JP3880166B2 - Pipe and case seal structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tube and case sealing structure in which a case divided into a plurality of fluid tubes made of a soft synthetic resin is watertightly covered with an arc-shaped packing.
[0002]
[Prior art]
As a repair member that covers and uses a resin main pipe joint, a sealing cover as shown in FIGS. 9 and 10 is known.
[0003]
This conventional sealing cover A is composed of two cases B, B provided with a flange C in which a bolt hole C1 is formed, and sealing materials D, D mounted in packing grooves E formed on the inner surface thereof. In the sealing material D, an arc-shaped seal portion D1 that is in pressure contact with the outer peripheral surface of the water main pipe G and a seal portion D2 that is in pressure contact with the seal portion D2 of the connected flange C are integrally formed. Of the arc-shaped seal portion C1 of the sealing material D, an outer peripheral surface portion having a predetermined angular range from both ends in the circumferential direction is formed as a tapered surface D3, and a taper surface E1 is formed in the packing groove E corresponding to the tapered surface.
[0004]
When the cases B and B are covered with the water main pipe G and the opposing flanges C and C are tightened with bolts and nuts F, the arc-shaped seal portion D1 is pressed against the outer peripheral surface of the water main pipe G, and the seal portion D2 is The sealing cover A is attached to the water main pipe G while maintaining water tightness by being pressed against each other. At this time, the opposite ends in the circumferential direction of the arc-shaped seal portions D1 and D1 have a force in the tube center direction due to the tapered surface E1, and the pressure contact force with respect to the outer peripheral surface of the water main pipe G increases. Further, since the packing grooves E corresponding to the opposite circumferential end portions of the arc-shaped seal portions D1 and D1 are formed with openings toward the outer peripheral surface of the tube, the circumferential end portions of the arc-shaped seal portion D1 are The deformation when compressed becomes a shape protruding in the direction of the outer peripheral surface of the pipe, and the pressure contact force with respect to the outer peripheral surface of the water main pipe G increases.
[0005]
By the way, in recent years, due to the problem of earthquake resistance, the main water pipe has been formed from a soft synthetic resin material, such as polyethylene or polybutene, to increase flexibility and make it difficult to break. This soft synthetic resin tube is flexible, has a large elongation, does not crack even when flattened until the inner surface of the tube comes into contact, and has the property of being restored to its original state when the load is removed.
[0006]
Also, if a certain amount of deformation (strain) is applied to the soft synthetic resin tube and held as it is, the stress generated immediately after the deformation, which is called “stress relaxation”, decreases with time. A phenomenon occurs. This is due to the fact that due to the applied deformation, the flow inside the material gradually occurs and the stress for holding the tube in a constant deformation state is reduced.
[0007]
When the sealing cover is used for a soft synthetic resin pipe such as a polyethylene pipe having such properties, the pipe is deformed by compression of the packing at the arc-shaped seal portion, particularly at the abutting portions at both ends of the arc-shaped seal portion. The pressure contact force with respect to the outer peripheral surface of the tube increased, the tube was recessed, stress relaxation was caused, and there was a risk of water leakage.
[0008]
[Problems to be solved by the invention]
The problem to be solved by the present invention is made to solve the above-mentioned problem, and it is possible to prevent stress relaxation while maintaining a sealing effect by suppressing excessive pressing force to the fluid pipe by packing. The present invention provides a sealed structure for the pipe and the case.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the pipe and case sealing structure of the present invention includes a plurality of divided cases covering the periphery of a fluid pipe made of soft synthetic resin, and a plurality of cases in which the case is watertightly installed on the fluid pipe. The arc-shaped packing comprises a flange for connecting the respective cases, and has a pipe-case sealing structure that connects the case and the fluid pipe in a water-tight manner by abutting the ends of the arc-shaped packing. And
A gap for inducing deformation of the packing is formed outside the abutting portion between the arc-shaped packings.
[0010]
In the arc-shaped packing, a joint portion formed on the outer periphery of the end portion of the arc-shaped packing that is abutted and pressed by a flange, and a concave portion that accommodates the joint portion is formed on a flange-facing surface where the flanges contact each other. Is preferred.
[0011]
In the arc-shaped packing, it is preferable that a rod-shaped packing for watertightly connecting the flanges is integrally formed by connecting a pair of joint portions.
[0012]
In the arc-shaped packing, it is preferable that a gap for inducing compressive deformation is formed on the surface of the arc-shaped packing that contacts the outer peripheral surface of the fluid pipe.
[0013]
According to the present invention, even if the packing is deformed due to compression, a gap for inducing the deformation of the packing is provided, so that the pressure contact force against the outer peripheral surface of the pipe is suppressed and stress relaxation is not caused. There is no fear.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0015]
1 to 6 show a first embodiment of the present invention, which is applied to a split T-shaped pipe used when a branch pipe is connected to a water main pipe. A case 2 is mounted on the outer peripheral surface of a water main pipe (fluid pipe) 1 of a polyethylene pipe buried in the ground while maintaining water tightness. The case 2 includes a first case 2a and a second case 2b that can be divided into two in the radial direction, and the first case 2a is provided with a branch port 2c for connection to a branch pipe.
[0016]
On both sides of the opposite end edge in the longitudinal direction of the case 2, flanges 3 are continuously provided outward, and five through holes 3 a are formed in each flange 3 so as to be aligned vertically.
[0017]
Each case 2a, 2b has a first packing groove 5 at both ends in the tube axis direction, a second packing groove 6 is formed at one of the flanges 3, and the packing 4 is attached. . A first joint portion (joint portion) 4f and a second joint portion (joint portion) 4g of the packing 4, which will be described later, are not moved in the pipe axis direction on the opposing surfaces of the flange 3 at both ends of the first packing groove 5. A receiving recess (recess) 7 to be fitted is formed.
[0018]
The packing 4 is formed of an arc-shaped packing 4a that seals the water main pipe 1 and the case 2, and a rod-shaped packing 4b that seals the flanges. The packing 4 has a symmetrical shape in the first case 2a and the second case 2b, and there is only one bar-shaped packing 4b for stopping the flange 3.
[0019]
The arcuate packing 4a is provided with a fixing portion 4c that fits into the first packing groove 5, and the first tongue-shaped piece 4d that contacts the outer peripheral surface of the water main pipe 1 and the inside of the case 2 are provided at both ends of the fixing portion 4c. The second tongue-like pieces 4e that come into contact with the peripheral surface are formed symmetrically in a state where they are opened outward. In the middle part, a second gap 9 is formed which is open on the surface side in contact with the water main pipe 1.
[0020]
At both ends of the arc-shaped packing 4a, there are provided a first joint portion 4f and a second joint portion 4g having flat portions 4h and 4h that abut against the opposing arc-shaped packing 4a. The first joint portion 4f, in which the rod-like packing 4b that connects the left and right arc-shaped packings 4a is connected, is formed thicker than the second joint portion 4g, and is inclined to form the first gap 8 when the case is attached. Part 4i is provided.
[0021]
When the water main pipe 1 is covered with the case 2 and the bolts and nuts 10 are inserted into the through holes 3a and tightened, the arc-shaped packing 4a is pressed against the outer peripheral surface of the water main pipe 1 and the rod-shaped packing of one flange 3 When 4b is pressed against the flat surface of the other flange, the water tightness of the space surrounded by the case 2 is ensured.
[0022]
At this time, as shown in FIGS. 6A and 6B, when the first joint portion 4f and the second joint portion 4g are brought into pressure contact with each other, they are compressed into the first gap 8 formed by the inclined portion 4i. Therefore, excessive pressure contact force on the outer peripheral surface of the pipe can be suppressed. Moreover, since the 1st junction part 4f and the 2nd junction part 4g are protruded and provided in the outer periphery of the circular-arc-shaped packing 4a, and are fitted in the accommodation recessed part 7 formed in the opposing surface of the flange 3, a 1st junction part The direction of butting between 4f and the second joint portion 4g matches the direction of tightening the flange, and when pressed, it does not escape in the tube axis direction, so the tightening force works effectively, and the flat portions 4h and 4h Water stoppage is improved. In FIG. 6, the water main 1 and the bolts and nuts 10 are not shown.
[0023]
Since the rod-shaped packing 4b is attached to the first joint 4f, the deformation due to the compression of the arc-shaped packing 4a and the rod-shaped packing 4b does not affect each other, so that the water tightness is improved.
[0024]
Even in the arc-shaped packing 4a that is pressed against the outer peripheral surface of the water pipe main pipe 1, compression deformation is induced in the second gap 9, and an excessive pressing force against the outer peripheral surface of the pipe can be suppressed.
[0025]
7A and 7B show a second embodiment of the present invention, in which FIG. 7A is a cross-sectional view before bolt tightening and FIG. 7B is a cross-sectional view after bolt tightening. In addition, illustration of the water main pipe 1 and the bolt and nut 10 is omitted.
[0026]
Instead of the inclined portion 4i of the first joint portion 4f of the first embodiment, the length of the first joint portion 4f in the diametrical direction is longer than the length in the diameter direction of the housing recess 7 into which the first joint portion 4f is fitted. It is provided to be shorter. In this way, since the first gap 8 is formed between the housing recess 7 and the first joint 4f, when the first joint 4f and the second joint 4g are brought into pressure contact with each other, they are compressed. Since the deformation is guided to the first gap 8, it is possible to suppress an excessive pressure contact force with respect to the outer peripheral surface of the pipe.
[0027]
8A and 8B show a third embodiment of the present invention, in which FIG. 8A is a cross-sectional view before bolt tightening and FIG. 8B is a cross-sectional view after bolt tightening. In addition, illustration of the water main pipe 1 and the bolt and nut 10 is omitted.
[0028]
A concave portion 7a having a substantially triangular cross section that forms the first gap 8 is provided on the outer side of the housing concave portion 7 into which the first joint portion 4f and the second joint portion 4g are fitted. Therefore, when the first joint portion 4f and the second joint portion 4g are brought into contact with each other and pressed, deformation due to compression is guided to the first gap 8, so that excessive pressure contact force on the outer peripheral surface of the pipe is suppressed. Can do.
[0029]
The present invention is not limited to the above embodiments.
[0030]
Although the example showed what was used for the split T-shaped pipe, it may be used for a case where the fluid pipe is covered when the valve is installed with constant water, and the damaged portion of the fluid pipe is covered and repaired. You may use for the case used in a case.
[0031]
In the first embodiment, the gap is provided by forming the inclined portion 4i at the end of the first joint portion 4f, but a recess may be provided in the middle of the first joint portion 4f.
[0032]
A plurality of gaps may be provided for one joint.
[0033]
【The invention's effect】
According to the present invention, it is possible to suppress an excessive pressure contact force against the fluid pipe when the packing is compressed and deformed.
[0034]
According to invention of Claim 2, the clamping force of a flange works effectively and the water stop property of a butting surface improves.
[0035]
According to invention of Claim 3, since the influence of a deformation | transformation of an arc-shaped packing and a rod-shaped packing does not reach each other, the water-stopping property of a case improves.
[0036]
According to invention of Claim 4, the excessive press-contact of the circumferential direction of the fluid pipe | tube by arc-shaped packing can be prevented.
[0037]
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view showing a first embodiment of the present invention.
FIG. 2 is also a partially cutaway side view.
FIG. 3 is a front view of the packing.
FIG. 4 is a side view of the same.
FIG. 5 is an enlarged cross-sectional view taken along the line II-II in FIG.
6 is an enlarged longitudinal sectional view taken along the line II in FIG. 1. FIG.
FIG. 7 is an enlarged longitudinal sectional view showing a second embodiment of the present invention.
FIG. 8 is an enlarged longitudinal sectional view showing a third embodiment of the present invention.
FIG. 9 is a partially cutaway front view of a conventional example.
10 is an enlarged longitudinal sectional view taken along line III-III in FIG. 9;
[Explanation of symbols]
1 Water main (fluid pipe)
2 Case 2a First case 2b Second case 2c Branch port 3 Flange 3a Through hole 4 Packing 4a Arc-shaped packing 4b Rod-shaped packing 4c Fixed portion 4d First tongue-like piece 4e Second tongue-like piece 4f First joint (joint) )
4g Second joint (joint)
4h Plane portion 4i Inclined portion 5 First packing groove 6 Second packing groove 7 Receiving recess (recess)
7a Concave portion 8 First gap 9 Second gap 10 Bolt / Nut

Claims (4)

A case made up of a plurality of cases covering a fluid pipe made of a soft synthetic resin and a plurality of arc-shaped packings installed in a fluid-tight manner on the fluid pipe, the case for connecting the cases together A pipe-case sealing structure that includes a flange and that connects the case and the fluid pipe in a water-tight manner by abutting the ends of the arc-shaped packing;
A tube / case sealing structure, wherein a gap for inducing deformation of the packing is formed outside the abutting portion between the arc-shaped packings. The pipe according to claim 1, wherein a joint portion formed on the outer periphery of the end portion of the arc-shaped packing which is pressed against each other by a flange and a concave portion which accommodates the joint portion is formed on a flange facing surface where the flanges abut each other. And case seal structure. 3. The tube / case sealing structure according to claim 1 or 2, wherein a rod-like packing for watertightly connecting the flanges is formed integrally by connecting a pair of joints. The pipe-case seal structure according to any one of claims 1 to 3, wherein a gap for inducing compressive deformation is formed on a surface of the arc-shaped packing that contacts the outer peripheral surface of the fluid pipe.

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