JP3569101B2 - Seismic connection structure for buried piping - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a seismic connection structure for buried pipes in pits (human holes) installed in underground pipes such as buried gas pipes, and more particularly to seismic vibration and displacement absorption to cope with an earthquake or land subsidence. It relates to a seismic connection structure with a function and a large pull-out stopping force.
[0002]
[Prior art]
In underground pipes such as buried gas pipes, pits are provided every 2 to 4 km so that pipes can be inspected and an emergency situation such as an earthquake or a fire can be immediately dealt with. A valve for opening / closing, a pipe-sliding pipe joint for absorbing expansion and contraction of a pipe line, a diffusion valve for diffusing fluid, and the like are provided. FIG. 5 shows an example of conventional piping equipment in a pit for buried gas piping, 11 is a pipe joint in the axial direction for absorbing expansion and contraction of the piping, 12 is a connecting short pipe, and 13 is a piping pipe. Reference numeral 14 denotes a valve for opening and closing, 14 denotes a diffusion valve for extracting gas from the pipeline in an emergency or in-pipe inspection, 15 denotes a buried pipe (main pipe), and 16 denotes a pit.
[0003]
That is, in the conventional piping system in a pit, the embedded pipe 15 is penetrated and supported on the side wall of the pit 16, and is connected to the embedded pipe 15 on the upstream side (the left side in FIG. An open / close valve 13 is disposed between the connecting short pipe 12 and the downstream (right side in FIG. 5) buried pipe 15, and a diffusion valve 14 is attached to each of the upstream and downstream buried pipes 15. Configuration.
[0004]
Here, the connection between the valve 13 for opening and closing the pipe passage and the upstream buried pipe 15 via the communication short pipe 12 connected by the pipe axially slidable pipe joint 11 is the connection short pipe. This is for facilitating the operation when inserting the blocking plate (gasket) 13-1 between the pipe 12 and the valve 13. The purpose of inserting the blocking plate 13-1 is to completely prevent gas leakage from the closed on-off valve 13. When inserting a blocking plate (gasket) 13-1 between the connecting short pipe 12 and the valve 13, once the connecting short pipe 12 is detached from the opening / closing valve 13, the connecting short pipe 12 is slid to the upstream buried pipe 15 side and the valve 13 is connected to the valve 13. Then, after inserting the blocking plate 13-1 in this state, the connecting short pipe 12 is bolted to the opening / closing valve 13 again.
[0005]
As shown in FIGS. 5 and 6, a conventional pipe-sliding pipe joint 11 for absorbing expansion and contraction of a pipe line in the above-mentioned piping equipment configuration has a communication with the upstream buried pipe 15 at a predetermined interval. A pair of fastening flanges 11-2 externally fitted to both joining pipe ends of the short pipe 12, and an annular projection wall 11-5 on the inner peripheral surface, and a joining pipe end between the fastening flanges. A joint body 11-1 which is slidably fitted to the outside, a fastening bolt 11-3 laterally provided between the fastening flanges 11-2, and both opening flanges of the joint body 11-1 and both fastening flanges 11-1. -2, and a seal ring (rubber packing) 11-4 interposed between the joint body 11-1 and the fastening flange 11 with the screwing of the fastening bolt 11-3. together form a structure to be connected are clamped between -2 plurality of collision for retaining provided to the joint pipe end contact short pipe 12 and the upstream side buried pipe 15 11-6 to the annular projection wall 11-5 is engaged and has a mechanism for escape of the joint body 11-1 can be prevented.
[0006]
That is, in the conventional earthquake-resistant connection structure, the joint body 11-1 is clamped through the seal ring 11-4 by the screwing of the fastening bolt 11-3 of the pipe axial direction pipe joint 11, and the connection is performed. When a tensile force acts on the connecting short pipe 12 in the pipe axis direction, the connecting short pipe and the pipe joint slide in the pipe axis direction with each other to absorb the displacement, and the upstream pipe is connected to the upstream side. The buried pipe 15 and the connecting short pipe 12 have a structure in which the detachment between the pipe joint 11 and the connecting short pipe 12 is prevented by a retaining projection 11-6 provided at the pipe end.
[0007]
[Problems to be solved by the invention]
However, such a conventional earthquake-resistant connection structure has the following problems.
That is, although the conventional pipe joint has the function of absorbing displacement in the pipe axis direction as described above, a plurality of retaining projections 11-6 provided at the end of the joining pipe between the upstream buried pipe 15 and the connecting short pipe 12 are provided. The distance between the annular projection wall 11-5 provided on the joint body side, that is, the stroke in the pipe axis direction, is set between the fastening flange of the on-off valve 13 and the flange of the connecting short pipe 12 fastened to the valve. Since it is enough that a gap necessary for inserting -1 is formed, it is not so large as apparent from the drawing, and the displacement absorption in the tube axis direction is small. In addition, since the pull-out preventing force of the pipe joint depends on the strength of the plurality of retaining projections 11-6 provided at the ends of the joined pipes on both sides, a strong tensile force is applied to the connecting short pipe due to an earthquake or the like. In this case, there is a possibility that the retaining projection 11-6 may be missing, and there is a drawback that a mechanically large pull-out resistance cannot be obtained.
[0008]
In addition, since the conventional pipe joint does not have a displacement absorbing function against bending in a structural manner, a large bending force is applied to the pipe line due to an earthquake or the like, and a short pipe connecting the pipe joint portion to the upstream buried pipe 15 side. If the 12 side is bent to cause misalignment, there is a possibility that the joint body 11-1 may be cracked or damaged, or the fastening bolt 11-3 may be broken.
[0009]
Further, since the conventional pipe joint has a structure in which a part of the seal ring 11-4 is exposed to the outside, there has been a problem that the ring is severely damaged and the durability has to be deteriorated.
[0010]
Furthermore, since the conventional pipe connection structure has a structure in which the emission valve 14 cannot be directly attached to the pipe joint portion, it must be provided in the upstream and downstream buried piping 15 as shown in the drawing, and the emission valve 14 Since the mutual slide width (stroke) in the pipe axis direction cannot be increased because of the obstruction, there is a disadvantage that maintenance performance such as replacement of the seal ring 11-4 is poor.
[0011]
The present invention has been made in order to solve the above-mentioned conventional problems, and a displacement absorbing function capable of securing a large amount of expansion and contraction and a desired amount of misalignment, and a pull-out preventing force equivalent to the tensile strength of a pipe are obtained. Another object of the present invention is to provide a seismic connection structure for buried piping which has excellent maintainability and is particularly reliable against earthquakes.
[0012]
[Means for Solving the Problems]
The seismic connection structure for buried piping according to the present invention includes, in a pit installed in the buried piping, a joining pipe fastened to an opening / closing valve of the buried piping and a joining pipe connected to the mating buried piping. A structure in which pipe joints are connected by pipe-sliding pipes in the axial direction, wherein both joint pipes use a short pipe body thicker than the buried pipe, and the joint body of the pipe joint is slightly larger than the outer diameter of both joint pipes. It has a straight pipe portion having an inner diameter and a diameter-enlarged portion that expands in a tapered shape from an open end portion of the straight pipe portion on the joining pipe end side, and an O-ring is interposed between a flange portion formed at the open end portion of the enlarged diameter portion. A straight pipe opening is fitted to the joining pipe at the rear of an annular projection wall provided on the inner peripheral wall of the straight pipe so as to be slidable on the outer peripheral surface of the pipe. Bolted to the end An elastic seal material constrained by a ring is incorporated, and a metal ring detachably fitted to the pipe joint ends of the two joint pipes by a concave and convex fitting method at a predetermined distance from the annular projection wall is provided. The joint body has a mechanism in which it is engaged with the straight pipe portion and is engaged with the annular projection wall to prevent the pipe from coming off, and the joint body has a structure in which at least one radiation hole is provided. A feature is that the metal ring has a notch in a part of the circumference and has an outer diameter slightly larger than the inner diameter of the straight pipe portion of the joint body.
[0013]
In the present invention, the joint body is divided into two parts in order to facilitate replacement of the seal member and the metal ring. Further, as the shape of the joint body, a straight pipe portion having an inner diameter slightly larger than the outer diameter of the pipe and a diameter-expanded portion that expands in a tapered shape from the open end of the joining pipe end of the straight pipe portion have a shape close to a drum shape. The reason for this is to increase the amount of expansion and contraction in the pipe axis direction and increase the amount of displacement (center misalignment) when the pipe is bent from the joint.
[0014]
Further, as means for preventing the pipe from coming off, a metal ring removably fitted to both ends of the joined pipe in a concave-convex fitting manner is cut into the straight pipe part of the joint body, and the annular projection is formed. The reason for adopting the method of locking to the wall is to obtain a greater pull-out preventing force and to facilitate replacement of the elastic sealing material. In other words, a tensile force in the pipe axis direction acts on the buried pipe, so that the joining pipe moves and the metal ring bites into the straight pipe portion of the joint body, so that a large pull-out preventing force is obtained. In addition, since the metal ring is detachable, the joint body can be easily extracted from both the joint pipes, so that the work of replacing the elastic sealing material can be easily performed.
[0015]
In the present invention, the metal ring is provided with a notch in a part of the circumference in order to facilitate attachment / detachment to the end of the joint pipe, and the outer diameter of the straight pipe part of the joint body is set to be not more than one. The reason for using a ring that is slightly larger than the inner diameter of the joint is to further enhance the pull-out inhibiting force obtained when the metal ring bites into the straight pipe portion of the joint body.
[0016]
The reason why a short pipe body thicker than the buried pipe is used for both the joint pipes is to secure a wall thickness capable of fitting the metal ring into and out of recesses. The cross-sectional shape of the metal ring is not particularly limited, but when the pipe is bent from the joint portion, the outer peripheral surface of the ring comes into surface contact with the inner peripheral surface of the enlarged diameter portion that expands in a tapered shape of the joint body. Preferably, the ring has a cross-sectional shape having a taper surface in the opposite direction to the taper surface of the joint body on the outer peripheral surface of the ring.
[0017]
Furthermore, the elastic sealing material is incorporated inside the rear part of the joint main body and is provided so as to be restrained by a pressing wheel to be bolted, in order to prevent damage to the sealing material, improve durability, and to facilitate replacement. It is.
[0018]
Since the present invention is configured as described above, a joint prevention body having a two-part structure having a straight pipe portion and a diameter-enlarging portion expanding in a tapered shape, and a retaining prevention mechanism including a metal ring and an annular projection wall, It is possible to increase the amount of expansion and contraction in the pipe axis direction, and it is possible to secure a large pull-out inhibiting force equivalent to that of the pipe by restraining the metal ring by cutting into the straight pipe portion of the joint body. . Further, the amount of misalignment of the pipe can be increased by the action of the enlarged diameter portion of the joint body. Further, by providing the joint body with the structure in which the radiation holes are provided, not only does the radiation valve not hinder the work, but also a large separation can be secured between the pit wall.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
1 is a side view showing an example of a seismic connection structure for buried piping according to the present invention, FIG. 2 is an enlarged longitudinal sectional view showing a buried piping joint in the connection structure of the above, and FIG. (A) is a vertical side view showing a normal state, (B) is a vertical side view showing a state in which a pipe is pulled, and FIG. 4 is a buried pipe of the same. (A) is a front view, (B) is a longitudinal sectional side view showing a part of a state attached to the connecting short pipe of the buried piping fitting, 1 is a pipe joint in the axial direction of the pipe, 2-1 and 2-2 are connecting short pipes, 3 is a metal ring, 3-1 is a tapered surface, 3-2 is a cutout, 4 is an elastic sealing material, 5 is It is a pressing wheel.
[0020]
The piping facilities in the pit 16 include a connecting short pipe 2-1 connected to the upstream buried pipe 15 by welding and a connecting short pipe 2 bolted to the on-off valve 13 connected to the downstream buried pipe 15. 2. It is composed of a pipe-type sliding pipe joint 1 for connecting the both-side connecting short pipes 2-1 and 2-2, and a dissipation valve 14. The pits 16 are made of concrete, and are set at intervals of 2 to 4 km in the buried piping as described above.
[0021]
The pipe joint 1 according to the present invention has a straight pipe portion 1-1 having an inner diameter slightly larger than the outer diameter of the both-side connecting short pipes 2-1 and 2-2, and a taper from a joint pipe end side open end of the straight pipe portion. A joint body is constituted by a pair of two cylindrical bodies having an enlarged diameter portion 1-2 which expands like a flange, and the joint body is formed by a flange portion 1 formed at an open end of the enlarged diameter portion 1-2 of both the cylindrical bodies. -3 are overlapped with an O-ring 1-4 interposed therebetween, and the flange portion 1-3 is fastened with bolts 1-5 to form a two-part structure. An annular projection wall 1-6 having an inner diameter slidable on the outer peripheral surface of the connecting short tube 2 is provided on the inner peripheral surface of the tube portion 1-1. A flange portion 1-7 for bolting a pressing wheel 5 that restrains an elastic sealing material 4 described later is provided. To have.
[0022]
The pull-out prevention mechanism of this pipe joint is detachably fitted to the joint pipe ends of the two-sided connecting short pipes 2-1 and 2-2 formed of a short pipe body thicker than the buried pipe 15 by using an uneven fitting method. An annular projection wall 1-6 provided on the inner peripheral surface of the straight tube portion 1-1 of the joint body so as to be slidable on the outer peripheral surface of the connecting short pipes 2-1 and 2-2 is fixed to the metal ring 3. We adopt method to let you do. Here, the metal ring 3 is provided so that, when the pipe is bent from the joint portion, the outer peripheral surface of the ring can make surface contact with the inner peripheral surface of the enlarged diameter portion 1-2 which expands in a tapered shape of the joint body. The outer peripheral surface is formed as a tapered surface 3-1 in a direction opposite to the tapered surface of the enlarged diameter portion 1-2. The metal ring 3 is connected to the straight pipe portion 1-1 of the joint body when the both-side connecting short pipes 2-1 and 2-2 move in directions opposite to each other due to a tensile force acting on the buried pipe 15. It is configured so as to bite into the space and be restrained, and to be locked to the annular projection wall 1-6 to prevent the pipe from coming off.
[0023]
As means for detachably fitting the metal ring 3 to the joining pipe ends of the connecting short pipes 2-1 and 2-2 on both sides in a concave-convex fitting manner, as shown in FIG. Can be easily and quickly fitted by a method such as cutting a part of the ring and fitting the ring outside, or fitting the ring into a two-part structure.
[0024]
The metal ring 3 shown in FIG. 4 is provided with a notch 3-2 in a part of the circumference of the ring, and a ring whose outer diameter is slightly larger than the inner diameter of the straight pipe portion 1-1 of the joint body. This is an example. When this metal ring is attached to the end of the connecting pipe of the connecting short pipes 2-1 and 2-2, the ring is pushed to the left and right to engage with the concave and convex. Further, as shown in FIG. 4B, since the outer diameter of this metal ring is slightly larger than the inner diameter of the straight pipe portion 1-1 of the joint body, a tensile force acts on the buried pipe 15 so that they are opposite to each other. When the both-side connecting short pipes 2-1 and 2-2 move in the direction, the pipes are narrowed by the straight pipe portion 1-1 of the joint body, so that a larger pull-out preventing force can be obtained.
[0025]
In addition, the elastic sealing material 4 in this pipe joint is fitted to the connecting short pipes 2-1 and 2-2 on both sides adjacent to the annular projection wall 1-6 of the straight pipe portion 1-1 of the joint main body, and the straight pipe is formed. It is attached to the flange 1-7 at the opening end so as to be restrained by the pressing wheel 5 fastened by the bolt 5-1.
[0026]
Among the diffusion valves 14 provided on both sides of the opening / closing valve 13, the pipe joint side is provided in the enlarged diameter portion 1-2 of one tubular body of the joint main body, and the other diffusion valve 14 is capable of reaching the buried pipe 15 on the downstream side. It is installed in close proximity to the opening and closing valve 13 to secure a desired separation from the pit wall on this side.
[0027]
In the pipe connection structure of the present invention, a short pipe having a thicker wall than the buried pipe 15 is used for the connecting short pipes 2-1 and 2-2 on both sides. Therefore, the upstream connecting short pipe 2-1 is welded. The other connecting short pipe 2-2, which is connected to the upstream buried pipe 15 and on which the blocking plate (gasket) 13-1 is inserted, is connected to the opening / closing valve 13 by bolting as in the related art.
[0028]
In the pipe connection structure having the above-described configuration, for example, when a large tensile force acts on both buried pipes 15 in directions opposite to each other due to an earthquake, the both-side connecting short pipes 2-1 and 2-2 slide, thereby causing both buried pipes 15 to slide. Since the metal rings 3 bite between the straight pipe portions 1-1 of the joint body and are constrained, a large pull-out inhibiting force can be secured, and each metal ring 3 contacts the annular projection wall 1-6. The contact short pipes 2-1 and 2-2 are not separated from the pipe joint by contact.
[0029]
Further, since the distance between the metal ring 3 and the annular projection wall 1-6 is much longer than the conventional one, it is possible to sufficiently absorb a large displacement due to an earthquake. Furthermore, when a large bending force is applied to the two-side connecting short pipes 2-1 and 2-2 due to an earthquake or the like, and the two-side connecting short pipes 2-1 and 2-2 are bent from the pipe joint portion and the center is shifted. A portion of a gap formed between the inner peripheral surface of the enlarged diameter portion 1-2 of the joint body and the metal ring 3 fitted into the open ends of the two-sided connecting short tubes 2-1 and 2-2. In this case, the displacement is absorbed, so that the effect on the joint body is extremely small.
[0030]
【The invention's effect】
As described above, the present invention has the following effects.
(1) The assembly is simple because the joint body is a two-part system composed of a pair of cylinders having a straight pipe portion and an enlarged diameter portion that expands in a tapered shape.
(2) The retaining mechanism, which is made up of a metal ring fitted unevenly to the connecting short pipe on both sides and an annular projection wall provided on the joint body side, makes it possible to increase the amount of expansion and contraction in the pipe axis direction. Since the metal ring has a structure in which the metal ring bites into the straight pipe portion of the joint main body and is stopped by being restrained, a large pull-out preventing force equal to or higher than the strength of the pipe can be secured.
(3) Since the amount of misalignment of the pipe can be increased by the action of the enlarged diameter portion of the joint body, a large bending force is applied to the both-side connecting short pipe, and the both-side connecting short pipe bends from the pipe joint. Even if the misalignment occurs, there is almost no possibility that the joint body is damaged.
(4) Since the metal ring is detachable, the joint body can be easily extracted from the joint pipe, and the replacement work of the elastic sealing material can be easily performed.
(5) The elastic sealing material of the pipe joint and the connecting short pipes on both sides is incorporated inside the rear part of the joint body, and is provided so as to be restrained by the pressing ring to be bolted, thereby preventing damage to the sealing material and improving durability. Peel off.
(6) Among the diffusion valves provided on both sides of the opening / closing valve, the pipe joint side is provided on the joint body itself, and the other diffusion valve can be provided as close to the opening / closing valve as possible. A desired separation can be ensured, the dissipating valve does not hinder the installation work in the pit, the installation is simplified even in a narrow place in the pit, and the metal ring and elasticity Since the replacement of the sealing material can be easily and quickly performed, the maintenance is easy.
(7) It has extremely high reliability, especially against earthquakes, in that it has a displacement absorption function that can secure a large amount of expansion and contraction and a desired amount of misalignment, and a pull-out prevention function equivalent to the tensile strength of piping.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of a seismic connection structure for buried piping according to the present invention.
FIG. 2 is an enlarged longitudinal side view of a buried piping pipe joint in the buried piping seismic connection structure.
FIG. 3 is an enlarged view of a part of the pipe joint for buried piping, in which (A) is a longitudinal sectional side view showing a normal state, and (B) is a longitudinal sectional side view showing a state in which the pipe is pulled. It is.
FIG. 4 illustrates another metal ring in the above-mentioned buried piping fitting, in which (A) is a front view, and (B) is a part of the buried piping fitting attached to a connecting short pipe. FIG.
FIG. 5 is a side view showing an example of a conventional connection structure for buried piping to which the present invention is applied.
FIG. 6 is a longitudinal sectional side view showing the conventional pipe joint for buried piping in an enlarged manner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pipe joint 2-1 and 2-2 Both-side connecting short pipe 3 Metal ring 3-1 Taper surface 3-2 Notch 4 Elastic sealing material 5 Pressing ring 13 Opening / closing valve 14 Dissipation valve 15 Buried piping 16 Pit

Claims (2)

In a pit installed in a buried pipeline, a joint pipe connected to the on-off valve of the buried pipeline and a joint pipe connected to the mating buried pipeline are connected by a pipe joint that slides in the axial direction. In addition, a short pipe body thicker than a buried pipe is used for the two joint pipes, and a joint body of the pipe joint is a joint between a straight pipe part having an inner diameter slightly larger than an outer diameter of the two joint pipes and the straight pipe part. It has a diameter-enlarging portion that expands in a tapered shape from the opening end of the tube end side, and has a two-part structure in which a flange formed at the opening end of the diameter-enlarging portion is bolted with an O-ring interposed therebetween, and Elasticity which is restrained by a pressing ring which is fitted to the joining pipe and is bolted to the opening end of the straight pipe portion, at the rear of an annular projection wall slidably provided on the inner circumferential wall of the straight pipe portion on the outer circumferential surface of the pipe. Built-in sealing material A metal ring removably fitted to the pipe joint end of each of the joint pipes at a predetermined distance from the annular projection wall by a concave-convex fitting method bites into a straight pipe portion of the joint body. A seismic connection structure for buried piping, characterized in that the joint main body is provided with at least one radiation hole without a mechanism for locking the annular projection wall to prevent the pipe from coming off. The said metal ring has a notch in a part of circumference, and the outer diameter is slightly larger than the inner diameter of the straight pipe part of a joint main body, The seismic resistant connection structure for buried piping of Claim 1 characterized by the above-mentioned. .

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