JPS6336880A - Painting method for inside wall of small-diameter piping - Google Patents

Abstract

PURPOSE:To efficiently form a uniformly coated film to the inside wall of a small-diameter piping by injecting a fluid paint formed by mixing a paint and air fluid from an injection port toward the inside wall of the pipe to be painted and injecting compressed air from the inside of said injection port to the inside of the pipe to be painted. CONSTITUTION:The paint is mixed wit the air fluid to form the fluid paint 18 and the mixture is injected from the paint injection port 7 toward the inside wall of the pipe 3 to be painted to stick the paint to the inside wall surface of the pipe to be painted in order to paint the inside wall of the small-diameter piping below 4b. The paint is gradually moved forward of the pipe to be painted along the inside wall while the paint sticking to the inside wall of the pipe to be painted is pressed to the inside wall by the compressed air 17 injected from the inside injection port 9 of the paint injection port 7 to the inside of the pipe to be painted. As a result, the uniformly coated film is efficiently formed with the smaller amt. of the paint to the inside wall of the small- diameter piping over a long section.

Description

[Detailed Description of the Invention] [Industrial Application Field] When water supply piping constructed of carbon steel pipes is used for many years, the inner wall surface corrodes and rusts, resulting in the formation of what is commonly known as red water J/ and the use of tap water. I can't do things. For this reason, it is necessary to paint the inner wall of the pipe, and the present invention relates to a method of painting the inner wall of this type of small-diameter pipe.

[Conventional technology]

BACKGROUND ART Conventionally, when painting the inner wall surface of a laid pipe, a method is known in which the inner wall of the pipe is prepared as a base, and then the paint is sprayed from the end of the pipe with compressed air to paint the inner wall surface of the pipe. Specific methods include spraying the paint from a spray nozzle onto the inner wall of the pipe in the form of a hollow inverted cone, or spraying the paint in a swirling manner within the pipe.

[Problem that the invention seeks to solve]

The conventional method described above is an excellent method, but when the piping route is long, even if the paint is sprayed from the end of the pipe onto the inner wall of the pipe in an inverted conical shape or in a spiral shape, the paint may be applied deeper than the inlet. The swirling energy of the fluid paint is attenuated as it enters the pipe, and the paint diffuses within the pipe.

For this reason, (1) In the case of horizontal piping, paint adhering to the earthen walls inside the pipe falls and concentrates at the bottom, making it impossible to obtain a uniform coating.

(2) There were problems such as the paint spreading inside the piping and requiring a large amount of paint to obtain a constant coating film. [Means to solve the problem] The present invention is based on the In order to solve the problem, the invention aims to improve the method of painting the inner wall surface of small-diameter pipes. Form a fluid paint and spray it from the end of the pipe to be painted toward the inner wall of the pipe to be painted from the paint injection port to make the paint adhere to the inner wall surface of the pipe to be painted, and then blow compressed air from inside the paint injection port. It is sprayed into the inside of the pipe to be painted, presses the paint layer adhering to the inner wall of the pipe to be painted, and gradually moves along the inside wall to the front of the pipe to be painted, thereby effectively applying less paint to the inner wall of small-diameter pipes. The object of the present invention is to provide a method for coating the inner wall of a small-diameter pipe that forms a well-uniform coating over a long distance.

[For production]

Since the present invention is such a method, it is used as follows.

First, a nozzle device is attached to the end of the pipe to be coated.

The installation method is a flange structure and can be installed with bolts and nuts,
For example, a female thread is installed on the nozzle device and a male thread is installed on the end of the pipe to be coated.

Further, a mixed fluid of compressed air and paint and a compressed air supply device are connected to the nozzle device.

Then, when the compressor is driven and each flow rate adjustment valve is fully adjusted, compressed air is supplied to the paint tank, and the accelerated injector in the paint tank generates fluid paint of paint and compressed air, and the nozzle device The mixed fluid is injected into the passage.

On the other hand, compressed air from the compressor is supplied to the compressed air passage in the center.The fluid paint thus supplied to the passage between the outer pipe body and the inner pipe body is ejected from the paint injection port formed at the tip of the fluid paint. It will be done.

Since the nozzle has an annular shape when viewed from the end surface, the fluid paint is ejected from the nozzle in a cylindrical shape. Since the outer pipe body has the same diameter as the pipe to be painted, the fluid paint is ejected along the inner wall of the pipe to be painted.

Therefore, the fluid paint comes into contact with the inner wall of the pipe to be painted, and the paint particles adhere to the inner wall and are suppressed toward the end of the pipe.

On the other hand, compressed air is ejected from the nozzle at the tip of the inner pipe body, pressurizing all the paint particles adhering to the inner wall and further promoting their progress toward the end.

The compressed air ejected from the nozzle at the tip of the central inner pipe body serves to increase the speed of coating the inner wall of the tube to be coated, and also helps to form a thin and uniform coating film. Further, by adjusting the flow rate regulating valve, the thickness of the coating film can be adjusted.

〔Example〕

An embodiment of the present invention will be described below based on the drawings. As shown in FIG. A mounting female screw 4 is formed to be screwed into the end portion. The inner diameter of the outer pipe body 2 is the same as that of the target pipe 3 to be painted.

There is a space with an annular cross section between the inner pipe body 1 and the outer pipe body 2, and this space with an annular cross section is assumed to be a passage 5 for the fluid paint 18, and the fluid paint 18 is introduced into this passage 5. Two inlets 6, 6, . . . are formed at equal intervals along the circumferential direction near the rear end of the outer pipe body 2. Further, the rear end of the passage 5 is closed, and the tip is configured as a lower spraying spout of the fluid paint 18. The jet lower may be configured by slightly enlarging the outer periphery of the tip of the inner pipe body 1 to narrow the outlet of the passage 5.

On the other hand, an inlet 8 for compressed air 17 is formed at the rear end of the inner pipe body 1, and a nozzle 9 is formed at the tip.

The fluid paint 18 and compressed air 17 are supplied to the following devices.

As shown in FIG. 1, this device includes a compressor 10 that generates all compressed air, a dryer 11, a paint tank 12, a flow rate adjustment valve 13 that adjusts the flow rate of the mixed fluid from the paint tank 12, and a compressor 10 that generates all compressed air. It is composed of a flow rate adjustment valve 14 that adjusts the flow rate of air.

The paint tank 12 is equipped with a nozzle device that mixes and sprays the compressed air generated by the compressor 10 and paint.

Note that 15 in FIG. 1 indicates the above-mentioned nozzle device.

Since this embodiment is configured as described above,
It becomes possible to paint the inner walls of small diameter pipes such as water pipes as follows.

Here, the entire case of painting the inner wall using a water pipe as the pipe to be painted 3 will be explained.

First, a nozzle device 15 having a female mounting thread 4 corresponding to the male thread formed at the end of the pipe 3 to be coated is selected. The pipe 3 to be painted is previously subjected to pretreatment such as removal of scale.

Then, the female fitting 4 is screwed onto the male thread at the end of the pipe 3 to be painted, and the nozzle device 15 is connected to the end of the pipe 3 to be painted.

Further, the nozzle device 15 includes, as shown in FIG.
Connect the mixed fluid and compressed air generator.

That is, first, the paint tank 12 is connected to the inlets 6,6, . . . formed in the outer pipe body 2 via the flow rate regulating valve 13. On the other hand, the compressor 10 is connected to the inlet 8 formed in the inner pipe body 1 via the dryer 11 and the flow rate regulating valve 14.

After the above preparations, when the device is driven, compressed air from the compressor 10 is supplied to the paint tank 12, and the compressed air and paint are mixed by the pressurized injection device, and the fluid paint 18 is mixed with the compressed air and paint.
is generated and injected into the passage 5 via the flow rate regulating valve 13. The fluid paint 18 injected into the passage 5 is then injected from the injection lower into the tube to be coated 3 in the form of a cylinder having a diameter approximately equal to the inner diameter of the tube. However, as shown in Figure 5,
The paint particles of the fluid paint 18 adhere to the inner wall of the tube 3 to be coated while progressing toward the end of the tube bed. That is, the paint layer 16 that is formed by adhesion progresses sequentially toward the end of the tube bed.

On the other hand, compressed air 17 from the compressor 10 is ejected into the central inner pipe body 1 via the dryer 11 and the flow rate regulating valve 14, and is ejected from the nozzle 9 of the inner pipe body 1 into the pipe to be coated 3. Therefore, as a result, the paint layer on the inner wall of the pipe to be painted 3 is further extended forward, and a thin and uniform paint film is formed. By adjusting the flow rate regulating valve 14, the coating thickness on the inner wall of the pipe 3 to be coated can be adjusted.

The compressed air 17 not only promotes forward movement of the paint layer 16 but also promotes fixation.

As described above, the paint layer 16 gradually advances on the inner wall of the tube 3 to be coated, and when it reaches the end of the tube, the coating is completed.

After completion, the apparatus is removed from the pipe to be painted 3 and organized.

〔Effect of the invention〕

According to the present invention, a uniform coating film can be obtained, efficient coating can be easily performed using a small amount of paint, and furthermore, this can be achieved using a simple device.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a conceptual diagram showing the state of use, FIG. 2 is a partial conceptual sectional view showing the state of use, and FIGS. FIG. 5 is a partially enlarged sectional view showing the nozzle device used, and FIGS. 6 and 7 are sectional views of the pipe to be coated, showing the state during painting. 1...Inner pipe body, 2...Outer pipe body, 3...
・Pipe to be painted, 4・Female mounting thread, 5...Passage, 6, 8・
...Inlet, 7, 9, spout, 10...Compressor,
11...Dryer, 12...Paint tank, 13.14...
- Flow rate adjustment valve, 15... Nozzle device, 16... Paint layer, 17... Compressed air, 18... Fluid paint. Patent applicant: System Maintenance Co., Ltd. Figure 1 Figure 3 Figure 3

Claims (1)

[Claims] In small-diameter pipes of less than 4B, the paint is mixed with air fluid to form a fluid paint, which is injected from the paint injection port toward the inner wall of the pipe to be painted, so that the paint adheres to the inner wall of the pipe to be painted. The inner wall of a small-diameter pipe where compressed air is injected from inside the injection port into the pipe to be painted, and the paint adhering to the inner wall of the pipe to be painted is pressed against the inner wall and gradually moves along the inner wall toward the front of the pipe to be painted. How to paint.