JP2801059B2 - Pig for lining inner wall of pipe and lining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention fills a pipe with a fluid lining material such as paint, inserts an elastic material pig behind the pipe, and supplies compressed air from the rear. The present invention relates to a method for forming a lining film on the inner wall surface of a pipe by moving resin forward, and relates to an improvement of a lining pig on the inner wall surface of the pipe and a lining method itself.

[Conventional technology]

Conventionally, as a rehabilitation method for existing pipelines, after removing the scale on the inner wall of the pipe, insert one or two pigs into the pipe and fill the paint before or between the pigs and fill the pig with air etc. A method of pressure feeding is known, and many patents have been filed in which the structure of the pig, the pressing method, the number of times the pig is moved, and the like are devised.

 For example, JP-A-60-172383 JP-A-61-18474 JP-A-63-69576 JP-A-63-162076 JP-A-63-31578 JP-A-63-4885 JP-A-63-31577 JP-A-63-274474 JP-A-63-59376, JP-A-1-240772, JP-A-55-44320, JP-A-52-78250, and JP-B-40-25273.

In these conventional methods, the shape of the pig is spherical or shell-like and the material is plastic or rubber having elasticity, and the outer diameter is slightly smaller or larger than the inner diameter of the pipe. When lining, place a lining material in front of these pigs and push the pig with air pressure etc. to run it.The pig is slightly deformed by the running speed and a certain gap is created between the pig and the inner surface of the pipe. The idea is that the lining is determined.

Japanese Patent Application Laid-Open No. 63-270580 describes a method of inflating a pig with air as a "lining method for the inner wall surface of a reduce pipe".

[Problems to be solved by the invention]

Conventionally, when the amount of deformation of the pig is increased, the stress of the pig increases in proportion to it, and when the stress increases, the thickness of the lining becomes thin, so that the pig can only be deformed within a very limited range. Was thought.

Therefore, the biggest problem of these methods is that the applicable pipe diameter is 1
It is limited to the type, and different diameter pipes must be separately constructed for each size.

Further, in the `` Method of lining the inner wall of a reduce pipe '' of JP-A-63-270580, the lining of different diameter pipes is possible by inflating the pig with air, but the adjustable range is as follows. JIS nominal diameter 100A → 90A
It is not suitable for use in actual piping because the width of 50A → 40A is narrow. It is also difficult to pressurize and hold the pig at an appropriate pressure.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a lining pig and a lining method for a pipe inner wall surface capable of efficiently lining even different diameter pipes having greatly different diameters.

[Means for solving the problem]

In order to solve the above problems, the present invention has taken the following measures.

The lining pig of the pipe inner wall surface of the present invention is formed of a synthetic resin elastic material, and its load-deflection curve:
The load that can cause 70% deflection is 6 times or less the load at the time of 10% deflection.

In the lining method of the inner wall surface of the pipe of the present invention, the pipe is filled with a flowable lining material, an elastic pig is inserted behind the pipe, compressed air is supplied from the rear, and the flowable lining material travels with the pig in the pipe. And lining the inner wall of the pipe with a flowable lining material, wherein the load-
This is a method using a pig formed of a synthetic resin elastic material having a bending characteristic.

 Hereinafter, the present invention will be described in more detail.

The elastic material constituting the pig of the present invention has a load of the above characteristic.
It has a deflection curve. Here, as the elastic material made of synthetic resin to be used, a soft polyurethane foam or a vinyl foam can be exemplified, but it is a matter of course that other materials may be used as long as the load-deflection characteristics are satisfied.

When the pig is formed in a cylindrical shape and inserted into a pipe, it is more preferable that the stress generated in the radial direction of the pig be 200 gr / cm ² or less.

If the outer diameter of the pig is cylindrical, molding can be facilitated and the pig can be produced at low cost. The conventional pig shape was processed into a spherical shape or a shell-like shape, and a mold was required for molding, so changing the size of the pig required recreating the mold, which was bothersome and expensive. I tended to be. It is preferable to make the outer shape cylindrical, since such a problem is solved.

When the pig is formed in a cylindrical shape, the diameter thereof is less than twice the diameter of the pipe having the smallest inner diameter of the pipes to be lined, and is equal to or greater than the diameter of the pipe having the largest inner diameter,
Moreover, the shaft length is preferably 1.0 to 2.0 times the diameter.

In the present invention, a flowable lining material and a lining pig are inserted into a different diameter pipe. When charging the pipes with different diameters, the flowable lining material is filled into the pipe first, and then the pig is inserted into the pipe. Another pig is inserted before the flowable lining material, and the two pigs are inserted. Lining may be performed with a fluid lining material interposed therebetween.

The type of the fluid lining material to be charged into the different diameter pipe together with the pig is not particularly problematic, but a two-component mixed type epoxy resin or the like is preferable. The viscosity of the flowable lining material is 5000
cP to 20000 cP is desirable. The amount of the flowable lining material used for the lining treatment is preferably increased by 10 to 40% of the calculation amount required for forming the specified film thickness on the pipe to be treated.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

FIG. 1 shows a load-deflection curve of the elastic material constituting the pig of the present invention. This figure is 50mm x 300mm x 3
FIG. 5 is a diagram showing the amount of deflection when a compression plate having a diameter of 200 φ is placed on a soft urethane foam of 00 mm and a load is applied thereon, expressed as a percentage.

From this figure, it can be seen that the load of this elastic material increases in proportion to the amount of deflection up to a deflection amount of 10%, but the load increase rate is very small up to a deflection amount of about 50% when the deflection amount exceeds 10%. %, The load gradually increases up to about 70%, and when it exceeds 70%, the load rapidly increases.

In the present invention, an elastic material in which the change in load is small with respect to the change in the amount of deflection, that is, an elastic material whose deflection is 70% and whose load is within 6 times that when the deflection is 10%, is formed into a columnar shape and pressed into the pipe. When this occurs, the stress generated in the radial direction of the pig is 200 g
Using a pig that is r / cm ² or less, combine it with a lining material having a viscosity of 5000 to 20000 cP, fill the lining material into the pipe, then insert the pig into the pipe, press the pig with air to move it, d ₀ the outer diameter of, when the inner diameter of the tube was d _1, found to exhibit a substantially constant lining thickness if this d ₁ is in the range of _{d 0 ≧ d 1 ≧ (1/2} ) d 0 did.

This is completely different from the conventional idea that the diameter of the pig is slightly larger or smaller than the inner diameter of the pipe. In the practical sense, the conventional idea was that only one pig could be applied to the same pipe diameter. As a result of the present invention, it has become possible to line pipes having different inner diameters within one range with the single pig.

When this is displayed, as shown in Table 1, it can be understood that one pig can cope with three stages of tube size changes. In the table
SGP is a steel pipe for gas specified by JIS.

Next, as shown in FIG. 2, a lining process was performed on a horizontal different-diameter pipe 1 in which the pipe diameters differed in three stages in a stepwise manner. The inner diameter of the minimum part 2 was 35.7 mm, and the inner diameter of the maximum part 3 was 52.9 mm.

The lining pig 4 was formed into a cylindrical shape using polyurethane foam. The diameter was 55 mm and the height was 55 mm. That is, the outer diameter of the pig was not more than twice the inner diameter of the minimum part 2 of the different diameter pipe 1, and the height was made equal to the diameter of the pig.

The pig 4 used has a load-deflection characteristic of the first type.
A material satisfying the characteristic diagram shown in the figure and having a stress generated in the radial direction of the pig when pressed into the pipe of 200 gr / cm ² or less was used.

As the lining material 5, a two-component mixed type epoxy resin paint having a viscosity of 5000 cP was used.

An L-shaped pipe 6 is flanged to the entrance of the largest part 3 of the horizontal different-diameter pipe 1, a lining material 5 is injected, and then a pig 4 is inserted. The L-tube 6 was covered and sealed. A gate valve 9 is provided in the air supply pipe 7.

The outlet of the minimum portion 2 of the different-diameter pipe 1 is open, and the end thereof is provided with a polyethylene bag for collecting excess lining material and pigs (not shown).

The amount of the lining material 5 to be injected into the L-shaped tube 6 was 100 cc per inch meter, and was increased by 30% from the calculation amount required to form a film having a thickness of 0.5 mm required for the different diameter tube.

Then, the gate valve 9 was opened and 0.3 kg · f / cm ² of compressed air was supplied to move the pig 4 and the lining material 5 forward at a substantially constant speed. A lining film having a thickness of 0.3 mm to 0.8 mm was formed on the inner wall of the different diameter pipe 1.

It was confirmed that the thickness of the lining film was almost constant.

In this embodiment, the pipe is closed by the lining material itself. However, when the pipe diameter becomes large, another pig of the same material and the same size is inserted in front of the lining material, and the two front and rear pigs are used. A lining material may be sandwiched between the pipes, and the lining material may be used to fill the pipeline.

〔The invention's effect〕

Since the present invention is configured as described above, lining can be efficiently performed even for pipes of different diameters having considerably different diameters.

[Brief description of the drawings]

FIG. 1 is an experimental graph showing a load-deflection curve of a flexible urethane foam, and FIG. 2 is a cross-sectional view of a different-diameter pipe lined in the embodiment. 1 ... Different diameter pipe 4 ... Pig 5 ... Lining material

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B05C 7/00-21/00 B05D 7/22

Claims (6)

(57) [Claims] 1. A lining for an inner wall surface of a pipe, which is formed of an elastic material made of a synthetic resin and has a load capable of causing 70% deflection in a load-deflection curve not more than 6 times a load at the time of 10% deflection. Pig. 2. The lining pig according to claim 1, wherein the synthetic resin elastic material is made of a flexible polyurethane foam or a vinyl foam. 3. The lining pig according to claim 1, wherein the outer shape is a cylindrical shape. 4. A pipe is filled with a flowable lining material, an elastic pig is inserted behind the pipe, compressed air is supplied from the rear, and the flowable lining material travels in the pipe together with the pig to form a flowable lining. A method of lining the inner wall surface of a pipe with a material, wherein the pig is formed of an elastic material made of synthetic resin, and in the load-deflection curve, a load capable of causing 70% deflection is a load of 10% deflection. A method for lining the inner wall surface of a pipe using a pig having a size of 6 times or less. 5. The pig is formed in a cylindrical shape, and when it is inserted into a pipe, a stress generated in a radial direction of the pig is 200 g.
The lining method of the pipe inner wall surface according to claim 4, wherein the lining is r / cm ² or less. 6. The above-mentioned pig is formed in a cylindrical shape, and has a diameter of not more than twice the diameter of the pipe having the smallest inner diameter and the diameter of the pipe having the largest inner diameter among the pipes to be lined. The method for lining the inner wall surface of a pipe according to claim 4, wherein the pipe length is 1.0 times to 2.0 times the diameter of the pipe.