JP3441927B2 - Slip-on type earthquake-resistant pipe joint and its joining method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic resistant pipe joint for preventing separation and entry due to an earthquake or water pressure in a pipe for fluid transportation used for water supply, gas and sewerage.

[0002]

2. Description of the Related Art The slip-on type joint is freed from the procedure in which a worker enters a narrow vertical shaft and assembles each member in an unnatural posture to perform fastening work. Since the pipes can be spliced together by the operation from the above, this is a method of forming a pipeline that is highly evaluated in terms of improving workability, ensuring safe work, and saving labor.

However, even if severe pitching and rolling are encountered due to a direct hit such as an earthquake after being laid, it is at least necessary to prevent the pipes from losing their function due to disconnection from each other. It is a limit request. In addition, temporary or constant dynamic load due to uneven settlement of the ground or passage of heavy vehicles, pipelines laid underground under static load always apply uneven external force in the vertical and horizontal directions, and Since a non-uniform force due to water pressure acts on the deformed pipe portion, it cannot be said that it is a reliable construction method even if there is an advantage in laying construction unless a structure that can cope with these stresses is adopted.

With respect to the pipe joint used for the slip-on type, various countermeasures have been proposed with emphasis on this problem and emphasis on prevention of disengagement and elasticity. For example, the conventional technique shown in FIG.
A lock ring groove 102 is provided near the opening end of 01, a lock ring 103 is fitted therein, and an insertion ring 105 is fixed to the insertion opening 104, in the hollow portion between the receiving inner peripheral surface and the insertion outer peripheral surface. A rubber ring 106 is interposed to maintain the watertightness of the joint. Even when a swing such as an earthquake strikes and stress is applied in the direction of pulling out the joint between the pipes, and the relative positional relationship between the socket and the socket changes, the lock ring 103 of the socket and It is stated that the insertion opening ring 105 of the insertion opening is engaged to prevent further movement, so that the tubes are prevented from being separated from each other and the function of the tubes is not lost.

The prior art shown in FIG.
(A) shows the positional relationship of each member in a normal joined state, and the opening side projection 202 and the deep side projection 203 are provided around the receiving port 201, respectively. The rubber ring 204 is fitted to the inside of the. On the other hand, a concave groove 206 is provided around the insertion opening 205, and a lock ring 207 is fitted in the concave groove. The distance from the tip of the insertion opening to the deepest part of the receiving opening is set as the insertion allowance L1 as shown in the figure to position the tubes. Figure (B) shows the situation when the pipe is subjected to the stress of pulling out in the axial direction of the pipe that has been joined due to shaking due to an earthquake, etc. Both pipes are relatively horizontal in the horizontal direction. Preventing slipping-off, the tip of the insertion opening moves to reach the deepest part of the receiving opening, and the opening-side side surface of the projection 203 on the back side of the receiving opening inserts into the concave groove 206 of the insertion opening. Since it plays a role of a stopper that comes into contact with the side surface and prevents further movement, it is possible to obtain an effect that there is no concern that the pipes are separated from each other and the pipeline is interrupted.

FIG. 6 is a cross-sectional view showing the outline of the pipe-in-pipe construction method. When replacing an old pipe T1 that has deteriorated, if the existing pipe T1 is dug up and the existing pipe T1 is taken out as in the conventional case, traffic jams and traffic will occur. It is a very inefficient work because it hinders the construction work, and it is extremely inefficient work.Recently, pipes have been installed for the purpose of cost reduction, shortening the construction period, and updating pipes such as main roads and intersections where the excavation method is impossible. The pipe method tends to be used more and more as it gets more attention. As shown in the figure, the starting pit 301 and the reaching pit 302 are located in the middle of the existing pipeline.
The new pipe T, in which the vertical shaft was dug down from the ground, part of the existing pipe exposed at the starting shaft was removed, and the leading sled 303 was attached to the tip.
2 is pushed horizontally into the pipe of the existing pipe which is still buried in the ground by the hydraulic jack 304, and the new pipe T2 is successively pushed.
It is a non-excavation pipeline laying method in which a new pipeline is formed in the old pipeline.

As a pipe joint in this case, as shown in FIG. 7, the insertion groove 401 is formed over a relatively long range on the outer peripheral surface of the insertion hole.
PII configured so that the lock ring 403 is fitted in the lock ring groove 402 on the inner surface of the receiving opening, and the lock ring is pressed against the groove bottom of the insertion opening groove by the set bolt 404.
A ductile cast iron pipe (JIS G 5526) is specified. With this configuration, even if a horizontal pressing force is applied from the starting shaft, the pressing force is transmitted by the lock ring 403 and the end portion 405 of the lock ring groove being engaged with each other, and the new pipe is pushed inside the existing pipe. Is said to proceed smoothly.

[0008]

In all of the prior arts illustrated here, when an external force in the pulling direction is applied to the pipe joint portion, a certain range for allowing movement in the pipe axis direction is provided to deal with the problem. There is no doubt that when the sideslip reaches the limit, the mutual convex portions come into contact with each other to act as a stopper and prevent movement beyond the limit, thus acting to prevent the pipe from coming off. However, a detailed examination of the situation in which the pipes for tap water, household gas, and sewer have suffered enormous damage due to the recent earthquake and tsunami, and the victims have suffered a great deal of labor, have found that pipe breakage is a simple pipe joint. The necessity of recognizing that it is a combined result of more complicated conditions has come to be questioned again.

For example, in the case of the prior art shown in FIG.
As shown in FIG. 8 (A), if the insertion ring 105 gets too far into the inside of the receiving opening, there is a concern that it may come into contact with the rubber ring 106 and damage the soft rubber material, impairing the water blocking performance. Further, when the insertion slot 104 moves inside the receiving opening due to an earthquake or the like and is pushed in until the tip comes into contact with the deepest part of the receiving opening as shown in FIG. 8B,
There is a possibility that they may rub against each other to damage or peel off the anticorrosion coating, losing anticorrosion properties and causing the generation of red water that pollutes water flow.

In the case of the prior art shown in FIG. 5, since the concave groove 206 is provided around the outer peripheral surface of the insertion port, the wall thickness of the pipe body is locally thinned, and the external force or bending to pull out the pipe joint is increased. When a moment acts, there is an undeniable concern that the strength is insufficient and stress concentrates on the thin portion of the insertion slot, causing breakage. If the wall thickness of the groove is increased, the wall thickness of the entire tube will be unnecessarily increased, which is an uneconomical condition. Furthermore, considering the state at the time of joining when the insertion port is inserted into the receiving port, the protrusion 20 on the opening side of the receiving port is considered.
The lock ring 207, which can be tightened freely, is housed freely on the inner surface of the step between the rear side 2 and the rear projection 203. There is a risk that at least the outer peripheral surface of the water contact portion from the tip of the insertion opening to the rubber ring will be damaged and the anticorrosion coating will be damaged or peeled off, because the procedure for encountering the concave groove 206 and fitting it there is performed. .

The requirements for a pipe joint equipped with earthquake resistance are that it can be dealt with by the flexibility and stretchability due to the change in the relative positions of the receiving port and the insertion port even when an unsteady external force is applied, and any withdrawal It is necessary to balance the two points of preventing mutual separation and maintaining the function of the pipeline even if a force is applied, but this stretchability causes damage and slip-on type seismic resistance in the excavation trench. The problem is that when a pipe joint is joined to form a pipe, a hydraulic test cannot be performed unless the pipes are backfilled to fix the positional relationship between the pipes. If a water pressure test is performed before backfilling, the expansion and contraction of the joint may cause the pipe to meander or the axis may be misaligned, and if a water pressure test is performed after backfilling and leakage is found. Is forced to perform complicated work such as digging up the pipe again and correcting it.

In the above-mentioned PII type joint, which is standardized as a seismic resistant pipe joint in the pipe-in-pipe construction method, a long groove is formed in the insertion port, so that the pipe thickness is made thick enough to withstand the pull-out force due to an earthquake or the like. It is necessary to increase the weight, which is an economically disadvantageous condition. In addition, PII on the existing pipe
When the ductile cast iron pipe is press-fitted, the lock ring 403 is locked to the groove end surface 405 of the insertion slot in FIG. 7, and if there is an earthquake, there is no margin to push in, so if a large earthquake occurs, the You may not be able to adapt to movement. At this time, a sudden pull-out force or push-in force acts and the lock ring engages with the insertion groove and the end face with a shock, so that the shock force may concentrate on this part, and in general, the pipe PII type ductile cast iron pipes for pipe construction are defined as ordinary seismic resistant pipe joints.
It is empirically and experimentally known that it has a separation preventing force which is about 1/2 of that of the S type and SII type pipe joints.

In order to solve the above problems, the present invention provides a slip-on type seismic resistant pipe joint, which is evaluated for its high productivity as a laying method itself, and is a seismic resistant pipe joint for ordinary pipelines, for example, Only about half the separation prevention force was recognized compared to the S type and SII type pipe joints. However, the seismic resistant pipeline with the separation prevention function comparable to that of the S type was formed and the pipeline was laid. The purpose of the present invention is to provide a pipe joint and its joining method that are effective for earthquake resistance of pipelines, especially in urban areas with heavy traffic, including the pipe-in-pipe construction method, which boasts high workability.

[0014]

DISCLOSURE OF THE INVENTION A slip-on type seismic resistant pipe joint according to the present invention is provided with a receiving opening 1, an insertion opening 2 inserted into the receiving opening 1, and an elastic member interposed in the hollow portions of both. It is a slip-on type that consists of the rubber ring 3 and is joined to each other without fastening to form a pipe line and moves in the pipe axis direction by an external force.
It is a pipe joint having elasticity allowing the above , and a groove 12 for fitting the lock ring 4 near the outer end 11 of the receiving port 1 and an outline of the length inside the end face of the receiving port, into which the insertion port is inserted. One-third
While the receiving projection 13 is provided at the position of 1, the insertion projection 21 is provided around the outer peripheral surface of the insertion opening in a range facing between the lock ring 4 and the receiving projection 13, Positional relationship between the receiving port 1 and the receiving port 2 against the withdrawal force by the water pressure test without pressing the outer peripheral surface of the insertion port with multiple set bolts penetrating the hole and backfilling to fix the positions of the pipes. Equipped with sharp locking claws 41 for immovably restraining
And a larger outside that exceeds the water pressure test such as an earthquake.
When a force is applied, the locking claw 41 is disengaged and the insertion projection 21 and the lock ring 4 or the receiving projection 13 are stretchable to allow mutual pipe movement until they are locked. After that, it is characterized by having a separation preventing force of 0.3 × D (ton) or more. Here, D is the nominal diameter (mm) of the pipe.

1 (A), (B) and (C) are vertical front views showing the basic operation of the present invention, and FIG. 1 (A) is a pipeline groove excavated from a slip-on type seismic resistant pipe joint. The positional relationship of the standard state joined by is shown. That is, the insertion opening 2 into the receiving opening 1
When the tube is inserted and the locking claws 41 of the lock ring 4 bite the outer peripheral surface of the insertion port to fix the positions of both tubes,
And the allowance L1 to the inner end 16 of the deepest part of the receiving opening and the allowance L2 to the inner side surface 43 of the lock ring 4 facing the outer peripheral surface 23 of the insertion protrusion are approximately equal and balanced. ing. This state is the hydraulic pressure before backfilling.
Even if the water pressure due to the strike is applied to the pipe joint, the locking claws bite into the outer peripheral surface of the insertion port, and the locking claws project on both side surfaces of the lock ring. It also exerts a restraining force in the direction and serves as a driving force for keeping the positions of the receiving port and the insertion port immovable.

FIG. 1 (B) shows that when an unsteady large external force such as an earthquake is applied and a large pushing force is exerted, it is caught in the outer peripheral surface of the insertion opening due to excessive pushing force (right direction in the figure). from the ring body or the locking claw 41 is buckling of the locking ring that had
When it breaks , the bite between the outer peripheral surface of the insertion opening and the lock ring is released, the locking claw is dragged by an external force, and the positional relationship between the reception opening and the insertion opening changes, and the reception projection 13 and the insertion projection 21 collide. It shows a state in which it has been hit and prevented from moving further. On the contrary, FIG. 1C shows a case where a large pulling force is applied, and shows a state in which the insertion protrusion 21 and the inner side surface 43 of the lock ring collide with each other and further pulling is prevented.

Further, when the slip-on type seismic resistant pipe joint of the present invention is applied to the pipe-in-pipe construction method, the constraint force between the locking claw 41 of the lock ring 4 and the outer peripheral surface of the insertion opening is changed to the new pipe T2. If it is set to be larger than the propulsive force that pushes the pipe end, the rear pipe pushes the front pipe and advances in the existing pipe T1 in the state of FIG. 1 (A). The pulling allowance and the entering allowance, which were impossible with the joint, are secured at the same time, and even if an excessive pulling force or pushing force is applied, the joint is not detached or pushed in.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiment of the present invention will be described in more detail with reference to FIG.
The standard positional relationship where (A) is joined, Fig. 1 (B) is an earthquake,
When the pushing force acts due to ground subsidence and the relative positions of the pipes fluctuate, Fig. 1 (C) shows the pulling force on the contrary and the positions of the pipes fluctuate. . If explaining from the form of the standard state of FIG.
Since the concave groove 12 is provided in the immediate vicinity of the outer end 11, the lock ring 4 is easily fitted from the outer end. Inside the end face of the receiving port 1, a receiving port projection 13 is provided at a position of approximately ½ of the length into which the insertion port is inserted. An elastic rubber ring 3 as a seal member is fitted in the inside thereof, and is engaged with and restrained by a small protrusion 14 protruding from the inner peripheral surface of the receiving port. On the other hand, an insertion protrusion 21 is provided around the insertion port 2, and the position after joining is in a state of protruding between the lock ring 4 of the reception port and the reception port protrusion 13 and is pulled out as shown in FIG. 1 (A). Teens L
It is the most desirable form that the 2 and the entrance fee L1 are almost balanced. In FIG. 1 (B), a large external force acts in the direction in which the pipe joint is compressed, so that the side surfaces of the insertion projection 21 and the reception projection 13 collide with each other, and the mutual pipe separation is prevented here. There is, however, the inner end of the socket 1 even at this position
It is desirable to set a margin L0 between 6 and the tip 22 of the insertion slot so that they do not collide with each other and cause deformation or damage to the anticorrosion coating.

2 (A), (B) and (C) exemplify the lock ring 4 in the embodiment of the present invention, (A) is a side view of the whole, (B) is a sectional view, and (C). 4) is a partially enlarged view of the cross-sectional view. The lock ring bites on the outer peripheral surface of the insertion slot
In order to make the pipe body (FCD400 phase of the ductile cast iron
Hard material made of metal than the equivalent), for example FCD600 Ya
It is composed of a ring-shaped body that is biased freely and has a split portion 44 made of SUS material, and is provided with notches 45 on the left and right so that it can be easily fitted into the recessed groove 12 of the receiving port. When it is fitted inside, it sticks to the bottom of the groove. Figure 2 (C)
As described above, the sharply pointed locking claws 41 project downward on the inner side surface 43 and the outer side surface 46 of the lock ring, and the locking claws are engaged with the outer peripheral surface of the insertion opening to counteract normal water pressure.

Conventional seismic resistant pipe fittings such as S type and SII
In the case of a shaped joint, the maximum separation prevention force F is represented by F ≧ 0.3 × D, but the slip-on type seismic resistant pipe joint of the present invention was designed and tested under the condition that the same level be maintained. As a result, the structure shown in FIG. 1 was reached. That is, the locking claw 41 of the lock ring has a required thrust F1 (nominal diameter 300 m) in the pipe-in-pipe construction method.
m, propulsion length of 100 m is about 4 Ton), and withdrawal force F2 due to internal water pressure when the pipeline is in service (about 5 at a nominal diameter of 300 mm)
Since Ton) is applied, it is necessary that the joint portion does not expand or contract under these forces or the locking claw does not buckle. At the same time, when a large external force F3 such as an earthquake occurs, the joint portion must move to absorb the displacement. For example, assuming that a tube having a nominal diameter of 300 mm is subjected to a compressive or tensile axial force of about 90 Ton, the tube is designed to be restrained up to that level. Assuming that the restraining force of the joint portion by the locking claw is F0, it is set so that the larger force of F1 or F2 <F0 <F3 is established, and the nominal diameter 30
Axial force of 90Ton at 0mm is 0.3 × D as the standard to be positioned as the highest rank of expansion type seismic resistant pipe joints.
Indicated by. When an axial force that exceeds the restraining force of the locking claws acts, if the receiving opening and the insertion opening move relative to each other and come out, the insertion opening protrusion contacts the lock ring, and if it enters, the insertion opening protrusion receives. It comes in contact with the mouth protrusion, but in any case 0.3 × D
It goes without saying that it should be designed so as to have a separation prevention force equal to or greater than Ton.

3 (A), (B) and (C) are vertical sectional front views showing the joining procedure of the seismic resistant pipe joint according to the present invention.
In FIG. 3A, the rubber ring 3, the lock ring 4, and the
The set bolt 5 is in a state of being deposited in the receiving port 1, and the insertion port 2 is inserted into the receiving port 1 in the arrow direction. In FIG. 3 (B), the insertion opening is inserted up to the specified body gap L1 (entry margin) L2.
Adjust to a distance approximately equal to. In FIG. 3 (C), the set bolt 5 is tightened to engage the locking claw of the lock ring with the outer peripheral surface of the insertion port to complete the joining.

[0022]

EFFECTS OF THE INVENTION The slip-on type seismic resistant pipe joint according to the present invention can form a pipe path by simply connecting pipes without fastening them together, but can maintain a steady force exerted by an axial force due to water pressure in the pipes. In use, the locking claws on the inner surface of the lock ring bite against the outer peripheral surface of the insertion opening to sufficiently oppose each other, and there is no risk of the tubes coming off, and the relative positional relationship between the tubes is kept immobile. . This means that the slip-on type construction method eliminates the condition that the pipes should be backfilled to fix the positional relationship between the pipes for water pressure testing before water supply after the pipes have been joined. The function of the joint can be confirmed by applying water pressure, and the effect on construction is extremely large.

Further, since it has a detachment prevention force F0 sufficient to antagonize the S-type and SII-type joints which are well-established as seismic resistant pipe joints of the fastening system using a push ring, it is the maximum advantage of the non-fastening system. While maintaining high productivity when laying a pipeline,
It has become possible to construct underground pipes with an earthquake-resistant structure, which is a requirement of the times, and it has the qualities of widely contributing to society as an ideal pipe joint that can meet two requirements at the same time.

The non-open cutting method is also a large technological flow required by the times, but the pipe-in-pipe method, which is a typical example of the non-open cutting method, is compared with the PII type earthquake-resistant pipe joint defined by the prior art. In addition, since it is not necessary to form a long insertion groove for reducing the wall thickness of the outer peripheral surface of the insertion opening, it is not necessary to reduce the pipe strength or increase the thickness to compensate for it. Also, when inserting a new pipe into an existing pipe due to the pipe-in-pipe construction method, the locking claw surely bites on the outer peripheral surface of the insertion opening and moves forward as a whole with the positional relationship between the two fixed. In addition, the insertion is completed in the state where the withdrawal allowance and the entrance allowance are secured, there is no concern that the insertion allowance is pushed into the receiving mouth, and there is an effect that it is possible to sufficiently cope with the movement of the ground.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a steady state (A), a pushing force applied state (B), and a pulling force applied state (C) according to an embodiment of the present invention.

FIG. 2 is a front view (A) of a lock ring embodiment of the present invention,
It is a longitudinal section (B) and an enlarged view (C) of an important section.

FIG. 3 is a vertical cross-sectional front view showing the joining procedure of the present invention in steps by (A), (B), and (C).

FIG. 4 is a vertical sectional front view showing a conventional earthquake-resistant pipe joint.

FIG. 5 is a vertical sectional front view showing a different state of another conventional seismic resistant pipe joint according to FIGS.

FIG. 6 is a vertical sectional front view showing the principle of the pipe-in-pipe construction method.

FIG. 7 is a vertical sectional front view showing a conventional earthquake-resistant pipe joint used in a pipe-in-pipe construction method.

FIG. 8 shows two problems in the conventional technique of FIG.
It is shown by a vertical sectional front view of (B).

[Explanation of symbols]

1 Receptacle 2 Insertion mouth 3 Rubber ring 4 Lock ring 5 Set bolt 11 Outer end 12 Recessed groove 13 Receiving mouth protrusion 14 Small protrusion 15 Bolt hole 16 Inner end 21 Insertion protrusion 22 Tip 23 Outer side surface 41 Locking claw 42 Top surface 43 Inner side surface 44 Split section 45 Notch 46 Outer side surface L1 Entry margin L2 Exiting margin T1 Existing pipe T2 New pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Shiomi 1-12-19 Kitahorie, Nishi-ku, Osaka City, Osaka Prefecture Kurimoto Iron Works Co., Ltd. (56) References JP-A-5-172278 (JP, A) Kaihei 9-126355 (JP, A) Actually open 4-133091 (JP, U) Actually open 59-59590 (JP, U) Actually open 49-148529 (JP, U) Actually open 59-59584 ( (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16L 1/00-1/11 F16L 21/00-21/08

Claims (3)

(57) [Claims] 1. A receptacle 1 and an insertion slot 2 to be inserted into the receptacle 1.
And an elastic rubber ring 3 interposed in the hollow portions of both,
In a slip-on type, which is joined together to form a pipe without fastening, and which has elasticity to allow movement in the pipe axial direction by an external force, an outer end 11 of the socket 1 is provided.
A recessed groove 12 for fitting the lock ring 4 is provided nearby, and a socket projection 13 is provided inside the end face of the socket and at a position of approximately ½ of the length into which the socket is inserted.
The insertion protrusion 21 is provided on the outer peripheral surface of the insertion opening in a range facing between the reception opening 13 and the reception projection 13, and the lock ring 4 is pushed by a plurality of set bolts penetrating the reception opening 1 and bites against the insertion insertion outer peripheral surface. Then, even if the positions of the pipes are not backfilled and the positions of the pipes are fixed, sharp locking claws 41 that immovably restrain the positional relationship between the receiving port 1 and the inserting port 2 on both sides against the exit force by the water pressure test are provided on both side surfaces. Equipment
Moreover, when a larger external force that exceeds the water pressure test such as an earthquake is applied, the locking claw 41 is disengaged and the insertion protrusion 21 and the lock ring 4 or the reception protrusion 13 are locked to each other. A slip-on type seismic resistant pipe joint that is stretchable to allow pipe movement and has a detachment prevention force of 0.3 x D (ton) or more after locking. However, D is the nominal diameter of the pipe (mm) 2. A method for joining a pipe to a digging trench for laying a pipe using a slip-on type seismic resistant pipe joint, wherein the position of the insertion port 2 to be inserted into the receiving port 1 is set to the tip of the insertion port. Two
2 and the entrance margin L1 to the innermost end 16 of the deepest part of the socket,
The slip-on type seismic resistant pipe joint according to claim 1 , characterized in that the slip-on type seismic resistant pipe joint is inserted until the outer side surface 23 of the insertion port projection and the withdrawal allowance L2 to the inner side surface 43 of the lock ring 4 facing each other become substantially equal. How to join the pipes used. 3. A part of the existing pipe is excavated from a starting resistance and a reaching resistance to remove a part of the exposed pipe, and a receiving port 1A having an outer diameter smaller than the inner diameter of the existing pipe T1 is provided. New tube T2
In the pipe-in-pipe construction method of horizontally pushing from the starting pit and inserting it into the existing pipe, the force of pushing the pipe end of the new pipe T2 is restrained by the locking claw 41 of the lock ring 4 with the outer peripheral surface of the insertion port. The slip-on type seismic resistant pipe joint according to claim 1 or 2 , characterized in that the new pipe T2 can be inserted while holding the entrance and exit margins at the same time. How to join the pipes used.