JP6075848B2 - How to repair leaks on the outside of gas piping - Google Patents

Description

  The present invention relates to a gas pipe outer surface leak repair method and a gas pipe outer surface leak repair tape, and is particularly suitable for use in repairing an outer leak of an existing gas buried pipe.

  In gas pipes (such as low-pressure main branch pipes and service pipes) made of steel pipes buried in the ground, if holes such as corrosion holes are formed in a part of the pipe due to aging, etc., gas flows from that part. Since there is a risk of leakage, leakage repair is performed to close the hole. At the time of this leak repair, the following method is used as an external leak repair method in which the repair material is stuck from the outer surface of the pipe without using fire (see, for example, Patent Document 1).

  That is, in this outer surface leakage repair method, first, a hole formed by corrosion or the like in the gas buried pipe is closed with a seal bond made of a two-component epoxy resin. Next, a seal tape made of butyl rubber and polyester film and a tape with a lead plate laminated on the unvulcanized butyl rubber-based adhesive layer (called rib-live tape) are sequentially wound spirally to cover this seal bond, Further, an anticorrosion tape made of butyl rubber and a polyester film is spirally wound.

JP-A-9-303622 (paragraph 0020)

  According to the above-described conventional external leak repair method, the external leak repair of the gas buried pipe can be performed quickly and reliably, but considering the environment, an environmentally friendly material can be used instead of the lead plate included in the ribbed tape. It is desirable to use it.

  Therefore, the problem to be solved by the present invention is to provide a gas piping outer surface leakage repair method capable of quickly and reliably performing a gas piping outer surface leakage repair without using a tape containing a lead plate, and to use the same. It is an object of the present invention to provide a suitable tape for repairing external leakage of gas piping.

  Another problem to be solved by the present invention is a gas pipe outer surface leakage repair method capable of preventing a seal breakage due to a creep phenomenon when a tape for repairing an outer surface leak of a gas pipe is pressed from the outer surface of the gas pipe and wound. Another object of the present invention is to provide a tape for repairing leakage of an outer surface of a gas pipe suitable for use therein.

In order to solve the above problems, the present invention provides:
A gas pipe outer surface leakage repair method for repairing a gas leak from a hole formed in a gas pipe,
An outer surface of the gas pipe, wherein a tape including at least one plate member selected from the group consisting of a zinc plate, an aluminum plate, and a PET (polyethylene terephthalate) plate is wound around a portion including the hole on the outer surface of the gas pipe. This is a leak repair method.

  Although the board | plate material contained in said tape is typically laminated | stacked on the unvulcanized butyl rubber-type adhesion layer, it is not limited to this. When the tape is wound around the outer surface of the gas pipe, the unvulcanized butyl rubber adhesive layer adheres to the outer surface. Although the thickness of a board | plate material is chosen as needed, it is 40 micrometers or more and 700 micrometers or less, for example. There may be only one plate material, but it may be a laminated plate in which a plurality of different plate materials are laminated. The thickness of the entire laminated plate is also 40 μm or more and 700 μm or less, for example.

  In this gas pipe outer surface leakage repair method, typically, holes formed in the gas pipe are closed with a seal putty mainly composed of liquid hydrocarbon resin and calcium carbonate, and the outer surface of the gas pipe is covered so as to cover the seal putty. Further, a sealing tape having an unvulcanized butyl rubber adhesive applied on both sides of a polypropylene film is spirally wound, a tape containing the above plate material is wound on the outer side thereof, and then an anticorrosion tape is further wound on the outer side.

In addition, this invention
It is a tape for repairing leakage of an outer surface of a gas pipe used for repairing leakage of gas from a hole formed in the gas pipe,
A tape for repairing external leakage of a gas pipe, comprising at least one plate selected from the group consisting of a zinc plate, an aluminum plate and a PET plate.

  In the invention of the gas pipe external surface leakage repair tape, what has been described in relation to the above-described invention of the gas pipe external surface leakage repair method is valid, as long as it is not contrary to the nature of the tape.

  According to the present invention, it is possible to quickly and surely and safely repair the leakage of the outer surface of the gas pipe without using a tape including a lead plate. Further, it is possible to prevent the seal breakage due to the creep phenomenon when the outer surface leakage repair tape of the gas pipe is pressed and wound from the outer surface of the gas pipe.

It is a perspective view for demonstrating the outer surface leak repair method of the gas piping by one Embodiment of this invention. It is sectional drawing which shows the novel rib live tape used in the outer surface leak repair method of the gas piping by one Embodiment of this invention. It is a graph for demonstrating the method of a shape retention test. It is a graph which shows the result of the shape retention test performed using the test pieces 1-3 which consist of a novel rib live tape.

Hereinafter, modes for carrying out the invention (hereinafter referred to as “embodiments”) will be described.
1A and 1B show a method for repairing external leakage of a gas pipe according to an embodiment.

  As shown in FIG. 1A, it is assumed that a hole 12 is formed in a gas pipe 11 made of a steel pipe due to corrosion or the like, and external leakage of the hole 12 is repaired.

  As shown in FIG. 1B, first, a seal putty 13 having a size covering the hole 12 of the gas pipe 11 is applied. For example, the seal putty 13 is mainly composed of a liquid hydrocarbon resin and calcium carbonate, but is not limited thereto. The properties of the seal putty 13 are, for example, specific gravity 1.9 ± 0.2 (according to JIS K 7112), water absorption 0.5% or less (according to JIS K 6911), penetration (25 ° C.) 60 + 10, −5 ( 55 to 70) (according to JIS K 2207. 50 g load). By sealing the hole 12 using the seal putty 13 in this way, not only can the workability be improved compared to the case where a seal bond made of a two-component epoxy resin is used as in the prior art, the seal putty 13 Since it is cheaper than a seal bond, the sealing cost can be reduced.

  Next, a sealing tape 14 is spirally wound around the outer surface of the gas pipe 11 so as to cover the sealing putty 13. The seal tape 14 is, for example, one in which an unvulcanized butyl rubber-based adhesive material is uniformly applied to both surfaces of a polypropylene film, but is not limited thereto. The dimensions of the seal tape 14 are, for example, a thickness of 0.5 ± 0.1 mm, a width of 50 ± 1.0 mm, and a length of 300 mm. The property of the seal tape 14 is, for example, a steel surface adhesive force of 3.92 N / 10 mm or more (according to JIS Z 0237).

Next, a new live tape 15 is spirally wound around the seal tape 14. As shown in FIG. 2, the new rib-live tape 15 is obtained by laminating an alternative material 15b of a lead plate on an unvulcanized butyl rubber adhesive layer 15a. A release paper (not shown) is attached to the surface of the unvulcanized butyl rubber adhesive layer 15a of the new ribbed tape 15 before use. Specifically, the lead plate substitute material 15b is formed by laminating at least one plate selected from the group consisting of a zinc plate, an aluminum plate, and a PET plate, or a plurality of different plates selected from these plates. It is a laminated board. The zinc plate and aluminum plate are typically foil-like. The PET plate is typically a film. The thicknesses of these zinc plate, aluminum plate and PET plate are, for example, 40 μm or more and 700 μm or less, but are not limited thereto. The thickness of the unvulcanized butyl rubber-based adhesive layer 15a is, for example, 0.8 mm or 1.0 mm. The properties of the unvulcanized butyl rubber adhesive layer 15a are, for example, specific gravity of 1.35 ± 0.1 (according to JIS K 7112), water absorption of 0.5% or less (JIS K).
6911), penetration (20 ° C.) 115 ± 15 (according to JIS K 2207), steel surface adhesive strength of 5.88 N / 10 mm or more (according to JIS Z 0237). After the new rib-live tape 15 was wound, the new rib-live tape 15 was crimped using a tool for a rib-live construction method (a pliers roller and a double roller). By this crimping finish, the new ribbed tape 15 is brought into close contact with the outer surface of the gas pipe 11, and the hole 12 is completely sealed.

  Next, the anticorrosion tape 16 is spirally wound around the new ribbed tape 15. The anticorrosion tape 16 is, for example, one in which an unvulcanized butyl rubber-based adhesive material is uniformly applied to one side of a polypropylene film, but is not limited thereto. The dimensions of the anticorrosion tape 16 are, for example, a thickness of 0.5 ± 0.1 mm, a width of 50 ± 1.0 mm, and a length of 300 mm. The property of the anticorrosion tape 16 is, for example, a steel surface adhesive force of 3.92 N / 10 mm or more (according to JIS Z 0237).

  As described above, the outer surface leakage repair of the gas pipe 11 is performed.

  In order to evaluate the performance of the new ribbed tape 15, test pieces 1 to 3 made of the new ribbed tape 15 were produced, and a pressure resistance test and a shape retention test were performed.

<Test piece 1>
A zinc foil having a thickness of 100 μm was used as an alternative material 15b for the lead plate of the new rib tape 15. This zinc foil is formed of anticorrosion zinc manufactured using high-purity zinc ingot (purity 99.995% or more). The thickness of the unvulcanized butyl rubber adhesive layer 15a is 800 μm, the width of the new rib-live tape 15 is 200 mm, and the length is 300 mm.

<Test piece 2>
As an alternative material 15b for the lead plate of the new ribbed tape 15, an aluminum foil having a thickness of 70 μm was used. The thickness of the unvulcanized butyl rubber adhesive layer 15a and the width and length of the new rib-live tape 15 are the same as those of the test piece 1.

<Test piece 3>
A PET film having a thickness of 50 μm was used as an alternative material 15b for the lead plate of the new live tape 15. The thickness of the unvulcanized butyl rubber adhesive layer 15a and the width and length of the new rib-live tape 15 are the same as those of the test piece 1.

  Table 1 summarizes alternative materials 15b for test pieces 1 to 3.

[Pressure resistance test]
A pressure resistance test was performed using the test pieces 1 to 3. The pressure resistance test was performed as follows. A straight pipe made of a steel pipe having a length of 400 mm and an inner diameter of 50 mm was used in which corrosion holes having a diameter of 24 mm were formed on the outer surface. One end of this straight pipe was closed, a valve was attached to the other end, and a precision regulator was attached to this valve. A pressure sensor is attached to the valve so that the pressure in the straight pipe can be measured. The compressed air can be supplied into the straight pipe through the precision regulator and the valve.

  The test pieces 1 to 3 were wound around the outer surface of the straight pipe so as to block the corrosion hole of the straight pipe, and further, an anticorrosion tape was wound around the outer side. The seal putty was not installed. Compressed air was supplied into the straight pipe through a precision regulator and a valve. The maximum load pressure was 0.2 MPa. Three of the same specimens 1 to 3 were prepared, and the average value of pressures measured for the three specimens was defined as P0. The load pressure holding time is recorded as the pressure at which no pressure drop occurs for 1 minute. Table 2 shows the three measured values and the average value P0 thereof.

  By applying a pressure of about 0.2 MPa in the straight pipe, it was confirmed that the surface of the corrosion hole (hole diameter: 24 mm) was raised to a pipe shape (outer shape). In all the test pieces, the air passage extended to the tube end, and the anticorrosion tape swelled like a balloon, leading to a pressure drop.

  The results of the pressure resistance test described above are the same as those of the current rib live tape using a lead plate (thickness 800 μm), and the new rib live tape 15 using zinc foil, aluminum foil and PET film has the same pressure resistance as the current rib live tape. It can be said that it has performance.

[Shape retention test]
The shape retention test (life evaluation) of the test pieces 1 to 3 was performed. The test method is as follows.

(1) the average value of the breakdown voltage and P _max, and _{P1 = 0.9P max, P2 = 0.7P} max. The breaking times t1 and t2 are the average breaking times at the pressures P1 and P2 (N number = 3). The target values of t1 and t2 are, for example, t1≈1 hour and t2≈10 hours.
(2) As shown in FIG. 3A, (P1, t1) and (P2, t2) are plotted on a log-log graph with the logarithm of failure time on the horizontal axis and the logarithm of load pressure (test pressure) on the vertical axis. And draw a straight line passing through both points.
(3) As shown in FIG. 3B, the pressure P3 that breaks in 10 ² hours (100 hours) and the pressure P4 that breaks in 10 ³ hours (1000 hours) are determined from the straight line created in (2).
(4) when the breaking time of t2 was much longer than 10 hours in the step (2), for example, and the like _{P3 = 0.8P max, P4 = 0.5P} max.

Specifically, the test was performed as follows. The pressure load value in the straight pipe is P _max = P0 = 0.2 MPa, and P1 = 0.9P0 and P2 = 0.7P0 are calculated. The results of P1 and P2 are entered in a log-log graph as shown in FIG. 3A, and a straight line is drawn using the method of least squares. From this straight line, a pressure P3 that breaks in 100 hours and a pressure P4 that breaks in 1000 hours were calculated, applied the calculated load pressure, and measured until a holding time of 1000 hours or more was reached. For those exceeding 1000 hours, data was continuously collected and used as additional data.

  The results of the shape retention test thus performed are shown in Tables 3 to 5.

  In FIG. 4, the result of the shape retention test performed using the test pieces 1 to 3 is shown in comparison with the result of the shape retention test of the current rib live tape using a lead plate (thickness: 800 μm). From FIG. 4, it was found that the elapsed time corresponding to 30 years was a pressure larger than the working pressure 2.3 kPa, and the test pieces 1 to 3 had sufficient shape retention. The result of this shape retention test is as good as or better than the current rib-live tape using lead plate, and the new rib-live tape 15 using zinc foil, aluminum foil and PET film is equivalent to the current rib-live tape. Or, it can be said that it has excellent shape retention performance.

  As described above, according to the gas pipe outer surface leakage repair method according to this embodiment, at least one plate material selected from the group consisting of a zinc plate, an aluminum plate, and a PET plate as the substitute material 15b of the lead plate, or these By using the new rib live tape 15 including a laminated plate in which a plurality of different plate materials selected from the above plate materials are laminated together, the gas pipe 11 in which the holes 12 are formed without using a tape containing a lead plate is used. External leakage repair can be performed quickly and reliably. Further, the new rib-live tape 15 can obtain excellent pressure resistance and shape retention that are equal to or higher than those of the current rib-live tape. Further, it is possible to prevent seal breakage due to a creep phenomenon when the outer surface leakage repair tape of the gas pipe 11 is pressed from the outer surface of the gas pipe 11 and wound. Further, since the hole 12 of the gas pipe 11 is closed not with the seal bond but with the seal putty 13, the workability of the sealing work can be improved and the cost can be reduced, and the cost of the external leakage repair can be reduced. Can do.

  Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications based on the technical idea of the present invention are possible.

  For example, the numerical values, materials, configurations, and the like given in the above-described embodiments are merely examples, and different numerical values, materials, configurations, etc. may be used as necessary.

  In addition to the zinc plate and the aluminum plate, other metals or alloys such as tin, copper, nickel, lead-tin alloy, brass, etc. can be used as the alternative material 15b for the lead plate of the new live tape 15. is there.

  DESCRIPTION OF SYMBOLS 11 ... Gas piping, 12 ... Corrosion hole, 13 ... Sealing putty, 14 ... Seal tape, 15 ... New rib live tape, 15a ... Unvulcanized butyl rubber adhesive layer, 15b ... Alternative material of lead plate, 16 ... Anticorrosion tape

Claims (6)

A gas pipe outer surface leakage repair method for repairing a gas leak from a hole formed in a gas pipe,
The hole on the outer surface of the gas pipe is closed with a seal putty, and a seal tape coated with an unvulcanized butyl rubber adhesive on both sides of the polypropylene film is spirally wound around the outer surface so as to cover the seal putty. After winding a tape containing at least one plate selected from the group consisting of an aluminum plate and a PET plate, the tape is brought into close contact with the outer surface by sealing the hole by sealing the tape. A method for repairing leaks on the outside of gas pipes.   2. The method for repairing leakage of an outer surface of a gas pipe according to claim 1, wherein the plate material is laminated on an unvulcanized butyl rubber-based adhesive layer. 3. The method for repairing leakage of an outer surface of a gas pipe according to claim 1, wherein the seal putty is mainly composed of a liquid hydrocarbon resin and calcium carbonate .   The method for repairing an outer surface leakage of a gas pipe according to any one of claims 1 to 3, wherein the thickness of the plate material is 40 µm or more and 700 µm or less.   2. The method for repairing an outer surface leakage of a gas pipe according to claim 1, wherein the tape includes a laminated plate in which a plurality of different plate materials are laminated. 6. The method for repairing an external leakage of a gas pipe according to claim 1, wherein after the tape is crimped, an anticorrosion tape is spirally wound around the outside of the tape.

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