. The protrusion is inserted into the bayonet groove through the missing portion and is received by the first circumferential wall surface. Therefore, the operator only has to push the plug member until the protrusion comes into contact with the first peripheral wall surface.

  Next, in the locking step, the plug member is rotated to shift the circumferential position of the protrusion, and the plug member is retracted. At this time, the operator only has to retract the plug member until the protrusion comes into contact with the second peripheral wall surface. The plug member is locked by the protrusion engaging the engaging wall and the axial movement is restricted. In addition, since the protrusion is disposed between the pair of restriction wall surfaces, the rotational movement of the plug member is restricted between the restriction wall surfaces. Thereby, even if the plug member rotates naturally due to the action of a water flow or the like, the locked state is not released alone.

  When releasing the locked state of the plug member, push the plug member into contact with the projection on the first circumferential wall surface, rotate the plug member to shift the circumferential position of the projection, and the projection passes through the missing part. Then, the plug member is pulled out. The operator may push the plug member until the protrusion comes into contact with the first circumferential wall surface, and then rotate and pull the plug member. The same is true when a protrusion is provided on the inner peripheral surface of the pipe branching portion and an engagement wall is provided on the outer periphery of the plug member. As described above, in the present invention, the plug member can be locked or released by a simple operation of the plug member, even though the inside of the pipe branch portion is not visible. .

  According to the present invention, since the pipe branching portion can be tightly plugged as described above, it is possible to remove the branch pipe together with the gate valve in the removal work of the branch pipe connected by the continuous water construction method. In addition, since the axial movement of the plug member can be restricted by rotating the plug member, the work of inserting, fixing and sealing the plug member can be performed efficiently without interposing the work of removing the gate valve or the like. In the present invention, a T-shaped tube, a cruciform tube, or other deformed tube can be adopted as the fluid tube having the tube branching portion, and the structure thereof may be an integral structure, or may be a split structure that can be attached to an existing tube.

  The pipe branching portion sealing method according to claim 2 of the present invention is the pipe branching portion sealing method according to claim 1, wherein the protrusion slides along the first peripheral wall surface in the locking step. The plug member is rotated as described above, and then the protrusion is guided to the second peripheral wall surface by a guide wall surface continuously provided on the first peripheral wall surface. According to this method, after the projection is received by the first circumferential wall surface of the bayonet groove, the projection can be moved along the first circumferential wall surface and guided to the second circumferential wall surface. Therefore, the operator does not need to be particularly concerned about the amount of rotation of the plug member, the timing of retracting the plug member, and the like, and can easily and reliably execute the operation of bringing the plug member into the locked state.

  The fluid pipe according to claim 3 of the present invention is a fluid pipe in which a cylindrical pipe branching portion is provided on a side surface, an engagement wall having a missing portion on an inner peripheral surface of the pipe branching portion, A bayonet groove that communicates with the missing portion, and the bayonet groove has a first circumferential wall surface that faces the missing portion, and a first circumferential wall surface that is provided closer to the opening side of the pipe branching portion than the first circumferential wall surface. A double wall surface and a pair of regulation wall surfaces provided on both sides in the circumferential direction of the second peripheral wall surface are provided.

  The fluid pipe having such a configuration can be used in the above-described pipe branching portion sealing method. That is, when the projection of the plug member inserted into the pipe branching portion is fitted into the bayonet groove through the missing portion, the projection is received by the first peripheral wall surface. Further, when the circumferential position of the projection is shifted and retracted, the projection is received by the second circumferential wall surface, and the projection is disposed between the pair of regulation wall surfaces, so that the plug member can be locked.

  Furthermore, the fluid pipe according to claim 4 of the present invention is a fluid pipe in which a cylindrical pipe branching portion is provided on a side surface, and an engagement wall having a missing portion on an inner peripheral surface of the pipe branching portion; A bayonet groove formed so that the projection of the plug member inserted into the branching portion can be inserted, and the bayonet groove receives the projection inserted through the lacking portion. A possible first circumferential wall surface, a second circumferential wall surface provided behind the first circumferential wall surface in the insertion direction of the plug member, and a pair of regulating wall surfaces provided on both sides in the circumferential direction of the second circumferential wall surface Is provided. Similar to the above, the fluid pipe having such a configuration can be used in the above-described pipe branching portion sealing method.

  A fluid pipe according to a fifth aspect of the present invention is the fluid pipe according to the third or fourth aspect, wherein the first circumferential wall surface and the second circumferential wall surface face each other and extend in the circumferential direction. The bayonet groove is provided with a guide wall surface that is connected to the first circumferential wall surface and extends toward the second circumferential wall surface as it is separated from the first circumferential wall surface in the circumferential direction. According to this configuration, after the protrusion is received by the first circumferential wall surface of the bayonet groove, the projection can be moved along the first circumferential wall surface and guided to the second circumferential wall surface. Therefore, the operator does not need to be particularly concerned about the amount of rotation of the plug member, the timing of retracting the plug member, and the like, and can easily and reliably execute the operation of bringing the plug member into the locked state.

  A fluid pipe according to a sixth aspect of the present invention is the fluid pipe according to the fifth aspect, wherein the guide wall surface is formed in a tapered shape. Thereby, a protrusion can be smoothly guided to a 2nd surrounding wall surface.

  The pipe branching portion sealing method according to claim 7 of the present invention is the pipe branching portion sealing method according to claim 1 or 2, wherein in the insertion step or the locking step, a piston member incorporated in the cylinder member is used. The stopper member or the operation shaft connected to the stopper member is connected, the inside of the cylinder member and the inside of the pipe branching portion are communicated with each other, the inside of the cylinder member is filled with fluid, and the inside of the cylinder member The fluid pressure is applied to the piston member.

  According to this method, since the fluid pressure in the cylinder member can be made the same as the fluid pressure in the pipe branch portion, the thrust force generated by the action of the fluid in the pipe branch portion pushing back the plug member causes the fluid in the cylinder member to flow. Is subtracted by the thrust force generated by acting on the piston member. For this reason, it becomes easy to push the plug member against the fluid pressure, and the pushed plug member can be smoothly rotated.

  The pipe branching portion sealing method according to an eighth aspect of the present invention is the pipe branching portion sealing method according to the first or second aspect, wherein in the insertion step, the operating shaft connected to the plug member or the plug member. In the state where the abutting portion of the pushing member is brought into contact with the elastic member and the elastic deformation of the abutting portion is regulated by the regulating means, the pushing portion is operated to apply a propulsive force to the abutting portion. The stopper member is pressed in the insertion direction, and in the locking step, the restriction by the restricting means is released as the stopper member rotates, and the backward movement of the stopper member in the insertion direction is caused by elastic deformation of the elastic body. Absorb.

  In this case, in the insertion step, the plug member is pressed using the propulsive force applied to the contact portion, so that the plug member can be simply pushed against the fluid pressure. At this time, the elastic deformation of the elastic body provided in the contact portion is regulated by the regulating means. Further, in the locking process, when the plug member is rotated, the restriction by the restricting means is released, and the plug member is rapidly moved by the fluid pressure by absorbing the backward movement of the plug member by elastic deformation of the elastic body. Can be prevented from being pushed back to the back.

Further , the tube branching portion sealing device that can be used in the above method is connected to a plug member on which a sealing material is fitted and detachably connected to the plug member, and operates the rotation and axial relative movement of the plug member. An operation shaft configured to be capable of being provided, a cylinder member provided with a supply port communicating with the inside, and a piston member which is built in with a tip end projecting from the cylinder member and connected to the operation shaft. is there.

  According to such a sealing device, the inside of the cylinder member can be communicated with the inside of the pipe branch portion through the supply port. As a result, the fluid pressure in the cylinder member is made the same as the fluid pressure in the pipe branch portion, and the fluid in the cylinder member acts on the piston member from the thrust force generated by the fluid in the pipe branch portion pushing back the plug member. The thrust force generated by the action can be subtracted. As a result, the plug member can be easily pushed against the fluid pressure, and the pushed plug member can be smoothly rotated.

A further pipe branching section sealing device that can be used in the above method is the above-described pipe branching section sealing device, wherein the cylinder member is arranged with its axis shifted with respect to the operation shaft, and the tip of the piston member is A fixing jig for fixing the position of the cylinder member and a connecting jig for connecting the piston member and the operating shaft so as to be positioned in front of the rear end portion of the operating shaft. According to the above configuration, the work space in the extending direction of the operation shaft can be reduced, so that it is possible to perform sealing work in a place where a large surrounding space cannot be secured, and the work required for construction work such as pit formation work is shortened. Efficiency can be increased.

Further, another pipe branch sealing device that can be used in the above method is a plug member on which a sealing material is externally fitted, and a plug member that is detachably connected to the plug member, and the rotation and axial relative movement of the plug member. The stopper member includes an operation shaft configured to be operable, and a pushing member having a contact portion that contacts the operation shaft, and applying a propulsive force to the contact portion by operation of the pressing member. Is configured to be able to be pressed in the insertion direction. In such a sealing plug device, the plug member can be easily pushed against the fluid pressure by pressing the plug member using the propulsive force applied to the contact portion.

A further pipe branching section sealing device that can be used in the above method is the above-described another pipe branching section sealing device, wherein the contact portion includes an elastic body, and a restricting means that regulates elastic deformation of the elastic body; The restriction by the restricting means is released by rotating the plug member in a state where the contact portion is in contact with the operation shaft, and the movement of the plug member in the rearward direction of insertion is elastic. It is configured to absorb by deformation. Thereby, when pushing in the plug member, the plug member can be appropriately pressed in a state where elastic deformation of the elastic body is restricted. Further, since the restriction by the restricting means is released along with the rotation of the plug member, the movement of the plug member to the rear in the insertion direction is absorbed by the elastic deformation of the elastic body, and the plug member is rapidly pushed back by the fluid pressure. Can be prevented.

Longitudinal sectional view of a water pipe with a branch pipe connected to the pipe branch through a gate valve Fig. 1 is a longitudinal sectional view showing an enlarged main part of the pipe branching portion of Fig. 1 1 is a front view of the pipe branching portion of FIG. Plan view sectional view for explaining sealing work Sectional drawing which shows the stopper member which concerns on 1st Embodiment of this invention, and the front end of an operating shaft. BB arrow sectional view of FIG. Sectional drawing of the rear end of the operating shaft which concerns on 1st Embodiment Sectional drawing for demonstrating the sealing method concerning 1st Embodiment Longitudinal sectional view and front view of pipe branch Sectional drawing for demonstrating the sealing method concerning 1st Embodiment Longitudinal sectional view and front view of pipe branch Sectional drawing for demonstrating the sealing method concerning 1st Embodiment Sectional drawing for demonstrating the sealing method concerning 1st Embodiment Longitudinal sectional view and front view of pipe branch Longitudinal sectional view and front view of pipe branch Longitudinal sectional view and front view of pipe branch Plan cross-sectional view showing an example of a tube component Kibe sealed device Plan view sectional drawing which shows the modification of the pipe branching part sealing device of FIG. The figure which shows a mode that the plug member was pushed in using the pipe branch part sealing plug apparatus of FIG. Plan cross-sectional view showing another example of the tube content Kibe sealed device Exploded view of contact part Front view of the clutch member 141 as seen from the front Rear view of clutch member 142 viewed from the rear (A) Front view and (b) Cross-sectional view of contact part The figure which shows a mode that the plug member was pushed in using the pipe branch part sealing plug apparatus of FIG. (A) Front view and (b) Cross-sectional view of contact part Sectional drawing which shows the stopper member which concerns on 2nd Embodiment of this invention, and the front end of an operating shaft. Sectional drawing of the rear end of the operating shaft which concerns on 2nd Embodiment Sectional drawing for demonstrating the sealing method concerning 2nd Embodiment Sectional drawing for demonstrating the sealing method concerning 2nd Embodiment Sectional drawing for demonstrating the sealing plug release in 2nd Embodiment The longitudinal cross-sectional view which shows the pipe branch part of the fluid pipe | tube used by 3rd Embodiment of this invention Sectional drawing which shows the stopper member which concerns on 3rd Embodiment, and the front end of an operating shaft Sectional drawing for demonstrating the sealing method concerning 3rd Embodiment Sectional drawing for demonstrating the sealing method concerning 3rd Embodiment The longitudinal cross-sectional view for demonstrating the sealing plug method which concerns on another embodiment of this invention Plan view sectional drawing for demonstrating the sealing method concerning another embodiment of this invention The side view of the engaging tool with which the plug member shown in FIG. 37 is provided. Sectional view of the plug member shown in FIG. Sectional drawing which shows a mode that it sealed with the plug member shown in FIG. Schematic showing an example of the procedure for updating an existing water pipe

  An embodiment of the present invention will be described with reference to the drawings, taking as an example the case of removing a branch pipe connected to a water pipe as a fluid pipe. FIG. 1 is a longitudinal sectional view of a water pipe having a branch pipe connected to a pipe branch portion via a gate valve. FIG. 2 is a longitudinal sectional view showing an enlarged main part of the pipe branching portion of FIG. FIG. 3 is a front view of the pipe branching portion. The cross section taken along the line AA in FIG. 3 corresponds to the vertical cross section of FIGS.

  A water pipe 1 (an example of a fluid pipe according to the present invention) constitutes a part of a pipe line extending in a direction perpendicular to the paper surface in FIG. It consists of a T-tube. The inside of the water pipe 1 is in a water-permeable state, and the pipe branching portion 1a is sealed with a method described later while maintaining the state of uninterrupted water, and the branch pipe 8 is removed together with the gate valve 9.

  If the water pipe 1 comprised by the T-shaped pipe of the integral structure like this embodiment itself is newly installed, it can be previously used for the location where the branch pipe 8 is connected at the time of the new installation. That is, in the example of FIG. 41, at the time when the water pipe in the A section is updated in (b) with respect to the place where the split T-shaped pipe 87 is attached in (d), the T-shaped pipe having such an integrated structure is provided. Can be previously incorporated into the pipeline. In this case, there is no need to attach the split T-shaped pipe to the water pipe as in the normal continuous water construction method, and the process can be omitted.

  A tubular pipe branching portion 1a communicating with the inside of the main body is provided on a side surface of the water pipe 1, and an engagement wall 11 raised radially inward is provided on the inner peripheral surface of the pipe branching portion 1a in the circumferential direction. Is provided. The engagement wall 11 has a missing portion 12, and in this embodiment, the missing portion 12 is formed at two locations in the circumferential direction. The missing portion 12 opens at the axial end surface 1b of the inner peripheral surface provided with the engagement wall 11, and is formed so that a protrusion of an engagement tool described later can be fitted therein. There are no particular restrictions on the circumferential length or number of the engaging walls 11 and the missing portions 12.

  Two bayonet grooves 14 communicating with the missing portion 12 as shown in FIG. 2 are formed on the inner peripheral surface of the pipe branching portion 1 a, and the engagement wall 11 is missing as a part of the groove wall of the bayonet groove 14. The portion 12 is formed as an entrance / exit of the bayonet groove 14. The bayonet groove 14 includes a front peripheral wall surface (corresponding to the first peripheral wall surface) 15 facing the missing portion 12 and a rear periphery provided on the opening side (right side in FIG. 2) of the pipe branching portion 1a with respect to the front peripheral wall surface 15. A wall surface (corresponding to the second circumferential wall surface) 16 and a pair of regulating wall surfaces 17 and 18 provided on both sides in the circumferential direction of the rear circumferential wall surface 16 are provided. Further, in this embodiment, the front peripheral wall surface 15 and the rear peripheral wall surface 16 face each other and extend in the circumferential direction, and the bayonet groove 14 is connected to the front peripheral wall surface 15 and extends from the front peripheral wall surface 15 in the circumferential direction. A taper-shaped guide wall surface 19 extending toward the rear peripheral wall surface 16 as it leaves is provided.

  The branch pipe 8 is connected to the pipe branch portion 1a via a gate valve 9. The gate valve 9 has a branch pipe side end on the right side in FIG. 1 flanged to the branch pipe 8 and a fluid pipe side end opposite to the branch pipe 8 connected to the pipe branch 1a of the water pipe 1. A passage that can communicate with each other is formed. The gate valve 9 has a built-in valve body 91 that can be opened and closed so that the passage can be shut off. In FIG. 1, the passage is blocked by the lowered valve body 91.

  The fluid pipe side end of the gate valve 9 is formed as a cylindrical insertion opening 92 and is inserted into the pipe branching portion 1a. A step portion 13 that receives the cylindrical insertion opening 92 is formed in the pipe branching portion 1a, and O-rings 93 are attached to the corners thereof. A flange (not shown) having an insertion hole is provided on the outer peripheral portion of the gate valve 9, and a bolt hole 1c (see FIG. 4) provided in the flange of the pipe branching portion 1a and a bolt inserted into the insertion hole with a nut. By tightening, the gate valve 9 is firmly connected to the pipe branching portion 1a. In such a configuration, since the distance from the water pipe 1 to the branch pipe side end of the gate valve 9 can be shortened compared to the flange connection, the arrangement area of the branch pipe 8 is reduced, which is useful when a large surrounding space cannot be secured. It becomes.

  To remove the branch pipe 8 together with the gate valve 9 from the water pipe 1 while maintaining the state of uninterrupted water, a plug member is inserted into the pipe branch portion 1a with the gate valve 9 connected to the pipe branch portion 1a. Need to be fixed. At that time, it is desirable from the viewpoint of workability and stability of the plug member that the plug member is inserted, fixed, and sealed without interposing the separation operation of the gate valve 9. The present invention can meet such a demand, and first to third embodiments will be described below as specific embodiments.

[First Embodiment]
FIG. 4 is a cross-sectional view in plan view for explaining the sealing operation. First, the branch pipe 8 is removed from the gate valve 9 while the passage in the gate valve 9 is blocked by the valve body 91. Next, as shown in FIG. 4, the plug member 2 of the sealing device is inserted into the branch pipe side end of the gate valve 9, and a fitting flange 95 is connected to the branch pipe side end of the gate valve 9. By connecting the mating flange 95, the movement stroke of the plug member 2 at the start of insertion can be secured, and the centering and insertion work of the plug member 2 is simplified. This hermetic plug device includes a plug member 2 and an operation shaft 3 for operating the plug member 2 by inserting it into the pipe branching portion 1a.

  FIG. 5 is a cross-sectional view of the plug member 2 and the front end of the operation shaft 3. 6 is a cross-sectional view taken along line BB in FIG. Hereinafter, the left direction in FIG. 5 is referred to as the front and the right direction in FIG. 5 is referred to as the rear in accordance with the insertion direction of the plug member 2. Further, when viewed from the rear along the insertion direction of the plug member 2, clockwise rotation around the axis is called right rotation and counterclockwise rotation is called left rotation. These names are the same in the second and third embodiments described later.

  The plug member 2 includes an engaging tool 21 having a protrusion 21a formed on the outer periphery, an inner stopper 22 that is combined with the engaging tool 21 so as to be capable of relative movement in the axial direction, and the inner stopper 22 being axially parallel. And an annular sealing material 23 that surrounds. The engagement tool 21 is formed in a cylindrical shape, and a pair of protrusions 21a are provided on the outer periphery thereof. The protrusion 21a has an outer diameter larger than the inner diameter of the engaging wall 11 of the pipe branching portion 1a, and is formed so as to be able to pass through the missing portion 12 of the engaging wall 11.

  A male screw 21b is formed on the rear outer peripheral surface of the engagement tool 21, and is screwed together with a female screw formed on the front inner peripheral surface of the cylindrical connection member 24. The engagement tool 21 has a front cylinder portion 21c on the front side of the protrusion 21a, and a seal member 23 is disposed adjacent to the front end of the front cylinder portion 21c. As shown in FIG. 6, a pair of guide projections 21d are provided along the axial direction on the inner periphery of the front cylindrical portion 21c, and a disk-like shape having a through hole 21e behind the guide projection 21d. A portion 21f is provided.

  The inner stopper 22 includes a columnar portion 22a accommodated in the front cylinder portion 21c, an overhang portion 22b projecting to the outer peripheral side at the front end thereof, and a shaft portion 22c inserted through the through hole 21e. A male screw is formed on the outer peripheral surface of the shaft portion 22c, and a hexagon nut 25 having a diameter larger than that of the through hole 21e is screwed. A C-shaped drop prevention ring 26 is externally fitted to the shaft portion 22c behind the hexagon nut 25.

  The columnar portion 22a is formed with a pair of guide grooves 22d into which the guide protrusions 21d are inserted, and is configured so that the inner stopper 22 does not rotate together when the hexagon nut 25 is rotated. Note that the structure for preventing co-rotation is not limited to this. For example, a through-hole extending in the radial direction may be provided in the front cylinder portion 21c, and a bolt inserted through the through-hole may be protruded to the inner peripheral side and fitted into the guide groove 22d instead of the guide protrusion 21d.

  The sealing material 23 is mounted so as to surround the cylindrical portion 22a, and is accommodated in a recessed portion 22e formed between the overhanging portion 22b and the front cylindrical portion 21c. In order to prevent damage and dropout of the sealing material 23 during the sealing operation, the outer diameter of the sealing material 23 is preferably equal to or less than the outer diameter of the overhanging portion 22b and the front cylindrical portion 21c.

  The operation shaft 3 is detachably connected to the plug member 2 and is configured to be capable of operating the rotation of the engagement tool 21 and the relative movement of the middle plug tool 22 in the axial direction with respect to the engagement tool 21. In the present embodiment, the operation shaft 3 includes a cylindrical main shaft 31 that is detachably connected to the engagement tool 21, a round bar-shaped center shaft 32 that is detachably connected to the inner stopper 22, and a rear side of the main shaft 31. And a reaction force receiving member 33 attached to the side.

  The main shaft 31 passes through the center hole 95a of the joint flange 95 so as to be slidable in the axial direction, and an O-ring for sealing a gap with the main shaft 31 is attached to the inner periphery of the center hole 95a. The front side portion of the main shaft 31 is formed with a relatively large diameter, and a protrusion 31 a formed on the outer peripheral surface is sandwiched and fixed by the rear end of the engagement tool 21 and the connection member 24. The drain hole 31b is a circular hole for discharging water that has entered inside during the sealing operation.

  The middle shaft 32 is inserted into the main shaft 31, and a front side portion having a relatively large diameter is fitted and connected to the middle stopper 22. In the present embodiment, the cylindrical portion 32a formed at the front end of the center shaft 32 is formed in a hexagonal shape so that the hexagonal nut 25 is fitted in, but may be fitted using a polygonal shape other than this. . An interval in the axial direction between the main shaft 31 and the middle shaft 32 is secured by a spacer 32 b that is extrapolated to the middle shaft 32. The spacer 32b is formed of, for example, a gun metal or a resin material.

  FIG. 7 is a cross-sectional view of the rear end of the operation shaft 3. The reaction force receiving member 33 is a cylindrical body having a pair of bars 33 a protruding in a direction perpendicular to the axis, and is externally fitted to the main shaft 31. Bolts 33 b are provided inside the bar 33 a and penetrate the main shaft 31 to press and fix the middle shaft 32. A handle (not shown) for rotating the middle shaft 32 is attached to the rear end 32 c of the middle shaft 32 protruding rearward from the reaction force receiving member 33. A connector (not shown) is attached to the bar 33a as necessary, and the water pipe 1 or the joint flange 95 and the reaction force receiving member 33 are connected.

  After connecting the joint flange 95 to the branch pipe side end of the gate valve 9 as shown in FIG. 4, the valve body 91 of the gate valve 9 is retracted upward to bring the passage into a communicating state. At this time, since the plug member 2 receives water pressure, it is preferable that the reaction force receiving member 33 is connected to the water pipe 1, the mating flange 95 or the like by a connecting tool such as a lever hoist to receive the reaction force. In this case, by pushing the operating shaft 3 through the jack of the lever hoist, the plug member 2 can be easily advanced against the water pressure.

  Next, the operating shaft 3 is pushed forward, the plug member 2 is inserted into the pipe branching portion 1a as shown in FIG. 8, and the protrusion 21a of the engaging tool 21 has passed through the missing portion 12 of the engaging wall 11. (Corresponding to the insertion step). As shown in FIG. 9, the protrusion 21 a that has passed through the missing portion 12 is inserted into the bayonet groove 14 and is received by the front peripheral wall surface 15. Therefore, the operator only has to push in the plug member 2 until the protrusion 21a contacts the front peripheral wall surface 15. For convenience of illustration, the plug member 2 is indicated by a solid line in the front views shown in FIGS.

  Subsequently, as shown in FIG. 10, the engagement tool 21 is rotated clockwise by rotating the main shaft 31, the circumferential positions of the protrusions 21 a and the engagement walls 11 are aligned and engaged in the axial direction. The movement of the member 2 in the axial direction is restricted to a locked state (corresponding to the locking step). In addition, since the relative rotation of the engagement tool 21 and the inner stopper 22 is restricted, the inner stopper 22 also rotates together. Since the water pipe 1 is in a water-permeable state and the plug member 2 receives fluid pressure (that is, water pressure) from the front, the protrusion 21a and the engagement wall 11 are firmly engaged.

  When the plug member 2 is brought into the locked state, the plug member 2 is rotated to the right to shift the circumferential position of the protrusion 21a, and the plug member 2 is moved rearward so that the protrusion 21a is received by the rear peripheral wall surface 16. In the present embodiment, when the engagement tool 21 is rotated clockwise, as shown in FIG. 11, the protrusion 21 a slides along the front peripheral wall surface 15 and is guided to the rear peripheral wall surface 16 by the guide wall surface 19. It arrange | positions between a pair of control wall surfaces 17 and 18. FIG.

  Thereby, the engagement tool 21 is in a state where the axial movement is restricted and the rotational movement is restricted between the pair of restriction wall surfaces 17 and 18. The operator may rotate the main shaft 31 to the right until the protrusion 21 a contacts the regulation wall surface 18 after the protrusion 21 a contacts the front peripheral wall surface 15. Thus, the plug member 2 can be locked by a simple operation while the inside of the pipe branching portion 1a is not visible. If it is in this state, even if the engaging tool 21 rotates naturally by the action of water flow or the like, the locked state of the plug member 2 is not released alone.

  Next, the hexagon nut 25 is rotated clockwise by rotating the middle shaft 32. At this time, since the co-rotation of the inner stopper 22 is prevented by the engagement between the guide protrusion 21d and the guide groove 22d, the hexagon nut 25 and the inner stopper 22 can be rotated relative to each other. The inner stopper 22 is moved relative to the engaging tool 21 in the axial direction by the screw action accompanying the rotation. The rotation operation of the middle shaft 32 can be executed by operating a handle attached to the rear end 32c. At this time, the pressing and fixing by the bar 33a may be loosened as necessary.

  In this embodiment, as shown in FIG. 12, when the hexagonal nut 25 and the inner stopper 22 are rotated relative to each other, the inner stopper 22 is retracted by the screw action accompanying the rotation operation, and the inner stopper 22 is engaged. It moves close to the tool 21. As a result, the seal member 23 interposed between the inner plug member 22 and the engagement member 21 is compressed, and the seal member 23 is expanded and deformed in the radial direction to seal between the plug member 2 and the pipe branching portion 1a. it can. Since the sealing material 23 is not compressed unless the hex nut 25 is rotated, it does not come into contact with the inner peripheral surface of the pipe branch portion 1a until the plug member 2 is inserted into the pipe branch portion 1a and fixed. Damage or dropping off of the sealing material 23 is preferably prevented.

  After completing the sealing of the pipe branch portion 1a, the reaction force receiving member 33 is removed from the main shaft 31, and the gate valve 9 and the fitting flange 95 are detached from the pipe branch portion 1a. Then, the connection between the operation shaft 3 and the plug member 2 is released, and the plug member 2 is left in the pipe branching portion 1a. To remove the operation shaft 3 from the plug member 2, it is only necessary to release the screwing between the connecting member 24 and the engagement tool 21. Finally, as shown in FIG. 13, the pipe branching portion 1a is covered with a flange lid 96, and the branch pipe removing operation is completed.

  When the pipe branching portion 1a that has been tightly sealed is reused due to various circumstances, the above procedure may be reversed. That is, the flange lid 96 is removed, the operating shaft 3 is connected to the plug member 2, and after the gate valve 9, the joint flange 95 and the reaction force receiving member 33 are attached, the plug member 2 is taken out from the pipe branching portion 1a. The valve body 91 may be lowered to block the passage of the gate valve 9.

  When the plug member 2 is taken out from the pipe branching portion 1a, the following procedure is performed. First, as shown in FIG. 14, the main shaft 31 is rotated counterclockwise until the protrusion 21 a of the engagement tool 21 contacts the restriction wall surface 17, and the protrusion 21 a is opposed to the front peripheral wall surface 15. Next, as shown in FIG. 15, the operation shaft 3 is pushed forward, and the protrusion 21 a is brought into contact with the front peripheral wall surface 15. Subsequently, as shown in FIG. 16, when the main shaft 31 is rotated counterclockwise, the operation shaft 3 is moved rearward and the protrusion 21a is pulled out from the bayonet groove 14, the plug member 2 is taken out from the pipe branching portion 1a.

  In this way, the locked state of the plug member 2 can be released by a simple operation while the inside of the pipe branching portion 1a is not visible. Moreover, since the locked state of the plug member 2 is not released alone, the operation of removing the flange lid 96 is also safe. The operator can grasp how much water pressure is applied to the plug member 2 at the stage of pushing the operating shaft 3 in FIG. 15 forward, so that the pull-out operation of the plug member 2 in FIG. 16 can be performed safely.

  As described above, since the plug member 2 is subjected to water pressure during the sealing operation, it is preferable to connect the sealing device to the water pipe 1 or the mating flange 95 with a connector such as a lever hoist. It becomes possible to push in the plug member 2 using a jack provided on the tool. However, in a situation where the water pressure is strong, the connecting tool is in a tight state, and therefore it may be difficult to operate the operation shaft 3 and rotate the plug member 2. An improvement measure for dealing with such a problem will be described with reference to FIGS. Among these, in FIGS. 17, 18 and 20, front views of the members are shown in a broken line frame.

FIG. 17 is a plan view sectional view showing an example of the pipe branching portion sealing device, and the plug member 2 and the operation shaft 3 are shown in a plan view. The hermetic plug device includes a plug member 2 to which a sealing material 23 is externally fitted, and an operation shaft 3 that is detachably connected to the plug member 2 and that can operate the rotation and axial relative movement of the plug member 2. A cylinder member 101 provided with a supply port 100 communicating with the inside, a piston member 103 that is connected to the operation shaft 3 with a tip end 102 protruding from the cylinder member 101 and connected to the operation shaft 3. And a hose 111 as a pipe.

  The cylinder member 101 is a cylindrical body configured to be watertight, and ball valves 105 and 106 are attached to a supply port 100 and an exhaust port 104 provided at the rear end thereof, respectively. The hose 111 is connected to the supply port 100 via the ball valve 105, and the opposite side is connected to the connection cylinder 95b via the ball valve 95d. The connecting cylinder 95b is attached to the side of the joint flange 95 and communicates with the inside of the pipe branching portion 1a.

  A fixing jig 107 is attached to the tip of the cylinder member 101. The fixing jig 107 includes a stay 108 extending in the insertion direction of the plug member 2 and a plate 110 fixed to the distal end portion of the stay 108. The stays 108 are arranged apart from each other in the circumferential direction so as not to come into contact with the bar 33a that rotates when the operation shaft 3 is operated. A cylindrical member 95c welded to the mating flange 95 is fitted into the notch 109 of the plate 110, whereby the relative position of the cylinder member 101 with respect to the water pipe 1 is fixed.

  In a state in which the cylinder member 101 is fixed, the cylinder member 101 and the piston member 103 are arranged coaxially with the operation shaft 3, and the tip end portion 102 of the piston member 103 is connected to the rear end portion of the operation shaft 3. In other words, the piston member 103 is connected to the plug member 2 with the operation shaft 3 interposed. In this embodiment, an example is shown in which the front end portion 102 is a cylindrical body whose front is open and abuts against the reaction force receiving member 33 from the axial direction so as to cover the rear end 32c of the middle shaft 32.

  According to such a configuration, the ball valve 105 and the ball valve 95d are opened from the state in which the valve body 91 of the gate valve 9 is retracted upward, so that the inside of the cylinder member 101 and the inside of the pipe branching portion 1a communicate with each other. Thus, the inside of the cylinder member 101 can be filled with water. At this time, if the ball valve 106 is opened, the air in the cylinder member 101 is discharged through the exhaust port 104.

  Thereby, since the water pressure in the cylinder member 101 and the water pressure in the pipe branch part 1a become the same pressure, the thrust force generated by the action of the water in the pipe branch part 1a pushing back the plug member 2 causes the cylinder member to The water in 101 is subtracted by the thrust force generated by acting on the piston member 103. In this case, it is preferable that the operating shaft 3 and the piston member 103 have substantially the same diameter, thereby making it possible to equalize both pressure receiving areas and cancel the thrust force. Therefore, the influence of the water pressure received by the plug member 2 during the sealing operation is reduced. It can be suppressed well.

  In the insertion step or the locking step, the inside of the cylinder member 101 and the inside of the pipe branching portion 1a are communicated as described above, and the water pressure in the cylinder member 101 is changed to the piston member 103 so as to press the plug member 2 in the insertion direction. By acting on the plug member 2, the plug member 2 can be simply pushed against the water pressure without using a jack or the like. FIG. 17 shows a state where the plug member 2 is pushed forward. Moreover, since the influence of the water pressure which the plug member 2 receives can be suppressed, the operation of the operation shaft 3 is facilitated, and the pressed plug member 2 can be smoothly rotated. After the rotation of the plug member 2, the sealing device is removed.

  18 has the same configuration as that of FIG. 17 except for a jig for fixing the position of the cylinder member 101 and a coupling structure of the piston member 103 and the operation shaft 3. The cylinder member 101 is attached to the joint flange 95 by a fixing jig 115. In a state where the position of the cylinder member 101 is fixed, the cylinder member 101 is arranged with its axis shifted with respect to the operation shaft 3, and the front end portion of the piston member 103 is positioned in front of the rear end portion of the operation shaft 3. In addition to the fixing jig 115, the sealing device includes a connecting jig 120 that connects the front end portion of the piston member 103 and the rear end portion of the operation shaft 3.

  The fixing jig 115 includes a plate 116 attached to the tip of the cylinder member 101, a bowl-shaped plate 117, and a plate 118 that connects them. The plate 116 is formed with an insertion hole 116 a for inserting the piston member 103 and an insertion hole 116 b for inserting the stay 123. The hook-shaped plate 117 engages with a plate material 95 e welded to the joint flange 95 and is fixed by the plunger 119. The stay 123 is spaced apart in the circumferential direction so as not to contact the rotating bar 33a.

  The connecting jig 120 includes a plate 121 connected to the front end portion of the piston member 103, a push-in plate 122 that can contact the rear end portion of the operation shaft 3, and a stay 123 that connects them. The plate 121 has a bolt hole 121a into which the front end portion of the piston member 103 is screwed, and a bolt hole 121b into which the front end portion of the stay 123 is screwed. The pushing plate 122 has a rear end portion of the stay 123 at the rear end portion. A bolt hole 122a to be screwed is provided. The end of the pushing plate 122 opposite to the bolt hole 122a is located slightly away from the rear end 32c of the center shaft 32, and a notch 124 is formed so as to surround the rear end 32c.

  Also in this sealing device, similarly to the sealing device of FIG. 17, it is possible to satisfactorily suppress the influence of water pressure applied to the plug member 2. In the example of FIG. 18, in the process of moving the piston member 103 forward, the push-in plate 122 is in contact with the rear end portion of the operation shaft 3 (reaction force receiving member 33 in this embodiment) from the axial direction, and they are connected. However, the stay 123 may be made shorter and connected from the beginning.

  FIG. 19 shows a state when the plug member 2 is pushed forward from the state of FIG. In this sealing device, since the operating shaft 3 and the cylinder member 101 overlap the axial position, the working space in the extending direction of the operating shaft 3 can be made smaller than that of the sealing device of FIG. Therefore, it is possible to perform a sealing work in a place where a wide surrounding space cannot be secured, and it is possible to shorten the time required for construction work such as pit formation work and to improve work efficiency.

FIG. 20 is a plan view sectional view showing another example of the tube branching portion sealing device, and the plug member 2 and the operation shaft 3 are shown in a plan view. The hermetic plug device includes a plug member 2 to which a sealing material 23 is externally fitted, and an operation shaft 3 that is detachably connected to the plug member 2 and that can operate the rotation and axial relative movement of the plug member 2. And a pushing member 125 having a contact portion 127 disposed on the rear end side of the operation shaft 3.

  The pushing member 125 includes a main body portion 126 whose position is fixed with respect to the water pipe 1 and an abutting portion 127 configured to be movable in the axial direction by operation of the main body portion 126. The main body 126 includes a feed screw 128 that extends in parallel with the operation shaft 3, a stay 129 that extends in parallel therewith, and a fixing jig 130 that fixes the position of the main body 126.

  The feed screw 128 is rotatably supported by a pair of plates 131 and 132, and a round handle 133 is connected and fixed to an end portion on the side penetrating the plate 132. Both ends of the stay 129 are fixed to the plates 131 and 132. The feed screw 128 and the stay 129 are arranged away from each other in the circumferential direction so as not to contact the rotating bar 33a. The plates 131 and 132 are formed with insertion holes 131a and 132a for inserting and supporting the end portions of the feed screw 128 and mounting holes 131b and 132b for supporting and fixing the end portions of the stay 129. Further, the plate 131 is formed with a through hole 131 c and a notch 134.

  The fixing jig 130 includes a plate 131 and a plunger 135. A cylindrical member 95c welded to the mating flange 95 is fitted into the notch 134 of the plate 131, and the plunger 135 inserted into the through hole 131c is attached to a plate material 95f fixed to the plate material 95e with screws. Thereby, the relative position of the main-body part 126 with respect to the water pipe 1 is fixed. Note that the plate member 95e and the plate member 95f may be integrated.

  FIG. 21 is an exploded view of the contact portion 127. The contact portion 127 includes a clutch member 141, a clutch member 142, a spring 143 (corresponding to the elastic body), and a restricting unit that restricts elastic deformation of the spring 143. As will be described later, this restricting means is constituted by protrusions 144 and 147 that abut against each other. 22 is a front view of the clutch member 141 as viewed from the front, and FIG. 23 is a rear view of the clutch member 142 as viewed from the rear. In the front view of FIG. 24, the protrusion 147 and the protrusion 149 of the clutch member 142 are superimposed on the clutch member 141.

  The clutch member 141 includes an insertion hole 141a in which the screw top 145 is mounted, an insertion hole 141b in which one stay 129 is inserted, an attachment hole 141c in which the clutch member 142 is attached, and a pair of protrusions protruding forward. And a protrusion 144. The screw top 145 is screwed onto the outer periphery of the feed screw 128, and when the feed screw 128 is rotated by operating the round handle 133, the contact portion 127 moves while being guided by the stay 129 by the screw action.

  The clutch member 142 includes a cylindrical body portion 146 whose front is opened, a pair of projections 147 that project rearward from the front end portion of the cylindrical body portion 146, and a male screw portion 148 provided at the rear of the cylindrical body portion 146. , A positioning projection 149 projecting from the front end surface, and an adjustment handle 150. The cylindrical portion 146 has an inner diameter that is large enough to accommodate the rear end 32c of the middle shaft 32, and an outer diameter that is set equal to or smaller than the inner diameter of the mounting hole 141c.

  20 and 24, the protrusion 151 of the clutch member 142 is abutted against the protrusion 144 of the clutch member 141, and the nut 151 is fastened to the male screw portion 148 protruding rearward from the mounting hole 141c. The spring 143 is mounted on the cylindrical body portion 146 of the clutch member 142 and is housed in a space 153 in which the axial length is secured by abutment between the protrusions 144 and 147 with a compression margin left. That is, the elastic deformation of the spring 143 is regulated by abutting the protrusions 144 and 147 together. The clutch member 142 is supported so as to be rotatable around the axis of the mounting hole 141c, and a bearing 152 is mounted between the cylindrical portion 146 and the clutch member 141.

  When inserting the plug member 2 into the pipe branching portion 1 a, first, the round handle 133 is operated to rotate the feed screw 128, and the contact portion 127 is advanced to contact the rear end portion of the operation shaft 3. At the same time, the protrusion 149 is inserted into the insertion hole 33 c of the reaction force receiving member 33, and the circumferential position of the clutch member 142 with respect to the operation shaft 3 is fixed. At this time, although the circumferential position of the protrusion 149 can be adjusted by the adjustment handle 150, it is performed within a range in which the protrusions 144 and 147 are not completely displaced.

  Next, the abutting portion 127 abutted on the operation shaft 3 is further advanced, and the plug member 2 is pressed in the insertion direction as shown in FIG. The abutting portion 127 is screwed into the main body portion 126 of the push-in member 125, and a propulsive force is applied by the screw action accompanying the rotation operation of the main body portion 126. Therefore, the plug member 2 can be easily resisted against water pressure. Can be pushed in. Even at this stage, the elastic deformation of the spring 143 is restricted by abutting the protrusions 144 and 147 together.

  After the plug member 2 is pushed forward, the plug member 2 is rotated by the operation of the operation shaft 3 to be locked. At this time, the clutch member 142 rotates with the rotation of the plug member 2, and the restriction on the elastic deformation of the spring 143 is released. That is, in the insertion step, the state shown in FIG. 24 is interlocked with the rotation of the plug member 2, and the circumferential positions of the protrusions 144 and 147 are shifted as shown in FIG. 26, so that the clutch member 142 can move backward. Thus, the spring 143 is compressed.

  Then, when the rotated plug member 2 moves rearward in the insertion direction, this movement is absorbed by the elastic deformation of the spring 143. That is, although the contact portion 127 itself does not move backward, the plug member 2 is allowed to move backward by the compression of the spring 143. Thereby, it is possible to prevent the plug member 2 from being suddenly pushed back by the water pressure using the repulsive force of the spring 143. In FIG. 24, the rapid reaction force due to the water pressure can be more reliably mitigated by slightly compressing the spring 143 so that the repulsive force is generated in advance.

  As described above, according to the sealing method and the sealing device according to the improvement measures described with reference to FIGS. 17 to 26, the stopper member 2 can be easily pushed in without using a connector having a jack such as a lever hoist. In addition, the rotation operation of the plug member 2 can be performed smoothly. The shape of a member such as a plate or a stay constituting the sealing device is not limited to the above. These improvement measures can be applied not only to the first embodiment but also to other embodiments such as second and third embodiments described later.

[Second Embodiment]
Since the second embodiment has the same configuration and operation as the first embodiment except for the configuration described below, common points will be omitted and differences will be mainly described. FIG. 27 is a cross-sectional view of the stopper member and the front end of the operation shaft according to the second embodiment. This hermetic plug device includes a plug member 4 and an operation shaft 5 for inserting and operating the plug member 4 into the pipe branching portion 1a. The plug member 4 includes an engagement tool 41 having a protrusion 41a formed on the outer periphery, an inner plug tool 42 that is combined with the engagement tool 41 so as to be capable of relative movement in the axial direction, and an inner plug tool 42 that is axially parallel. And an annular sealing material 43 surrounding the.

  On the rear side of the engagement tool 41, through holes 41b are provided at two positions across the shaft center, and a rivet 45 as a restricting member is inserted through each of the through holes 41b. The tip of the rivet 45 is fitted into a circular hole 42 g of the inner stopper 42, and relative movement between the engaging tool 41 and the inner stopper 42 is restricted by the rivet 45. A female thread 41d is formed on the inner peripheral surface of the front tube portion 41c of the engaging tool 41, and is screwed together with the male thread 42h on the outer peripheral surface of the inner stopper 42. This screwing is due to a left-hand thread, and when the middle stopper 42 is rotated to the right relative to the engaging tool 41, the inner stopper 42 moves rearward due to the screw action.

  The inner stopper 42 includes a cylindrical portion 42a accommodated in the front cylinder portion 41c, an overhang portion 42b that protrudes to the outer peripheral side in front of it, and a connecting portion 42c that is formed in a relatively small diameter at the rear. Have. The connecting portion 42c protrudes rearward from the engaging tool 41, a male screw 42d is formed on the outer peripheral surface thereof, and a polygonal (hexagonal in this embodiment) fitting hole 42f is formed on the inner peripheral side. Has been. The male screw 42d of the coupling part 42c is screwed with a female screw formed on the inner peripheral surface of the connecting member 44. This screwing is due to a right-hand screw, and is reverse to the screwing of the male screw 42h and the female screw 41d.

  The sealing material 43 is mounted so as to surround the cylindrical portion 42a, and is accommodated in a recessed portion 42e formed between the projecting portion 42b and the front cylindrical portion 41c. The outer diameter of the sealing material 43 is set to be equal to or smaller than the outer diameters of the overhanging portion 42b and the front cylindrical portion 41c so that the sealing material 43 can be reliably prevented from being damaged and dropped during the sealing operation.

  The operation shaft 5 is detachably connected to the plug member 4 and is configured to be capable of operating the rotation of the engagement tool 41 and the relative movement in the axial direction of the middle plug tool 42 with respect to the engagement tool 41. In the present embodiment, the operation shaft 5 is a round bar-shaped core shaft 51 that is detachably connected to the inner stopper 42, and a reaction force receiving member 53 that is attached to the rear side of the core shaft 51 (see FIG. 28). With. The front end of the core shaft 51 is provided with a columnar portion 51a having a polygonal cross section (in this embodiment, a hexagonal shape) and fitted into the fitting hole 42f of the inner stopper 42, and the columnar portion 51a. A collar portion 51b is provided around the rear side.

  The connecting member 44 has a flange-shaped front end 44a having an outer diameter larger than the inner diameter of the rear end of the engagement tool 41, and an inner flange-shaped rear end 44b having an inner diameter smaller than the outer diameter of the flange 51b. The core shaft 51 has a flange 51b sandwiched and fixed by the rear end of the inner stopper 42 and the rear end 44b of the connecting member 44. On the rear side of the operation shaft 5, as shown in FIG. 28, a reaction force receiving member 53 having a pair of bars 53a is externally fitted to the rear end portion of the core shaft 51 formed in a prismatic shape, and the nut portion 53b It is fixed by tightening.

  After the joint flange 95 is connected to the branch pipe side end portion of the gate valve 9, the valve body 91 of the gate valve 9 is retracted upward to make the passage communicate with the operation shaft as in the first embodiment described above. 5 is pushed forward, and the plug member 4 is inserted into the pipe branching portion 1a so that the protrusion 41a of the engaging tool 41 passes through the missing portion 12 of the engaging wall 11 (corresponding to the inserting step). The protrusion 41a that has passed through the missing portion 12 is fitted into the bayonet groove 14 and is received by the front peripheral wall surface 15 (see FIG. 9).

  Subsequently, as shown in FIG. 29, by rotating the operation shaft 5, the inner stopper 42 and the engaging tool 41 whose relative movement with respect to the inner stopper 42 is restricted by the rivet 45 are rotated to the right. Then, the circumferential positions of the protrusion 41a and the engaging wall 11 are aligned and engaged in the axial direction, thereby restricting the axial movement of the plug member 4 (corresponding to the locking step). At this time, the protrusion 41a is disposed between the pair of regulating wall surfaces 17 and 18 of the bayonet groove 14 (see FIG. 11).

  Next, from the state in which the protrusion 41a is in contact with the restriction wall surface 18, that is, the state in which the right rotation of the engagement tool 41 is restricted, the operation shaft 5 is rotated, and the inner stopper 42 is further rotated to the right to form the rivet 45 A predetermined load is applied. Then, as shown in FIG. 30, the rivet 45 is sheared, and the restriction on the relative movement between the engagement tool 41 and the inner plug tool 42 is released. As a result, the inner stopper 42 can be rotated to the right relative to the engaging tool 41, the inner stopper 42 is moved close to the engaging tool 41 by its screw action, and the sealing material 43 is expanded and deformed by compression. The space between the plug member 4 and the pipe branching portion 1a can be sealed. The rivet 45 is made of a soft metal such as copper, for example.

  Thus, in this embodiment, the rotation of the engaging member 41 for restricting the axial movement of the plug member 4 and the gap between the plug member 4 and the pipe branching portion 1a only by the rotation operation of the core shaft 51. The inner stopper 42 is moved in the axial direction for sealing, and damage and dropout of the sealing material 43 are also suitably prevented. For this reason, the operation of the plug member 4 is greatly simplified, and the mechanism of the operation shaft 5 is also simplified.

  After completing the sealing of the pipe branching portion 1a, the reaction force receiving member 53 is removed from the core shaft 51, the gate valve 9 and the fitting flange 95 are detached from the pipe branching portion 1a, and the operation shaft 5 and the plug member 4 are connected. And the flange branch 96 is placed on the pipe branching portion 1a where the plug member 4 is left, and the branch pipe removal operation is completed. In order to remove the operation shaft 5 from the plug member 4, it is only necessary to release the screwing between the connecting portion 42 c and the connection member 44.

  When the sealed pipe branch 1a is used again, the flange lid 96 is removed, the operation shaft 5 is connected to the plug member 4, and the gate valve 9, the joint flange 95 and the reaction force receiving member 53 are attached. The plug member 4 may be taken out from the pipe branching portion 1a and the valve body 91 may be lowered to block the passage of the gate valve 9. When the plug member 4 is taken out from the pipe branching portion 1a, the inner plug 42 is rotated counterclockwise by rotating the operation shaft 5, and the inner plug 42 is moved forward by the screw action to compress the sealing material 43. To release.

  In the above, when the inner stopper 42 starts to rotate counterclockwise, the engaging tool 41 also rotates counterclockwise, but the protrusion 41a immediately contacts the regulating wall surface 17 (see FIG. 14), and the inner stopper 42 is You can move forward. After the compression of the seal material 43 is released, when the inner stopper 42 further moves forward, the front end portion 44a of the connecting member 44 and the rear end of the engagement tool 41 are pressed against each other in the axial direction as shown in FIG. Integrated. For this reason, the plug member 4 can be taken out from the pipe branching portion 1a by pushing the operating shaft 5 forward and rotating left (see FIGS. 15 and 16).

[Third Embodiment]
Since the third embodiment has the same configuration and operation as the first embodiment except for the configuration described below, common points will be omitted and mainly the differences will be described. In the present embodiment, as shown in FIG. 32, the pipe branching portion 1 a has a small diameter region 1 d having a relatively small inner diameter in front of the bayonet groove 14. At the rear end of the small-diameter region 1d, a tapered surface 1e that increases in diameter toward the rear is formed. The inner diameter of the small diameter region 1d is set to be smaller than the outer diameter of the sealing material 63 described later before compression.

  FIG. 33 is an enlarged cross-sectional view of the plug member and the front end of the operation shaft in the third embodiment. The hermetic plug device includes a plug member 6 and an operation shaft 7 for operating the plug member 6 by inserting the plug member 6 into the pipe branching portion 1a. The plug member 6 includes an engaging tool 61 having a protrusion 61 a formed on the outer periphery, an inner plug tool 62 combined so as to be capable of relative movement in the axial direction with respect to the engaging tool 61, and the inner plug tool 62 being axially parallel. And an annular sealing material 63 that surrounds.

  The engaging tool 61 has a cylindrical body, and a male screw 61b is formed on the rear outer peripheral surface thereof. The engaging tool 61 is screwed to a female screw formed on the front inner peripheral surface of the connecting member 64 having a cylindrical shape. ing. When the middle stopper 62 is rotated to the right relative to the engaging tool 61, the inner stopper 62 moves forward by the screw action. A female screw 61 c is formed on the inner peripheral surface of the engagement tool 61, and is screwed together with a male screw 62 f formed on the outer peripheral surface of the rear cylinder portion 62 b of the inner stopper 62.

  The inner stopper 62 includes a disk-shaped portion 62 a having an accommodation groove 62 c formed on the outer periphery, and a rear cylinder portion 62 b inserted through the engaging tool 61. The depth dimension of the accommodation groove 62 c is smaller than the diameter dimension of the sealing material 63, and the sealing material 63 protrudes to the outer peripheral side and is attached to the inner stopper 62. A tapered surface 62d having a diameter increasing toward the front is formed behind the housing groove 62c. The rear end surface of the disk-shaped part 62a is in a state in which the front end surface of the engagement tool 61 is in contact.

  The operation shaft 7 is detachably connected to the plug member 6 and is configured to be capable of operating the rotation of the engagement tool 61 and the relative movement in the axial direction of the middle plug tool 62 with respect to the engagement tool 61. In the present embodiment, the operation shaft 7 has a cylindrical main shaft 71 that is detachably connected to the engagement tool 61, a round bar-shaped center shaft 72 that is detachably connected to the inner plug device 62, and a rear side of the main shaft 71. And a reaction force receiving member attached to the side.

  The front side portion of the main shaft 71 is formed with a relatively large diameter, and a protrusion 71 a formed on the outer peripheral surface is sandwiched and fixed by the rear end of the engagement tool 61 and the connection member 64. The middle shaft 72 is inserted into the main shaft 71, and a columnar portion 72a having a polygonal cross section (in this embodiment, a hexagonal shape) is provided at the front end. The columnar portion 72a is inserted into a fitting hole 62e having a polygonal shape (in this embodiment, a hexagonal shape) formed in the rear cylinder portion 62b of the inner stopper 62, and the inner shaft 72 and the inner stopper 62 are connected by fitting. Has been. The rear ends of the main shaft 71 and the middle shaft 72 and the structure of the reaction force receiving member are the same as those in the first embodiment.

  After the joint flange 95 is connected to the branch pipe side end portion of the gate valve 9, the valve body 91 of the gate valve 9 is retracted upward to make the passage communicate with the operation shaft as in the first embodiment described above. 7 is pushed forward, and the plug member 6 is inserted into the pipe branching portion 1a so that the projection 61a of the engaging tool 61 passes through the missing portion 12 of the engaging wall 11 (corresponding to the inserting step). The protrusion 61a that has passed through the missing portion 12 is fitted into the bayonet groove 14 and is received by the front peripheral wall surface 15 (see FIG. 9). At this stage, it is preferable that the sealing material 63 is not yet disposed in the small diameter region 1d.

  Subsequently, as shown in FIG. 34, the engaging tool 61 is rotated to the right by rotating the main shaft 71, the circumferential positions of the protrusion 61a and the engaging wall 11 are aligned and engaged in the axial direction. The axial movement of the member 6 is restricted (corresponding to the locking step). At this time, the protrusion 61a is disposed between the pair of regulating wall surfaces 17 and 18 of the bayonet groove 14 (see FIG. 11).

  Next, by rotating the middle shaft 72, the middle stopper 62 is rotated to the right, the inner stopper 62 and the engaging tool 61 are rotated relative to each other, and the inner stopper 62 is engaged by the screw action associated with the rotation operation. It is moved relative to the tool 61 in the axial direction. In the present embodiment, as shown in FIG. 35, when the middle stopper 62 is rotated to the right relative to the engaging tool 61, the inner stopper 22 moves forward in the insertion direction of the stopper member 6, and the sealing material 63 is inserted into the small diameter region 1d. Thereby, the sealing material 63 can be compressed by the inner peripheral surface of the small diameter region 1d, and the gap between the plug member 6 and the pipe branching portion 1a can be sealed. The operator may advance the inner stopper 62 until the tapered surface 62d of the inner stopper 62 abuts against the tapered surface 1e of the small diameter region 1d.

  After completing the sealing of the pipe branching portion 1a, the reaction force receiving member is removed from the main shaft 71, the gate valve 9 and the fitting flange 95 are detached from the pipe branching portion 1a, and the connection between the operation shaft 7 and the plug member 6 is released. Then, the flange lid 96 is put on the pipe branching portion 1a where the stopper member 6 is left, and the branch pipe removing operation is completed. In order to remove the operation shaft 7 from the plug member 6, it is only necessary to release the engagement between the engagement tool 61 and the connection member 64.

  When the sealed tube branch 1a is used again, the above procedure may be reversed. That is, the flange lid 96 is removed, the operating shaft 7 is connected to the plug member 6, and after the gate valve 9, the joint flange 95 and the reaction force receiving member are attached, the plug member 6 is taken out from the pipe branching portion 1a (see FIG. 14-16), the valve body 91 may be lowered to block the passage of the gate valve 9.

[Another embodiment]
(1) In the above-described embodiment, an example in which the fluid pipe that performs the sealing plug is a T-shaped pipe having an integral structure that does not have a divided part is shown. However, the present invention is not limited to this, and a pipe branching part such as a cross pipe. Other deformed pipes having Further, the present invention can also be applied to a fluid pipe having a split structure. As illustrated in FIG. 36, the pipe branch portion 97a of the split T-shaped pipe 97 attached to the existing water pipe 90 can be sealed. It is. In this case, an engagement wall 98 having a missing portion 99 is provided on the inner peripheral surface of the pipe branching portion 97a.

  (2) In the above-described embodiment, the example in which the protrusion provided on the outer periphery of the plug member is inserted into the bayonet groove provided on the inner peripheral surface of the pipe branching portion is shown. However, in the present invention, the protrusion is provided on the outer periphery of the plug member. A protrusion provided on the inner peripheral surface of the pipe branching portion may be inserted into the bayonet groove. In this case, since there is no fear that rust and dust accumulate in the bayonet groove on the inner peripheral surface of the pipe branching portion, a more reliable sealing operation can be performed.

  In the water pipe 161 shown in FIG. 37, the protrusion 162 is provided in two places of the circumferential direction of the internal peripheral surface of the pipe branch part 161a. Further, as shown in FIG. 38, an engagement wall 171 that protrudes radially outward is provided on the outer periphery of the plug member 170 in the circumferential direction. The engagement wall 171 has a missing portion 172 that opens forward, and the projection 162 is fitted into the bayonet groove 174 through the missing portion 172. The bayonet groove 174 has a shape obtained by inverting the above-described bayonet groove 14, and includes a front peripheral wall surface (corresponding to the second peripheral wall surface) 175, a rear peripheral wall surface (corresponding to the first peripheral wall surface) 176, and a pair of restrictions. Wall surfaces 177 and 178 and a guide wall surface 179 are provided.

  As shown in FIG. 39, the plug member 170 includes an engagement tool 181 having a bayonet groove 174 provided on the outer periphery, and an intermediate plug tool 182 combined with the engagement tool 181 so as to be capable of relative movement in the axial direction. And an annular sealing member 183 surrounding the inner stopper 182 in an axially parallel manner. The engaging tool 181 has a front cylinder part 181a having a bayonet groove 174, and a shaft part 181b having a male screw formed on the outer periphery, and the inner plug 182 has an overhanging part 182a projecting on the outer peripheral side, It has an insertion hole 182b through which the portion 181b is inserted, and a hexagon nut 182c screwed into the shaft portion 181b. The sealing material 183 is disposed between the rear end of the front cylinder portion 181a and the overhang portion 182a.

  The operation shaft 190 is detachably connected to the plug member 170, and is configured to be capable of operating the rotation of the engagement tool 181 and the relative movement in the axial direction of the intermediate plug 182 with respect to the engagement tool 181. The operation shaft 190 includes a cylindrical main shaft 191 and a round bar-shaped intermediate shaft 192 inserted therein. The rear side portion of the operation shaft 190 is configured in the same manner as the operation shaft 3 described above. A hexagonal nut 182c is fitted into the distal end portion of the main shaft 191, and the distal end portion of the middle shaft 192 is connected and fixed to the rear end portion 181c of the shaft portion 181b.

  In the sealing operation, the plug member 170 is advanced from the state shown in FIG. 37 and inserted into the pipe branching portion 161a so that the projection 162 passes through the missing portion 172 of the engaging wall 171 (corresponding to the insertion step). The protrusion 162 that has passed through the missing portion 172 is fitted into the bayonet groove 174 and is received by the rear peripheral wall surface 176. Subsequently, the engagement tool 181 is rotated clockwise by the operation of the middle shaft 192 via the handle 193, the circumferential position of the protrusion 162 is relatively shifted, and the circumferential position of the protrusion 162 and the engagement wall 171 is aligned and locked. State (corresponding to the locking step). When the engagement tool 181 is rotated to the right, the protrusion 162 is guided to the front peripheral wall surface 175 by the guide wall surface 179 and is disposed between the pair of regulation wall surfaces 177 and 178.

  Next, the main shaft 191 is operated to rotate the hexagon nut 182c, and the inner stopper 182 is moved relative to the engaging tool 181 in the axial direction by the screw action accompanying the rotation. In this embodiment, as shown in FIG. 40, when the inner stopper 182 moves forward, the sealing material 183 is compressed and expanded in the radial direction, and the gap between the stopper member 170 and the pipe branching portion 161a is sealed. The

  When the sealing material 183 is arranged behind the bayonet groove 174 as in this embodiment, it is not necessary for the sealing material 183 to pass through the protrusions 162, and therefore the outer diameter of the sealing material 183 is set large. be able to. As a result, there is an advantage that the inner diameter of the pipe branching portion 161a is set to be large and the flow rate is easily secured.

  (3) In the present invention, the shape of the bayonet groove is not limited to that shown in FIGS. 2 and 38, and various improvements and modifications can be made without departing from the spirit of the invention. For example, the guide wall surface does not extend in a tapered shape but may be curved in an arc shape. Further, the bayonet groove is not limited to one having a guide wall surface, and for example, in the bayonet groove 14 described above, the front peripheral wall surface 15 and the regulation wall surface 18 may be orthogonal to each other.

  (4) The structure of the plug member used in the method for sealing a pipe branch portion of the present invention has a protrusion on the outer periphery that can pass through a missing portion of an engagement wall provided in the pipe branch portion, or is provided in the pipe branch portion. The projection is not particularly limited as long as it has a bayonet groove that is inserted through the lacking portion of the engagement wall and can seal between the tube branching portion. In the above-described embodiment, an example in which the plug member is locked and the inner plug is operated to compress the sealing material and the gap between the plug member and the pipe branching portion is sealed. Before the member is locked, the sealing material may seal between the pipe branching portion.

  Therefore, the plug member used in the pipe branching portion sealing method of the present invention does not have a complicated structure as shown in the above-described embodiment. For example, a projection or bayonet groove is provided on the outer periphery of a simple cylindrical member. The structure may be such that a sealant is mounted in front of or behind the protrusion or bayonet groove. However, in the case of the plug member according to the above-described embodiment, the seal material can be compressed after the plug member is brought into the locked state, so that the seal material can be satisfactorily prevented from being damaged or dropped off.

  (5) In the above-described embodiment, the hermetic plug of the fluid pipe in the water passing state has been described. However, if the fluid pipe according to the present invention is used, the stopper member can be easily locked even in the empty pipe state. be able to.

  (6) The present invention is not limited to removing the branch pipe for renewal of the water pipe, but can be applied to the case where the pipe branch portion of the fluid pipe is sealed for other reasons.

  (7) In the above-described embodiment, the water pipe is taken as an example of the fluid pipe. However, the present invention is not limited to this and is applied to a fluid pipe used for various liquids / gases other than water. it can.

DESCRIPTION OF SYMBOLS 1 Water pipe 1a Pipe branch part 1d Small diameter area 2, 4, 6 Plug member 3, 5, 7 Operation shaft 8 Branch pipe 9 Gate valve 11 Engagement wall 12 Missing part 14 Bayonet groove 15 Front peripheral wall surface (1st peripheral wall surface)
16 Rear circumferential wall (second circumferential wall)
17 Restriction wall 18 Restriction wall 19 Guide wall surface 21, 41, 61 Engagement tool 21a, 41a, 61a Protrusion 22, 42, 62 Inner plug 23, 43, 63 Sealing material 24, 44, 64 Connection member 25 Hexagon nut 31, 71 Spindle (first operation member)
32, 72 Center shaft (second operation member)
33, 53 Reaction force receiving member 45 Rivet (regulating member)
51 Core shaft 95 Joint flange 96 Flange lid 100 Supply port 101 Cylinder member 103 Piston member 115 Fixing jig 120 Connection jig 125 Pushing member 127 Contacting part 143 Spring (elastic body)

Claims (8)

A plug member is inserted into a cylindrical pipe branch provided on the side surface of the fluid pipe, and the other end of the engagement wall provided on one of the inner peripheral surface of the pipe branch and the outer periphery of the plug member is An insertion step for allowing the protrusion provided on the shaft to pass through, and rotating the plug member so that the circumferential positions of the protrusion and the engagement wall are aligned and engaged in the axial direction. A locking process for restricting directional movement,
In the insertion step, the protrusion is inserted into the bayonet groove through the missing portion, and the protrusion is received on the first circumferential wall surface of the bayonet groove,
In the locking step, the plug member is rotated to relatively shift the circumferential position of the projection, and the plug member is moved rearward in the insertion direction to receive the projection on the second circumferential wall surface of the bayonet groove. A pipe branching portion sealing method in which the protrusion is disposed between a pair of regulating wall surfaces provided at intervals in the circumferential direction.   In the locking step, the plug member is rotated so that the protrusion slides along the first peripheral wall surface, and then the protrusion is connected to the second peripheral wall surface by a guide wall surface continuously provided on the first peripheral wall surface. The pipe branching portion sealing method according to claim 1, wherein the pipe branching portion is sealed. In a fluid pipe provided with a tubular pipe branching portion on its side surface,
An engagement wall having a missing portion and a bayonet groove leading to the missing portion are provided on the inner peripheral surface of the pipe branching portion,
The bayonet groove has a first circumferential wall surface facing the missing portion, a second circumferential wall surface provided closer to the opening side of the pipe branching portion than the first circumferential wall surface, and both circumferential sides of the second circumferential wall surface A fluid pipe, comprising: a pair of regulating wall surfaces provided on the wall. In a fluid pipe provided with a tubular pipe branching portion on its side surface,
An engagement wall having a missing part and a bayonet groove formed so that the projection of the plug member inserted into the branch part can be fitted into the inner wall of the pipe branching part and having the missing part as an entrance / exit. And
The bayonet groove is capable of receiving the protrusion inserted through the missing part, a second peripheral wall surface provided behind the first peripheral wall surface in the insertion direction of the plug member, and the first A fluid pipe, comprising: a pair of regulating wall surfaces provided on both circumferential sides of the two circumferential wall surfaces.   The first circumferential wall surface and the second circumferential wall surface face each other and extend in the circumferential direction, and the bayonet groove is connected to the first circumferential wall surface and is separated from the first circumferential wall surface in the circumferential direction. The fluid pipe according to claim 3 or 4, further comprising a guide wall surface extending toward the second peripheral wall surface.   The fluid pipe according to claim 5, wherein the guide wall surface is formed in a tapered shape.   In the inserting step or the locking step, a piston member built in the cylinder member is connected to the stopper member or an operating shaft connected to the stopper member, and the inside of the cylinder member and the inside of the pipe branching portion are communicated. The pipe branching portion sealing method according to claim 1 or 2, wherein the inside of the cylinder member is filled with fluid, and the fluid pressure inside the cylinder member is applied to the piston member. In the insertion step, the stopper member or the operation shaft connected to the stopper member is brought into contact with the abutting portion of the pushing member, and the elastic deformation of the elastic body provided in the abutting portion is regulated by regulating means, Applying a propulsive force to the contact portion by operating the push member to press the plug member in the insertion direction,
3. The tube according to claim 1, wherein, in the locking step, the restriction by the restricting means is released with the rotation of the plug member, and the movement of the plug member backward in the insertion direction is absorbed by elastic deformation of the elastic body. How to seal the bifurcation.

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