JP2975461B2 - Lining method of pipe inner surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to an improvement in a method for lining a pipe inner surface of various pipes such as a water pipe and 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
A method of blowing a paint into a pipe by air flow and lining it is widely used for rehabilitation of water pipes and gas pipes, and is described in, for example, JP-A-2-68177.

[0003] In this technique, if the viscosity and the air velocity of the coating material are properly selected and a coating material having good dripping characteristics is used, very good lining can be performed. However, in this method, the only problem that is difficult to solve is that the lining film thickness on the back of the elbow tends to be thin.

[0004] This is because, when the air current collides with the back of the elbow and the direction is changed, the film spreads strongly, and it is difficult to secure a practically necessary film thickness in the range of the air flow rate required by the air flow method. is there.

[0005] In addition, in this method, if the coating conditions such as the flow rate are incorrect, there may be a problem that the coating film becomes thicker or thinner than necessary. As a method of solving these problems, a method of smoothing and correcting the thickness of a coating film through a shaping pig while the coating material is not cured after coating by an air current method has been performed (for example, Japanese Patent Application Laid-Open No. Sho 62-266178). No.
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. Pigs are used. Therefore, in this method, the pig has a size corresponding to the minimum size of the target pipe, so that when the pipe size is different, there is a problem that a sufficient effect cannot be obtained in a portion having a large size. In addition, since the pig is moved from the large-sized main pipeline to the small-sized branch pipeline, the pig does not enter the branch pipeline at the branch portion, so that the pig easily moves straight through the main pipeline.

As a solution to this problem, Japanese Patent Laid-Open Publication No.
The publication proposes a method in which the pig is pushed from the opposite side of the main pipeline with air to guide the pig to the branch pipeline (see FIG. 4, where 1 is a main pipe and 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. Even if the pig is pushed by the airflow from the opposite side of the main pipeline at the branch portion, the paint accumulated before the pig is also removed. It is easy to move to the main pipe on the opposite side without entering the branch pipe due to inertial force. Since the pig is pushed by the airflow from the other side of the main pipe, the pig that moved to the other side is pushed back and moves to the branch pipe soon, but the paint pushed by the pig is hardened and left thick in the main pipe. Therefore, it is out of the purpose of shaping the inner surface.

Further, Japanese Patent Application Laid-Open No. 1-304086 discloses a method in which a paint is placed in front of a pig and pressed with gas from behind the pig, instead of shaping a coating film lined by an air flow method. States that when the size of the branch conduit is smaller than the main conduit, the outer diameter of the pig is reduced by compression.

However, since the properties of the pig are not further defined, it is doubtful whether the required coating thickness will be formed by the reduced diameter pig. The purpose of the present invention is
It is an object of the present invention to solve the above-mentioned problems in the prior art and to provide a lining method for an inner surface of a pipe which can be formed into a substantially uniform film thickness even in a lining of a manifold pipe having a different size, particularly, an elbow portion.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-purpose pipe in which a plurality of branches are branched from a main pipe, after injecting paint into the pipe from one end of the main pipe or each branch pipe.
The lining of the inner surface of the pipe is constructed by introducing gas, and then a sponge made of an elastic foam made of synthetic resin and having open cells, having a diameter larger than the inner diameter of the pipe from the end of each branch pipe. inserted, then it can be achieved by lining method of the present invention by pressing the sponge in air pressure.

Specific examples of the synthetic resin sponge used in the method of the present invention include polyurethane foam, polyvinyl chloride foam, latex foam, silicone rubber foam and the like. Among these sponges, load-deflection characteristics are preferable. The load at the time of 70% deflection is 60 kg or less, preferably 10 to 60 kg, more preferably 20 to 40 kg, and the load at a compression ratio of 70% is 6 times or less the load at a compression ratio of 10%, preferably, 1.0
特性 6.0 times, more preferably 1.0 to 3.0 times, and the dimensions (and shape) are as follows: the diameter of the sponge is D, the minimum diameter of the pipe is d ₁ , and the maximum diameter of the pipe is To d ₂
D is 1.0 × d ₂ or more, preferably 1.0 × d ₂
× d _{2 to} 3.0 × d ₁ , more preferably 1.1 × d ₂ to
Length at 2.0 × d ₁ satisfies a condition that is cylindrical or D is 0.5 × D~3.0 × D is spherical is 1.1 × d ₂ ~2.0 × d ₁ Are preferred.

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. Molded sponge outer shaped as a cylindrical sponge is facilitated, preferable because inexpensive to produce.

The synthetic resin foam constituting the sponge preferably has a density of about 10 to 70 kg / m ^{3 in} order to exhibit the effects of the present invention. When the sponge satisfies the condition that the load at the time of 70% deflection in the load-deflection characteristic is 60 kg or less, the stress generated in the radial direction of the sponge is even smaller. Further, the load at a compression rate of 70% is 6 times or less the load at a compression rate of 10%, and the change in the load due to deformation is even 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 when the pipe becomes thin, so that the lining surface of the whole pipe can be shaped more uniformly.

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

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

This step is more preferably performed by opening the inlet of the main pipe line and sending a small amount of backflow preventing air from the other branch pipe end to guide the sponge to the main pipe inlet port. The result is obtained.

Therefore, the method of the present invention provides the best results when the above operation is performed using a sponge which satisfies the above-mentioned characteristics and dimensional conditions. The coating used in the method of the present invention may be any of those conventionally used in the lining method of the inner surface of the pipe, and examples thereof include an epoxy resin coating. When lining the inside of a pipe with such a paint, air is usually used as a gas, but an inert gas such as nitrogen can also be used. In this case, the pressure (or flow rate) of the gas can vary depending on the inner diameter of the pipe, the length of the pipe, and the like, but is generally about 1.0 to 5.0 atmospheres.

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 runs inside the painted pipe while the paint is not cured. When this is performed, the state becomes the same as when the inside of the tube is painted with a so-called sponge brush, and the excess paint on the tube wall is sucked by the sponge and a new film can be formed in a thin portion of the film.

Particularly in the elbow portion, when the sponge changes direction, the sponge is strongly pressed against the tube wall, so that the paint contained in the sponge is pushed out excessively to form a thick coating film. In the present invention, if necessary, the sponge can be impregnated with a paint for shaping in advance, or the sponge can be pushed in after the paint for shaping has been put in the end of the pipeline in advance. In any case, the amount of the paint for shaping is suitably 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 presses the wall surface becomes substantially constant.

Therefore, the lining surface can be formed into a uniform film thickness with the sponge, and the sponge does not scrape off a part of the lining surface. The above was confirmed by the following experiment.

That is, two sponge-like elastic bodies are prepared (one has open cells and can be impregnated with a paint, and the other has discontinuous cells and cannot be impregnated with a paint), and one of them contains a paint. On the other hand, when the painted surface immediately after painting was slid while pressing with the same compressive force without containing the paint, in the former case the paint film could be held, whereas in the latter case the paint was scraped off .

This means that the principle of shaping the coating film according to the present invention is disclosed in Japanese Patent Application 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 Patent Application Publication No. 74 (1994).

That is, the conventional pig has no function of absorbing the paint, but forms the coating simply by adjusting the gap between the pig and the pipe wall. It is.

After lining by the airflow method as described above, when the sponge of the present invention is pushed and moved with air in a range where the compressive force is substantially constant, as described above, the surface of the coating film is smoothed and substantially uniform. Become thick. In addition, it was found that a thicker coating film was formed on the back surface of the elbow by the passage of the sponge in the elbow portion.

The range of sponge strain of 10% to 70% covers, for example, three sizes in terms of JIS pipe size, so that the case of ordinary door-to-door water pipes using pipes of 15A to 25A is used. Applicable to and very effective.

When the sponge is inserted from the end of the branch line and moved toward the main line, the sponge is usually connected to the side of the main line at the branch point from the main line. There is no choice but to bend in either left or right direction, and it is ensured that only a slight air flow is formed from the upstream side to be shifted to the opening side of the main pipeline (see FIG. 2, where 1 is the main pipe and 1A is the main pipe). Branch pipe). After that, the sponge can be reliably guided to the opening of the main pipeline only by entering a small amount of air for preventing backflow into the branch pipeline on the way because it is only necessary to go straight in the main pipeline.

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

[0030]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 3 shows a general load-deflection curve of the elastic foam material constituting the sponge used in this example.
This figure is 300mm long x 300mm wide x 50m high
FIG. 4 is a diagram showing, as a percentage, the amount of deflection when a plate having a diameter of 200 mm is placed on a soft urethane foam of m and compressed, and a load is applied thereon at a compression speed of 50 mm / min.

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

Next, an embodiment of the method of the present invention using such a sponge will be described. FIG. 1 is a view for explaining an embodiment 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 line 1 of the water supply pipe is provided with a line 5 which is a kind of branch line at the end, and a branch line is provided between the line 5 and the other end 2 of the main line 1. Conduits 10A, 10B,
10C and 10D are connected.

In preparation for the lining operation, the water meter is removed from the other end 2 of the main pipe 1, and the faucet is removed from the one end 6 of the pipe 5 and the ends 11A to 11D of the branch pipes 10A to 10D. At one end 6 and ends 11A to 11D, a connection pipe with an opening facing upward is added, and this opening is formed so that an air hose can be attached and detached. An air hose 25 connected to one end 6 of the pipe line 5 has , A pressure gauge 24 and a valve 23, and air gauges 25A to 25D connected to ends 11A to 11D of the branch pipes 10A to 10D, respectively.
A to 24D and valves 23A to 23D are connected,
3A to 23D were connected to an air compressor 20 via a flow meter 22 and a dehumidifier 21 in that order.

The size of each pipe is 25A in JIS nominal diameter from 2 to 12A of the main pipe, branch pipes 5 and 10A to 1A.
0D has a nominal diameter of 20A and a portion connected to the faucet at the end is 1
A 5A x 20A different diameter elbow is attached.

For lining, pipes 5 and 10A
A required amount of epoxy resin paint is poured from the end of the 10D to 10D with a measuring cup and painted toward the main conduit side. For this coating method, a method described in JP-A-2-68177 was used.

As soon as the coating of all pipelines is completed, the density is 20K.
30m diameter made of a soft polyurethane foam of g / m ³
A cylindrical sponge having a length of 50 mm and a length of 50 mm is inserted into the connecting pipe used for injecting the paint at the end of the pipe line 5, and the hose 25 is connected.

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

Next, a similar sponge is inserted into the connecting pipe at the end 11A of the branch pipe 10A, backflow preventing air is injected into the other branch pipes, and the sponge is sent in the same procedure to feed the sponge into the other main pipe.
Collect from end 2.

Thereafter, a sponge is passed through all branch pipes in the same manner. As a result, when the airflow method alone was used, the thickness of the coating on the back of the elbow was 0.3 mm or less, but the thickness of the back on all elbows was 0.3 m by passing through a sponge.
m to 1.0 mm could be secured. The thickness of the coating film other than the elbow portion was 0.3 to 2.0 mm.

Further, the movement of the sponge to the other end 2 of the main pipe was very smooth, and no anxiety was felt. Instead of a cylindrical sponge, a spherical sponge having a diameter of 30 mm made of a flexible polyurethane foam (a load at the time of 70% deflection is 25 kg, and a load at a compressibility of 70% is 5 times a load at a compressibility of 10%) is used. When the same operation was performed, the same result as that of the present example was obtained.

[0042]

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

[Brief description of the 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 pipe of an apartment.

FIG. 2 is a view 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 pipe to a branch pipe.

[Explanation of symbols]

P · · · · · sponge, 1 · · · · main pipeline, 5, 10A
-10D ····· Branch pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B05D 1/00-7/26 B05C 7/08 B05C 7/04

Claims (8)

(57) [Claims] A lining of a pipe inner surface by injecting paint into a pipe from one end of the main pipe or one of the branch pipes and then feeding a gas into a manifold pipe in which a plurality of branch pipes are branched from the main pipe. After that, from the end of each branch conduit, insert a sponge made of an elastic foam having a diameter larger than the inner diameter of the tube and made of synthetic resin and having open cells, and press the sponge with air pressure. A lining method for an inner surface of a pipeline, wherein the lining surface is shaped by the method. 2. The synthetic resin sponge has a load-deflection characteristic such that the load at 70% deflection is 60 kg or less, and the load at 70% compression is 6 times or less the load at 10% compression. 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 ×
Lining process according to claim 1 wherein the length in d ₂ or more is cylindrical or D is 0.5 × D~3.0 × D is 1.1 × d ₂ to 2.0 spherical × d _1. 3. The sponge according to the above characteristics, wherein the load at 70% deflection is 10 to 60 kg, and the load at 70% compression is 1.0 to 6.0 times the load at 10% compression. , And when the sponge is cylindrical, D is 1.0 × d ₂ ~
3.0 lining method according to claim 2, wherein a × d _1. 4. The sponge has a density of about 10 to 70 kg / m.
³ a lining method according to claim 1, wherein the. 5. The sponge is a flexible polyurethane foam,
The lining method according to any one of claims 1 to 4, wherein the lining method comprises a polyvinyl chloride foam, a latex foam, or a silicone rubber foam. 6. When the sponge is pressed from the end of the branch pipe by air pressure, the sponge is opened to the main pipe inlet by opening the inlet of the main pipe and sending a small amount of backflow preventing air from the other branch pipe end. 2. The lining method according to claim 1, which leads. 7. The lining method according to claim 1, wherein the sponge inserted into the end of the branch pipe is impregnated with a shaping paint in advance. 8. When inserting a sponge into a branch pipe end,
2. The lining method according to claim 1, wherein a shaping paint is previously injected into the pipe end.