JPH02298388A - Method for painting branched pipeline - Google Patents

Abstract

PURPOSE:To perform painting of high quality by employing a process wherein the terminal of a branch pipe is closed and a main pipe is painted from one end thereof toward the other end and a process wherein the other end of the main pipe is closed to apply painting from one end of the main pipe toward the terminal of the branch pipe. CONSTITUTION:In such a state that the terminals of respective branch pipes are closed by plugs 15, 16, 17, the respective different diameter parts of a main pipe 1 are painted from a small diameter part 2 toward a large diameter part 4. When the outflow of paint from the terminal of the large diameter part 4 is confirmed, it is judged that the painting of the main pipe 1 is completed. Then, the terminal of the large diameter part 4 is closed by a plug 14 and the plug 17 of the branch pipe 7 on the side of the large diameter part 4 is detached to reopen painting. Next, the terminal of the branch pipe 7 is again closed by the plug 17 and the plug 16 of the terminal of the branch pipe 6 is detached to perform the painting of the branch pipe 6. By this method, an inner surface can be painted uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a method for painting the inner surface of a branch pipe in pipe rehabilitation work and the like.

<Prior art> As a pipe rehabilitation method, the inner surface of the pipe is polished by sandblasting etc., and then the inner surface is painted with epoxy resin etc. to rehabilitate such pipes, which are used for example as water pipes. The technology is known. However,
Actual water pipes consist of a main pipe and a large number of branch pipes branching from the main pipe, and it has been difficult to uniformly apply paint to the inside of the pipe. For example, as described in Japanese Patent Publication No. 62-8233, in a method in which paint is poured into a pipe to be painted all at once, paint tends to flow excessively toward the branch pipe side. From the point at which paint is seen flowing out at the end of each branch pipe, and it is determined that the painting of the branch pipe is complete, the paint is returned to the main pipe by blowing air from the end of the branch pipe. Accordingly, a technique has been proposed to prevent paint from being biased towards the branch pipe side. However, according to this construction method, the paint initially introduced into each branch pipe and returned to the main pipe is repeated until it reaches the downstream end of the main pipe. As the curing progresses, problems may occur, such as insufficient coating at the downstream end of the main pipe or, conversely, an excessive coating thickness at the downstream end of the main pipe.

JP-A-60-7974 discloses, as a second invention, a method for painting a pipe having a main pipe made of a reuse pipe and a large number of branch pipes branching from the main pipe. Air is introduced from the middle of the reuse pipe, and air, which tends to be insufficient when sequentially painting each branch pipe or each different diameter portion of the main pipe, is introduced from the small diameter end of the main pipe. According to this method, the paint is generally introduced from the middle of the longest main pipe, which has the advantage of reducing the distance the paint travels, but it is difficult to paint the different diameter parts of the branch pipe or each branch pipe. necessary for a m M';l
It is necessary to accurately feed the nails at each point, which poses a problem in workability.

<Problems to be Solved by the Invention> In view of the problems of the prior art, the main purpose of the present invention is to provide a coating method for branch pipes that is easy to implement and can provide high-quality coating results. The purpose is to provide a method.

[Structure of the Invention] Means for Solving the Problems According to the present invention, such problems can be solved by using a method in which the inner surface of a pipe line consisting of a main pipe and a plurality of branch pipes branching from the main pipe contains a curable resin. A method for coating with a gas-liquid mixture, the method comprising:
closing the end of the branch pipe and painting the main pipe from one end to the other; closing the other end of the main pipe; ! Open the branch pipe located on the end side,
A process of painting from one end of the main pipe to an end of the branch pipe, and a process of closing the end of the branch pipe closest to the other end, and applying the paint to the end of the branch pipe located closer to the one end than that. The process of painting from the one end of the main pipe and the process described above are repeated, and after all the branch pipes have been painted, air is sent from the one end of the main pipe and the end of each branch pipe to the other end of the main pipe. This is achieved by providing a method for painting a pipe, which comprises the steps of:

<Operation> As described above, according to the present invention, the amount of paint considered necessary for painting the pipe body is simply supplied into the pipe line over a certain period of time, and the paint is applied to the pipe line body. By supplying air all over the body and having a final air supply process, it is possible to eliminate the formation of paint pools, and it is possible to easily and high-quality paint.

Embodiments The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

Figures 1 to 5 show the method for painting inside a pipe according to the present invention, and the target pipes are a small diameter part 2, a medium diameter part 3
, a main pipe 1 consisting of a large diameter part 4, and branch pipes 5.6.7 branching from each of these parts. Generally, for example, in medium- and high-rise residential buildings, a main pipe 1 is installed vertically, and a branch pipe branches off from the main pipe for each floor. In this case, the paint is made of a two-component epoxy resin, and is cured by being supplied from a resin mixing device 8 equipped with a metering pump, such as the one disclosed in Japanese Patent Application No. 62-023541N filed by the same applicant. For example, in a patent application filed in 1982 by the same applicant,
Using a device such as that described in No. 069870, it is atomized and introduced into the pipeline together with compressed air.

When painting the inside of the pipe, first, with the ends of each branch pipe closed with plugs 15, 16, and 17, the different diameter portions of the main pipe 1 are painted from the small diameter portion 2 to the large diameter portion 4.

At this time, since the flow velocity inside the pipe is high in the pipe on the side of the small diameter part 2, the coating film thickness in this part is relatively small.
On the contrary, the coating film thickness in the large diameter portion 4 is relatively large.

If it is confirmed that the paint flows out from the end of the large diameter part 4,
It is judged that the painting of the main pipe 1 is almost completed, and as shown in FIG. Resume painting. In this way, when it is confirmed that the paint has flowed out from the end of the branch pipe 7, the painting of the branch pipe 7 is completed.

Next, as shown in FIG. 3, plug the end of the branch pipe 7 into the plug 1.
7, the plug 16 at the end of the branch pipe 6 is removed, and the branch pipe 6 is painted in the same manner. Furthermore, as shown in FIG. 4, the branch pipe 5 is painted in the same manner as described above.

At this time, since the coating is repeated on the small diameter part 2, it is necessary to compensate for the fact that the coating film thickness on the small diameter part 2 was small during the process shown in Figure 1, and as a result, To,
The coating is uniform throughout. In addition, the amount of air to be introduced should be determined according to the maximum diameter portion of the pipe through which air should flow in each process, and in the case of this example as well, the amount of air introduced in Figs. It is preferable to sequentially reduce the air flow rate in each process.

Finally, as shown in Fig. 5, all the plugs 14 to 17 are removed, and drying air is introduced at an appropriate speed from the small diameter q of the main pipe 1 (and from the ends of each branch pipe 5 to 7) to remove the paint stagnation. etc., and accelerates the curing of the resin.

As described above, according to the present invention, it is possible to judge whether the painting of each part is completed by checking the outflow of paint from the end of each part, and therefore it is possible to avoid insufficient painting.
Moreover, since the residence time of the paint in the tube is short, the required coating is completed before the paint hardens, so the coating thickness will not be too large or too small, and the final Uniform coating film thickness is preferably achieved by drying with gentle air.

[Effects of the Invention] According to the present invention, the inner surface of the pipe can be uniformly coated using a relatively simple procedure, and the effect is extremely large.

[Brief explanation of drawings]

1 to 5 are piping diagrams showing each painting process to show the procedure of the painting method based on the present invention. 1... Main pipe 2... Small diameter section 3... Medium diameter section 4... Large diameter section 5-7... Branch pipe
8...Mixing device 14-17...Plug patent applicant NIR Equipment Co., Ltd. Agent
Person Patent Attorney Yo Oshima - Figure 5

Claims (2)

[Claims] (1) A method for coating the inner surface of a pipeline consisting of a main pipe and a plurality of branch pipes branching from the main pipe with a gas-liquid mixture containing a curable resin, the method comprising: closing the end of the branch pipe; a process of painting the main pipe from one end to the other end; closing the other end of the main pipe and opening the branch pipe located closest to the other end; starting from one end of the main pipe to the end of the branch pipe; a step of closing the end of the branch pipe closest to the other end, and painting from the one end of the main pipe toward the end of the branch pipe located closer to the one end; The method further comprises a step of repeating the above process and, after finishing painting all the branch pipes, supplying air from the one end of the main pipe and the end of each of the branch pipes to the other end of the main pipe. How to paint pipes. (2) The method for painting a pipe line according to claim 1, characterized in that the amount of air fed is sequentially reduced in each of the steps.