JP4157413B2 - Flange joint security jig, pit valve safety jig, and security method using these jigs - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flange joint security jig, a safety jig for a valve in a pit, and a security method using these jigs.
[0002]
[Prior art]
Flange joining is joining means that abuts the joining surfaces of a pair of flanges provided at the end of the connection object, passes bolts through holes that penetrate the flanges, and fastens them with bolts and nuts. This flange joint is generally employed as a joint portion of a high-pressure fluid pipe or container because it is highly airtight and strong joint is possible by interposing a packing between joint surfaces (non-patent document 1 below). reference). The joint strength of the flange joint is determined by the strength of the flange and the strength of the bolt, and the flange width, bolt diameter, number of bolts, etc. are designed and selected in order to obtain the joint strength according to the application.
[0003]
Such a flange joint portion is also employed in a connection portion between the end portion of the buried conduit and the end portion of the valve in the pit. The valve in the pit is a valve that interrupts the gas conduction by interposing a medium- and high-pressure buried gas conduit. It is buried in the ground to protect the valve from external loads and to facilitate the operation and maintenance of the valve. It is arranged in a valve pit consisting of a concrete manhole. The end of the buried conduit and the end of the valve in the pit are connected by drawing the end of the buried conduit into the valve pit, in which the end of the buried conduit is connected to the end of the valve via a flange joint. The ends are connected (see Non-Patent Document 2 below).
[0004]
[Non-Patent Document 1]
Piping Engineering Study Group “Piping Handbook 4th Edition” October 21, 1980, p. 1046
[Non-Patent Document 2]
“Guidelines for Design of Branch (Design) JGA Finger-201-85” issued by the Japan Gas Association Technical Standards Committee for Gas Workpieces, November 25, 1985, p. 149-150
[0005]
[Problems to be solved by the invention]
For the flange joint, the joint strength is set according to the application situation. However, there is a case where the possibility of applying external force exceeding the environmental change of the application situation or an assumed situation may be found after construction, and the design change of the joint strength may be forced. In addition, due to aging of the flanges or bolts, the initial joint strength may not be obtained over time. To deal with these, replacement of bolts, etc. can be considered, but in the case of flange joints applied to pipes and containers that conduct or contain high-pressure fluid, temporary joint strength by removing the bolts can be considered. The decrease leads to a decrease in airtightness, which is problematic in terms of safety. In addition, there is a problem in that a decrease in airtightness due to deformation of the flange portion cannot be avoided only by reinforcing the bolts.
[0006]
In the above-mentioned valve in the pit, a space where the earth pressure is released by the valve pit is formed in the middle of the buried conduit whose periphery is held by earth pressure, and a large displacement due to an earthquake or the like is applied to the buried conduit. Has been pointed out that large bending or tension is concentrated on the valve in the pit and the valve connecting portion in the pit. When a large earthquake exceeding the strength standard at the time of laying is assumed, there is a case where the joint strength of the flange joint portion employed in the valve connection portion in the pit must be changed.
[0007]
However, since the valve in the pit is connected to a medium / high pressure buried gas conduit, it is practically impossible to take measures by exchanging bolts as described above. Further, it is not possible to avoid a decrease in airtightness due to deformation of the flange portion only by reinforcing the strength of the bolt. And in the case of high-strength pit valves (made of ductile cast iron, etc.) that have been laid in recent years, the flange on the valve side is rarely deformed, but the flange on the end side of the buried conduit is deformed to improve airtightness. Damage has been confirmed by testing.
[0008]
As one of countermeasures, there has been proposed a safety device that hermetically covers the entire valve in the pit including the flange joint (see, for example, Japanese Patent Laid-Open Nos. 2001-289389 and 2001-99382). Because of the high cost and construction time, it is difficult to spread quickly, and there is a problem that it cannot be handled in urban areas with many construction objects. Furthermore, according to such a large-scale safety device, there is a problem that an excessive investment is required for a facility using the above-described high-strength valve which only needs to reinforce the flange joint.
[0009]
The present invention has been proposed in order to cope with such a situation, and for flange joints that need to maintain airtightness, it is possible to simply reinforce the joint strength of the flanges after laying, thereby ensuring safety. For the flange joint of the valve in the pit where bending or pulling is concentrated when a large displacement due to an earthquake or the like occurs in the buried conduit, the joint strength of the flange can be easily reinforced after installation. The purpose is to increase
[0010]
[Means for Solving the Problems]
In order to achieve such an object, the present invention includes features according to the following claims.
[0011]
One aspect of the present invention is a flange joint security jig that airtightly joins the joint surfaces of a pair of flanges , and is individually attached along the fastening bolts and nuts in the flange joint, A pair of clamping members that abut the back surface of the flange and clamp the flange joint; and a coupling member that couples the pair of clamping members and presses against the back surface, the clamping member comprising the flange There is a relief hole for escaping the bolt head or nut of the joint or a recess for receiving the bolt head or nut of the flange joint, and the joint strength of the flange joint by the strength of the clamping member and the coupling member It is characterized by reinforcing.
[0012]
In another aspect, the sandwiching member includes a pressing portion that presses at least a root portion of the flange on the rear surface of the low-strength flange.
[0013]
Also, one aspect is a method for securing a flange joint part that hermetically joins the joint surfaces of a pair of flanges, wherein the flange joint part is individually attached along a bolt and nut for fastening in the flange joint part. A pair of clamping members having a relief hole for escaping the bolt head or nut or a recess for accommodating the bolt head or nut of the flange joint, and the pair of clamping members are brought into contact from the back surface of the flange. The flange joint portion is sandwiched, the pair of sandwiching members are coupled by a coupling member to press the back surface, the outer periphery of the flange is sealed with a sealing material, and the sandwiching member and the coupling member The strength of the flange joint is reinforced by strength, and the sealing material is used to maintain airtightness in the flange joint.
[0014]
The present invention also relates to a safety jig for a valve in a pit connected to an end of an embedded conduit to be connected in a valve pit via a flange joint, and a bolt and nut for fastening in the flange joint. A pair of sandwiching members that are individually attached along the rear surface of the flange on the buried conduit end side and the flange on the valve side to sandwich the flange joint, and the pair of sandwiching members A coupling member that presses against the back surface, and the clamping member has a relief hole for escaping the bolt head or nut of the flange joint or a recess that accommodates the bolt head or nut of the flange joint. And a pressing portion that presses at least the root portion of the flange on the flange rear surface on the buried conduit end side, and the flange is reinforced by the strength of the clamping member and the coupling member. Characterized in that to reinforce the bonding strength of the di-junction.
[0015]
The present invention also relates to a method for securing a valve in a pit that is connected to an end of an embedded conduit to be connected in a valve pit via a flange joint, and is provided along a bolt and nut for fastening in the flange joint. Using a pair of clamping members that are individually attached and have a relief hole for escaping the bolt head or nut of the flange joint or a recess that accommodates the bolt head or nut of the flange joint. The pair of clamping members are brought into contact with each other from the back surface of the flange on the side of the valve and the flange on the valve side, the flange joint portion is clamped, and the pair of clamping members are coupled by a coupling member to press the back surface The flange root portion on at least the flange rear surface on the buried conduit end side is pressed by the pressing portion of the clamping member, and the clamping member and the coupling member are strengthened. Characterized in that to reinforce the bonding strength of the flange joint portion by.
[0023]
According to the flange joint security jig, the pit valve safety jig, or the security method using these jigs according to each claim, the following effects are obtained.
[0024]
First, according to the flange joint security jig having the above-described configuration and the security method using this jig, the pair of clamping members are pressed against the back surface of the flange while maintaining the airtight state of the flange joint. Then, the attachment of the jig is completed only by connecting the both clamping members with the connecting member. According to this, the strength by the clamping member and the joining member is added to the joining strength of the flange joint before mounting the jig, and the aging or insufficient strength of the flange joint is reinforced by simple construction. be able to.
[0025]
Further, by providing the clamping member with a relief hole for escaping the bolt head or nut of the flange joint, or by providing a recess for accommodating the bolt head or nut of the flange joint on the clamping member, the flange joint It is possible to attach a jig along the bolt of the bolt, and it is possible to appropriately cope with the reinforcement of the bolt and the aging of the bolt.
[0026]
Furthermore, by providing the clamping member with a pressing portion that presses at least the flange base portion on the back surface of the flange on the low strength side, the base portion of the low strength side flange can be brought into close contact with the high strength side flange by a jig. Further, even when a large bending or tensile force is applied to the flange joint, it is possible to prevent a decrease in hermeticity.
[0029]
As a method for securing the flange joint using such a jig, the outer periphery of the flange is further sealed with a sealing member, so that the airtightness of the flange joint can be more reliably maintained.
[0030]
When the flange joint security jig described above is used to secure the flange joint of the valve in the pit, the valve connection part in the valve pit can be easily reinforced, and a large displacement due to an earthquake or the like occurred in the buried conduit. In this case, effective security measures can be taken for valves in the pit where bending or tension is concentrated.
[0031]
That is, as a security measure for the valve in the pit, it is only necessary to attach the above-described jig to the flange joint portion of the valve connection portion exposed in the valve pit. Therefore, it is possible to respond at a low cost compared with the case where a large-scale safety device is installed. is there. And, as mentioned above, the jig installation is completed easily and quickly, so even in urban areas where there are many valves in the pits to be protected, security measures should be taken immediately for all objects. Is possible.
[0032]
When a high-strength valve is used, the base of the flange on the back of the flange on the end of the existing conduit can be pressed against the flange on the valve by the pressing part of the clamping member of the jig. It is possible to effectively avoid a decrease in airtightness due to the deformation of the end side flange .
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram for explaining a reference flange joint security jig and a security method using the jig (FIG. 1 (a) is a partial sectional view, and FIG. 1 (b) is a front view). Yes.) The security jig 10 is connected to the pair of sandwiching members 11A and 11B that are in contact with the back surfaces of the pair of flanges 1A and 1B in the flange joint 1 to sandwich the flange joint 1 and the sandwiching members 11A and 11B. And a connecting member 12 that presses against the back of 1A and 1B. And clamping member 11A, 11B has press part 11a, 11b so that the root part of the flange in a flange back surface may be pressed.
[0034]
The flange joint portion 1 is formed by interposing a packing 1C between the joint surfaces of the flanges 1A and 1B and fastening with bolts and nuts 2, and the joint strength set by the strength of the flanges 1A and 1B and the bolts and nuts 2 In a state where the set bonding strength is ensured, high airtightness can be maintained. However, when an external force such as bending or tension exceeding the set joint strength acts on the flange joint 1, the flanges 1 </ b> A, 1 </ b> B or the bolts / nuts 2 are deformed or stretched, and the air tightness of the flange joint 1. Cannot be maintained. Further, when the strength of the flanges 1A and 1B or the bolts and nuts 2 is deteriorated due to aging, the airtightness of the flange joint 1 even if it is bent or pulled within the initially set joint strength range. May be damaged.
[0035]
Therefore, when such a situation is predicted, the security jig 10 described above is attached to the flange joint 1. At the time of attachment, the coupling member 12 is loosened so that the holding members 11A and 11B are slightly separated from each other. In the embodiment shown in FIG. 1, the holding members 11A and 11B are arranged on the back surface of the flanges 1A and 1B between the bolts and nuts 2. Then, the coupling member 12 is tightened so that the clamping members 11A and 11B are brought close to each other, and the pressing portions 11a and 11b of the clamping members 11A and 11B are pressed against the base portions on the back surfaces of the flanges 1A and 1B.
[0036]
As a result, the joint strength of the flange joint portion 1 is obtained by adding the strength of the holding members 11A and 11B of the safety jig 10 and the strength of the coupling member 12 to the strength of the bolts and nuts 2 for fastening. By pressing the base portions of 1A and 1B against each other, deformation of the flange itself can be prevented and airtightness can be maintained, so that the airtightness of the flange joint 1 is impaired against the predicted situation. Can be prevented in advance. Further, since the reinforcement is completed without removing and replacing the fastening bolts and nuts 2 of the flange joint 1, the construction can be performed while maintaining the airtightness of the flange joint 1. In addition to attaching the safety jig 10, if necessary, a sealing member 3 made of resin or the like is applied to the outer periphery of the flange 1 to seal between the flanges, thereby further ensuring airtightness. Can do.
[0037]
The coupling member 12 in the security jig 10 can be constituted by a member having a screw portion, and the clamping members 11A and 11B can be brought close to or separated from each other by tightening or loosening the screw portion. A plurality of coupling members 12 may be provided between the sandwiching members 11A and 11B, and the number of the coupling members 12 can be set according to the degree of reinforcement. The sandwiching members 11A and 11B are made of a light and high-strength plate material as much as possible.
[0038]
Figure 2 is an explanatory diagram for explaining a security method using the flange joint security jig and its jig according to implementation embodiments of the present invention (FIG. (A) is a partial cross-sectional view and FIG. (B) Shows a front view.) The description and common parts of FIG. 1 partially omitted explanations are indicated by the same symbols. In this embodiment, the clamping member 11A, 11B is provided with a recess 13 for receiving a bolt head or nut in the fastening bolt / nut 2 of the flange joint 1. The sandwiching members 11A and 11B are arranged on the bolts and nuts 2 and are pressed against the back surfaces of the flanges 1A and 1B by the coupling member 12.
[0039]
According to this embodiment, in addition to the operation of the above-described embodiment, since the security jig 10 can be attached along the bolt and nut 2, it is effective when it is desired to reinforce the bolt and nut 2 in a concentrated manner. Further, since the bolt heads or nuts of the bolts and nuts 2 are fitted into the recesses 13 of the clamping members 11A and 11B, the positioning and holding of the clamping members 11A and 11B are ensured, and handling and stability after installation are improved. There is an advantage that it becomes higher. Instead of providing the recess 13, an escape hole for escaping the bolt head or nut in the fastening bolt / nut 2 may be provided.
[0040]
FIG. 3 is an explanatory diagram (partial cross-sectional view) for explaining a flange joint security jig and a security method using the jig according to another embodiment of the present invention. Portions common to the above-described embodiment are denoted by the same reference numerals, and overlapping description is partially omitted. In this embodiment, the pressing member 11a that presses the base portion of the flange on the rear surface of the flange is provided on the holding member 11A on one side. In this embodiment, when one flange 1A in the flange joint 1 has a low strength relative to the other flange 1B, the base portion of the low-strength flange 1A is pressed against the high-strength flange 1B. Deformation can be prevented.
[0041]
FIG. 4 is an explanatory diagram (front view) for explaining a reference flange joint security jig and a security method using the jig. Portions common to the above-described embodiment are denoted by the same reference numerals, and overlapping description is partially omitted. In this embodiment, one or both of the clamping members described above are formed by a ring-shaped member divided body 11C that abuts the entire back surface of the flange 1A (1B). According to this embodiment, the divided body 11C is combined, the safety jig 10 is installed on the entire circumference of the flange, and the root portion of the entire circumference of the flange is pressed by the pressing portion 11c in the divided body 11C, thereby ensuring more airtightness. It becomes possible to hold. In the example shown in the figure, the divided body is ½ of the entire circumference, but is not limited thereto, and may be divided into 1/3, 1/4, etc.
[0042]
FIG. 5 is an explanatory diagram for explaining a safety jig and a safety method for a valve in a pit that employs the jig of the embodiment described above. In the figure, a valve pit 30 is a valve management space formed by a concrete manhole 30A buried in the ground. The in-pit valve 31 is a valve that interrupts the gas conduction by being interposed between the medium and high pressure buried gas conduits 32A and 32B. In order to facilitate protection from the external load on the valve and operation / maintenance management of the valve. It is provided in the valve pit 30. Then, the end portions of the buried gas conduits 32A and 32B are drawn into the valve pit 30, and the valve 31 in the pit is connected to the end portions of the buried gas conduits 32A and 32B through the flange joint portion 1 therein. Near the ends of the buried gas conduits 32A and 32B, bypass junctions 33A and 33B for bypass are provided.
[0043]
Thus, the flange joint portion 1 provided at the connection portion connecting the valve 31 in the pit and the buried gas conduits 32A and 32B has the same structure as described above, and is set while ensuring airtightness. Have high bonding strength. However, the flange joint 1 disposed in the valve pit 30 is exposed to the open space with respect to the buried gas conduits 32A and 32B whose surroundings are held at earth pressure, and the buried gas conduits 32A and 32B are exposed due to an earthquake or the like. When a large displacement occurs in 32B, bending and tension are concentrated on the flange joint 1.
[0044]
When a large earthquake such as the Great Hanshin Awaji Earthquake is assumed, the design standard at the beginning of installation may be exceeded, and the joint strength of the flange joint 1 may have to be changed. However, such a valve 31 in the pit is connected to the medium / high pressure buried gas conduits 32A and 32B, and the measure of replacing the bolts and nuts of the flange joint 1 in a live pipe state is a safe measure. Is hard to say. In addition, if the valve upstream of the valve 31 in the pit to be constructed is shut off, the gas supply to a wide area will be interrupted because the shutoff target is a medium / high pressure gas conduit, The impact on the region is greater.
[0045]
In order to cope with this, the above-described safety jig 10 is used as a safety jig for the in-pit valve 31, and the flange joint 1 is reinforced. FIG. 5 shows the attached state, and a plurality of security jigs 10 are attached around the flange joint 1 for reinforcement.
[0046]
When such a safety jig 10 is employed in the flange joint 1 of the valve 31 in the pit, it is only necessary to attach the jig to the flange joint 1 of the valve connection portion exposed in the valve pit 30, and a large-scale safety device. Compared with the case of mounting the valve, it is possible to cope with a low cost, particularly when the valve itself has sufficient strength and it is sufficient to reinforce only the valve connecting portion. Since the installation of the security jig 10 is completed easily and quickly as described above, even in urban areas where there are a large number of valves in the pit to be protected, security measures are quickly implemented for all targets. It does not affect the gas supply to the surrounding area .
[0047]
【Example】
Hereinafter, more specific examples of the above-described flange joint security jig or the pit valve safety jig (hereinafter collectively referred to as a jig) will be described with reference to FIGS. The configuration of the present invention is not particularly limited to this embodiment (the same reference numerals are given to portions common to the above description, and a part of the description is omitted).
[0048]
The jig 40 of the embodiment shown in FIG. 6 (FIG. 6A is a front view and FIG. 6B is a partial cross-sectional view) includes clamping members 41A and 41B made of a pair of opposing plate members. Provided, one holding member 41A has two bridge portions 41C projecting toward the other holding member 41B, and screw members 42A and 42B for connecting the holding member 41B to the bridge portion 41C are screwed together. Furthermore, screw members 42C and 42D for connecting the clamping members 41A and 41B are screwed together. That is, a coupling member is constituted by the screw members 42A and 42B and the screw members 42C and 42D. One clamping member 41A is provided with a pressing portion 41a that presses the base portion of the flange on the rear surface of the flange, and the other clamping member 41B is provided with an escape hole 41b that allows the bolt head or nut to escape at the flange joint portion. It has been.
[0049]
As a method for attaching the jig 40, the screw members 42A, 42B, 42C, and 42D are loosened and the clamping members 41A and 41B are separated from each other and placed on the back surface of the flange, and the screw members 42A, 42B, 42C, and 42D are tightened. Thus, the clamping members 41A and 41B are pressed against the back surface of the flange.
[0050]
The jig 50 of the embodiment shown in FIG. 7 includes a first sandwiching member 51A having a U-shape and a second sandwiching member 51B arranged in a U-shape, and the second sandwiching member 51B. A screw part 52 projecting from the first screwing member 51A is screwed to the first clamping member 51A. The first clamping member 51A is provided with a pressing part 51a for pressing the root portion of the flange on the rear surface of the flange. The sandwiching member 51B is provided with a recess 51b for receiving a bolt head or a nut at the flange joint. As a method for attaching the jig 50, the screw member 52 is loosened and the opposing surfaces of the holding members 51A and 51B are spaced apart from each other and arranged on the back surface of the flange, and the screw member 52 is tightened to fix the holding members 51A and 51B. The opposing surface is pressed against the back surface of the flange.
[0051]
【The invention's effect】
Since this invention is comprised in this way, a security measure can be simply taken with respect to the flange junction part which needs to maintain airtightness. Further, simple and effective security measures can be taken for the flange joint portion of the valve in the pit where bending or pulling is concentrated when a large displacement due to an earthquake or the like occurs in the buried conduit.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram for explaining a reference flange joint security jig and a security method using the jig (FIG. 1 (a) is a partial sectional view, and FIG. 1 (b) is a front view). ing.).
2A and 2B are explanatory diagrams for explaining a flange joint security jig and a security method using the jig according to the embodiment of the present invention (FIG. 2A is a partial cross-sectional view, and FIG. A front view is shown.).
FIG. 3 is an explanatory diagram (partial cross-sectional view) for explaining a flange joint security jig and a security method using the jig according to another embodiment of the present invention.
FIG. 4 is an explanatory diagram (front view) for explaining a flange joint portion security jig for reference and a security method using the jig.
FIG. 5 is an explanatory diagram illustrating a pit valve safety jig and a security method according to an embodiment of the present invention.
FIGS. 6A and 6B are explanatory views showing an embodiment of a flange joint security jig or a pit valve safety jig according to the present invention (FIG. 6A is a front view, and FIG. 6B is a side view). Yes.)
FIG. 7 is an explanatory view showing an embodiment of a flange joint security jig or a pit valve safety jig according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Flange joint part 1A, 1B Flange 2 Bolt and nut 10 Safety jig 11A, 11B Holding member 12 Coupling member 13, 61a, 61b Recessed part 30 Valve pit 30A Concrete manhole 31 Pit valve 32A, 32B Buried gas conduits 33A, 33B Branch joint 40, 50 jig (flange joint security jig, pit valve safety jig)
41A, 41B, 51A, 51B
Holding member 41C Bridge portion 41a Pressing portion 41b Escape holes 42A to 42D Screw member 52 Screw portion

Claims (5)

A flange jig safety jig for airtightly joining the joint surfaces of a pair of flanges,
A pair of clamping members that are individually attached along fastening bolts and nuts in the flange joint portion, abut against the back surface of the flange, and sandwich the flange joint portion, and the pair of sandwiching members coupled to each other. A coupling member for pressing the back surface,
The clamping member has a relief hole for escaping the bolt head or nut of the flange joint or a recess for receiving the bolt head or nut of the flange joint,
A flange joint security jig, wherein the joint strength of the flange joint is reinforced by the strength of the clamping member and the coupling member. The clamping member may, according to claim 1, wherein the flanges joint security jig and having a pressing portion for pressing the base portion of the flange at the flange back of the at least a low intensity side. A flange joint security method for airtightly joining the joint surfaces of a pair of flanges,
A relief hole that is individually attached along the fastening bolt and nut in the flange joint, and that escapes the bolt head or nut of the flange joint or a recess that accommodates the bolt head or nut of the flange joint. Using a pair of clamping members
Contact is not the pair of holding members from the back of the flange to sandwich the flange joint portion, performs pressing to the rear by coupling the pair of holding members by a coupling member, sealing the outer periphery of the flange A flange that is sealed with a stopper and reinforces the joint strength of the flange joint by the strength of the sandwiching member and the coupling member, and also maintains airtightness at the flange joint by the sealant. How to secure the joint. A safety jig for a valve in a pit connected to an end of an embedded conduit to be connected in a valve pit via a flange joint,
A pair of clamps that are individually attached along the fastening bolts and nuts at the flange joint, and that are in contact with the back surfaces of the flange on the buried conduit end side and the flange on the valve side to clamp the flange joint A member and a coupling member that couples the pair of clamping members and presses against the back surface,
The clamping member has a relief hole for escaping the bolt head or nut of the flange joint or a recess for receiving the bolt head or nut of the flange joint, and at least on the flange back surface on the embedded conduit end side. It has a pressing part that presses the base part of the flange,
A safety jig for a valve in a pit, characterized in that the strength of the flange joint is reinforced by the strength of the clamping member and the coupling member. A method for securing a valve in a pit connected to an end of an embedded conduit to be connected in a valve pit via a flange joint,
A relief hole that is individually attached along the fastening bolt and nut in the flange joint, and that escapes the bolt head or nut of the flange joint or a recess that accommodates the bolt head or nut of the flange joint. Using a pair of clamping members
Wherein the buried conduit end side of the flange from the back of the valve side of the flange is brought into contact with the pair of clamping members sandwiching the flange joint, the back attached to the pair of holding members by a coupling member And pressing at least the root portion of the flange on the back surface of the flange on the embedded conduit end side with the pressing portion of the clamping member, and the bonding strength of the flange joint portion is determined by the strength of the clamping member and the coupling member. A method for securing a valve in a pit characterized by reinforcing.

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