JPH09206679A - Method for lining inner surface of pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a time for double coating by forming an undercoat film on the inner surface of a pipe in a primary coating process and a finishing film in a secondary coating process when the undercoat film is in a finger-touch dry condition. SOLUTION: When existing piping such as a water supply pipe to which branch pipes are connected through joint parts 2 is subjected to implementation, in the regeneration of the existing piping, after the discharge member of each branch pipe being removed, dirt such as scale in the existing piping is removed by a polishing means, and the inside is made dry and clean. Next, lining is performed in sequence from the terminal side of the piping toward the base end side. First, enough paint to coat one partitioned section is charged at a stroke and extruded by a compressed air flow, and the inner surface of the pipe is coated with the paint transferred. When the primary coating is finished, a weak air flow is passed to make sure of the air-passage condition, and the paint is dried so that it does not adhere to a finger when touched. After that, a finishing film 6 is formed in a secondary coating process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe such as an existing water supply pipe arranged in a building, after removing stains such as rust and scales on the inside and scouring, and then modifying a predetermined paint. The present invention relates to a method in which a slag flow is blown into an annular flow and the inner surface of the pipe is lined twice.

[0002]

2. Description of the Related Art As a technique for lining the inner surface of a pipe twice, for example, the technique disclosed in Japanese Patent Publication No. 4-34463 is well known as a conventional example.

This prior art technique is a method in which a liquid lining material is caused to flow along an inner wall surface of a pipe by an air flow to line the inner wall surface of a branch conduit having a plurality of openings. While sequentially moving the lining material and the airflow supply location while making the location the lining material and the airflow supply location in the next lining, all the openings of the pipeline forming the branch pipeline are at least once the supply location and This is a lining method in which the lining material is reciprocally flowed the same number of times inside all the pipelines forming the branch pipelines, as well as at the discharge point.

[0004]

According to the lining method of the prior art, the paint is reciprocally flowed. In this case, the reciprocating flow is performed while the paint applied by flowing in the outward path is not dried. In addition, the paint on the return path is supplied and fluidized, and the paint supplied on the outward path also flows together with the paint supplied on the return path, and a uniform film cannot be formed by such reciprocating flow. .

That is, even if the coating material previously supplied and applied has a fluid state and a new coating material is supplied and applied twice, the coating film cannot be substantially thickened or made uniform. is there. In particular, if the paint applied to the elbow is in an undried state, the paint at the abutting portion will be washed away and thinned no matter which direction it is made to flow, and a uniform and thick film will not be formed.

Further, since the coating material in this conventional example is supplied by a mixing injector, it is sequentially supplied in the form of a spray, and the viscosity is low and it easily flows. It can be understood that the coating material supplied in the outward path flows back and forth together with the coating material supplied in the return path to form a film as described above, and as a result, the film is formed by the flow in the returning path. As described above, there is a problem that a thick and uniform film cannot be formed.

If, in the above-mentioned conventional example, the drying process is performed for each of the routes (A → B, B → C → D, D → E, etc.) that are divided in the coating process, the drying is performed for each route. There is a problem that it takes too much time and the coating process cannot be applied on the same day.

Therefore, in the above-mentioned conventional example, there is a problem to be solved particularly in forming a thick uniform coating on the same day at a joint portion such as an elbow or a chase at a branch portion where rust is likely to occur. ing.

[0009]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention forms an undercoat coating film on the inner surface of a pipe to be treated by a primary coating process, and the undercoat coating film is dried by touch. In order to provide a lining method for the inner surface of the pipe, which is characterized by forming a finish coating film by a secondary coating process when the condition is reached, the coating process is performed in advance according to the length and inner diameter of the pipe to be treated. An amount of paint capable of forming a set film thickness is added all at once, and the paint is blown sequentially from the modified slag flow to an annular flow by an air flow of a predetermined pressure to form a coating film; Type two-component epoxy resin coating material; the undercoat coating film and the finish coating film are formed into an integral coating film by a cross-linking reaction; and the cheese forming the branch point of the pipe to be treated is a secondary Straight line in the painting process Is intended to include is Risa.

By performing the secondary coating process after the undercoat coating film in the primary coating process is in a dry state to the touch, the undercoat coating film receives the pressure of the air flow in the secondary coating process. A stable coating film state is maintained without fluidization, and the undercoat coating film promotes a crosslinking reaction with the finish coating film in the secondary coating process, so that both are integrated. In addition, the presence of the undercoat coating film allows the flow of the paint in the air flow in the secondary coating process to be performed smoothly, and the secondary coating process can be performed in a relatively short time. Further, since the teeth at the branch points are linearly coated in the secondary coating step, a good thick coating film can be formed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to the illustrated embodiment. In FIG. 1, reference numeral 1 is an existing pipe such as a water supply pipe, and the existing pipe has a joint portion 2 such as an elbow or a chase. A plurality of branch pipes 1a, 1b, 1c, ... Are branched and connected, and the direction of the branch pipes is changed to stand up. A discharge member such as a faucet is generally attached to the end of each branch pipe. There is. In addition, M is an end to which the meter is attached.

When the existing pipe is to be regenerated, the joint portion 2 and the branch pipes 1a, 1 are removed after removing the discharge member of each branch pipe.
The inside of the existing pipe 1 including b, 1c, ... Has been cleaned in advance by removing stains such as rust and scale by an appropriate scouring means and drying the inside.

In the existing pipe 1 whose interior has been cleaned in this way, lining is sequentially performed from each branch pipe from the end side of the pipe to the base end side (end portion M where the meter is attached). In this case, the branch pipes are categorized in a tentative manner. For example, the branch pipe 1a to the branch point X ₁ of the branch pipe 1b is defined as the first section A, and the branch pipe 1b is used.
To the branch point X ₂ of the branch pipe 1c as a second section B, the branch pipe c to the branch point X ₃ as a third section C, and the branch pipe 1d to the meter mounting end portion M of the fourth section
The section D is divided into sections, and the sections are sequentially lined.

In this lining, working pipes for supplying paint are attached to the ends from which discharge members such as faucets are removed, and a quantity of paint capable of coating each of the divided sections is collectively packaged in the working pipe. Then, the coating materials that have been supplied all at once are extruded by a predetermined compressed air flow, and the coating is made to flow while transitioning from the modified slag flow to the annular flow. It should be noted that the amount of paint to be supplied is calculated in advance that the pipe diameter, pipe length and predetermined film thickness of the pipe in each section are formed, and the amount of paint is 1 to more than the calculated amount.
About 30% will be added.

The reason for this is that extra paint is required due to the presence of somebody or the accumulation in the joint.

When the first section A is painted, the paint is made to flow from the free end side of the branch pipe 1a to paint, and it is determined at the end of the branch pipe 1b whether or not the paint reaches the branch point X ₁ . It can be detected by the pressure difference. After the coating of the first section A is completed, the coating of the second section B is performed. In this case as well, the paint is made to flow from the free end side of the branch pipe 1b for coating, and it is detected at the branch point X ₂ whether or not the paint has arrived by the branch pipe 1c.

In this way, also in the third section C, paint is supplied from the free end of the branch pipe 1c to the branch point X ₃ , and
Finally, in the fourth section D, paint is supplied from the free end of the branch pipe 1d to the meter mounting end M. In each section, the coating is done slightly beyond the branch point.

The above-mentioned primary coating is applied in order from the meter mounting end M toward the meter mounting end M side. The meter mounting end M side is opened and the other branch pipe 1
All of a to 1d are coated in a closed state except the one to which the paint is supplied. Of course, it goes without saying that the paint collecting member is attached to the meter attachment end M side.

After the completion of the primary coating, a weak air flow is made to flow from each branch pipe side to check the ventilation state and the coating film is dried. This drying is not complete drying but so-called finger-drying, which is a state in which the coating material is so dry that it does not adhere to the finger when touched with the finger. In such a state, the air flow for painting hardly flows.

After the coating film of the primary coating is dry to the touch, the secondary coating is performed. In this case, although irregular, coating is performed at each branch point of each branch pipe. That is, the branch pipe 1a is substantially X ₃
Since it is branched at, the coating is performed from the branch pipe 1b branched at the branch point X ₁ farthest from the meter mounting portion M. That is, the area from the free end of the branch pipe 1b to the branch point X ₁ is painted. Whether or not the paint has reached this branch point depends on the branch pipe 1a.
It can be checked by detecting the pressure fluctuation at the free end of the.

Then, from the free end of the branch pipe 1c to the branch point X
Paint up to ₂ . Whether or not the paint has reached this branch point can be checked at the free end of the branch pipe 1b or the free end of the branch pipe 1a. Next, the straight line portion including the elbow and the chase from the free end of the branch pipe 1a to the branch point X ₃ is painted all at once. Whether or not the paint has reached this branch point X ₃ can be checked at the free end of the branch pipe 1d. Finally, the free end of the branch pipe 1d to the meter mounting end M is painted.

By applying the coating up to the branch points of the branch pipes in this way, the cheeth portions forming the branch points are each linearly coated, so that a relatively thick and uniform coating film can be formed. Of.

In these secondary coatings as well, the coating is performed under substantially the same conditions as in the primary coating, and the pipe diameter, pipe length, coating thickness, etc. of the section to be coated are calculated in advance to determine the amount of coating. It is determined and added in an amount of about 20 to 40% more, and the coating is made to flow while transitioning from the metamorphic slag flow to the annular flow by the compressed air flow.

In this secondary coating, even if the same coating is used, the primary coating is applied first, so that the flow of the coating including the branch point and the straight pipe portion is faster, and the coating is shorter than the primary coating. Now you can paint. Therefore, by shortening the coating time, the spread of the coating material by the air flow is reduced, and a thick coating film is formed as a whole.

By carrying out the primary coating and the secondary coating in this way, as shown in FIG. 2 and FIG. 3, the joint portion 2 such as the elbow 3 and the chase 4 in the pipe can be coated well. It will be.

That is, in the elbow 3 and the cheath 4, the finish coating film 6 formed by the secondary coating is overlapped and integrated on the surface of the undercoat coating film 5 formed by the primary coating, and especially the elbow 3 is curved. The predetermined area 3a on the inside of the outer bulging portion becomes the abutting portion regardless of the direction of the air flow, so that the paint adhered (painted) to the area 3a is easily blown off by the strong air flow that abuts. Because of this, it is a thick part that cannot be painted.

With respect to the cheese 4, the portion of the area 4a corresponding to the T-shaped top portion is also the portion against which the airflow supplied from the branch pipes (1b, 1c) side abuts, and in that portion of the area 4a. It is difficult to form a thick coating film.

However, these areas 3a, 4a
Also in the above, the undercoat coating film 5 formed by the primary coating and the finish coating film 6 formed by the secondary coating provide a coating film having a predetermined thickness. In other words, after finishing the primary coating process,
The finish coating film 6 is overcoated by the secondary coating process on the undercoat coating film 5 that has been dried by touch with the finger, so that the sum of both coating films provides a coating film having a predetermined thickness. In particular, in the case of the cheath 4, a thick coating film is relatively reasonably formed because of the straight coating in the secondary coating, and the corrosion resistance is excellent.

In this case, in order to facilitate understanding in the illustrated embodiment, the undercoat coating film 5 and the finish coating film 6 are shown separately, but the undercoat coating film 5 is dry to the touch and completely Since it is not in a dry state, the cross-linking reaction is promoted between the secondary coating and the finish coating film 6, and there is substantially no boundary between the undercoat coating film 5 and the finish coating film 6. It becomes almost integrated and is formed as one coating film.

The paint used here is preferably a two-part epoxy resin paint comprising a solvent-free base material and a curing agent. Then, the crosslinking reaction is promoted when the main agent and the curing agent are mixed, but the lining is performed after a predetermined time has elapsed.
The predetermined time in this case is, for example, in the range of about 10 to 30 minutes, although it depends on the viscosity and the Ti value of the paint.

In any case, a primary coating process and a secondary coating process are performed on a pipe of a predetermined length to be lined to form a coating film of a predetermined thickness, which is a primary coating process. Secondary coating is performed when the coating film formed by the process becomes dry to the touch, which can significantly reduce the coating time and work even with double coating, enabling the same day construction. It will be.

[0032]

As described above, according to the pipe inner surface lining method of the present invention, an undercoat coating film is formed on the inner surface of a pipe to be treated by a primary coating process, and the undercoat coating film is in a touch-free state. By the way, the finish coating is done by the secondary coating process, and since the undercoat coating is dry to the touch, even if the secondary coating process is carried out, the undercoat coating film is still produced by the air flow of the secondary coating. Is stable and does not flow, and a finish coating film is formed on it by the secondary coating process, so not only the coating film of the intended film thickness can be obtained, but also the coating can be done even by double coating. The time or working time is remarkably shortened, so that the lining of the pipe inner surface can be performed on the same day, which is an excellent effect.

Further, by superimposing the coating film of the finish coating on the coating film of the undercoating in a dry state to the touch, the cross-linking reaction between the coating films is promoted and the coating film becomes an integral effect. Play.

Further, the existing pipe, that is, the portion forming the branch point of the pipe to be treated is linearly coated in the secondary coating step, so that a good thick coating film can be formed.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a state of an existing pipe for explaining a pipe inner surface lining method according to the present invention.

FIG. 2 is an enlarged sectional view showing an elbow portion of an existing pipe lined by the lining method.

FIG. 3 is a cross-sectional view showing, in an enlarged manner, a cheese portion of an existing pipe lined by the lining method.

[Explanation of symbols]

1 Existing piping 1a, 1b, 1c, 1d Branch pipe 2 Joint part 3 Elbow 3a, 4a Area 4 Cheese 5 Undercoat coating film 6 Finish coating film A, B, C, D Temporarily divided section X _{1 to} X ₃ Branch points

Claims (5)

[Claims] 1. An undercoat coating film is formed on the inner surface of a pipe to be treated by a primary coating process, and a finish coating film is formed by a secondary coating process when the undercoat coating film is dry to the touch. How to lining the inner surface of the pipe. 2. In the coating step, a quantity of paint capable of forming a film thickness set in advance corresponding to the length and inner diameter of the pipe to be treated is put all at once, and the paint is transformed by an air flow of a predetermined pressure. 2. The pipe inner surface lining method according to claim 1, wherein the coating film is formed by sequentially blowing the slag flow into an annular flow. 3. The pipe inner surface lining method according to claim 1, wherein the paint is a solventless two-part epoxy resin paint. 4. The pipe inner surface lining method according to claim 1, wherein the undercoat coating film and the finish coating film are formed into an integral coating film by a crosslinking reaction. 5. The pipe inner surface lining method according to claim 1, wherein the teeth forming the branch points of the pipe to be treated are linearly coated in the secondary coating step.