JP2007309474A - Branch pipe connecting device and branch pipe connecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a branch pipe connecting device and a branch pipe connecting method, preventing a fluid in the interior of a pipe from easily leaking out from a connecting part even when a large load is suddenly applied to a connecting part between an existing pipe and a branch pipe or a larger load is applied gradually due to a change with te passage of time. <P>SOLUTION: This branch pipe connecting device includes: a branch case 1 composed of split bodies 1A, 1B which may be water-tightly mounted on the existing pipe K; and a partition valve 2 connected to the branch case 1 and incorporated with a valve element to be connected to the branch pipe, thereby connecting the branch pipe. The branch case 1 is mounted on the existing pipe K and rotatable, split surfaces of the branch case 1 are flange-connected to each other, and the flange-connected split surfaces are located substantially in the horizontal direction to the axial direction of the branch pipe and fastened by a fastener 3. By fastening of the fastener 3, the connection between the branch case 1 and the partition valve 2 is achieved through a seal material 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a branch pipe connecting device and a branch pipe connecting method, and more specifically, a branch case composed of a split body that can be watertightly attached to an existing pipe, and a branch body that is connected to the branch case and has a built-in valve body. The present invention relates to a branch pipe connecting device and a branch pipe connecting method for connecting a branch pipe with a possible gate valve.

  When forming a branch pipe from the middle of an existing fluid pipe such as a water pipe, a method of attaching a branch pipe after drilling a hole in the existing pipe using a branch pipe connecting device equipped with a gate valve etc. Is frequently used (for example, Patent Document 1). This is because it is not necessary to cut off the water when forming the branch pipe, which is highly convenient for tap water users.

  When a branch pipe is formed on an existing pipe by the continuous water method, it is generally performed using a working gate valve (hereinafter also referred to as “gate valve”) as shown in FIGS. That is, the bifurcated branch case 51 is fitted and attached to the outer peripheral portion of the existing pipe K in a watertight state. And in order to connect the branch case 51 and the gate valve 52, the flange part 51a of the branch case 51 and the flange 52a of the gate valve 52 are connected with a volt | bolt and a nut.

  Next, in order to connect the punching device 53 to the other end side of the gate valve 52, the flange 52b on the other end side of the gate valve 52 and the flange portion 53a of the punching device 53 are fixedly attached with bolts and nuts. After mounting the piercing device 53, the valve body of the gate valve 52 is retracted upward to open the inside of the gate valve 52 in a communicating state, and a predetermined portion of the existing pipe K is punched by the piercing device 53.

  Although not shown, the drilling device 53 includes a cylindrical hole saw provided with a cutting edge at the tip, and a central drill located at the center of the cylinder and protruding forward from the cutting tip of the hole saw. Yes. Then, the handle 54 provided on the rear stage side of the drilling device 53 is rotated to feed the hole saw to the existing pipe K side, and the existing pipe is rotated while the hole saw and the center drill are rotated by a drive unit (not shown) provided separately. Drill a predetermined portion of K.

  When the drilling is completed, the rotation of the hole saw is stopped, and the drilling device 53 is moved backward while rotating the handle 54 in the reverse direction. A part of the cut-out existing pipe is caught and discharged by the center drill as the drilling device 53 moves backward.

  When the hole saw and the center drill are sufficiently retracted, the valve body of the gate valve 52 that has been retracted upward is lowered to close the communication state. Thereafter, as shown in FIG. 14, the punching device 53 is removed, and instead, the flange portion 52b of the gate valve 52 and the flange 56a of the connection pipe 56 provided with the receiving port are connected by bolts and nuts. The distal end of the branch pipe 55 is inserted into the receiving port of the pipe 56 to terminate the connection, and the branch pipe 55 can be used.

JP 2002-154004 A

  However, in the above prior art, the connection between the members is a flange connection, and the connection between the flange portions is positioned in a direction perpendicular to the connected branch pipe. When a large load is applied to the pipe side, the flange part that is the connection part, especially the flange part at the connection part with the branch pipe close to the existing pipe, is easy to open, and if it opens, the fluid inside the pipe leaks from the flange part. is there. Normally, piping is in the soil, so even if it leaks, it is difficult to detect it, and the countermeasures tend to be delayed, and the loss due to the outflow of fluid is not small.

  For this reason, there is a case where a method is adopted in which the entire connection point is hardened by covering with concrete, but in this case as well, cracking occurs in the concrete or leakage from the concrete. There was a problem that maintenance work could not be done because it was not possible, and there was a strong request for improvement.

  Therefore, the object of the present invention is to facilitate the fluid in the pipe from the connection point even if a large load is suddenly applied to the connection point between the existing pipe and the branch pipe or a large load is gradually applied due to secular change. It is an object of the present invention to provide a branch pipe connecting device that is difficult to leak and a branch pipe connecting method using the same.

  The above-mentioned subject is achieved by the invention described in each claim. That is, the characteristic configuration of the branch pipe connecting device according to the present invention is a branch case made of a split body that can be water-tightly attached to an existing pipe, and can be connected to the branch pipe with a built-in valve body connected to the branch case. In the device having a gate valve and enabling connection of the branch pipe, the branch case is mounted on the existing pipe and is rotatable, and the split surfaces of the branch case are flange-connected to each other. The flange-connected split surface is positioned in a substantially horizontal direction with respect to the axial direction of the branch pipe and is fastened by a fastener. By fastening the fastener, the connection between the branch case and the gate valve is a sealing material. Is to be done through.

  According to this configuration, since the split surface of the branch case connected to the flange is positioned in a substantially horizontal direction with respect to the axial direction of the branch pipe and is fastened by the fastener, a large load acts on the connected branch pipe. However, since the split surface is not positioned in the opening direction, a large load is not applied to the fastener that fastens the split surface, and it is difficult to apply a load in the direction in which the fastener, for example, the bolt is extended. It is possible to reliably and effectively prevent the leakage of the fluid inside the pipe. Therefore, in order to prevent the fluid from leaking from the inside of the pipe, it is not necessary to harden the entire connection portion by covering it with concrete. Moreover, according to the present invention, since the branch case is mounted on the existing pipe and is rotatable, when the pit is excavated, only the space in the depth direction is secured and the branch case is mounted on the existing pipe. In addition, by connecting and rotating the branch case and the gate valve, it is possible to perform drilling of the existing pipe and subsequent connection work of the branch pipe. The surrounding space can be reduced and branch pipe connection work can be performed in a place where a wide surrounding space cannot be secured, and construction work (for example, pit formation work with securing a large space) can be performed in a short time, resulting in high work efficiency. Become.

  As a result, even if a large load is suddenly applied to the connection point between the existing pipe and the branch pipe, or a large load is gradually applied due to aging, the branch pipe in which the fluid inside the pipe does not easily leak from the connection point. A connection device could be provided.

  On the inner peripheral surface of the branch valve side end portion of the branch case, one or a plurality of recesses having an inclined surface that is inclined in a diameter-expanding manner and opened outwards are formed, and a protrusion that fits into the recess is It is preferable that one or a plurality of outer peripheral surfaces of the gate valve in the vicinity of the existing pipe side end portion are provided so that the inclined surface of the concave portion and the inclined surface of the projection can be brought into surface contact.

  According to this configuration, when the branch case and the gate valve are connected, the relative rotation is prevented to facilitate the construction work, and the connection between the two is strengthened by surface contact.

  As the fastener is tightened, the contact area between the inclined surface of the concave portion of the branch case and the inclined surface of the projection of the gate valve increases, and the inclined surface of the branch case presses the inclined surface of the projection, A concave groove is formed in the inner peripheral surface of the other end side of the branch case, and a concave groove is formed in the inner peripheral surface of the other end side of the branch case. It is preferable that the inner rib wall and an overhang portion formed on the existing pipe side end face of the gate valve come into contact with each other to stop the gate valve from moving away from the branch case.

  According to this configuration, since the connection between the branch case and the gate valve is strengthened by the surface contact between the projection having the inclined surface and the concave portion, the wedge effect is generated, so that the connection between the branch case and the gate valve is abrupt like a crustal movement. Even when a large load is applied or against displacement due to secular change, the connection location can be held firmly.

  In addition to the connection between the branch case and the gate valve being performed by fastening the fastener, the branch case and the gate valve are inserted by inserting a bolt into a bolt hole formed near the other end of the branch case. It is preferable to make a connection.

  According to this configuration, the connection between the branch case and the gate valve can be made securely and firmly.

  It is preferable that the existing pipe side end surface of the gate valve has a concave shape that allows surface contact with the outer peripheral surface of the existing pipe.

  According to this structure, the operation | work which attaches a gate valve to an existing pipe can be performed stably, work becomes easy, and work efficiency increases so much.

  Moreover, the characteristic structure of the branch pipe connection method according to the present invention includes a split body having a flange surface and a valve that is built in a predetermined upper surface of the existing pipe and is equipped with a gate valve that can be connected to the branch pipe. The branch case is attached to the existing pipe so as to be held by the existing pipe, the flange surfaces of the split body of the branch case are fastened by a fastener, and the branch case and the gate valve are connected to the gate valve. The split part connected by the flange is positioned so as to be positioned in a substantially horizontal direction with respect to the axial direction of the branch pipe, and the split case is split using the fastener. By further tightening each other, the branch case and the gate valve are firmly connected, a punching device is connected to the gate valve, a predetermined portion of the existing pipe is punched, and after the drilling by the punching device is completed, Perforation Removal is to connect the branch pipe to the gate valve.

  According to this configuration, even if a large load is suddenly applied to the connection point between the existing pipe and the branch pipe or a large load is gradually applied due to secular change, the fluid inside the pipe easily leaks from the connection point. A branch pipe connection method using a difficult branch pipe connection device can be provided.

  One or a plurality of recesses having an inclined surface which is formed on the inner peripheral surface of the branch valve side end portion of the branch case and which has an inclined surface which is inclined in an enlarged diameter and opens outwardly. It is preferable that the inclined surface of the protrusion and the inclined surface of one or a plurality of projections provided on the outer peripheral surface near the existing pipe side end of the gate valve are in surface contact with each other. .

  According to this structure, while making it easy to perform the connection construction work of a branch case and a gate valve, both connection is strengthened.

  When the fastener is tightened, the contact area between the inclined surface of the concave portion of the branch case and the inclined surface of the protrusion of the gate valve increases, and the inclined surface of the branch case presses the inclined surface of the protrusion. The inner wall of the concave groove formed to fit the sealing material on the inner peripheral surface of the other end side of the branch case, and acting in a direction to move the gate valve away from the branch case; It is preferable that the projecting portion formed on the existing pipe side end surface is in contact with the branch case to stop the gate valve from moving away from the branch case.

  According to this configuration, since the wedge effect is generated in the connection between the branch case and the gate valve, the connection portion can be firmly held.

In addition to the connection between the branch case and the gate valve being performed by fastening the fastener, the branch case and the gate valve are inserted by inserting a bolt into a bolt hole formed in the vicinity of the other end of the branch case. According to this configuration, the connection between the branch case and the gate valve can be securely and firmly established.

  An embodiment of a branch pipe connecting device and a branch pipe connecting method according to the present invention will be described in detail with reference to the drawings, taking as an example the case of connecting a branch pipe to an existing water pipe. FIGS. 1-9 shows the branch pipe connection construction method which connects a branch pipe to the existing pipe K using the branch pipe connection apparatus concerning this embodiment.

  This branch pipe connection device includes a branch case 1 having a split surface that can be water-tightly attached to an existing pipe, and a gate valve 2 that is connected to the branch case 1 and has a built-in valve body so as to communicate with the branch pipe. However, the split surface of the branch case 1 that is rotatably attached to the existing pipe and is connected to the flange is positioned substantially horizontally with the axial direction of the branch pipe. The branch case 1 and the gate valve 2 are connected to each other via the sealing material 5 by fastening the fastener 3 such as a bolt and a nut. Hereinafter, a branch pipe connection method for connecting a branch pipe to an existing pipe using this branch pipe connection apparatus will be described.

  First, as shown in FIG. 1, the gate valve 2 is mounted at a predetermined position on the upper surface of the existing pipe K (temporary placement). The existing pipe K is normally buried in the soil, and a pit is formed by excavating a peripheral portion where the branch pipe is connected. The gate valve 2 has a protruding portion 2a in the circumferential direction of the one end side edge placed on the upper surface of the existing pipe K, and has a receiving portion 2b having an enlarged diameter at the other end side. A valve body (not shown) that forms a possible passage and rotates the passage by attaching a jig (not shown) to the top portion 2c so that the passage can be shut off. Built-in.

  One or a plurality of protrusions 2d in the circumferential direction are inclined in the circumferential direction on the outer peripheral surface near the other end of the gate valve from the one end protruding portion 2a (in this embodiment, in the present embodiment). 2), and when the branch case 1 and the gate valve 2 are connected as shown in FIG. Make it easy to do, and strengthen the connection between them. Further, one end side of the gate valve 2 placed on the upper surface of the existing pipe K has a curved surface having a radius of curvature substantially the same as the outer circumference of the existing pipe K so that its end face can be placed along the outer peripheral face of the existing pipe K. It is formed in a concave shape. If it does in this way, since temporary placement to the upper surface predetermined location of the existing pipe K will be stabilized, it will become easy to perform construction and workability can be improved.

  Then, as shown in FIG. 2, the branch case 1 is mounted so as to hold the existing pipe K from below the existing pipe K, and the branch case 1 is connected to the gate valve 2. The branch case 1 has a split T-tube shape, and in the state shown in FIG. 2, the branch case 1 is composed of split bodies 1A and 1B that are split into left and right parts, and is connected to the gate valve 2 without a flange connection. 2 is positioned and connected so as to be fitted on the outer peripheral surface in the vicinity of one end side.

  In other words, the inner peripheral surface of the other end portion of the branch case 1 that is fitted on the gate valve 2 has a concave portion 1b (in this embodiment, a projection 2d and an inclined surface 1b1 that is inclined in an enlarged diameter and opens outward. Similarly, an example in which two are provided) is formed, and the inclined surface 2d1 of the protrusion 2d and the inclined surface 1b1 of the recess 1b formed on the outer peripheral surface of the gate valve 2 are in surface contact with each other, It is slidable. In this case, since the projection 2d is fitted into the recess 1b, as described above, when connecting the branch case 1 and the gate valve 2, the relative rotation is prevented to facilitate the construction work. . At this stage, the bolt 3a and the nut 3b, which are the fasteners 3 that fasten the split end portion of the branch case 1, are temporarily fixed without being sufficiently tightened. When the fastener 3 is further tightened, as will be described later, it is connected in a watertight manner by a sealing material 4 built in the split end portion and a sealing material 5 fitted on the outer peripheral surface of the gate valve 2, and a branch case. 1 and gate valve 2 are firmly connected. The connection between the branch case 1 and the gate valve 2 will be described later.

  Next, as shown in FIG. 3, the branch case 1 is rotated about 90 ° to the right so that the top 2 c of the gate valve 2 is positioned upward. In this case, the board 6 is placed on the ground so that the leg 1a of the branch case 1 and the overhanging portion of the other end side receiving portion 2b of the gate valve 2 are substantially in the same horizontal plane. By rotating in this way, the connection point of the split case 1 having the split T-shaped pipe shape, which was divided into the left and right parts in FIG. Direction). Therefore, even when a branch pipe is connected to the existing pipe K, even if a large load is suddenly applied to the connection portion or a large load is gradually applied due to aging, the branch case 1 connected to the flange is connected. It becomes a structure which can prevent surely and effectively that a big extension load is applied to the bolt at the split end connecting portion, and the flange connecting portion is opened to leak the fluid inside the pipe.

  In addition, when excavating the periphery of the existing pipe K connecting the branch pipe to form a pit, even if it is a place where a large surrounding space cannot be secured, such as an existing building in the vicinity, the pit is somewhat deeper By forming and attaching the branch case 1 to the existing pipe K, the branch pipe connection work can be performed, and the construction work, for example, the pit forming work with securing a large space can be performed in a short time, and the work efficiency is increased. .

  Further, when the fastener 3 is tightened, an inclined surface at the other end of the branch case 1 is shown in FIG. 4 (hereinafter, the board 6 is omitted) as shown in an enlarged view of the connection point between the branch case 1 and the gate valve 2. 1 b 1 is in surface contact with the inclined surface 2 d 1 of the protrusion 2 d provided on the outer peripheral surface of the gate valve 2. In this case, as can be seen in FIG. 5 showing the AA arrow structure of FIG. 4 (the existing pipe K is indicated by a two-dot chain line for convenience), the inclined surface 1b1 of the branch case 1 and the gate valve 2 at two locations on the upper and lower sides. The inclined surface 2d1 of the projection 2d contacts. In this case, the sealing material 5 has a closed circular shape that is fitted in a groove formed on the inner peripheral surface of the other end side of the branch case 1.

  When the fastener 3 is tightened more strongly, the inclined surface 1b1 of the branch case 1 and the protrusion 2d of the gate valve 2 at the two upper and lower positions further contact each other as shown in FIGS. To increase the contact area. When the contact area increases, the inclined surface 1b1 of the branch case 1 presses the inclined surface 2d1 of the protrusion 2d and acts in a direction to move the gate valve 2 away from the branch case 1.

  Further, as shown in FIGS. 8 and 9, the fastener 3 is further tightened so that the contact area between the inclined surface 1 b 1 of the branch case 1 and the protrusion 2 d of the gate valve 2 is maximized. The inclined surface 1b1 of the branch case 1 presses the inclined surface 2d1 of the projection 2d and acts in a direction to move the gate valve 2 away from the branch case 1, and the inner side of the groove into which the sealing material 5 is fitted. The protruding wall 1c and the overhanging portion 2a of the gate valve come into contact with each other to stop the gate valve 2 from moving away from the branch case 1, and the fastening by the fastener 3 is completed. Since it has such a configuration, even when a large load is applied after the branch pipe is connected, the connection between the branch case 1 and the gate valve 2 is strengthened, so that the fluid can be effectively leaked. Prevent it.

  Then, as shown in FIGS. 10 and 11, the other fastening points of the split case 1 having a split T-shaped pipe shape are fastened by using bolts and nuts which are the fasteners 7 and 8, and the branch attached to the existing pipe K. The water tightness of case 1 is ensured. Reference numeral 9 denotes a reinforcing rib, and the fastener 8 is fixed and fastened from the upper surface of the reinforcing rib 9 in the longitudinal direction.

  After the branch case 1 and the gate valve 2 are connected, a punching device (not shown) is connected to the receiving portion 2b on the other end side of the gate valve 2 in the same manner as in the prior art. After retreating upward and opening the inside of the gate valve 2 in a communicating state, a predetermined portion of the existing pipe K is punched by a punching device.

  When the drilling is completed, the rotation of the hole saw built in the drilling device is stopped, the drilling device is retracted, and a part of the cut-off existing pipe is discharged as the drilling device is retracted. Instead, the tip of the branch pipe (not shown) is inserted into the receiving portion 2b of the gate valve 2 instead to terminate the connection, and the branch pipe can be used.

[Another embodiment]
(1) In the above embodiment, the branch case 1 and the gate valve 2 are connected by fastening with the fastener 3, and as the fastener 3 is tightened, the inclined surface 1b1 of the concave portion of the branch case and the projection 2d of the gate valve. Although the contact area with the inclined surface 2d1 increases, the inclined surface 1b1 of the branch case presses the inclined surface 2d1 of the projection, and the connection is made by acting in the direction of moving the gate valve 2 away from the branch case 1. In order to strengthen the connection between the branch case 1 and the gate valve 2, a bolt 10 may be interposed as shown in FIGS.

  That is, a bolt hole in which a female screw is formed is formed at a position between the concave groove formed on the inner peripheral surface of the other end of the branch case 1 and into which the sealing material 5 is fitted and the inclined surface 1b1. By screwing the bolt 10, the connection between the branch case 1 and the gate valve 2 is further strengthened. In this case, as shown in FIGS. 4 to 8, as the fastener 3 is tightened, the inclined surface 1b1 of the branch case presses the inclined surface 2d1 of the protrusion as shown in FIGS. 12 (a) to 12 (c). Then, after the inner ridge wall 1c of the branch case 1 and the overhanging portion 2a at the one end side edge of the gate valve come into contact with each other and stop, as shown in FIG. 12 (d), the bolt 10 is screwed and screwed. . The screw 10 may be screwed at one place or a plurality of places. Moreover, you may connect the volt | bolt 10 so that it may act in the direction which keeps the gate valve 2 away from the branch case 1 by pressing the inclined surface 2d1 of a protrusion directly. However, when such a bolt 10 is interposed, a configuration in which the inclined surface 1b1 of the branch case presses the inclined surface 2d1 of the protrusion and acts to connect the gate valve 2 away from the branch case 1 is connected. The branch case 1 and the gate valve 2 may be connected by fastening the fastener 3 and screwing the bolt 10.

  (2) In the above embodiment, the tap water is taken as an example of the fluid inside the pipe. However, the present invention is not limited to this and can be applied to fluids such as various liquids and gases.

  (3) In the above embodiment, two projections 2d are provided in the circumferential direction of the outer peripheral surface of the gate valve 2, and two inner projections on the other end of the branch case 1 are provided corresponding to the projections 2d. Although the example which provided the recessed part 1b was shown, the combination of the processus | protrusion 2d and the recessed part 1b may be 1 set, and 3 or more sets may be sufficient as it.

The fragmentary sectional view which shows the state which attached the branch pipe connection apparatus which concerns on one Embodiment of this invention to the existing pipe | tube. Partial sectional view showing a state where a branch case is mounted Partial sectional view showing the state where the branch case is rotated The same figure as FIG. 3 which shows the state which fastened the fastener AA arrow view of FIG. Furthermore, the figure similar to FIG. 4 which shows the state which fastened the fastener AA arrow view of FIG. The same figure as FIG. 4 which shows the state which tightened the fastener and was completed AA arrow view of FIG. The top view which shows the state which tightened the fastener and was completed Left side view of FIG. The figure similar to the enlarged view in a circle of Drawing 4 explaining the modification of the connection process of a branch case and a gate valve Sectional drawing explaining the branch pipe connection method of the prior art Sectional drawing explaining the branch pipe connection method of the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Branch case 1A, 1B Divided body 1b Recessed part 1b1 Recessed part inclined surface 1c Inner protrusion wall 2 Gate valve 2a Overhang | projection part 2d Projection 2d1 Projection inclined surface 3 Fastener 5 Seal material K Existing pipe

Claims (9)

A branch case made of a split body that can be water-tightly attached to an existing pipe, and a gate valve that is connected to the branch case and has a built-in valve body that can be connected to the branch pipe, so that the branch pipe can be connected. In the branch pipe connection device,
The branch case is mounted on the existing pipe and is rotatable, the split surfaces of the branch case are flanged to each other, and the split face that is flange-connected is substantially the axial direction of the branch pipe. A branch pipe connecting device, wherein the branch pipe connecting device is located in a horizontal direction and fastened by a fastener, and the branch case and the gate valve are connected via a sealing material by fastening of the fastener. On the inner peripheral surface of the branch valve side end portion of the branch case, one or a plurality of recesses having an inclined surface that is inclined in a diameter-expanding manner and opened outwards are formed, and a protrusion that fits into the recess is The branch pipe connection according to claim 1, wherein one or a plurality of outer peripheral surfaces in the vicinity of the existing pipe side end of the gate valve are provided so that the inclined surface of the recess and the inclined surface of the projection can be in surface contact. apparatus. As the fastener is tightened, the contact area between the inclined surface of the concave portion of the branch case and the inclined surface of the projection of the gate valve increases, and the inclined surface of the branch case presses the inclined surface of the projection, A concave groove is formed in the inner peripheral surface of the other end side of the branch case, and a concave groove is formed in the inner peripheral surface of the other end side of the branch case. The inner protrusion wall and an overhang portion formed on an existing pipe side end face of the gate valve come into contact with each other, and the gate valve can be stopped from moving away from the branch case. Branch pipe connection device. In addition to the connection between the branch case and the gate valve being performed by fastening the fastener, the branch case and the gate valve are inserted by inserting a bolt into a bolt hole formed near the other end of the branch case. The branch pipe connecting device according to any one of claims 1 to 3, wherein the branch pipe connecting device is connected to the pipe. The branch pipe connection device according to any one of claims 1 to 4, wherein the existing pipe side end face of the gate valve has a concave shape capable of surface contact with an outer peripheral face of the existing pipe. A partition valve that incorporates a valve body and can be connected to the branch pipe is mounted at a predetermined position on the upper surface of the existing pipe, and the branch case made of a split body having a flange surface is held by the existing pipe. Attached to the tube,
The flange surface of the split body of the branch case is fastened by a fastener, and the split case and the gate valve are connected so that the top of the gate valve is positioned upward, and the split surface is flange-connected. Is positioned substantially horizontally with the axial direction of the branch pipe,
By further tightening the split cases of the branch case using the fastener, the branch case and the gate valve are firmly connected,
Connecting a punching device to the gate valve, drilling a predetermined portion of the existing pipe,
After completion of drilling by the punching device, the punching device is removed,
A branch pipe connection method for connecting the branch pipe to the gate valve. After connecting the branch case and the gate valve, the branch case and the gate valve are integrally rotated so that the top of the gate valve is positioned upward, and between the branch case and the gate valve. A connection is formed on the inner peripheral surface of the branch case side end portion of the branch case. 7. The branch pipe connecting method according to claim 6, wherein the branch pipe connecting method is carried out by being in contact with each other and one or a plurality of inclined surfaces provided on the outer peripheral surface in the vicinity of the existing pipe side end of the gate valve. When the fastener is tightened, the contact area between the inclined surface of the concave portion of the branch case and the inclined surface of the protrusion of the gate valve increases, and the inclined surface of the branch case presses the inclined surface of the protrusion. The inner wall of the concave groove formed to fit the sealing material on the inner peripheral surface of the other end side of the branch case, and acting in a direction to move the gate valve away from the branch case; 8. The branch pipe connection method according to claim 7, wherein the projecting portion formed on the existing pipe side end face comes into contact with the branch case to stop the gate valve from moving away from the branch case. In addition to the connection between the branch case and the gate valve being performed by fastening the fastener, the branch case and the gate valve are inserted by inserting a bolt into a bolt hole formed in the vicinity of the other end of the branch case. The branch pipe connection construction method according to any one of claims 6 to 8, wherein the connection is performed with the pipe.

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