JPH09126355A - Earthquake-proof fluid piping system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earthquake-proof fluid piping system where removal preventing function acts effectively only at the time of the destruction limit of fluid piping. SOLUTION: In this fluid piping, a unit rigid connection line RL and a telescopic joint M are mutually connected and buried under the ground. In the case where destruction limit force in the minimum strength spot of the rigid connection line RL is designated by F0 ; the outer diameter of a pipe in the unit rigid connection line is done by D; ground restricting force per the unit surface area of a pipe body in the unit rigid connection line is done by τ; and the length of the unit rigid connection line RL is done by T, the length of the unit rigid connection line RL is prescribed so as to satisfy the expression of T<=F0 /(πDτ), and the unit rigid connection line RL and the telescopic joint M are mutually connected to compose the fluid piping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic resistant fluid piping system that exhibits a function of preventing pipes from separating during an earthquake.

[0002]

2. Description of the Related Art Currently, water pipes and the like piped underground are
As shown in FIG. 4, the fluid pipe a of ductile cast iron having a length of about 4 to 6 m is continuously nested, that is, the insertion port 02 at one end of one fluid pipe a is connected to the other fluid pipe a. A fluid pipe is constructed by sequentially inserting it into the receiving port 01 at one end via a seal (not shown).

However, in such a fluid pipe in a nested pipe connection state, once the ground is displaced due to an earthquake or the like, the receiving portion 01 of the fluid pipe a to the insertion portion 0 of another fluid pipe a.
2 will come out, water will leak out from this connecting part b, and water supply to each household will be easily caused.

In order to prevent such a danger, as shown in FIG. 5, there is a fluid pipe A consisting of a connecting portion B having an expansion / contraction function capable of absorbing the movement of the ground.

A brief description of this expansion / contraction mechanism will be given below.
In FIG. 6, 01 is a receiving part, 02 is an insertion part, and an insertion part 0
An annular protrusion 03 is formed on the outer surface of the distal end of the No. 2. The projection 03 is a ring-shaped member made of ductile cast iron, steel, or the like fixed to the insertion opening 02 by welding. The protrusion 03 may be formed integrally with the insertion port 02. On the other hand, on the inner surface of the receiving portion 01, a tapered surface 05 for installing the packing 04 is formed at the opening end thereof, and an annular groove 06 is formed on the inner side thereof.

Reference numeral 07 denotes a lock ring which can be inserted into the inner side of the receiving portion 01 from the annular space between the inner surface of the receiving portion 01 and the outer surface of the inserting portion 02, and has a diametrically expanding biasing force for dividing into a ring groove. It is fitted in 06. The annular groove 06 has a depth such that the inner peripheral portion of the lock ring 07 fitted therein can engage with the projection 03 at the tip of the insertion opening 02 in the pipe axial direction. The lock ring 07 is made of ductile cast iron, steel, or the like, and a backup ring 08 that abuts against the side surface of the packing 04 is disposed on the inner side of the receptacle 01.

Numeral 09 is a push ring split into two for pushing the packing 04, and a T-shaped bolt 011 and a nut inserted through the hole provided in the flange 010 of the receptacle 01 and the hole provided in the push ring 09. It is attached by 012. By tightening the bolt 011 and the nut 012, a pressing force acts on the packing 04, and the sealing property between the receiving portion 1 and the insertion portion 02 is ensured.

In such a connecting portion B, as shown by a chain double-dashed line in the drawing, between the rear end surface 013 of the receiving portion 01 and the lock ring 07, the receiving portion 01 and the insertion portion 02 are arranged in the axial direction. Is allowed to move relative to each other, and the protrusion 03 and the lock ring 07 are engaged with each other to prevent the lock ring from coming off.

[0009]

However, in such fluid pipes, the connecting portion B allows relative movement between the fluid pipes with some force, so that the ground is not in a small earthquake or earthquake. If the allowable amount of movement has already been exhausted for a certain stroke due to subsidence, etc. and a large-scale earthquake occurs, the fluid pipes will be disconnected from the joint, which is the most burdensome.

Further, it is conceivable to fix all the connecting portions of the fluid pipes by using flanges and bolts and nuts, or fix them all by welding, but if the fluid pipes are in a completely rigid state, an earthquake will occur. In doing so, a huge force acts on the fluid pipe due to the ground restraining force, and the fluid pipe is surely broken at the place of the lowest strength in the pipe.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a seismic resistant fluid pipe system in which the expansion and contraction function works effectively only at the breaking limit of the fluid pipe.

[0012]

In order to achieve the above object, in the seismic resistant fluid pipe piping system of the present invention, unit rigid connection lines RL and expansion joints M are alternately connected and buried in the ground. The fluid pipe FL and the rigid connection line RL.
F0 is the fracture limit force in the local area of the lowest strength, D is the pipe outer diameter of the unit rigid connection line, τ is the ground restraint force per unit surface area of the tubular body in the unit rigid connection line, and the length of the unit rigid connection line RL If T, then T ≦ Fo / (πDτ)
The length of the unit rigid connection line RL is defined so as to satisfy the above condition, and the unit rigid connection line RL and the expansion joint M are alternately connected to configure the fluid pipe FL.

In the seismic resistant fluid pipe piping system of the present invention, the unit rigid joint line RL is constructed by joining n unit pipe bodies P having the same length l so as to restrain expansion and contraction at the joint portion G. Part G has a breaking limit force Fo at the lowest strength of the rigid bond line RL, and T = nl ≦ Fo / (πDτ), that is, n ≦ Fo / (πDτl) (n: integer), It is preferable that the number n of the unit tubes P forming the unit rigid connection line RL is determined.

The seismic resistant fluid pipe system of the present invention is
It is preferable that the number n of the unit tubes P is determined so as to satisfy / (πDτl) -1 ≦ n ≦ Fo / (πDτl).

In the above structure, the unit rigid connection line RL means a continuous pipe so as to always restrain the expansion and contraction integrally, and the expansion joint M is a fluid pipe inside when a predetermined expansion force is generated. It is a joint having the function of at least changing its length without affecting the flow of.

Here, the length T of the unit rigid connection line RL
(Nl) depends on the nature of each ground, but the longer the length, the larger the ground restraint force can be obtained. Therefore, even if the ground slightly moves due to a small earthquake or simple ground subsidence, this unit rigid connection The line does not expand and contract as a rigid body. That is, since the ground restraining force corresponding to the length T is sufficiently working, the expansion joint M does not easily expand and contract, and the expansion and contraction of the expansion joint M causes the minimum strength of the rigid joint line RL due to a large-scale earthquake or the like. Only when the local area nears the limit of destruction.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. In FIG. 1, a fluid pipe 2 (corresponding to P) having a predetermined length (for example, 6 m) is firmly and substantially rigid. That is, the joint portions (G) are non-expandably connected, and the plurality of joined fluid pipes 2 are connected to each other by the unit rigid joint line (R).
L).

Reference numeral 1 denotes an expansion joint (M), which is interposed between this unit rigid connection line (RL) and the next unit rigid connection line (RL) to connect them.

Various patterns are conceivable for the joint portion (G) of the fluid pipe 2 and the fluid pipe constituting the unit rigid connection line (RL) described above, and taps are formed in the fluid pipe to screw the fluid pipes together. There is no limitation on the connecting method, such as forming a flange in advance on the fluid pipe and connecting with a bolt and nut, and further by welding.

Further, the expansion joint (M) is not limited, either, without stopping the flow of water.
The point is that it can be expanded and contracted so that the force is released only when a predetermined load is applied.

Here, an example of the expansion joint (M) and the joint portion (G) will be described with reference to FIG. 2. At each end of each fluid pipe 2, an insertion portion 2a and a flange portion 3 are formed.
And a receiving portion 2b having a shape are formed so that they can be connected to each other.

The expandable joint 1 has a partially expandable wavy tube 19
A flange portion 6 is formed at one end of the expandable wavy tube 19, and an annular fixture 12 is connected to the flange portion 6 via a T-shaped bolt 13 and a nut 14. . A locking claw 15 as a locking means is provided inside the fixture 12, and the locking claw 15 is used to push the bolt 1.
By pressing the outer surface of the fluid pipe 2 with 6, the fixture 12
Can be fixed to the fluid pipe 2.

Numeral 17 is a packing for sealing between the inner surface of the opening of the expandable wavy tube 19 and the outer surface of the fluid tube 2, and
By tightening the nut 14 of the V-shaped bolt 13, the pressing portion 12a of the fixture 12 is always urged inwardly of the expandable wavy tube 19.

Since the other end of the expandable wavy tube 19 can be inserted into the receiving portion 2b of another fluid pipe 2 having the flange portion 3, the fixing tool 12 and the packing 17 similar to those described above are provided.
The other fluid pipe 2 can be connected and fixed by using.

An example of another expansion joint M is shown in FIG. 3, and the expansion joint 1 has an outer diameter of the insertion portion 2 of the fluid pipe 2.
a first tubular body 4 having a diameter larger than the outer diameter of a, and a second tubular body 5 having an outer diameter substantially the same as the outer diameter of the insertion opening 2a,
The second tubular body 5 is slidably fitted in the first tubular body 4. In the elastic fluid tube 1, the first tubular body 4 itself functions as a receiving portion, and the second tubular body 5 itself functions as an insertion portion.

A flange portion 6 is formed at one end of the first tubular body 4, and an annular fixture 12 is connected to the flange portion 6 via a T-shaped bolt 13 and a nut 14. A locking claw 15 as a locking means is provided inside the fixture 12, and the locking claw 15 is pressed against the outer surface of the fluid pipe 2 by a push bolt 16 to move the fixture 12 to the fluid pipe 2.
Can be fixed to.

Reference numeral 17 denotes the inner surface of the opening of the first tubular body 4 and the fluid pipe 2.
It is a packing for sealing the outer surface, and by tightening the nut 14 of the T-shaped bolt 13, the pressing portion 12a of the fixture 12 is always urged inwardly of the first tubular body 4. .

Reference numeral 11 denotes a stopper ring having a substantially L-shaped cross section, which has a biasing force for expanding the diameter in one piece and has an inner diameter smaller than at least the outer diameters of the second pipe body 5 and the other fluid pipes 2. Is fitted in the annular groove 10 of the first pipe body 4 so as to regulate the contact between the end face of the fluid pipe 2 and the end face of the second pipe body 5, respectively.

On the inner peripheral surface of the other end of the first tubular body 4, annular projecting portions 7 and 8 are provided so as to be spaced apart from each other, and between the projecting portions 7 and 8 of the first tubular body 4. A packing 9 that seals between the inner surface and the outer surface of the second tubular body 5 is fitted. These protrusions 7 and 8 are guides for preventing positional displacement of the packing 9 in the left-right direction, and particularly in the protrusion 8, an annular protrusion formed on the outer periphery of the end of the second tubular body 5. 18 is abutted and regulated, and functions as a regulation member that prevents the second tubular body 5 from coming off.

Since the other end of the second pipe body 5 can be inserted into the receiving portion 2b of the other fluid pipe 2 having the flange portion 3, the same fixture 12 and packing 17 as described above are used. The other fluid pipe 2 can be connected and fixed.

The essential points of the present invention will be described with reference to FIG. 1. As described above, the unit rigid connection line (RL) is n.
The fluid pipe 2 having a length of 1 constitutes a flow channel firmly fixed so as to restrain expansion and contraction, and has a total length T (cm), that is, a length of nl (cm). The unit rigid connection lines (RL) of this unit length are sequentially connected in the same manner through the expansion joints (M) to form a water pipe as a fluid pipe (FL).

Under the condition of the present invention, the surrounding soil comes into contact with each of the fluid pipes 2 buried in the ground, and this soil applies a pressing force to the fluid pipes, and due to the frictional force thereof, the fluid is always fluidized. Ground restraining force τ (kgf / c per unit surface area of pipe)
m ² ) is working.

Therefore, in a structure in which fluid pipes are simply fitted in a nesting manner, each fluid pipe is held by a ground restraining force, and when a small earthquake or a slight ground subsidence occurs, the ground displacement is restrained by the ground. Since a force is applied to move the joint portion between the fluid pipes in the pull-out direction, the fluid pipes are disengaged from each other, and water cutoff is easily caused.

When all the fluid pipes (FL) are connected by fluid pipes having an expansion / contraction function, for example, due to the same reason, an expansion / contraction stroke provided in the event of a large earthquake such as a small earthquake or ground subsidence. Moves easily. For example, when a plurality of fluid pipes are all stretched, the buried fluid pipes (FL) cannot be seen from the outside, and when a large-scale earthquake occurs, the moving stroke cannot be absorbed and the movement stroke cannot be absorbed. The connection between the fluid pipes, which is burdensome, is disconnected.

In the present invention, for example, the joint portion (G) between the fluid pipes is a portion having the lowest strength in the rigid connection line (RL), and the breaking limit force thereof is defined as Fo (kgf). Here, the average outer diameter of the unit rigid connection line (RL) is D (cm), and the length of one fluid pipe 2 is l (c).
m), the ground restraining force applied to one fluid pipe 2 is πDτl, and the length T of the unit rigid connection line (RL) that satisfies T = nl ≦ Fo / (πDτ), that is, l Is a standard, the condition of the number n of the fluid pipes 2 of the unit rigid connection line (RL) that satisfies n ≦ Fo / (πDτl) is determined. If this condition is satisfied, the joint portion (G) or The lowest strength local part of the unit rigid connection line (RL) is not dropped or destroyed.

If the condition of T = nl ≦ Fo / (πDτ) is satisfied and T = nl≈ ≦ Fo / (πDτ) is satisfied, the expandable joint ( Expansion joint (M) before M) does not operate and the lowest strength part is destroyed by a large earthquake etc.
Will work.

Under the above conditions, the unit rigid bond line (R
To determine the number n of the fluid pipes 2 that compose L), Fo /
The expression (πDτl) -1 ≦ n ≦ Fo / (πDτl) can be used.

By doing so, an extremely inexpensive fluid pipe (FL) can be constructed without using many expensive flexible portions.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and even if there are changes and additions within the scope not departing from the gist of the present invention, the present invention is not limited. Included in the invention.

[0040]

According to the present invention, the unit rigid connection line RL
The length T (nl) depends on the characteristics of each ground, but the longer the length, the larger the ground restraint force can be obtained. Therefore, even if the ground moves a little due to a small earthquake or simple ground subsidence, This unit rigid connection line does not expand and contract as a rigid body.
That is, since the ground restraining force corresponding to the length T is sufficiently exerted, the expansion joint M does not easily expand and contract, and the expansion and contraction of the expansion joint M is caused by a large-scale earthquake or the like and the rigid connection line RL
Only when the lowest strength region of is approaching the breaking limit.

[0041]

[Brief description of the drawings]

FIG. 1 is a schematic view of a fluid pipe according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a connection between the expansion joint of FIG. 1 and another fluid pipe.

FIG. 3 is a sectional view showing an expansion joint of another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a connected state of a conventional fluid pipe.

FIG. 5 is a partial cross-sectional view showing a connected state of another conventional fluid pipe.

6 is a partially enlarged sectional view corresponding to FIG.

[Explanation of symbols]

 1 Expansion Joint (M) 2 Fluid Pipe (P) 2a Insertion Portion 2b Receiving Portion 3 Flange Portion 4 First Fluid Pipe 5 Second Fluid Pipe 6 Flange Portion 7 Protrusion 8 Protrusion (Regulating Means) 9 Packing 10 Annular groove (groove) 11 Stopper ring 12 Fixing tool 12a Pressing part 13 T-shaped bolt 14 Nut 15 Locking claw (locking means) 16 Push bolt 17 Packing 18 Projection (regulating means) 19 Expandable wavy tube

Claims (3)

[Claims] 1. A unit rigid connection line RL and an expansion joint M
Is a fluid pipe FL which is alternately connected and is buried in the ground. The fracture limit force at the lowest strength local portion of the rigid connection line RL is Fo, the pipe outer diameter of the unit rigid connection line is D, and the unit rigid connection is When the ground restraint force per unit surface area of the pipe in the line is τ and the length of the unit rigid joint line RL is T, the length of the unit rigid joint line RL is set so as to satisfy T ≦ Fo / (πDτ). A seismic resistant fluid piping system that defines and rigidly connects the unit rigid connection lines RL and expansion joints M alternately to form a fluid piping FL. 2. The unit rigid connection line RL is configured by connecting n unit fluid pipes P of the same length l so as to restrain expansion and contraction at a joint portion G, and the joint portion G is connected to the rigid joint line RL. The unit rigid bond line RL is configured so as to have a local breaking limit force Fo of the lowest strength and satisfy T = nl ≦ Fo / (πDτ), that is, n ≦ Fo / (πDτl) (n: integer) The earthquake-resistant fluid piping system according to claim 1, wherein the number n of the unit fluid pipes P to be determined is determined. 3. Fo / (πDτl) -1 ≦ n ≦ Fo / (π
The seismic resistant fluid piping system according to claim 2, wherein the number n of the unit fluid pipes P is determined so as to satisfy Dτl).