JPS6059030B2 - How to paint the inner wall of the pipe - Google Patents

Description

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

Conventionally, two or more pigs made of soft or semi-hard foamed polyurethane resin are molded into cylindrical or cannonball shapes are loaded into a pipe, paint or rust preventive is filled between the pigs, and pressurized fluid is used. A method of painting the inner wall of a pipe has been proposed, which involves pumping the inside of the pipe under pressure.

In this case, Lu , L, , 1- is 1-゜, -i, -,
It is an elastic body, and its diameter is usually slightly larger than the internal dimension of the deposits on the inner wall of the pipe to be cleaned, but in the painting method, it is Some methods use small-diameter pigs. In this method, the paint is simply passed through the inner wall of the pipe to be painted, and the pig presses it against the inner wall of the pipe. It is not possible to obtain the so-called "brushing" effect.

Therefore, for example, if there are oils or fine particles that are difficult to dissolve in the paint that remain attached to the inside of the pipe, these will not be replaced with the paint sufficiently, and the pig will not make sufficient contact with the parts such as the corner of a 90-degree elbow. It is not possible to completely paint the surfaces. Furthermore, since the paint is simply pressed against the inner wall of the pipe, uneven thickness of the paint film is unavoidable. As a result of research to solve the above-mentioned drawbacks, the present inventors used a conventional pig with a long groove provided on its surface and a polymer having a three-dimensional skeleton network structure bonded to one end surface of the pig. The inventors have discovered that the above-mentioned drawbacks can be solved by doing the following, and have arrived at the present invention.

The purpose of the present invention is to add a brushing effect to a pipe inner wall painting method using pigs to achieve defect-free and uniform painting. Each pig is provided with a plurality of long grooves extending approximately in the longitudinal direction of the pipe on the surface of the pig that is to come into contact with the inner wall of the pipe, and a polymer material having a three-dimensional skeleton network structure is provided on the rear end surface of the pig. Glue the pig, load the pig into the tube,
There is a method for painting an inner wall of a pipe, which is characterized by filling a paint between the groups of pigs and pumping the paint into the pipe.

(2) The present invention further provides, in the above-mentioned invention (1), a polymer having a three-dimensional skeleton network structure with a diameter larger than the inner diameter of the tube is interposed between the plurality of pigs loaded in the tube. This can be further improved.

This will be explained below with reference to the drawings.

FIG. 1 is an illustration of a pig used in the present invention. During or after molding, the pig 1 is provided with a plurality of straight or curved long grooves 2 in a direction generally parallel to the pipe axis on the surface that is to come into contact with the inner wall of the pipe, and has a three-dimensional skeleton network structure on the rear end surface. The polymer body 3 having the above-mentioned properties is adhered. The pig 1 is made of an elastic foam material with high wear resistance, and is usually cylindrical or bullet-shaped, and the one used for painting has an outer diameter 1 to 2% smaller than the inner diameter of the pipe.

This is because it does not prevent the paint from adhering to the pipe wall and prevents the filled paint from flowing out from between the pipe wall and the pipe wall. Long groove 2
These act as guide paths for paint, and their cross sections may be rectangular, semicircular, or crescent-shaped, and the number of them can be changed as desired.

By adjusting the cross section and number of these long grooves, it is possible to adjust the coating film thickness. The polymer body 3 having a three-dimensional skeleton network structure is... For example, the cell membrane of a foam made from polyurethane, polyethylene, silicone, vinyl chloride, etc. as a raw material is completely destroyed, leaving only the three-dimensional mesh cell skeleton.
It is a foam with open cells and has the ability to shrink and expand!
It has excellent elasticity or restoring force, occlusion ability, and abrasion resistance. For example, Everlight Scotto (product name,
Manufactured by Bridgestone Tire Co.). The shape of the polymer body 3 having a three-dimensional skeleton network structure to be adhered to the pig may be a cylinder, a truncated cone, etc. with a diameter equal to or slightly larger than the inner diameter of the pipe, and the adhesive material with the pig may be Any adhesive may be used as long as the adhesive strength is not reduced by paint, but rubber-based adhesives are most suitable. FIG. 2 is an explanatory diagram of an embodiment of the present invention, illustrating a case where there are two pigs.

4 is the tube to be painted.

Open the opening/closing part 9 of the launcher 8 and insert the pigs 1 and 1a. The pigs 1 and 1a are provided with long grooves 2, and have a polymeric material 3 having a three-dimensional skeleton network structure adhered thereto. The polymer body 3 is
It is placed at the rear of the pig in the direction of travel. Close the opening/closing part 9, open the exhaust hole 6, and pour the paint 7 through the paint press-in hole 5 into the pig 1.
, 1a. The coating material 7 is impregnated into the polymer body 3 having a three-dimensional skeleton network structure. Any type of paint 7 may be used, but epoxy resins, silicone resins, acrylic resins, and mixtures thereof with antirust agents and antifungal agents may also be used.

Next, the compressor 10 pumps the pigs 1 and 1a and the paint 7 into the pipe.

Each pig runs inside the tube 4 while towing the polymer body 3 having a three-dimensional skeleton network structure. The leading pig receives back pressure, and a part of the paint impregnated with the polymer 3 having a three-dimensional skeleton network structure is transmitted through the long groove 2 to the front of the pig, and the polymer 3 self-transfers this. It is rubbed against the inner wall of the pipe together with the impregnating paint, and is further pressed while creating a brushing effect.

The polymer body 3, which has a three-dimensional skeleton network structure and is adhered to the rear part of the following pig, receives the static pressure and dynamic pressure of the paint either directly or through the long grooves 2, and presses the paint against the inner wall of the pipe, causing it to be brushed. In addition, if this is the last pig, it also serves as a finishing brush for the applied paint surface.

In this way, a small amount of paint can be applied by the painting method of the present invention, in which a plurality of pigs, which are provided with long paint guiding grooves and bonded with a polymer having a three-dimensional skeleton network structure, are loaded into a pipe and are pumped together with the paint. The action of penetrating the front of the leading pig and rubbing it against the inner wall of the pipe, the action of the polymer in the paint being pressed against the inner wall of the pipe and sliding, and the action of the polymer at the end receiving paint from the long groove. You can easily achieve a brushing effect, such as finishing the painted surface.

Therefore, the remaining oil and particles inside the pipe are completely replaced with the paint, and the pig can also contact curved pipe parts that could not be touched with conventional methods, making it possible to completely paint the inside wall of the pipe without any defects. At the same time, it is possible to paint uniformly with no excess or deficiency in any part.

Next, the second invention will be explained.

In the second invention, in addition to the first invention, a polymer body 3a having a three-dimensional skeleton network structure such as a cylindrical shape, a bullet shape, a Daen body, or a spherical shape having a diameter larger than the inner diameter of the tube between the pigs.
This is to intervene.

This polymer material 3a has a diameter larger than the inner diameter of the tube, but it is further impregnated with the paint and swells, and is pushed from behind by the following pig and contracts in length in the tube axis direction. It is strongly crimped against the inner wall of the pipe and produces a strong brushing effect.In particular, it is pressed against the inner wall of the pipe even better by the backing of the bullet-shaped head of the subsequent pig, and also has a shape that makes it difficult to adhere to the pig. Vibration lines including curved pipes, pipes with different diameters, constricted pipes, pipes with irregularities, etc., which can be used with Daen bodies and spherical shapes with a large degree of deformation, and for which the application of the first invention is not sufficient. It is possible to paint without any defects. FIG. 3 is an explanatory view of the present invention, and FIG. 4 is an explanatory view showing a situation in which the object passes through a bent pipe section.

For comparison, FIG. 5 shows the condition of a bent pipe section obtained by the conventional method. In the present invention, the polymer 3a having a three-dimensional skeletal network structure interposed between the pigs makes good contact with the corners of the curved pipe to form a defect-free coating film. The present invention involves loading a plurality of pigs into a tube, provided with long grooves for guiding paint, and bonded with a polymeric material having a three-dimensional skeleton network structure. This is a coating method in which a polymer having a network structure is interposed and is pumped together with the paint, and the polymer adhered to the pig allows a small amount of paint to seep out in front of the leading pig and transfer it to the inner wall of the pipe. In addition to the effects of rubbing, sliding by pressing against the inner wall of the pipe, and finishing the painted surface, the following pigs push the large diameter polymer interposed between the pigs. By doing so, it is possible to apply an extremely strong brushing effect, and it is also possible to deform greatly and come into contact with any part of the pipe. Therefore, even if the vibrating line includes curved pipes, pipes with different diameters, constricted pipes, pipes with complicated shapes, or pipes with uneven surfaces, the residual oil and fine particles inside the pipes can be completely replaced with paint. This makes it possible to paint the inner wall of the pipe completely without any defects by contacting each part of the pipe well, and at the same time, it is possible to paint uniformly with no excess or deficiency in any part.

[Brief explanation of the drawing]

FIG. 1 is an illustration of a pig used in the present invention, FIGS. 2 to 4 are explanatory diagrams of embodiments of the present invention, and FIG. 5 is an explanatory diagram showing a situation in a bent pipe section in a conventional method. 1,1a...Zeg, 2...Long groove on the surface of Zeg, 3,3a...
...Polymer having a three-dimensional skeleton network structure, 4...
Pipe to be painted, 5... Paint press-in hole, 6... Exhaust hole,
-7... Paint, 8... Launcher, 9... Launcher opening/closing part, 10... Compressor.

Claims (1)

[Scope of Claims] 1. A plurality of pigs are used, and each of the pigs is provided with a plurality of long grooves extending approximately in the longitudinal direction of the pipe on the surface of the pig that is to come into contact with the inner wall of the pipe, and a plurality of long grooves extending approximately in the longitudinal direction of the pipe are provided on the rear end surface of the pig. A method for painting an inner wall of a pipe, which comprises adhering a polymer having a three-dimensional skeleton network structure, loading the pigs into the pipe, filling paint between the groups of pigs, and pumping the paint through the pipe. . 2 A plurality of pigs are used, and each of the pigs is provided with a plurality of long grooves extending approximately in the longitudinal direction of the pipe on the surface of the pig that is to come into contact with the inner wall of the pipe, and a three-dimensional skeleton network structure is provided on the rear end surface of the pig. The pigs are loaded into a pipe, and a polymer having a three-dimensional skeleton network structure with a diameter larger than the inner diameter of the pipe is interposed between the pigs, and a paint is filled. A method for painting the inner wall of a pipe, which is characterized by pressure-feeding the inside of the pipe.