JPH10332061A - Separation preventing pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both earthquake resistance and integral reinforcement in a joint part of a pipeline having many bending parts laid in the underground. SOLUTION: In this separation preventing pipe joint, a step difference 11 continued to the deepest part inside a joint from a fitting position of a lock ring 4 in an internal peripheral surface of a socket 1 is hollowly provided, a flexible positioning spacer 5 is internally fitted, in an inner circumferential surface side of this positioning spacer 5, a fitting groove 51 internally fitting a spigot protrusion 21 peripherally provided in the vicinity of an end part 22 of a spigot 2 is engraved. The positioning spacer 5, utilizing flexibility, is fitted to the fitting groove 51, and even by applying a pressure of water in a pipe at ordinary time, mutually connecting relation is maintained sufficiently opposite to the water pressure. Even against non-averaged force acting in a pipe of different shape, flexibility of the positioning spacer acts to be adjusted by performing suitable deformation so as to obtain uniform external force. When large-scaled movement of the ground is generated, fitting is unlocked, the lock ring 4 and the spigot protrusion 21 butt on each other, any more separation is completely impeded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint which is buried underground such as for water supply, sewerage, gas, etc., and is a pipe joint for preventing separation.

[0002]

2. Description of the Related Art Ductile cast iron pipes which are excellent in workability at the time of laying are mainly composed of pipes which form pipes buried underground. In this pipe, the insertion end of the other pipe end is inserted into the socket whose one pipe end is enlarged, and a rubber ring is interposed in the gap between them to maintain the watertightness of the pipe line, It plays a major role in pipelines that supply fluids such as sewage and household gas. Since pipes are buried underground, prevention of separation between pipes is an important factor, and water leakage from pipe joints must not waste valuable water resources.

At present, most of the joints used for ductile cast iron pipes are standardized as K-type, A-type, T-type, and the like. It is a flexible pipeline that adapts to some degree of earthquake and crustal deformation on soft ground. However, the demand for seismic pipes in recent years has been further increased in the wake of the Great Hanshin Earthquake, and the development of higher-level joints for seismic pipes has been urgently required. In this context, SII type joints have been developed and put into practical use.

FIG. 10 is a longitudinal sectional front view showing the structure of an SII type joint for ductile cast iron pipe. Reception port 101 and insertion port 10
A rubber ring 103 for stopping water is interposed in a gap defined between the two bolts, and the outer end surface of the rubber ring 103 is fixed to a T-head bolt 1 through a pressing ring 106.
Tighten 07 to maintain a constant water pressure above a certain level. The lock ring 104 set in the annular groove on the inner surface of the receptacle engages with the projection 121 at the tip of the receptacle 102, so that even when there is a change in the ground, the locking ring 104 prevents the receptacle from coming out of the receptacle. . The SII type joint has a large amount of expansion and contraction and high detachment prevention performance due to this structure, and the joint expands and contracts in response to a large ground deformation, and finally functions to prevent detachment. The constructed pipeline is also commonly referred to as a chain-structure pipeline.

[0005] In addition, as the prior art relating to seismic pipe fittings, various other improvement measures have been proposed, and in particular, a slip-on type developed with emphasis on workability at the time of laying, that is, a non-fastened type. Japanese Unexamined Utility Model Application Publication No. 4-133090 as a joint used in a laying system in which a cast iron pipe is joined to form a pipeline.
No. 4-133091 and No. 4-13309
Nos. 2 and 3 are found, but the concept of engaging the lock ring, engaging with the insertion ring and exerting an anti-separation action against the external force to be pulled out is the same as that of the aforementioned SII type joint. It consists of almost common points.

[0006] On the other hand, pipes for tap water and the like installed underground are, as is well known, not only composed of straight pipes, but are necessarily bent by roads or the like by a combination of straight pipes and deformed pipes. It is a general principle to follow the pipeline. For sudden pitching and rolling in the event of an earthquake or the like, the variability of the pipeline following the swing is an essential requirement. But,
Speaking of the joints between the deformed pipe and straight pipe, it is needless to say that prevention of detachment and prevention of excessive intrusion is a major premise, but straight pipes that simply allow large flexibility and strengthen earthquake resistance It should be noted that if the concept is directly used and the bending or expansion and contraction of the pipe joint is freely permitted, the adverse effect of losing the function of the entire pipe line may be attained.

As a joint part of a pipe including a deformed pipe, a detachable pipe joint in which the deformed pipe part is firmly integrated is usually used. Fig. 1
1 KF type and UF type joint of FIG.
The structure is such that the lock rings 204 and 304 are engaged with each other so as to straddle between the insertion openings to prevent mutual disengagement. Also, as shown in FIG. 13, for the small diameter type, joints which limit the expansion and contraction by using the liner 400 in combination with the SII type joint having earthquake resistance are also used, but these joints prevent detachment and resist uneven external pressure. Therefore, although it is oriented to the integrated structure, it has high bending rigidity and has no expansion and contraction amount, so that it cannot be denied that the adaptability to the ground fluctuation tends to be inferior to that of the ordinary unintegrated pipe portion.

[0008]

In the prior art joints for SII type and other straight pipes, emphasis is placed on the aseismic structure, and the receiving port and the insertion port can be moved within the mutual insertion range. The greatest condition is to have a stretching action that changes the positional relationship. However, on the other hand, in order to conduct a water pressure test on the spliced joints in the work of laying pipes due to this expansion and contraction work, if the pipes are not backfilled and the relative position of the pipes is fixed,
In the free state, there is a possibility that the relative positional relationship of the joints may fluctuate, and there is a problem that the pipeline may meander or the axis may fluctuate.

On the other hand, in a pipeline including a deformed pipe, there is a unique problem of setting protection against an average force caused by bending of the pipeline. More specifically, in the state where water pressure acts on the entire pipeline as illustrated in FIG. 14, an external force acting on the irregularly shaped pipe portion B to move the pipe outwards acts on the deformed pipe portion B. This non-average force is calculated by the following equation. P = 2pA sin (θ / 2) where A: pipe cross section p: water pressure Protective work with concrete blocks is usually applied to counter this external force, but concrete blocks become excessively large or complicated pipes When it is not possible to cast a concrete block in response to the bending of the road, a joint provided with a detachment prevention mechanism is generally used, and a joint for preventing movement of the deformed pipe is rigidly connected. At this time, it is a necessary condition for the joint used for the deformed pipe to have a bending rigidity enough to withstand the bending moment acting on the rigidly connected joint. If the critical bending moment (flexural rigidity) of the joint is low, the distance that must be integrated (rigidly connected) increases, so many pipe joints with a structure that restricts the flexibility and expansion and contraction must be interposed. In the end, however, it is oriented in a direction contrary to social needs that should form a pipeline with a reinforced seismic structure that has high rigidity like the above KF type and UF type but easily adapts to changes in the ground. There remains the task of being forced to do so.

In order to solve the above-mentioned problems, the present invention provides a so-called chain structure pipeline capable of adapting to a large ground deformation such as an earthquake in a straight pipe portion, and has a restraining force capable of performing a water pressure test before backfilling. With a large pull-out force that exceeds the restraining force during use, such as an earthquake, it can cope with normal pipeline pressure, and finally the release prevention function works to maintain the water flow through the pipeline. For the purpose of providing.

[0011]

SUMMARY OF THE INVENTION A detachable pipe joint according to the present invention comprises a receiving port 1 and an insertion port 2, a rubber ring 3 interposed between the two, and a detachable interposition between both pipes. In the basic structure including the lock ring 4, a step 11 is recessed in a part or the entire length of the inner peripheral surface of the socket 1 from the fitting position of the lock ring 4 to the inner end 13 of the socket. 11, a flexible positioning spacer 5 is internally fitted, and a fitting groove 51 is formed on the inner circumferential surface side of the positioning spacer 5 so that the insertion projection 21 provided near the end 22 of the insertion opening 2 is internally fitted. The engraving is a feature of the configuration.

FIG. 1A shows a use state in which normal water pressure is applied to the pipe line. When the socket 1 and the insertion port 2 of the pipe are joined, the fitting position of the lock ring 4 of the socket 1 is shown. The positioning spacer 5 fitted inside the step 11 formed from the inside of the joint to the deepest part is fitted into the fitting groove 51 provided near the end of the insertion opening 1 with flexibility. Even if water pressure in the pipes is applied at normal time, the pipes are sufficiently opposed to each other to maintain the jointing relationship. Therefore, as in the SII type, which is a typical example of a seismic joint between straight pipes, and as in other conventional techniques, it can be expanded and contracted. When joints with a structure that can withstand external forces are joined, a water pressure test can be performed without backfilling and fixing the mutual positions of the pipes, and the workability is significantly improved. On the other hand, even if an irregular force is applied to the deformed pipe when the deformed pipe is interposed in the pipeline, the flexibility of the positioning spacer acts to make an appropriate external force and adjust it by applying appropriate deformation. By this action, external force can be evenly received without special integration.

FIG. 1 (B) shows that a large-scale ground fluctuation such as a large earthquake hits directly, and a pulling-out force exceeding a fitting force between the insertion projection 21 and the fitting groove 51 of the positioning spacer directly hits the fitting. This shows a stage in which the positioning spacer is deflected and the relative movement of the pipe is caused, and the lock ring 4 and the insertion projection 21 abut against each other to exert an action of completely preventing further detachment, so that the seismic resistance structure is exhibited. Maintain the function of. The above-described problem is solved because the detachment prevention function works even when the pipeline faces any situation due to the combination of the normal restraining force and the emergency locking force.

[0014]

FIG. 2 is a longitudinal sectional front view showing an embodiment of the present invention, in which an insertion port 2 is inserted into a receptacle 1 and a water seal is inserted between an inner peripheral face of the receptacle and an outer peripheral face of the receptacle. Of the rubber ring 3 and press the exposed outer end surface 31 of the rubber ring 3, a T-head bolt 7 and a nut 71 for fastening the pressing ring 6 and the flange 12 of the socket 1 to form a basic configuration. Has formed.
In this embodiment, the backup ring 32 made of synthetic resin is sandwiched between the inner ends of the rubber ring 3 to protect the inner end of the rubber ring. The backup ring 32 is made of resin and is bias cut at one location in the circumferential direction, and is mounted on the outer peripheral surface of the insertion opening. The insertion projection 21 is fixed to the entire periphery of the insertion projection 2 near the end 22 by welding or the like.

FIGS. 3A and 3B are a longitudinal sectional front view (A) and a side view showing a preferred embodiment of the positioning spacer 5, and the positioning spacer 5 is formed of a cylindrical body having a split 53. FIG. In addition, it is recommended that a synthetic resin having a strength sufficient to be fitted to the insertion projection 21 and exhibit a detachment preventing action against normal water pressure be selected as a material. As materials with appropriate flexibility and strength, choose from well-known water-insoluble and harmless plastics such as polyethylene, polypropylene, nylon, etc., and at the time of strength and unsteady conditions, for example, when encountering a direct impact such as an earthquake However, stainless steel or the like can be freely selected as a metal material which has flexibility (elasticity or bendability) that can be adapted and has sufficient corrosion resistance. The strength, flexibility, dimensions, and the like are appropriately determined in consideration of necessary factors such as the water pressure in the pipe at the joint, the diameter of the pipe, and the properties of the laid ground.

FIG. 4 is a longitudinal sectional front view of the elastic centering rubber 52 sandwiched between the outer peripheral surface of the positioning spacer 5 and the inner peripheral surface of the step 11 of the receiving port. It is composed of an outer peripheral surface that repeats irregularities by drawing and acts as a centering action of the positioning spacer 5 and works to evenly fit in the pipe. For places where the cross section is not always formed in an accurate circular shape such as a deformed pipe Even with moderate elastic deformation,
It plays a role of assisting the positioning spacers to be fitted evenly so that the expected function can be reliably exhibited.

5 (A) to 5 (G) are longitudinal sectional front views each showing a construction procedure when connecting a pipeline using the detachable pipe joint according to the embodiment of the present invention. A): Rubber ring 3 and backup ring 3 to insertion port 2
2. The lock ring 4 is deposited, and the centering rubber 52 is mounted in the step 11 of the receptacle 1 so that the position of the positioning spacer does not deviate from the center. FIG. (B): The positioning spacer 5 is attached to the socket 1. Fig. (C): The insertion port 2 is inserted into the reception port 1. The positioning spacer 5 is deformed and expanded as the insertion protrusion 21 passes, but the deformation of the positioning spacer made of a flexible material allows the insertion. Fig. (D): The insertion projection 21 and the fitting groove 51 of the positioning spacer 5 are fitted to each other, and a fixed relationship is established in which the two can resist the normal water pressure. Fig. (E): The lock ring 4 is mounted in the lock ring fitting groove 14 of the socket. Figure (F): Attach backup ring 32. Figure (G): The ring 3 is fastened by the T-head bolt 7 and the nut 71 via the pressing wheel 6, and the joining operation is completed.

FIG. 5 shows an ideal positional relationship at the beginning of joining.
As shown in FIG. 1 (G) or FIG. 1 (A), the extension side and the contraction side have substantially the same margin, and the distance L1 from the lock ring 4 to the insertion projection 21 and the insertion end 22 The distance L2 to the inner end 13 of the socket is balanced and the fitting groove 51 of the positioning spacer is fitted so as to fit with the insertion projection 21 at a position where there is a margin on both the extension side and the contraction side. It is desirable.

6 to 9 are longitudinal sectional front views showing different embodiments of the present invention. FIG. 6 shows a configuration in which the positioning rigidity 5A is fitted without any gap over the entire length from the lock ring 4A to the inner end 13A of the socket to further improve the bending rigidity. In the following embodiments including this figure, illustration of the centering rubber is omitted, but it is needless to say that it is desirable to interpose it as needed. FIG. 7 is based on the same idea as FIG. 6, except that the insertion port 2B is inserted into the reception port 1B, and the extension side L1 formed by the distance between the side surface of the lock ring 4B and the side surface of the insertion projection 21B is inserted. The contraction side L2 formed by the distance between the mouth end 22B and the receiving end 13B.
Is increased so that the inner diameter of the positioning spacer 5B in the range fitted to the contraction side L2 is substantially the same as the inner diameter of the pipe, and the end of the insertion port This example is characterized in that an anticorrosion rubber 54 is interposed on a contact surface with the anti-corrosion rubber 22B, thereby enhancing bending rigidity, improving flexibility, and improving the anticorrosion function.

FIG. 8 shows a step 11C from the fitting position of the lock ring 4C to the inner end 13C of the joint formed by a frusto-conical surface having a gradient that increases in diameter toward the inside, and is divided into two steps in the circumferential direction. positioning spacers 5C that also bisected in the longitudinal direction in the fitting groove 51C _1, 5C ₂ is a fitted configuration, stepped positioning spacers 5C force escape the spigot acts 1
The holding force is further increased along the 1C gradient surface, and the effect of further enhancing the pull-out force is exhibited. In the case of FIG. 9, similarly to FIG. 8, it is formed with a slope surface that increases in diameter as the step 11D proceeds inward, and the rear end surface of the positioning spacer 5D divided into two parts before and after is directly pressed against the side surface of the lock ring 4D. The feature of the operation is that it receives the reaction force of the exit force.

[0021]

The hydraulic pressure test before backfilling can be carried out even with S-type, SII-type and other highly elastic joints as typical pipe-preventing pipe joints of straight pipes, so the construction procedure is greatly improved. Inspection efficiency is remarkably improved. In addition, even if water leaks as a result of the test, it can be detected immediately, and since it is an exposed pipeline before backfilling, quick repair is possible, and the improvement of inspection efficiency is an outstanding effect. Appear.

On the other hand, it is possible to easily and uniformly integrate a deformed pipe which is frequently used in a bent and complicated pipe line rapidly increasing in an urban area to form a robust joint part which can withstand an unbalanced force. Even in the event of an excessive change such as a large earthquake or land subsidence, it flexibly accommodates flexion and expansion and contraction prevention functions, so it is a highly reliable detachment prevention fitting, especially in urban areas. The social benefits of securing a lifeline and protecting the roots of citizens' lives in the event of an earthquake or disaster are irreplaceable.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional front view showing an operation of a normal state (A) and an emergency state (B) of an embodiment of the present invention.

FIG. 2 is a longitudinal sectional front view showing details of the same embodiment of the present invention.

FIG. 3 shows a vertical sectional front view (A) and a side view (B) of a positioning spacer in the same embodiment.

FIG. 4 shows a longitudinal sectional front view of the centering rubber in the same embodiment.

5 (A) to 5 (G) are longitudinal sectional front views showing a joining procedure of the pipe joint of the present invention.

FIG. 6 is a longitudinal sectional front view showing another embodiment of the present invention.

FIG. 7 is a longitudinal sectional front view showing still another embodiment.

FIG. 8 is a longitudinal sectional front view showing still another embodiment.

FIG. 9 is a longitudinal sectional front view showing still another embodiment.

FIG. 10 is a longitudinal sectional front view of a conventional SII joint.

FIG. 11 is a longitudinal sectional front view of a conventional KF joint.

FIG. 12 is a longitudinal sectional front view of a conventional UF type joint.

FIG. 13 shows an SII type joint using a conventional liner.

FIG. 14 is a plan view illustrating a problem unique to a deformed pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiving port 2 Insertion opening 3 Rubber ring 4 Lock ring 5 Positioning spacer 6 Pressing ring 7 T-head bolt 11 Step 12 Flange 13 Inner end 21 Insert projection 22 End 31 Outer end surface 32 Backup ring 51 Fitting groove 52 Centering rubber 54 Anticorrosion rubber 71 nut

Claims (7)

[Claims] 1. A detachable pipe joint comprising a receiving port 1 and an insertion port 2, a rubber ring 3 interposed between the two, and a lock ring 4 interposed between both pipes to prevent disengagement. The step 11 is recessed in a part or the entire length from the fitting position of the lock ring 4 on the inner peripheral surface to the inner end 13 of the socket, and the flexible positioning spacer 5 is fitted therein, and the positioning spacer 5 Insertion protrusion 2 provided near the end 22 of the insertion opening 2 on the inner circumferential surface side
A detachable pipe joint characterized in that a fitting groove 51 into which 1 is fitted is formed. 2. The positioning spacer 5 according to claim 1,
Is formed of a single-piece cylindrical body, and is flexible enough to engage with the insertion projection 21 to exhibit a detachment preventing action with respect to normal water pressure and adapt to an excessive external force in an unsteady state. A detachable pipe joint characterized by being formed of a synthetic resin or metal having resistance and corrosion resistance. 3. The method according to claim 1, wherein the outer peripheral surface of the positioning spacer 5 and the inner peripheral surface of the step 11 of the receiving port are positioned between the outer peripheral surface and the inner peripheral surface.
A detachable pipe joint characterized by sandwiching an elastic centering rubber 52 whose outer peripheral surface draws a waveform and repeats irregularities. 4. The positioning spacer 5A according to any one of claims 1 to 3, wherein a positioning spacer 5A is fitted without any gap to increase bending rigidity over the entire length from the side surface of the lock ring 4A to the inner end 13A of the socket. Detachable pipe fitting. 5. The method according to claim 4, wherein the insertion opening 2B is connected to the receiving opening 1B.
The side of the lock ring 4B and the insertion projection 21B
The extension side L1 formed by the distance between the side faces and the insertion end 22B
With respect to a standard position where the contraction side L2 formed by the distance between the inner end 13B and the receiving end 13B is substantially equal, the inner diameter of the positioning spacer 5B in the range fitted to the contraction side L2 is substantially the same as the inner diameter of the pipe. A detachable pipe joint characterized in that the thickness of the pipe joint is increased and an anticorrosion rubber 54 is interposed on the contact surface with the end 22B of the insertion opening. 6. A stepped frustoconical surface according to claim 1, wherein a step 11C extending from the fitting position of the lock ring 4C to the joint inner end 13C is formed to have a slope whose diameter increases toward the inside. Positioning spacers 5C ₁ , 5C ₂ which are divided into two parts in the circumferential direction into 11C and into two parts in the front-rear direction by fitting grooves 51C.
A detachable pipe fitting characterized by fitting with the above. 7. The detachable pipe joint according to claim 6, wherein a rear end of the positioning spacer 5D fitted to the step 11D formed by the inclined surface is in pressure contact with a side surface of the lock ring 4D.