JPH05169020A - Method for lining inner face of pipeline - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] To provide a method for lining the inner surface of a conduit, which can form a substantially uniform thin film even when lining the elbow portion of manifolds of different sizes. [Structure] In a manifold that has a plurality of branch pipes branched from the main pipe, paint is injected into the pipe from one end of the main pipe or each branch pipe, and then gas is sent to lining the inner surface of the pipe. After construction, from the end of each branch line,
A lining surface is shaped by inserting a sponge made of elastic foam having a diameter larger than the inner diameter of the tube and made of synthetic resin and having open cells, and then pushing the sponge with air pressure.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a pipe inner surface lining method for a variety of pipes such as a water pipe or a gas pipe in which a plurality of branch pipes are branched from a main pipe, and more particularly to a method for shaping a lining surface.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
The method of blowing paint into a pipe with an air stream is widely used for rehabilitating water pipes and gas pipes, and is described in, for example, Japanese Patent Application Laid-Open No. 2-68177.

In this technique, if the viscosity and the air velocity of the paint are properly selected and a paint having a good sag characteristic is used, a very good lining can be performed. However, this method has a problem that the lining film thickness on the back portion of the elbow tends to be thin as the only difficult problem to solve.

This is because when the air flow collides with the back surface of the elbow and the coating film spreads strongly when the air flow direction changes, it is difficult to secure a practically required coating film thickness within the range of the air flow velocity required by the air flow method. is there.

Further, in this method, when the coating conditions such as the flow velocity are wrong, the problem that the coating film becomes thicker or thinner than necessary may occur. As a method of solving these problems, a method of smoothing the coating film and correcting the thickness through a shaping pig is used while the coating material is not cured after being coated by the air flow method (for example, JP-A-62-266178). Bulletin,
JP-A-63-274474).

However, the pig used in the conventional method has a high density, and if it is strongly compressed, the force pressing against the inner wall of the tube becomes too strong and the coating film is scraped off. Pig is used. Therefore, in this method, the pig has a size corresponding to the minimum size of the target pipe, and therefore there is a problem that when the pipe size is different, a sufficient effect cannot be obtained in a large size portion. Moreover, since the pig is moved from the side of the main pipe having a large size to the side of the branch pipe having a small size, the pig does not enter the branch pipe at the branch portion, and thus the pig can easily go straight on the main pipe portion.

As a solution to this, Japanese Patent Laid-Open No. 1-304086
In the publication, a method is proposed in which air is pushed from the opposite side of the main pipe to guide the pig to the branch pipe (see FIG. 4, 1 in the drawing is a main pipe, 1A is a branch pipe).

However, also in this case, the movement of the pig is in the direction from the main pipeline to the branch pipeline, and even if the pig is pushed by the airflow from the opposite side of the main pipeline at the branch section, the paint accumulated in front of the pig is also generated. It is easy to move to the main pipeline on the opposite side without entering the branch pipeline due to inertial force. Since the pig is being pushed by the airflow from the opposite side of the main pipeline, the pig that moved to the opposite side will eventually be pushed back and moved to the branch pipeline, but the paint pushed by the pig will thicken and remain in the main pipeline. Therefore, it is deviated from the purpose of shaping the inner surface.

Further, Japanese Laid-Open Patent Publication No. 1-304086 discloses a method of placing a paint in front of a pig and pushing it with gas from behind the pig instead of shaping the coating lined by an air flow method. If the size of the branch pipeline is smaller than the main pipeline, the outer diameter of the pig is reduced by compression.

However, it is questionable whether a reduced diameter pig will produce the required coating thickness as the properties of the pig are not further specified. The purpose of the present invention is to
It is an object of the present invention to solve the above problems in the prior art, and to provide a method for lining the inner surface of a conduit which can form a substantially uniform thin film even in the lining of elbow portions of various-sized piping.

[0011]

Means for Solving the Problems The above-mentioned object is, in a multi-way pipe in which a plurality of branch passages are branched from a main pipeline, after injecting paint into the pipeline from one end of the main pipeline or each branch pipeline,
The inner surface of the pipe is lined by feeding gas, and then a sponge made of an elastic foam made of synthetic resin and having open cells with a diameter larger than the inner diameter of the pipe from the end of each branch pipe. This can be achieved by the lining method of the present invention by inserting and then pressing the sponge with an air thickness.

Specific examples of the synthetic resin sponge used in the method of the present invention include polyurethane foam, polyvinyl chloride foam, latex foam and silicone rubber foam. Among these sponges, load-deflection characteristics In 70%, the load at the time of deflection is 60 kg or less, preferably 10 to 60 kg, more preferably 20 to 40 kg, and the load at a compression rate of 70% is 6 times or less than the load at a compression rate of 10%, preferably 1.0
To 6.0 times, more preferably 1.0 to 3.0 times, and the size (and shape) is such that the diameter of the sponge is D, the minimum inner diameter of the pipe is d ₁ , and the maximum inner diameter of the pipe is To d ₂
And D is 1.0 × d ₂ or more, preferably 1.0
× d _{2 to} 3.0 × d ₁ , more preferably 1.1 × d ₂ to
Satisfies the condition that it is a cylinder of 2.0 × d ₁ and a length of 0.5 × D to 3.0 × D or a spherical shape of D of 1.1 × d _{2 to} 2.0 × d _1. Those are preferable.

When these conditions are satisfied, the lining surface of the inner surface of the different diameter pipe can be shaped more appropriately while the sponge is appropriately deformed. It is preferable that the outer diameter of the sponge is columnar because the sponge can be easily molded and can be manufactured at low cost.

The synthetic resin foam constituting this sponge is preferable for exhibiting the effect of the present invention when the density is about 10 to 70 kg / m ³ . In the load-deflection characteristic of the sponge, when the load at the time of deflection of 70% satisfies the condition of 60 kg or less, the stress generated in the radial direction of the sponge is further smaller. Further, the load at the compression rate of 70% is 6 times or less than the load at the compression rate of 10%, and the change of the load due to the deformation is further smaller in this range.

Therefore, when the sponge satisfies the above conditions, when shaping the lining surface when the pipe diameter changes,
From a thick pipe to a thin pipe, it can be deformed according to the pipe diameter, and the stress on the pipe wall does not increase sharply even if the pipe becomes thin, so the lining surface of the entire pipe can be shaped more uniformly.

Here, the load-deflection characteristic is a compression speed of 50.
200 mmφ compression plate and size 50 at mm / min
AS using a sample of mm × 300 mm × 300 mm
It shall be measured according to TMD3574.

In the present invention, when the sponge is pushed by air pressure from the end of each branch pipe, the air pressure can be variously changed depending on the pipe diameter, the size and shape of the sponge, the state of the coating film, etc. It is about 0.5 atm.

If this step is performed by opening the inlet of the main pipeline and sending a small amount of backflow preventing air from the other end of the branch pipeline to guide the sponge to the inlet of the main pipeline, it is even better. The result is obtained.

Therefore, the method of the present invention gives the best results when the above operation is carried out using a sponge satisfying the above-mentioned characteristics and dimensional conditions. The paint used in the method of the present invention may be one that has been conventionally used in the lining method for the inner surface of the pipe, and examples thereof include an epoxy resin paint. Further, when lining the inside of the pipe with such a paint, air is usually used as the gas, but an inert gas such as nitrogen can also be used. The pressure (or flow rate) of the gas in this case can be variously changed depending on the inner diameter of the pipe, the length of the pipe, etc., but is generally about 1.0 to 5.0 atm.

As described above, since the sponge of the present invention is made of a foam having open cells, it can contain a large amount of paint inside, and the sponge is sent while the paint does not harden in the painted pipe. By doing so, the inside of the tube is in the same state as when painting the inside of the tube with a so-called sponge brush, and the extra paint on the tube wall is absorbed by the sponge, and a new coating film can be formed in the thin portion of the coating film.

Particularly in the elbow portion, when the sponge changes its direction, the paint contained in the sponge is excessively pushed out because it is strongly pressed against the tube wall to form a thick coating film. In the present invention, the sponge can be impregnated with a paint for shaping in advance, or the sponge can be pushed in after the shaping paint has been put in the end portion of the conduit, if necessary. In any case, it is appropriate that the amount of the shaping paint is equal to or less than the saturated impregnation amount of the sponge. When the sponge satisfies the characteristics and dimensional conditions, the force with which the sponge pushes the wall surface becomes substantially constant.

Therefore, the lining surface can be shaped with a uniform thickness with the sponge, and the sponge does not scrape off a part of the lining surface. The above was also confirmed by the following experiments.

That is, two sponge-like elastic bodies are prepared (one has open cells and can be impregnated with the paint, the other has discontinuous cells and cannot be impregnated with the paint), and one of them contains the paint. On the other hand, when the coated surface was not pressed and the coated surface was slid while pressing it with the same compression force, the former could retain the coating, whereas the latter scraped the coating. ..

This means that the coating film shaping principle of the present invention is the same as that of the conventional Japanese Patent Laid-Open Nos. 62-266178 and 63-2744.
This means that it is completely different from the case of the shaping pig proposed in Japanese Laid-Open Patent Publication No. 74-74.

That is, the conventional pig does not have a function of absorbing the paint, and the coating is shaped by simply adjusting the gap between the pig and the tube wall, which is the same as a rubber spatula that pushes the coating to shape it. Is.

After lining by the air flow method as described above, the sponge of the present invention is moved by pushing with air in a range where the compressive force is substantially constant, and as described above, the coating film surface is smoothed and substantially constant. It becomes thick. It was also found that the elbow portion forms a thicker coating film on the back surface of the elbow due to passage of the sponge.

The strain range of 10% to 70% of the sponge covers, for example, 3 sizes according to the JIS pipe size, and therefore, in the case of ordinary door-to-door water pipes in which the pipe range of 15A to 25A is used. It can be applied to and is very effective.

When the sponge is inserted from the end of the branch conduit and moved to the main conduit side, it is common that the branch conduit is connected to the side surface of the main conduit at the branch part with the main conduit, so the sponge is There is no choice but to bend in either the left or right direction, and a slight air flow is formed from the upstream side, so that the air is reliably transferred to the opening side of the main pipeline (see FIG. 2, 1 in FIG. Branch pipe). After that, since it is only necessary to go straight through the main pipeline, the sponge can be reliably guided to the opening of the main pipeline by adding a small amount of backflow preventing air to the branch pipeline on the way.

Thus, according to the present invention, when the inner surface of the manifold having the branch pipe is lined, the elbow portion of the lining surface can be shaped to have a substantially uniform thickness.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. First, a general load-deflection curve of the elastic foam material forming the sponge used in this example is shown in FIG.
This figure is vertical 300 mm × width 300 mm × height 50 m
It is the figure which showed the deflection amount at the time of putting a board of diameter 200mm (phi) on m soft urethane foam, and compressing, and applying a load from it on at a compression speed of 50mm / min as a percentage.

From this figure, this elastic foam material increases in load in proportion to the amount of deflection up to a deflection amount of 10%, but
When it exceeds 0%, the load increase rate is very small up to about 50%, and when it exceeds 50%, the load increase gradually up to about 70%, and when it exceeds 70%, it rapidly increases. It can be seen that it has the property of increasing the load.

Next, an example of the method of the present invention using such a sponge will be described. FIG. 1 is a diagram for explaining the example in which the present invention is applied to a pipe assembled according to a water supply pipe of an apartment. ..

In this figure, the main pipeline 1 of the water supply pipe is provided with a pipeline 5 which is a kind of branch pipeline at the end, and a branch is provided between this pipeline 5 and the other end 2 of the main pipeline 1. Pipelines 10A, 10B,
10C and 10D are connected.

In preparation for lining, the water meter is removed from the other end 2 of the main pipeline 1, and the faucet is removed from one end 6 of the pipeline 5 and ends 11A to 11D of the branch pipelines 10A to 10D. The end portion 6 and the end portions 11A to 11D are connected with connecting pipes whose openings are directed upward, and the openings are formed so that an air hose can be attached and detached. , The pressure gauge 24 and the valve 23 are connected to the air hoses 25A to 25D connected to the end portions 11A to 11D of the respective branch pipelines 10A to 10D.
A-24D and valves 23A-23D are connected to each valve 23,2.
3A to 23D were connected to the air compressor 20 through the flowmeter 22 and the dehumidifier 21 in that order.

Regarding the size of each pipe, the main pipe line from 2 to 12 A has a JIS nominal diameter of 25 A, and the branch pipe lines 5 and 10 A to 1
0D is the part that connects to the faucet at the end according to JIS 20A and is JI
The different diameter elbow of S15A is attached.

For the lining, the pipe lines 5 and 10A
From the end of 10D, inject a required amount of epoxy resin paint with a measuring cup and paint toward the main pipeline side. As the coating method, the method described in JP-A-2-68177 was used.

Immediately after painting of all pipelines, the density is 20K.
30m diameter made of g / m ³ flexible polyurethane foam
A cylindrical sponge having a length of m and a length of 50 mm is inserted into the connecting pipe used for injecting the paint at the end of the pipe 5, and the hose 25 is connected.

In the load-deflection characteristics of the sponge used, the load at the time of 70% deflection was 25 kg, and the load at the compression rate of 70% was 5 times the load at the compression rate of 10%. The other end 2 of the main pipeline is open and the other branch pipelines 10A-10
A small amount of backflow prevention air (0.1 atm) valve 23A to D
Open 23D and insert. Next, when the valve 23 is slightly opened and 0.3 atm of air is sent to the pipe 5, the sponge advances in the pipe and is discharged from the other end 2 of the main pipe line.

Next, the same sponge is inserted into the connecting pipe at the end 11A of the branch pipe 10A, backflow preventing air is introduced into the other branch pipes, and the sponge is sent in the same procedure and collected from 2.

In the same manner, sponge is passed through all the branch lines. As a result, the coating film thickness on the back surface of the elbow was 0.3 mm or less only by the air flow method, but the back surface thickness was 0.3 m for all the elbows by passing the sponge.
m-1.0 mm was secured. The coating film thickness other than the elbow portion was 0.3 to 2.0 mm.

The movement of the sponge to the main conduit opening portion 2 was extremely smooth, and no anxiety was felt. In addition, instead of the cylindrical sponge, a spherical polyurethane sponge made of soft polyurethane foam and having a diameter of 30 mm (load at 70% deflection is 25 Kg, load at 70% compression rate is 5 times load at 10% compression rate) is used. When the same operation was performed, the same result as this example was obtained.

[0042]

According to the method of the present invention, it is possible to form a substantially uniform thin film even in the lining of elbow portions of manifolds of different sizes.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example in which the present invention is applied to a pipe assembled according to a water supply pipe of an apartment.

FIG. 2 is a diagram showing a method of moving a sponge from a branch pipe to a main pipe.

FIG. 3 is a diagram showing a load-deflection curve of the sponge of the present invention.

FIG. 4 is a diagram showing a method of moving a sponge from a main pipeline to a branch pipeline.

[Explanation of symbols]

P ... Sponge, 1 ... Main pipeline, 5, 10A
-10D: Branch pipe

Claims (8)

[Claims] 1. A diversified pipe in which a plurality of branch pipes are branched from a main pipe, by injecting a paint into the pipe from one end of the main pipe or each branch pipe, and then introducing a gas to lining the inner surface of the pipe. After that, insert a sponge made of elastic foam that has a diameter larger than the inner diameter of the pipe and is made of synthetic resin and has open cells from the end of each branch pipe, and push this sponge with air pressure. A method for lining the inner surface of a pipe, characterized by shaping the lining surface by means of. 2. In the load-deflection characteristic, the synthetic resin sponge has a load of 60 kg or less at 70% deflection and a load of 70% or less at a compression rate of 6 times or less than a load at a compression rate of 10%. When the diameter of the sponge is D, the minimum inner diameter of the pipe is d ₁ and the maximum inner diameter of the pipe is d ₂ , D is 1.0 ×
The lining method according to claim 1, wherein the lining method is a columnar shape having a length of 0.5 x D to 3.0 x D and a length of d ₂ or more, or a spherical shape of D of 1.1 x d _{2 to} 2.0 x d ₁ . 3. In the above-mentioned characteristics of the sponge, the load at a 70% deflection is 10 to 60 kg, and the load at a compression rate of 70% is 1.0 to 6.0 times the load at a compression rate of 10%. If the sponge has a cylindrical shape, D is 1.0 × d ₂ ~
The lining method according to claim 2, wherein the lining method is 3.0 × d ₁ . 4. The sponge has a density of about 10 to 70 kg / m.
The lining method according to claim 1, wherein the lining method is ³ . 5. The sponge is a flexible polyurethane foam,
The lining method according to each of claims 1 to 4, which is made of polyvinyl chloride foam, latex foam, or silicone rubber foam. 6. When the sponge is pushed from the end of the branch pipe by air pressure, the inlet of the main pipe is opened and a small amount of backflow preventing air is sent from the other end of the branch pipe to send the sponge to the main pipe inlet. The lining method according to claim 1, which leads. 7. The lining method according to claim 1, wherein the sponge inserted at the end of the branch pipe is impregnated with a shaping paint in advance. 8. When inserting a sponge into the end of the branch pipe,
The lining method according to claim 1, wherein a shaping paint is preliminarily injected into the end of the conduit.