JPH1122879A - Slip-on type antiseismic pipe fitting and its fitting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the antiseismic property of a pipe fitting for cast iron pipes, of the slip-on type whereby the pipes are fit together without being fastened. SOLUTION: A groove 12 and a faucet projection 13 located in a position that is approximately half of insertion length away from the outer end 11 of a faucet 1 are provided near the outer end 11, and a lock ring 4 which fits into the groove 12 has on each side a locking claw 41 which meshes with the outer peripheral surface of a spigot 2, and spigot projections 21 are provided on the outer peripheral surface of the spigot 2. At normal hydraulic pressure, the locking claws 41 bite into the outer peripheral surface of the spigot 2, exhibiting binding forces in the directions of withdrawing and pushing forces, and thus keeping immobile the positions of the faucet 1 and the spigot 2. If a non-steady-state load works as in an earthquake, the outer peripheral surface of the spigot 2 is unlocked from the lock ring 4, the relative positions of the faucet 1 and the spigot 2 are changed, and the spigot projections 21 collide with the faucet projections 13 or the lock ring 4, preventing further movement and maintaining the functions of a duct.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Slip-on type joining is free from the procedure of assembling and fastening members in an unnatural posture when an operator enters a narrow pit, and especially if special equipment is prepared, Since the pipes can be joined with each other from the point of view, this is a method of forming pipes that is highly evaluated in terms of improving workability, securing safe work, and saving labor.

[0003] However, even if the vehicle experiences severe pitching or rolling due to a direct hit such as an earthquake after laying, it is at least necessary to prevent the joints from being detached from each other so that the function of the pipeline is not lost. Request. In addition, temporary or permanent dynamic loads due to uneven settlement of the ground and the passage of heavy vehicles, vertical and horizontal external forces are always unevenly applied to pipelines laid underground due to static loads, and Since an irregular force due to water pressure acts on the deformed pipe portion, it is hard to say that a construction method that can be used at all when laying and constructing is extremely reliable unless a configuration that can cope with these stresses is adopted.

With regard to pipe joints used for slip-on types, various countermeasures have been proposed with emphasis on prevention of disengagement and expansion and contraction with emphasis on this problem. For example, the prior art shown in FIG.
A lock ring groove 102 is provided in the vicinity of the open end of No. 01 and a lock ring 103 is fitted therein. Further, an insertion ring 105 is fixedly attached to the insertion opening 104, and is provided in a hollow portion between the inner peripheral surface of the receiving opening and the outer peripheral surface of the insertion opening. The 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, the relative position of the receiving port and the receiving port fluctuates, and even if the relative positional relationship of the receiving port changes, Since the insertion ring 105 is engaged with the insertion ring 105 to prevent further movement, it is stated that the separation of the tubes is prevented 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 an opening-side ridge 202 is provided around a receiving port 201 and a rear-side ridge 203 is provided at a deep portion. Is fitted with a rubber ring 204 inside. 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 between the distal end of the insertion port and the deepest part of the receiving port is set as the insertion margin L1 as shown in the figure, and positioning of the tubes is performed. Fig. (B) shows the state when the pipe is subjected to the stress of pulling out in the direction of the pipe axis, which has undergone the swing such as an earthquake, and both pipes are relatively horizontal in the horizontal direction. To prevent slip-off, the tip of the insertion port moves to reach the deepest part of the receptacle, and the opening side surface of the back side ridge 203 of the receptacle is on the tip side of the lock ring 207 fitted in the concave groove 206 of the receptacle. Since it plays the role of a stopper that abuts against the side surface and prevents further movement, there is obtained an effect that there is no fear 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 method. In replacing the aging existing pipe T1, when the existing pipe T1 is dug up and the existing pipe T1 is taken out as in the prior art, traffic congestion or traffic becomes difficult. Construction is extremely complicated and extremely inefficient.Therefore, in recent years, pipe-in has been implemented to reduce costs and shorten the construction period, and to renew pipes on arterial roads and intersections where excavation is not possible. The pipe method tends to be used more and more as soon as attention is paid. As shown in the figure, the starting shaft 301 and the reaching shaft 302 are located between the existing pipelines.
A new pipe T was dug from the ground to remove a part of the existing pipe exposed to the starting pit, and attached a leading sled 303 to the tip.
2 is pushed horizontally by the hydraulic jack 304 into the existing pipes buried underground and propelled.
This is a method of laying unopened pipelines to form a new pipeline in the old pipeline by adding

As a pipe joint in this case, as shown in FIG. 7, the insertion groove 401 extends over a relatively long range on the outer peripheral surface of the insertion port.
And a lock ring 403 is fitted in the lock ring groove 402 on the inner surface of the socket, and the lock ring is pressed against the groove bottom of the insertion groove by the set bolt 404.
A ductile cast iron pipe (JIS G 5526) is specified. With this configuration, even when a horizontal pressing force is applied from the starting pit, the pressing force is transmitted by the engagement between the lock ring 403 and the lock ring groove end 405, and the new pipe is pushed forward inside the existing pipe. Is said to proceed smoothly.

[0008]

In the prior arts exemplified here, any external force in the pulling-out direction is applied to the pipe joint portion by providing a certain range that allows movement in the pipe axis direction. When the sideslip travels to the limit, the mutually convex portions come into contact with each other to act as a stopper and prevent the movement beyond the limit, so that there is no doubt that the function of preventing the pipe from being removed works. However, a close examination of the state in which the pipes of tap water, household gas, and sewers were severely damaged in the recent great earthquake disaster and forced the victims to work enormously showed that the destruction of the pipes was a simple joint. The necessity of recognizing that it is not only the withdrawal and withdrawal from but also the result of the synthesis of more complicated conditions has been asked again.

For example, in the case of the prior art shown in FIG.
As shown in FIG. 8A, when the insertion ring 105 enters too far into the receptacle, there is a possibility that the soft rubber material may be damaged due to contact with the rubber ring 106 and the water stopping property may be impaired. Also, when the insertion port 104 moves inside the receptacle due to an earthquake or the like, and is pushed in until the tip contacts the deepest part of the receptacle as shown in FIG.
The anticorrosive coatings may be rubbed against each other to damage or peel off, thereby losing the anticorrosive properties, and possibly causing red water to pollute the water flow.

In the case of the prior art shown in FIG. 5, since the concave groove 206 is provided on the outer peripheral surface of the insertion port, the wall thickness of the pipe is locally reduced, and an external force or bending to be pulled out to the pipe joint is required. When a moment acts, there is no denying that the strength is insufficient and the stress concentrates on the thin portion of the insertion opening to cause breakage. If the thickness of the groove is increased, the thickness of the entire tube becomes unnecessarily thick, which is uneconomical. Further, considering the state at the time of joining when inserting the insertion port into the receiving port, the opening side ridge 20 of the receiving port is considered.
The lock ring 207, which is freely tightened and is freely housed in the inner surface of the step between the second protrusion 2 and the rear side ridge 203, is enlarged at the inclined surface at the front end of the insertion port, and is used for the lock ring while rubbing the outer peripheral surface of the insertion port. Since it goes through the procedure of meeting the concave groove 206 and fitting it here, there is no danger that at least the outer peripheral surface of the water contact portion from the insertion tip to the rubber ring will be damaged and the anticorrosive coating will be damaged or peeled off .

[0011] The requirement of a pipe joint having earthquake resistance is that even when an unsteady external force is applied, it can be dealt with by bending and stretching due to fluctuations in the relative positions of the receiving port and the insertion port, and any pull-out. Even if force is applied, the two points must be compatible: mutual separation is prevented and the function of the pipeline is maintained. The problem is that when the pipe joints are joined to form a pipe, the water pressure 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 joints may work, and the pipeline may meander or the axis may be out of order.If a water pressure test is performed after backfilling and a leak is found Requires tedious work such as digging up the pipe again and correcting it.

In the above-mentioned PII type joint, which has been standardized as an earthquake-resistant pipe joint in the pipe-in-pipe method, a long groove is formed in an insertion opening, and the pipe thickness is increased so as to sufficiently withstand a pull-out force due to an earthquake or the like. Need to be added, resulting in an increase in weight, which is an economically disadvantageous condition. PII on existing pipe
When the ductile cast iron pipe is press-fitted, the lock ring 403 is engaged with the groove end face 405 of the insertion groove in FIG. 7 and there is no margin for pushing in if an earthquake occurs. You may not be able to adapt to the movement. Also, at this time, a sudden pull-out force or push-in force acts to lock the lock ring with the insertion groove and the end face with an impact. PII type ductile cast iron pipes for pipe construction are defined as ordinary seismic joints.
It is empirically and experimentally known that it has only about 1/2 of the detachment prevention force of the SII type pipe joint.

According to the present invention, a slip-on type earthquake-resistant pipe joint, which has been evaluated as having high productivity as a laying method itself in order to solve the above-described problems, is a conventional pipe-line earthquake-resistant pipe joint, for example. Almost half of the S-type and SII-type pipe fittings could be recognized as a separation prevention force, but a seismic pipe with a separation prevention function comparable to that of the S-type was formed, and the pipeline was laid. The objective is to provide pipe joints that are effective in improving the seismic resistance of pipelines, especially in urban areas with heavy traffic, including the pipe-in-pipe method that boasts high workability at the time of construction, and to provide a joining method therefor.

[0014]

SUMMARY OF THE INVENTION A slip-on type earthquake-resistant pipe joint according to the present invention comprises a receiving port 1, an insertion port 2 inserted into the receiving port 1, and an elastic member interposed in a hollow portion between the two. A pipe ring which is connected to each other in a non-fastened manner to form a pipe, and a lock ring 4 is provided near the outer end 11 of the receiving port 1.
A sharp locking claw that is provided with a concave groove 12 that fits therein and a receiving projection 13 at a deep portion in the receiving port, and that engages with the outer peripheral surface of the insertion port 2 and restricts the positional relationship between the two pipes at normal water pressure. The lock ring 4 having 41 on both sides is held down and fixed with a plurality of set bolts 5 penetrating the socket, and the locking force of the locking claw against an unsteady external force on the outer peripheral surface of the insertion port 2 The relative position of the receiving port and the receiving port fluctuates beyond that, and the connecting projection 21 is provided around the locking ring 4 or the receiving projection 13 to prevent the detachment. I do.

1 (A), 1 (B) and 1 (C) are longitudinal front views showing the basic operation of the present invention. FIG. 1 (A) shows a slip-on type seismic pipe joint in a pipe groove excavated. The positional relationship of the standard state joined by is shown. That is, insert 2 into receptacle 1
Is inserted into the outer peripheral surface of the insertion hole with the locking claw 41 of the lock ring 4 to fix the positions of both pipes.
And the allowance L1 up to the inner end 16 at the deepest part of the socket and the allowance L2 up to the inner side 43 of the lock ring 4 facing the outer side 23 of the insertion projection are almost in balance. ing. In this state, even if normal water pressure is applied to the pipe joint, the locking claws bite into the outer peripheral surface of the insertion hole, and the locking claws protrude from both side surfaces of the lock ring. It exerts a restraining force in any direction of force and becomes a source power for keeping the positions of the receiving port and the inserting port immovable.

FIG. 1B shows that when an unsteady large external force such as an earthquake applies a large pushing force, the pushing force (rightward in the figure) causes the pin to bite into the outer peripheral surface of the insertion opening. The locking claw 41 of the lock ring is buckled, the engagement between the outer peripheral surface of the opening and the lock ring is released, and the locking claw is dragged by an external force. 13 shows a state in which the projection 13 and the insertion projection 21 hit each other to prevent further movement. FIG. 1 (C) shows a case where a large pulling force acts on the contrary, and shows a state where the insertion projection 21 and the inner side surface 43 of the lock ring hit each other to prevent further pulling out.

Further, when the slip-on type earthquake-resistant pipe joint of the present invention is applied to the pipe-in-pipe method, the restraining force between the locking claw 41 of the lock ring 4 and the outer peripheral surface of the insertion port is changed to a new pipe T2. If the propulsion force is set to be larger than the pushing force for pressing the end of the pipe, the rear pipe presses the front pipe and proceeds in the existing pipe T1 in the state of FIG. At the same time, a pull-out allowance and a penetration allowance, which were impossible with a joint, are secured, and even if an excessive pull-out force or push-in force is applied, the joint is not separated or pushed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the present invention will be described in more detail with reference to FIG.
(A) is the positional relationship of the joined standard, FIG. 1 (B) is the earthquake,
FIG. 1C shows the case where the relative position between the tubes fluctuates due to the indentation force acting due to the land subsidence, and the case where the position between the tubes fluctuates due to the pulling force acting reversely. . Explaining from the state of the standard state in FIG.
The lock ring 4 is easily fitted from the outer end because the concave groove 12 is provided in the vicinity of the outer end 11. A receiving projection 13 is provided on the inner side of the end face of the receiving port 1 and at a position approximately half the length of the insertion port. An elastic rubber ring 3 as a seal material is fitted into the inside, and is engaged with and restrained by a small projection 14 protruding from the inner peripheral surface of the socket. On the other hand, an insertion projection 21 is provided around the insertion opening 2, and the position after joining is in a state of protruding between the lock ring 4 of the reception opening and the reception projection 13, and comes out as shown in FIG. L
It is the most desirable form that the balance between 2 and the entry margin L1 is substantially balanced. In FIG. 1 (B), a large external force acts in the direction of compressing and shrinking the pipe joint, so that the side surfaces of the insertion projection 21 and the reception projection 13 hit each other, and the pipes are prevented from being detached from each other. However, even if this position is reached,
It is desirable that there is a margin L0 between the plug 6 and the insertion tip 22 so as to prevent collision with each other so as not to cause a state in which deformation or damage to the anticorrosive coating is induced.

FIGS. 2A, 2B, and 2C illustrate the lock ring 4 in the embodiment of the present invention. FIG. 2A is an overall side view, FIG. 2B is a sectional view, and FIG. () Is a partially enlarged view of the sectional view. The lock ring is made of metal made of a material harder than ductile cast iron and is formed of an annular body which is urged to open and has a split portion 44, and has a notch 45 so as to be easily fitted into the groove 12 of the socket. Are fitted on the left and right sides, and when they are fitted into the concave groove 12, they are tightly attached to the groove bottom. FIG.
As shown in (C), the inner surface 43 and the outer surface 46 of the lock ring.
A sharply pointed locking claw 41 projects downward, and this locking claw bites into the outer peripheral surface of the insertion opening to oppose normal water pressure.

Conventional earthquake-resistant pipe joints, such as S type and SII
In the case of a shaped joint, the maximum detachment prevention force F is represented by F ≧ 0.3 × D. However, the slip-on type earthquake-resistant pipe joint of the present invention was designed on the condition that a similar level was maintained, and an experiment was conducted. As a result, the configuration shown in FIG. 1 is reached. That is, the required thrust F1 (nominal diameter 300 m
m, the propulsion length is 100m, about 4 Ton), and the exit force F2 due to the internal water pressure when the pipeline is in service (about 5mm for a nominal diameter of 300mm
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 is generated, the joint must move to absorb the displacement. For example, assuming that a compression or tensile axial force of about 90 Ton is applied to a pipe having a nominal diameter of 300 mm, the pipe is designed to be able to restrain the pipe to that level. Assuming that the restraining force of the joint portion by the locking claw is F0, a setting is made such that the larger force of F1 or F2 <F0 <F3 holds, and the nominal diameter is 30.
The axial force of 90 Ton at 0 mm is the above-mentioned 0.3 x D
Indicated by When an axial force exceeding the restraining force of the locking claw is applied, the socket and the insertion port move relative to each other, and when they come out, the insertion projection comes into contact with the lock ring. Contact with the mouth protrusion, 0.3 × D in any case
Needless to say, it should be designed to withstand an axial force of Ton or more.

3 (A), 3 (B) and 3 (C) are longitudinal sectional front views for respective steps showing a joining procedure of the earthquake-resistant pipe joint of the present invention.
In FIG. 3A, the rubber ring 3, the lock ring 4,
In this state, the set bolt 5 is deposited in the receptacle 1 and the insertion port 2 is inserted into the receptacle 1 in the direction of the arrow. In FIG. 3 (B), the insertion hole is inserted up to the prescribed body gap L1 (entrance allowance) and L2 is inserted.
Adjust to a distance approximately equal to. In FIG. 3C, the set bolt 5 is tightened to engage the locking claw of the lock ring with the outer peripheral surface of the insertion opening, thereby completing the joining.

[0022]

The slip-on type earthquake-resistant pipe joint according to the present invention can be easily joined without forming pipes to form a pipe line, but the stationary pipe joint is always subjected to an axial force due to water pressure in the pipe. In the use state, the locking claws on the inner surface of the lock ring bite against the outer peripheral surface of the insertion hole and sufficiently oppose to each other, so that there is no possibility that the tubes are detached, and the relative positional relationship between the tubes is kept immovable. . This eliminates the condition that the pipes are backfilled to fix the positional relationship between the pipes in order to perform a water pressure test before water supply after joining the pipes in the slip-on type method, and the test is performed with the pipes exposed after laying The function of the joint can be confirmed by applying water pressure, and the effect on the construction is extremely large.

In addition, since it has a detachment prevention force F0 just enough to antagonize the S-type and SII-type joints, which are well-established as fastening-type earthquake-resistant pipe joints using a push ring, the best advantage of the non-fastening type is provided. While maintaining high productivity when laying a pipeline,
It is possible to construct a seismic structure underground conduit, which is also required by the times, and has the qualities that contribute to society as an ideal pipe joint that can meet both requirements simultaneously.

The non-cutting method is also a large technical flow required by the times, but the pipe-in-pipe method, which is a typical example, is also compared with the PII type earthquake-resistant pipe joint according to the prior art. Also, since it is not necessary to form a long insertion groove for reducing the thickness of the outer peripheral surface of the insertion port, there is no need to lower the pipe strength or increase the wall thickness to compensate for it. Also, when inserting a new pipe into an existing pipe for the pipe-in-pipe method, the locking claw surely bites into the outer peripheral surface of the insertion port and the whole body moves forward with the positional relationship between them fixed. Thus, the insertion is completed in a state in which the exit allowance and the entry allowance are secured, and there is no fear that the insertion port is pushed into the receiving port, so that there is an effect that the ground movement can be sufficiently coped with.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a steady state (A), a state where a pushing force is applied (B), and a state where a pulling force is applied (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 a main part of a section.

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

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

FIGS. 5A and 5B are longitudinal sectional front views showing different states of another conventional earthquake-resistant pipe joint according to FIGS.

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

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

8A shows two problems in the prior art shown in FIG. 5; FIG.
(B) is shown in a vertical sectional front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reception opening 2 Insertion opening 3 Rubber ring 4 Lock ring 5 Set bolt 11 Outer end 12 Concave groove 13 Reception protrusion 14 Small protrusion 15 Bolt hole 16 Inner end 21 Insert protrusion 22 Top 23 Outer surface 41 Locking claw 42 Top Surface 43 Inner surface 44 Split part 45 Notch 46 Outer surface L1 Entrance allowance L2 Exit allowance T1 Existing pipe T2 New pipe

Claims (3)

[Claims] 1. A receiving port 1 and an insertion port 2 inserted into the receiving port 1.
And an elastic rubber ring 3 interposed in both hollow portions,
In a slip-on type pipe joint which joins each other without fastening to form a pipe, a concave groove 12 in which the lock ring 4 is fitted near the outer end 11 of the socket 1,
A receiving projection 13 is provided at a position approximately one-half of the length into which the insertion port enters, and is sharply engaged with the outer peripheral surface of the insertion port 2 to restrict the positional relationship between the two pipes at normal water pressure. The lock ring 4 having the claws 41 on both sides is held down and fixed by a plurality of set bolts 5 penetrating through the socket, and the relative position of the two pipes to the outer peripheral surface of the insertion port 2 against an unsteady external force. A slip-on type earthquake-resistant pipe joint, wherein an insertion projection 21 is provided around the lock ring 4 or the reception projection 13 to prevent the detachment by coming into contact with the lock ring 4 or the reception projection 13 by changing the positional relationship. 2. A method of joining a pipe to an excavation trench for laying a pipeline by using a slip-on type earthquake-resistant pipe joint, wherein a position of an insertion port 2 to be inserted into a receiving port 1 is determined by a tip of the insertion port. 2
2 and the entrance allowance L1 up to the innermost end 16 of the socket,
A pipe joining method using a slip-on type earthquake-resistant pipe joint, which is inserted until an allowance L2 from the outer surface 23 of the insertion projection to the inner surface 43 of the lock ring 4 opposed to the outer surface 23 becomes substantially equal. . 3. A receiving port 1A having an outer diameter smaller than the inner diameter of the existing pipe T1. New tube T2
In the pipe-in-pipe method in which the pipe is horizontally pushed from the starting pit and inserted into the existing pipe, the restraining force of the locking claw 41 of the lock ring 4 with the outer peripheral surface of the insertion port is given by the propulsive force pressing the pipe end of the new pipe T2. The method for joining pipes using a slip-on type earthquake-resistant pipe joint characterized in that a new pipe T2 can be inserted while simultaneously setting the entry allowance and the exit allowance by setting a large value.