CN102527623A - Method for coating inner wall of bent and abnormally-shaped pipeline with small aperture by using painting - Google Patents

Abstract

The invention relates to a method for coating the inner wall of small-diameter and curved special-shaped pipelines with paint. The method includes the following steps: (1) pulling an inflatable ball with a rope tied at one end into the pipeline from an port of the pipeline, blocking the port of the pipeline, and pulling the free end of the rope out of the pipeline. (2) inject paint into the pipeline from the other unblocked port of the pipeline to above the inflatable ball in the pipeline; ( 3) Pull the free end of the rope at a constant speed to make the inflatable ball pass through the entire pipeline. The invention is not affected by the viscosity of the coating, and can conveniently, uniformly and smoothly coat various anti-corrosion coatings on the inner wall of the pipeline that needs to be protected, and the construction cost is low. The challenge of painting effectively.

Description

A method of coating the inner wall of small-diameter and curved special-shaped pipes with paint

technical field

The invention relates to a paint construction method for the inner wall of a pipeline, in particular to a method for coating the inner wall of a small-caliber, curved special-shaped pipeline with a paint. the

Background technique

In the process of pipeline installation, in most cases, no anti-corrosion treatment is performed on the inner wall of small-diameter and curved special-shaped pipelines, so the pipeline has poor corrosion resistance, short service life, and shortened maintenance cycle. In order to solve this problem, the current method is dipping or pouring, which is to apply low-viscosity paint on the inner wall of the pipeline, but this method is limited by the viscosity of the paint, and the coating film is not uniform, and the protective effect is not ideal.

The existing method of coating the inner wall of the pipeline is the double-ball walker extrusion lining method, which first sprays the paint into the pipe with an injector, and then launches the first ball walker into the pipe after the paint is sprayed, and the nitrogen drives it. Move toward the front end of the tube. After that, the paint is sprayed into the tube, and the second ball walker is launched into the tube after the material is stopped. This method squeezes the paint from one end of the pipeline to the other by spraying the paint twice and putting in a ball walker. Although it can coat the inner wall of the pipeline with paint, the process is complicated, and the requirements for surface preparation, paint selection and extrusion process are very high. It is very strict, and it is also affected by the radius of curvature of the pipe turning (the radius of curvature of the pipe turning should not be less than 5 times the pipe diameter).

Chinese Patent Publication No.: 101773891A discloses a small-diameter metal pipe inner wall spraying device and process, which is to directly extend the spray gun into the metal pipe, and carry out coating by moving the spray gun and heating device. The coating used in this invention is thermoplastic Powder coatings and thermosetting powder coatings. And only the inner wall of the straight small-diameter metal pipe can be painted, and the small-diameter pipe with curved shape cannot be painted, and the powder coating used needs to be heated, and the construction procedure is complicated.

Therefore, it is necessary to provide a method for coating the inner wall of small-diameter and curved special-shaped pipes with paint to solve the above problems.

the

Contents of the invention

The purpose of the present invention is to provide a method for conveniently and uniformly coating various paints on the inner wall of small-diameter and curved special-shaped pipes.

Aiming at the shortcomings of the coating construction method for the inner wall of small-diameter and curved special-shaped pipes in the prior art, the inventors, after research and practice, proposed a method of coating on the inner wall of small-diameter and curved special-shaped pipes (length less than 6m, inner diameter 30mm ~ 100mm). A pumping construction method of liquid paint, which has a unique effect on the inner wall coating of curved special-shaped pipes.

For realizing above-mentioned purpose of the invention of the present invention, the present invention adopts following technical scheme:

A method for coating the inner wall of a small-caliber, curved special-shaped pipe with paint, the method includes the following steps: (1) Pull an inflatable ball with a rope tied at one end into the pipe from one port of the pipe, and block the pipe the port of the pipe, and pass the free end of the rope from the pipe to the other port of the pipe; (2) from the other port that is not blocked to the pipe Injecting the paint above the inflatable ball in the pipeline; (3) pulling the free end of the rope at a constant speed so that the inflatable ball passes through the entire pipeline.

Wherein, the diameter of the inflatable ball is 1.1-1.2 times the inner diameter of the pipeline, and the length of the rope is greater than the length of the pipeline.

Wherein, the inflatable ball is a thin-walled sphere made of polyurethane rubber, fluorosilicone rubber or nitrile rubber with good solvent resistance, preferably polyurethane rubber, and the wall thickness of the balloon is 0.5 mm to 1.0 mm, and There is an air hole for inflation. The inflatable ball can also be a thin-walled rubber tube made of the above-mentioned materials, and then cut into a sphere.

Wherein, when coating the pipeline, first place the pipeline at an angle of 30 degrees, and when the inflatable ball is drawn obliquely upwards to reach the other port of the pipeline that is not blocked, the pipeline Lay flat to allow excess paint to drain into collection trough.

The present invention adopts the pumping coating construction method, through which the elastic hollow sphere (inflatable ball) moves relatively evenly in the pipeline, and the paint is squeezed to the inner wall of the pipeline to form a relatively uniform coating film. The size of the ball depends on the diameter of the pipe, generally 1.1 to 1.2 times the inner diameter of the pipe. Utilizing the characteristics that the inflatable ball is easy to change instantly according to the shape of the inner wall of the pipeline, the elastic balloon should be inflated to an outer diameter larger than the inner diameter of the pipeline during construction, generally controlled at 1.1:1~1.2:1, so as to ensure that the inflatable ball has The high extrusion force can make the balloon move easily in the pipe and ensure uniform coating. Especially in the elbow part, the inflatable ball can evenly apply pressure on all directions of the pipe wall, extruding the paint to form a relatively uniform coating film.

The paint applied by the pumping method generally adopts a high-build paint (the viscosity of the paint is greater than 350 mPa·s), which can make the paint form a uniform coating film on the pipe wall. After the fluid with too low viscosity is squeezed, the coating film is too thin and difficult to be uniform. The quality (thickness, uniformity) of the coating film formed by this construction method is greatly affected by the size of the balloon (pressure), the viscosity of the paint, and the drawing speed. When other conditions remain unchanged, the greater the pressure, the thinner the coating film; The higher the viscosity, the thicker the coating film; the faster the drawing speed, the thinner the coating film, and vice versa. The specific construction can be adjusted in due course according to the above factors and mastered proficiently. In order to ensure uniform coating, it is best to carry out multi-layer construction, generally more than three layers, at least two layers, and the interval between coatings should be based on the actual drying of the previous layer of paint. Due to the poor air flow on the inner wall of the pipe, it is recommended to use drying method to dry the paint.

The invention is suitable for coating the inner walls of circular pipes such as water supply pipes, water supply pipes, gas pipes, and oil pipes. It is especially suitable for pumping and coating construction on parts that are easy to corrode in small and medium-sized pipes and curved special-shaped pipes.

The coating method of the invention is not affected by the viscosity of the coating, and can conveniently, uniformly and smoothly coat various anti-corrosion coatings on the inner wall of the pipeline that needs to be protected, thereby playing a better antirust and antiscaling effect on the inner wall of the pipeline. And the construction cost is low, which solves the problem that various coatings cannot be effectively coated on the inner wall of small-caliber, curved and special-shaped pipes.

the

Description of drawings

Fig. 1 is the schematic diagram that adopts coating method of the present invention to coat paint on the inner wall of small diameter straight pipeline.

Fig. 2 is a schematic diagram of coating paint on the inner wall of a curved special-shaped pipe by using the coating method of the present invention.

Description of main component symbols:

a pipe wall b rope c coating d inflatable ball e coating film f Bracket

Detailed ways

The present invention is further described through several groups of typical embodiments below, but the present invention is not limited to these embodiments.

The coating method of the present invention is further described in conjunction with accompanying drawing 1-2:

Referring to Figure 1, when coating a small-diameter straight pipe, first tilt the pipe to 30 degrees through the bracket f, and then pull the inflatable ball d with the rope b fixed on the upper end into the lower port of the pipe from the bottom of the pipe to block the pipe and inflate the ball The outer diameter of d is 1.2 times the inner diameter of the pipe to be coated. Then pass the free end of the rope b from the pipeline to the upper port of the pipeline. Then pour the liquid paint c from the upper port of the pipe into the pipe to maintain a certain amount of paint, then pull the free end of the rope b evenly and quickly to make the inflatable ball d move at a constant speed in the pipe, and the inflatable ball d will reach the pipe When opening the port, lay the pipe flat so that the excess paint c flows into the collection tank, which not only saves paint but also ensures the cleanliness of the port on the pipe. Finally, pull out the inflatable ball d to complete the first coating of the pipe wall a. After drying the first coating film to make it dry, repeat the above operation to coat the pipeline with the second and third coating films.

Referring to FIG. 2 , for coating curved special-shaped pipes, except for omitting the oblique support of the bracket f in the above-mentioned embodiment, the coating method is basically the same as that for coating small-diameter straight pipes, and will not be repeated here. The outer diameter of the inflatable ball d is 1.1 times the inner diameter of the pipe to be coated.

The invention is particularly suitable for the anticorrosion paint coating on the inner wall of the small-caliber, curved special-shaped pipeline. This method is also especially suitable for the coating of high-build coatings that cannot be poured into curved special-shaped pipes.

After coating the inner wall of small-diameter and curved special-shaped pipes by the method of the present invention, the coating effect test data are shown in the following table:

serial number project Test Results 1 apparent state The surface of the paint film is smooth and smooth 2 One-time film thickness, μm 60～100 3 Adhesion (pull-off method), MPa 10 4 Impact strength, cm 50

It can be seen from the above data that after coating the inner wall of the pipeline by the method of the present invention, the surface state of the coating is good, and it has excellent adhesion and impact strength with the pipe wall, and the comprehensive performance is excellent.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention to other forms. Any skilled person who is familiar with this profession may use the technical content disclosed above to change or modify the equivalent of equivalent changes. Example. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims (8)

1. A method for coating small-diameter, curved special-shaped pipeline inwalls with paint, is characterized in that: the method may further comprise the steps: (1) Pull an inflatable ball with a rope tied at one end into the pipeline from a port of the pipeline, block the port of the pipeline, and pass the free end of the rope out of the pipeline to the outside the other port of the pipeline; (2) Inject paint into the pipeline from the other unblocked port of the pipeline to above the inflatable ball in the pipeline; (3) Pulling the free end of the rope at a constant speed so that the inflatable ball passes through the entire pipeline. 2. A method according to claim 1, characterized in that: the diameter of the inflatable ball is 1.1-1.2 times the inner diameter of the pipeline, and the length of the rope is greater than the length of the pipeline. 3. A method as claimed in claim 1, characterized in that: the inflatable ball is a thin-walled sphere made of polyurethane rubber, fluorosilicone rubber or nitrile rubber, and has an air hole for inflating. 4. A method as claimed in claim 1, characterized in that: the inflatable ball is a sphere made by cutting a thin-walled rubber tube made of polyurethane rubber, fluorosilicone rubber or nitrile rubber. 5. A method according to any one of claims 1-4, characterized in that: the wall thickness of the inflatable ball is 0.5mm-1.0mm. 6. A method according to claim 1, characterized in that: the method further comprises placing the pipeline at an inclination of 30 degrees after the step (1), and in the step (3) when the When the inflatable ball is to be drawn to the other unblocked port of the pipeline, lay the pipeline flat to allow excess paint to flow into the collection tank. 7. A method as claimed in claim 1, characterized in that: said coating is a thick build type coating with a viscosity greater than 350 mPa·s. 8. A method according to claim 1, characterized in that: the length of the pipeline is less than 6m, and the inner diameter is 30mm-100mm.

Images