JP2001021079A - Expansion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of concentrated deformation, to shorten a molding time, and to improve productivity by forming a cylindrical main body by rubber reinforced with fiber codes, forming the inner surface of the main body straight, and burying a reinforcing ring in a center part. SOLUTION: An expansion joint 1 is composed of a cylindrical main body 2 and flanges 3 disposed on both ends of the main body 2. The cylindrical main body 2 is formed of rubber reinforced by fiber codes, its inner surface is formed straight, and a reinforcing ring 7 is buried in its center part. A reinforcing fiber layer 8 is formed on an inner surface of the flange 3 and on the fiber code 4, and a rubber 9 made of soft rubber is buried between the fiber layer 8 and the reinforcing ring 7. The upper part of the rubber 9 is covered with a reinforcing canvas 10 and an outer surface rubber 6. Inner pressure is borne by the reinforcing codes 4 and the reinforcing ring 7, and outer pressure in borne by the reinforcing ring 7 and the flanges 3 disposed on both sides of the main body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible expansion joint for allowing relative displacement occurring in various piping systems.
In particular, it relates to a flexible expansion joint having excellent durability and productivity.

[0002]

2. Description of the Related Art Conventionally, a pipe system has been protected from expansion and contraction of a pipe caused by a temperature difference, a displacement of the pipe system due to land subsidence or a natural disaster, and also, in order to adjust the alignment of pipes in piping work and to absorb vibration. Flexible expansion joints are used. As shown in FIG. 4, a known flexible expansion joint of this type includes a cylindrical main body 22 and flanges 23 provided at both ends thereof. That is, the cylindrical main body 22 is made of an inner rubber 25 and an outer rubber 26 reinforced with a fiber cord 24, a central portion is formed as an arch portion 28, and reinforcing rings 27, 27 are provided on both sides of the arch portion 28. It is buried.

[0003] In such a conventional flexible expansion joint, if a displacement or the like occurs in the piping system, the arch portion 2 is not moved.
8 is deformed vertically and horizontally and absorbs eccentricity, expansion and contraction. In addition, the inside of the flexible expansion joint normally allows fluid to pass therethrough.
The reinforcing rings 27, 27 are required so that the fiber reinforced rubber portions on both sides of the rubber member do not collapse and deform.

[0004] However, the displacement is absorbed by the arch portion 28.
Therefore, rubber distortion tends to concentrate on the R portion, and there is a problem in durability. Also, regarding the pressure resistance performance,
It is necessary to individually design the arch portion 28 and the cylindrical main body 22 other than the arch portion, and it is difficult to make the structure due to the influence of the arch portion 28, requiring a large number of man-hours in molding time, and having a problem in productivity. Was something.

[0005]

SUMMARY OF THE INVENTION The present invention is an improvement on such a conventional flexible expansion joint, which eliminates the occurrence of concentrated strain, shortens the molding time, and improves the productivity. It is an object of the present invention to provide a flexible expansion joint that can be used.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its gist is a flexible expansion joint comprising a cylindrical main body and flanges provided at both ends thereof. , The cylindrical body is made of rubber reinforced with a fiber cord, the inner surface of which is linear, and a reinforcing ring is embedded in the center.
Preferably, both ends of the fiber cord constituting the cylindrical main body are folded back to the flange surface, the cylindrical main body has a fiber layer for reinforcing the inside of both flanges, and both the fiber layer and the reinforcing ring Is a concave portion, or a cylindrical body has a fiber layer that reinforces the inside of both flanges, and rubber is provided between both fiber layers and the reinforcing ring. It relates to a buried flexible expansion joint. More preferably, the present invention relates to a flexible expansion joint in which each bolt hole of the flange is threaded, or a nut is welded inside each bolt hole.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The flexible expansion joint of the present invention has a straight inner surface. For this reason, eccentricity, expansion, and contraction of the entire flange surface are absorbed by the displacement of the piping system. In other words, as compared with the conventional flexible expansion joint which absorbs eccentricity or the like only by the arch portion, the limit displacement amount for expansion and contraction must be slightly reduced, but the limit displacement amount for eccentricity increases on the contrary. This fact does not mean that the flexible expansion joint of the present invention has a portion that is inferior in performance to the conventional one. Because, in many cases, the displacement of the piping system due to land subsidence or the amount of adjustment of the pipe alignment at the time of plumbing work is larger than the expansion and contraction of the pipe due to the temperature difference, the flexible expansion joint of the present invention is not sufficient. This is because it should be understood that the eccentricity absorption performance is improved while ensuring the absorption performance of the expansion and contraction, and the problem of concentration distortion and productivity caused by the arch portion is overcome.

[0008] The flexible expansion joint of the present invention has a reinforcing ring embedded in the center. That is, when a negative pressure specific to the flexible expansion joint is generated, it is necessary to embed a reinforcing ring so that the cylindrical body is not crushed and deformed.
Instead of being on both sides of the arch as in the prior art, there is only one location at the center. Therefore, not only the economy and productivity are improved, but also the ratio of the fiber reinforced rubber occupying between the flange surfaces is relatively high, which also contributes to the improvement of the eccentric absorption performance.

Here, both ends of the fiber cord constituting the cylindrical main body may be folded back on the flange surface. This is because the folding increases the fixing force between the flange and the fiber cord, and also improves the sealing property between the flexible expansion joint and the pipe.
However, in the present invention, the return of the fiber cord is not indispensable, and if there is no return, the molding time can be reduced and the productivity can be improved.

In the present invention, the cylindrical body may have a recess between the fiber layer for reinforcing the inside of both flanges and the reinforcing ring, or rubber may be embedded in each.
In the case where the space between the surfaces of the flexible expansion joint is reduced at the time of installation, the smaller the thickness of the concave portion is, the smaller the contraction load value is, so that the mounting workability is further improved. In the case of burying rubber, rubber having the lowest possible hardness (about 40 degrees HS) is preferable in order to reduce the shrinkage load.

When installing the flexible expansion joint, there is a case where the pipe is inserted into an existing piping system to connect the pipes. Therefore, it is necessary to reduce the distance between the flange surfaces when inserting the flexible expansion joint. Therefore, it is preferable to cut a screw in each bolt hole of the flange or weld a nut inside each bolt hole. In this way, a turnbuckle-like member can be attached between the flanges to easily adjust the distance between the flange surfaces.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view showing a flexible expansion joint 1 of the present invention. Here, the flexible expansion joint 1 includes a cylindrical main body 2 and flanges 3 and 3 provided at both ends thereof. The cylindrical main body 2 is made of an inner surface rubber 5 reinforced by a fiber cord 4, the inner surface of which is linear, and a reinforcing ring 7 is embedded in the center. A fiber layer 8 is provided on the fiber cord 4 and inside the flange, and a burying rubber 9 is provided around the reinforcing ring 7. Have been. In FIG. 1, the distance between the flange surfaces is longer than the actual distance for convenience.

FIG. 2 is a sectional view showing a first embodiment of the flexible expansion joint 1 of the present invention. In the first embodiment, both ends of the fiber cord 4 are folded back to the flanges 3 and 3. Also, a fiber layer 8, which reinforces the inside of the flanges 3, 3,
In addition, embedded rubbers 9, 9 made of soft rubber are embedded between the fiber layers 8, 8 and the reinforcing ring 7, respectively.

The allowable eccentric displacement of the flexible expansion joint 1 in the first embodiment is 10% between the flange surfaces, and the allowable displacement of expansion and contraction is 7% between the flange surfaces. Therefore, for example, a diameter of 1200 mm, a distance between flange surfaces of 300 mm
If so, the eccentricity can be allowed up to 30 mm, and the expansion and contraction can be allowed up to 21 mm. On the other hand, in a conventional flexible expansion joint having the same diameter and between the flange surfaces, the eccentricity
mm, elongation 25 mm, and contraction 35 mm, the flexible expansion joint 1 in the first embodiment has a smaller allowable value of the amount of expansion and contraction than the conventional product, but can have a large amount of eccentricity. By extending the distance between the flange surfaces, the allowable value of each displacement amount can be increased.

In the first embodiment, the reinforcing cord 4 mainly bears the internal pressure against the internal pressure, but the reinforcing ring 7 also contributes. Therefore, the conventional flexible expansion joint shown in FIG.
This is advantageous compared with the case where only the pressure resistance 4 is responsible for the pressure resistance. With the same pressure resistance performance, the number of plies of the reinforcing cord 4 can be reduced by half. It should be noted that the reinforcing ring 7 and the flanges 3 at both ends are responsible for external pressure.

Further, when the flexible expansion joint 1 of the first embodiment was used and subjected to 10,000 times of expansion and contraction fatigue tests with an expansion and contraction amount of 21 mm, no abnormality was observed. Was confirmed. Further, in the above-described example of the diameter of 1200 mm and the distance between the flange surfaces of 300 mm, the productivity was improved by about 30% as compared with the conventional flexible expansion joint having the same diameter and the distance between the flange surfaces. Since the inner surface is linear, there is almost no pressure loss.

FIG. 3 is a sectional view showing a second embodiment of the flexible expansion joint 1 of the present invention. In the second embodiment, both ends of the fiber cord 4 are not folded back to the surfaces of the flanges 3 and 3, and the fiber layers 8 and
A recess is formed between the reinforcing ring 8 and the reinforcing ring 7.
Here, a filling rubber 9 is buried under the reinforcing ring 7, but since it is a portion which does not affect the flexibility, it is not necessary to use a soft rubber unlike the case of the first embodiment. Further, in the second embodiment, a nut 1 is provided inside each of the bolt holes of the flanges 3 and 3 for adjustment between flange surfaces described later.
1, 11 are welded. The second embodiment has the same operation and effect as the first embodiment.

Next, according to the flexible expansion joint of the second embodiment,
A method of connecting both by inserting between existing pipes (not shown) will be described. First, face-to-face adjustment bolts 12, 12 are screwed into welding nuts 11, 11, respectively. Next, the face-to-face adjustment bolts 12
They are connected by adjusting fittings 14 via 3 and 13. Therefore, if the nuts 13 are tightened, the space between the flange surfaces can be easily contracted and inserted between the pipes. Then, if the nuts 13 are loosened after the insertion and the bolt holes of the flanges 3 and 3 and the buried pipe are tightened with bolts and nuts, the connection between the flexible expansion joint and the pipe is completed. Note that gaps 15 exist between the adjustment fitting 14 and the inter-plane adjustment bolts 12. The gaps 15, 15 are not necessarily provided between the face-to-face adjustment bolts 12, 1.
Since the two are not linear, they are provided to absorb eccentricity.

[0019]

According to the present invention, there is provided a flexible expansion joint comprising a cylindrical body and flanges provided at both ends thereof, wherein the cylindrical body is made of rubber reinforced with a fiber cord,
In addition, since the inner surface is straight and the reinforcing ring is buried in the center, displacement of the piping system can be absorbed in the entire space between the surfaces, so that concentrated distortion can be prevented. Further, since there is no arch unlike the conventional flexible expansion joint, the molding time can be reduced, and not only the productivity can be improved, but also the pressure loss can be almost eliminated.
Further, if a screw is cut in each bolt hole of the flange or a nut is welded inside each bolt hole, the distance between the flange surfaces can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a flexible expansion joint according to the present invention.

FIG. 2 is a sectional view showing a first embodiment of the flexible expansion joint according to the present invention.

FIG. 3 is a sectional view showing a second embodiment of the flexible expansion joint according to the present invention.

FIG. 4 is a sectional view showing a conventional flexible expansion joint.

[Explanation of symbols]

 1 ‥ Flexible expansion joint 2 ‥ Cylindrical body 3 ‥ Flange 4 ‥ Fiber cord 5 ‥ Inner rubber 6 ‥ Outer rubber 7 ‥ Reinforcing ring 8 ‥ Fiber layer 9 ‥ Filled rubber 10 ‥ Reinforced canvas 11 ‥ Nut 12 ‥ Adjustment bolt 13 Nut 14 Adjustment bracket 15 Clearance 22 Cylindrical body 23 Flange 24 Fiber cord 25 Inner rubber 26 Outer rubber 27 Reinforcement ring 28 Arch

Claims (5)

[Claims] 1. A flexible expansion joint comprising a cylindrical main body and flanges provided at both ends thereof, wherein said cylindrical main body is made of rubber reinforced with a fiber cord, and an inner surface thereof is straight. A flexible expansion joint characterized in that a reinforcing ring is buried in a central portion. 2. The flexible expansion joint according to claim 1, wherein both ends of the fiber cord constituting the cylindrical main body are folded back on a flange surface. 3. The cylindrical body has a fiber layer for reinforcing the inside of both flanges, and a recess is formed between each of the fiber layers and the reinforcing ring. 3. The flexible expansion joint according to 1 or 2. 4. The cylindrical body has a fiber layer for reinforcing the inside of both flanges, and rubber is embedded between the fiber layers and the reinforcing ring, respectively. Item 3. The flexible expansion joint according to item 1 or 2. 5. The flexible expansion joint according to claim 1, wherein each bolt hole of the flange is threaded, or a nut is welded inside each bolt hole. .