JPH1073190A - Leakage preventive method and device for fluid pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent fluid leakage due to breakage of low strength portion by arranging a dividable case body so as to form a closed space between its center and a fluid pipe, introducing pressure fluid into the closed space, and confirming the airtightness. SOLUTION: An outer peripheral surface of a fluid pipe 2 having a welded portion 15 is covered with upper and lower cases 1a, 1b each having a widened center portion so as to surround the welded portion 15, together with a packing 7 and an locking claw 13. Flanges 3 are fastened by means of a bolt 4 and a nut 5 to obtain a united case body 1. A plug 10 of an introduction port 9 of the upper case 1a is demounted followed by screwing of a fluid supply pipe. Pressure fluid is fed into a closed space S, and airtight test is performed in respect to a contact portion between the case body 1 and the fluid pipe 2. In the case that airtightness is held, airtight phegging is done again by means of the plug 10. It is possible to prevent fluid leakage to the outside even craking occurs at the welded portion 15 owing to earthquake, if the case body 1 is mounted on a portion having a problem of strength at the time of installing the fluid pipe 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for preventing a fluid from leaking from a low-strength portion such as a welded portion of a gas pipe or a water pipe.

[0002]

2. Description of the Related Art A general steel pipe used for a gas pipe, a water pipe or the like is constructed by joining steel pipes of a predetermined length by welding and joining them.

[0003] When a fluid pipe joined by such welding is buried in the ground and a large bending load or a tensile load is applied due to an earthquake or the like, stress is concentrated at the joint and a crack or the like may occur.

[0004] When a fluid leaks due to the cracks or the like, conventionally, a split joint type casing is hermetically mounted around the damaged portion of the fluid pipe by repair work so as to prevent the leak. Met.

[0005]

In the above-mentioned repair work after fluid leakage, it takes a considerable amount of time to identify the damaged portion and start the work, and during that time the fluid continues to leak. With such fluids, there is a risk of ignition.

In addition, repair work must be performed after extensively excavating the ground around the damaged part, and the work and backfilling work are troublesome.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is provided in advance around a low-strength portion such as a welded portion of a fluid pipe so that a fluid at the time of the breakage of the portion is damaged. Leakage can be completely prevented,
A first object is to provide a leakage prevention method and device.

A second object of the present invention is to reinforce a low strength portion such as a weld.

[0009]

According to a first aspect of the present invention, there is provided a method of the present invention, wherein a case body which can be divided into a plurality of portions is provided on an outer peripheral surface surrounding a low strength portion of a fluid pipe. After mounting so that a closed space is formed between the surface and the outer peripheral surface of the fluid pipe, a pressure fluid is introduced into the closed space through an opening formed in a part of the case body, and the fluid pipe is It is characterized in that the airtightness between the housing and the case body is confirmed, and the opening is sealed.

According to the first aspect of the present invention, there is provided an apparatus according to the present invention, wherein a plurality of cases whose central portions are enlarged in diameter are connected to each other to form a cylindrical shape, and the outer peripheral surface of the fluid pipe is hermetically sealed. An opening communicating with the inside of the case main body is provided at an appropriate position on the outer peripheral surface of the case main body which is formed in a sealed manner on the outer peripheral surface of the fluid pipe, and the opening is sealed with a removable plug. Features.

A second object of the present invention is to provide a detachment prevention fitting provided with a locking claw that can bite into the outer peripheral surface of the fluid pipe by operating a push bolt at both ends of the case body. It is achieved by providing so that it can engage with.

In this case, it is preferable that the detachment prevention fitting is provided integrally with the case body.

The locking claw is provided so as to be rotatable around the tip of the push bolt, and when a load is applied to the fluid pipe in a pulling direction, the locking claw is rotated outward and bites into the fluid pipe. It is preferred that

According to the method of the present invention, the case main body is previously mounted on the low-strength portion of the fluid pipe, and a pressurized fluid is introduced into a closed space formed between the case main body and the fluid pipe to check the airtightness. By doing so, even if the low-strength portion of the fluid pipe is damaged and the fluid leaks, the fluid remains in the airtight space and does not leak to the outside.

According to the apparatus of the present invention, when the case main body is mounted on the fluid pipe, a closed space is formed at the center between the inner peripheral surface of the case main body and the outer peripheral surface of the fluid pipe, and an opening is formed in this space. Since the pressure fluid can be introduced by removing the provided plug, the above method can be easily performed.

[0016] Further, when the separation prevention metal fittings having the locking claws are provided at both ends of the case body, the low strength portion is reinforced when a tensile load is applied to the fluid pipe.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

First, a water leakage prevention device of the present invention will be described with reference to FIGS. The right half in FIG. 1 is a push bolt 1 of a detachment prevention metal fitting 11 described later for convenience.
The structure is shown in a vertical section at the center of No. 4.

Reference numeral 1 denotes a cylindrical case body which is mounted on the outer peripheral surface of a steel fluid pipe 2 and has a two-part structure of an upper case 1a and a lower case 1b which form a half-cylindrical shape. A flange 3 is formed at the opposite end of the upper case 1a and the lower case 1b. By tightening a T-head bolt 4 inserted through the flange 3 with a nut 5, the upper and lower cases 1a and 1b are integrally formed. Assembled.

The upper and lower cases 1a and 1b are tapered at their central portions so that the required space S is formed between the inner peripheral surface and the outer peripheral surface of the fluid pipe 2. .

At both ends of each of the cases 1a and 1b, an enlarged diameter portion 6 is formed, and a packing 7 made of synthetic rubber or the like is inserted into an annular groove 6a on the inner surface thereof. The watertightness of the building is improved. The packing 7 is integrally provided with a packing 8 for sealing the joint surface between the flange portions 3.

At the center of the upper surface of the upper case 1a, an inlet 9 for a fluid for leak inspection is protruded upward so as to communicate with the internal space S, and is always hermetically sealed by a plug 10.

At both ends of the upper and lower cases 1a and 1b, detachment prevention fittings 11 are integrally connected, and an arc-shaped groove 12 formed on the inner surface thereof has a sharp-edged blade portion. The arcuate locking claw 13 is accommodated.

Each locking claw 13 is pressed in the centripetal direction by two push bolts 14 screwed into the bulging portion 11 a on the outer peripheral surface of the metal fitting 11, and can be cut into the outer peripheral surface of the fluid pipe 2.

Next, a leakage prevention procedure using the leakage prevention device of the above embodiment will be described.

First, the upper and lower cases 1a and 1b are put on the outer peripheral surface of the fluid pipe 2 having the welded portion 15 together with the packing 7 and the locking claw 13 so as to surround the welded portion 15, and the flange portions 3 of each other are T-headed. The case 4 is tightened by the bolts 4 and the nuts 5 to form an integral case body 1.

At this time, the packing 7 is pressed against the outer peripheral surface of the fluid pipe 2, and the packing 8 is pressed against the facing surface of the flange 3, so that the watertightness between the case body 1 and the fluid pipe 2 is maintained. .

Each locking claw 13 has its tip slightly biting into the outer peripheral surface of the fluid pipe 2 by tightening the push bolt 14. In addition, this work is performed
May be appropriately tightened so that the tip of the locking claw 13 is slightly protruded, and may be performed simultaneously with the fastening of the T-head bolt 4 and the nut 5.

Next, after removing the plug 10 at the inlet 9 of the upper case 1a, a hollow screw 17 attached to the tip of the fluid supply pipe 16 is screwed in as shown in FIG. , A pressurized fluid such as nitrogen gas, compressed air, high-pressure water, etc., is supplied to the airtight test of the contact portion (packing mounting portion) between the case body 1 and the fluid pipe 2.

That is, after connecting the fluid supply pipe 16 to a pressure fluid source and sending a fluid of a constant pressure into the space S, the on-off valve 18 is closed, and a pressure gauge 19 connected to the fluid supply pipe 16 is used to connect the fluid inside the pipe. Check pressure drop.

If there is no pressure drop, it is considered that the airtightness of the space S is maintained, the fluid supply pipe 16 is removed, and the inlet 9 is plugged again with the plug 10.

Thus, leakage of fluid from the fluid pipe 2 located in the case body 1 is completely prevented.

That is, when the fluid pipe 2 is installed, if the case body is previously attached to a place considered to be problematic in strength, such as a welded part of the pipe, a crack is formed in the welded part 15 due to an earthquake or the like. Even if a situation occurs in which the fluid enters and leaks, the surrounding area is completely sealed by the case body 1, so there is no danger of leakage to the outside.

Accordingly, troublesome repair work as in the prior art is not required, and there is no danger that dangerous liquid such as gas will continue to leak for a long time.

In the present invention, since the case body 1 has the detachment prevention fittings 11 at both ends, the fluid pipe 2 is provided.
Is strengthened when a tensile load is applied to the welded portion 15.

That is, when the fluid pipe 2 is pulled in the left-right direction about the welded portion 15 and tends to expand, the locking claws 13 of the detachment prevention metal fitting 11 rotate outward with the tip of the push bolt 14 as a fulcrum. By doing so, it penetrates deeply into the outer peripheral surface of the fluid pipe 2 and regulates the elongation of the fluid pipe 2.

Accordingly, a large tensile stress does not act on the welded portion 15, and cracks and the like are less likely to occur.

The present invention is not limited to the above embodiments, but can take various embodiments.

For example, in the above embodiment, the detachment prevention fitting 1
1 is integrally connected to both ends of the upper and lower cases 1a and 1b, but may be separately provided.

That is, as shown in FIG. 4, a fixing portion 23 which can be fastened by a bolt 21 and a nut 22 to a plurality of locations of a flange 20 formed on the enlarged diameter portion 6 at both ends of the upper and lower cases 1a and 1b, and a packing. 7, a bulging portion 26 capable of accommodating a plurality of arcuate locking claws 25, and a plurality of push bolts 27, which can be divided into two in the circumferential direction. It may be attached as a separate body.

In the case where only reinforcement of the fluid is merely required and no reinforcement is required, the above-mentioned detachment prevention fittings 11 and 2 may be used.
8 may be omitted.

[0042]

According to the method and apparatus of the present invention, the following effects can be obtained.

(A) By attaching the case body to the low-strength part of the fluid pipe in advance, the low-strength part may be damaged,
Even if the fluid leaks, it is completely prevented from leaking to the outside.

(B) Therefore, the conventional repair work or the like becomes unnecessary, and there is no danger of dangerous fluid such as gas leaking for a long time.

(C) According to the third aspect of the present invention, since the locking claw of the detachment prevention fitting regulates the elongation due to the tensile load acting on the fluid pipe, the low-strength portion is reinforced and hardly damaged.

(D) According to the invention of claim 4, the workability is improved and the strength is advantageous.

(E) According to the fifth aspect of the invention, the effect of regulating the elongation of the fluid pipe is increased, and the reinforcing effect is also increased.

[0048]

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention by cutting through a main part.

FIG. 2 is also a partially cutaway front view.

FIG. 3 is a vertical sectional side view showing the procedure for checking the airtightness of a sealed space.

FIG. 4 is a longitudinal sectional side view of a main part showing another example of a detachment prevention fitting separately provided.

[Description of Signs] 1 Case body 1a Upper case 1b Lower case 2 Fluid pipe 3 Flange 4 T-head bolt 5 Nut 6 Large diameter portion 6a Annular concave groove 7, 8 Packing 9 Inlet (opening) 10 Plug (plug) 11) Detachment prevention fitting 11a Swelling portion 12 Depressed groove 13 Locking claw 14 Push bolt 15 Welding portion 16 Fluid supply pipe 17 Hollow screw 18 Open / close valve 19 Pressure gauge 20 Flange 21 Bolt 22 Nut 23 Fixing portion 24 Pressing portion 25 Locking Claw 26 Swelling part 27 Push bolt 28 Separation prevention fitting S Space

Claims (5)

[Claims] 1. A case body which can be divided into a plurality of parts on an outer peripheral surface surrounding a low-strength portion of a fluid pipe so that a sealed space is formed between an inner peripheral face of a central portion thereof and an outer peripheral face of the fluid pipe. After mounting, a pressure fluid is introduced into the sealed space from an opening formed in a part of the case main body, the airtightness between the fluid pipe and the case main body is confirmed, and the opening is sealed. To prevent leakage of fluid pipes. 2. A plurality of cases whose central portions are enlarged in diameter are connected to each other to form a cylindrical shape and a hermetically sealed outer peripheral surface of a fluid pipe, and a hermetically sealed outer peripheral face of a fluid pipe. A leakage prevention device for a fluid pipe, wherein an opening communicating with the inside of the case main body is provided at an appropriate position on an outer peripheral surface of the case main body to be mounted, and the opening is sealed with a removable plug. 3. A detachable metal fitting having a locking claw that can bite into the outer peripheral surface of the fluid pipe by operating push bolts at both ends of the case main body, a part of which can be engaged with the case main body. The leakage prevention device for a fluid pipe according to claim 2, wherein the leakage prevention device is provided as described above. 4. The leakage prevention device for a fluid pipe according to claim 3, wherein the detachment prevention fitting is provided integrally with the case body. 5. A locking claw is provided so as to be rotatable around a tip of a push bolt, and when a load in a pulling direction is applied to the fluid pipe, the locking claw is rotated outward and bites into the fluid pipe deeply. The leak prevention device for a fluid pipe according to claim 3 or 4, wherein: