JPS6223482A - Method for coating inner surface of pipeline - Google Patents

Abstract

PURPOSE:To uniformly form a film, by using two non-mixing type liquid adhesives as a coating material and applying either one of said liquid adhesives to a pipeline to form a film and subsequently filling said pipeline with the other liquid adhesive before performing air blow. CONSTITUTION:Air blow is applied to the interior of a pipeline (a) so that a part of a primer 1 remains in a state adhered to the inner surface of the pipeline (a) in a thin film form to form a thin primer film 2a. Subsequently, the pipeline (a) is filled with a main agent 7 and lids 8' are applied to both pipe openings of the pipeline (a) to hold a closed state until the main agent is reacted and cured at the contact boundary interface with the thin film 2a. Thereafter, the lid 8' are detached and air blow is applied to discharge and recover the excessive main agent 7 to form a film 11 on the inner surface of the pipeline (a). By this method, the film can be uniformly formed to the pipeline over the whole thereof without irregularity.

Description

[Detailed description of the invention] The present invention relates to a method for painting the inner surface of a pipe.

Conventional methods for painting the inner surface of pipes include the pick method, in which the coating material is deposited on the inner surface of the pipe while moving the elbow inside the pipe using fluid pressure or traction force, and the air injection method, in which the coating material is blown out with air. A method has been proposed.

However, with the elbow method, there is no particular problem when applied to straight pipes of the same diameter, but when the pipes are complex and have different diameters, such as indoor city gas piping, Since the pipe cannot be moved in a circle at the same time, it is necessary to make a large number of cutting recesses, which has the disadvantage of lacking workability. In addition, the air injection method has a good overflow inside the pipe, but has the disadvantage that the state of coating film formation tends to vary and the reliability of the coating is lacking.

The present invention has been made with the aim of eliminating such conventional problems.

The present invention uses a two-component non-mixable adhesive as a coating material, fills the pipe with liquid A (or three liquids), and then blows air to coat the inner surface of the pipe with liquid A (or liquid B). ), then fill the pipe with liquid B (or liquid A), and
%3 This relates to a method for painting the inner surface of a pipe, which is characterized in that both liquids are reacted and cured at the contact interface, and then the excess liquid B (or liquid A) is discharged from the inside of the pipe by air blowing.

An embodiment of the construction method of the present invention will be described below based on the accompanying drawings.

In the method of painting the inner surface of a pipe according to the present invention, a two-component non-mixable adhesive is used as the coating material. This two-component non-mixable adhesive itself is well known; for example, a primer type and a two-component main adhesive type are commercially available, both of which can be used, but the primer type is particularly preferred.

Zurimer type adhesive is divided into basic rules and zurimer,
Due to the action of the primer, the main principle causes a chemical reaction and hardens. Generally, the main rule is that the elastomer, the acrylic heptamine, the curing catalyst and the stabilizer are comprised, while the primer is the curing co-catalyst and is mainly composed of peroxide.

This two-component formulation still contains an elastomer component such as nitrile rubber in both Part A and Part B, and Part A contains a curing catalyst,
Part B contains a curing accelerator. This adhesive is A
Agent and Agent B have approximately the same viscosity.

The case where the method of the present invention is implemented using a primer type adhesive will be explained below.

The pipe (a) includes a drinking pipe (a□) and two branch pipes (a2) with a smaller diameter than the main pipe (a□), and within this pipe (a), the pipe shown in FIG. Fill the primer (2) from the direction of the arrow (1) as shown in Figure 2.
) The size of the limer (2) filled inside the pipe (a) is removed by air blowing under conditions such that a part of the limer (1) remains as a thin film on the inner surface of the pipe (a). Place the portion in a tank (4
), (5) and (6). Primer(
1) has low viscosity and good adhesion to the inner surface of pipe (a), so
A thin film (2a) of the primer can be uniformly formed over the entire surface of the pipe (a).

Next, as shown in FIG. Until the reaction hardens in
For example, hold it as it is for about 10 to 60 minutes.

After 10 to 60 minutes have passed, that is, after the main rule (7) has sufficiently reacted and hardened at the contact area with the primer thin film (2a), M(
Remove 8), turn on the air, and follow the basic rule of excess (7).
By discharging and collecting into tanks (8), (9) and 00,
A coating film αυ made of a cured adhesive can be formed on the inner surface of the pipe (a). In this case, a small amount of unreacted and uncured primer remains on the inner surface of the coating film, so the primer is refilled in the pipe (a) to harden the remaining primer. Alternatively, post-treatment can be performed without or after refilling the limer, such as washing the inner surface of the pipe with a suitable washing liquid. The order of filling the primer and the mains may be reversed from the illustrated example, such as the mains and then the primer.

When using a two-component coating material, it is desirable to use one with as low a viscosity as possible in consideration of adhesion to the inner surface of the pipe, and if there is a difference in viscosity between Part A and Part B, It is preferable to fill the one with lower viscosity first.

In this way, in the construction method of the present invention, a two-component non-mixable adhesive is used as the coating material, and a method is adopted in which the adhesive is filled into the pipe to form a coating film. Even if the route is a complex piping system that includes many bends, branches, and sections with different diameters, it is possible to
It can be applied over a wide area at once, improving workability.

Furthermore, since the coating material is cured by contact with the filling material, it is possible to form a coating film evenly and uniformly over the entire pipeline, even for complex pipelines, and a coating film of good quality can be formed.

Furthermore, since the coating material is a two-component non-mixable type, there are no restrictions on pot life and it is easy to work with, and it also has the advantage of being able to form a coating film in a short time because it reacts and cures immediately upon contact.

Furthermore, the coating material penetrates into the corroded holes and gaps between the joints of the pipes and reacts and hardens, sealing them and the reaction hardening takes place quickly, so there is no chance of air leaks occurring at the same time. It is possible to reliably repair the pipeline without any problems.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4 are schematic explanatory diagrams showing an embodiment of the construction method of the present invention in the order of steps. In the diagram, (2) hazu limer, (7) is the main rule, (8)
is the lid, and (11) is the coating film. (The above) Agent: Patent attorney Eiji Saegusa ・”−2”・
″：

Claims (1)

[Claims] (1) Using a two-component non-mixable adhesive as a coating material, fill the pipe with liquid A (or liquid B) of the adhesive and then blow air to coat the inner surface of the pipe with liquid A (or liquid B). Form a thin coating film, then fill the pipe with liquid B (or liquid A), react and cure both liquids A and B at the contact interface, and then blow with air.
A method for painting the inner surface of a pipe, which is characterized by draining excess liquid B (or liquid A) from inside the pipe.