JPH044846Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a spray nozzle used for one-way painting.

Conventional Technology Conventionally, in order to spray epoxy powder or the like onto the heated inner surface of a tube to form a coating film on the inner surface of the tube, for example, as shown in FIG. Insert the long lance 2, and while spraying the powder 4 from the spray nozzle 3 provided at the tip of the lance 2, move the coating gun (not shown) and remove the lance 2.
The powder 4 was coated multiple times on the inner surface of the tube 1 by reciprocating in the tube axis direction A. Here, the reason why the inner surface of the tube 1 is coated multiple times is as shown in FIG.
This is because if the amount of powder 4 necessary to form the target coating film is applied at one time, the gas remaining during casting will blow out onto the inner surface of the tube, causing pinholes 6 in the coating film 5. For this purpose, a mist coat is applied to seal the pinhole 6 by the first application, and a second coat is applied.
By the subsequent coatings, the coating film was uniformly finished into the target coating film having the desired thickness. However, when painting small-diameter pipes, the lance 2 is long and curved so that the middle part of the lance 2 comes into contact with the inner wall of the pipe 1, or the spray nozzle 3 provided at the tip of the lance 2 is placed at a desired position inside the pipe 1. There was a problem that it could not be maintained. For this reason, a holding member 7 that holds the lance 2 inside the tube 1 must be placed in contact with the inside of the tube, and this contact of the holding member 7 causes the lance 2 to reciprocate and apply multiple coatings. Therefore, one-way painting was performed in which the lance 2 was pulled out only once in the direction of the tube axis.

Problems that the invention aims to solve: However, in the one-way coating described above, the target coating film must be formed in one application, and as a result, the amount of powder sprayed increases and the coating film becomes spiral. There is a problem that patterns occur and the gloss of the coating decreases.
Furthermore, since it is not possible to apply a mist coat, there is a problem in that pinholes are likely to occur.

This invention solves the above-mentioned problems.In one-way painting, a mist coat is applied and a uniform target film is achieved without creating a spiral pattern on the paint film or reducing the gloss of the paint film. The aim is to provide a spray nozzle that can be formed.

Means for Solving the Problems In order to solve the above problems, the present invention provides a nozzle that applies powder to the inner surface of the tube while being pulled out in one direction in the axial direction of the tube, and which applies powder to the inner surface of the tube on the tip side and the base. It has a spray nozzle for spraying powder on the end side, and among the spray nozzles, the one located on the proximal side,
The spray nozzle is formed as a first spray nozzle for swirling a mist coat on the inner surface of the tube, and the one located on the tip side is formed as a second spray nozzle for swirling a target coating film on the inner surface of the tube. The configuration is such that a first injection hole that opens at one spray nozzle portion and a second injection hole that opens at a second nozzle portion communicate with each other at their base end portions.

Operation In the above configuration, the nozzle is pulled out in one direction in the tube axis direction while spraying the powder from the first and second spray ports to apply the powder to the inner surface of the tube. At this time, the powder sprayed from the first spray port located at the front in the drawing direction and applied to the inner surface of the tube forms a mist coat to prevent the formation of pinholes. Then, the powder subsequently sprayed from the second spray port is applied over the mist coat, and together with the thickness of the mist coat, forms a target coating film having a required thickness. Therefore, the amount of powder necessary to form the target coating film is supplied homogeneously to the mutually communicating base ends of the first injection hole and the second injection hole,
Since the powder is dispersedly sprayed from the first and second spray openings of the nozzle and applied multiple times to the inner surface of the tube, no spiral pattern is generated on the coating film, and the gloss of the coating film is not reduced.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings. In FIG. 1, a rotating heated tube 1
A lance 12 of a painting gun (not shown) inserted into the tube 1 can be freely inserted and removed in the axial direction of the tube 1, and the nozzle is attached to the tip of the tube to prevent curvature due to its long length. A retaining device 14 is provided at the distal end to hold 13 in the required position within the tube 11. The holding device 14 has a roller 15 that is rotatable in contact with the inner surface of the tube 11, and the rotational axis of the roller 15 is inclined at a predetermined angle with respect to the rotational axis of the tube 11. This angle is determined by the rotational speed of the tube 11 and the drawing speed of the lance 12, and the lance 1 is lower than the rotating tube 11.
When pulling out the tube 2, the rollers 15 run spirally on the inner surface of the tube 11. Nozzle 1
3 has a spray nozzle 17 on the distal end side and the base end side for spraying powder 16 such as epoxy supplied from the lance 12 onto the inner surface of the tube 11. Then, when the lance 12 is pulled out in one direction B in the tube axis direction, the one located forward in the moving direction of the nozzle 13, that is, the one provided on the proximal end side, constitutes the first spray nozzle part 17a,
The one located at the rear, that is, the one provided on the tip side is the second spray nozzle 17b. Second
The nozzle 13 will be explained in more detail with reference to FIGS. The nozzle 13 is provided with a first injection hole 18 that opens at the base end side of the nozzle 13 and a second injection hole 19 that opens at the tip side of the nozzle 13. is formed smaller than the second injection hole 19, and the second injection hole 19 is formed smaller than the second injection hole 19.
A small amount of powder 16 is injected compared to the above. The first injection hole 18 and the second injection hole 19 are
They communicate at their proximal ends. And the first
A first diffusion surface 20 for diffusing the powder 16 injected from the first injection hole 18 toward the inner surface of the tube 11 is formed in front of the opening of the injection hole 18 . The first diffusion surface 20 is inclined at approximately 30 degrees with respect to the axis of the first injection hole 18 . The first spray port 17a is formed by the first injection hole 18 and the first diffusion surface 20.
is formed. The powder 16 injected from the second injection hole 19 is placed in front of the opening of the second injection hole 19.
A second diffusion surface 21 for diffusion toward the inner surface of the tube 11 is formed. The second diffusion surface 21
It is provided at an angle of approximately 30 degrees with respect to the axis of the injection hole 19, and a tongue piece 22 formed in a curved surface is provided at the tip thereof. Further, the base end of the nozzle 13 has a threaded portion 2 that is screwed into the tip of the lance 12.
3 and is detachably attached to the lance 12.

The operation of the above configuration will be explained. First, the lance 12 equipped with the nozzle 13 is inserted into the heated tube 11. Next, while rotating the tube 11 and spraying the powder 16 onto the inner surface of the tube 11 from the first and second spray ports 17a and 17b of the nozzle 13, the lance 12 is moved to one position in the axial direction of the tube 11. Pull it out in direction B. At this time, as shown in FIG. 7, the powder 16 injected from the first injection hole 18 is
It is diffused by the first diffusion surface 20 and sprayed toward the inner surface of the tube 11 . The sprayed powder 16 is applied onto the inner surface to form a mist coat 24 to prevent pinholes from occurring. Then, the second
The powder 16 injected from the injection hole 19 is diffused by the second diffusion surface 21 and sprayed toward the inner surface of the tube 11 . The sprayed powder 16 is applied over the mist coat 24 to form a target coating film 25 having a required thickness in combination with the thickness of the mist coat 24. Therefore, the amount of powder 16 necessary to form the target coating film 25 is supplied homogeneously to the base end where the first injection hole 18 and the second injection hole 19 communicate with each other, and and the first diffusion surface 20, the second injection hole 19, and the second diffusion surface 21.
Since the spray can be dispersed and applied multiple times onto the inner surface of the tube 11 from the second spray nozzle 17b, a threaded pattern does not occur on the target coating film 25, and the gloss of the coating film can be reduced. do not have. In this embodiment, the spray nozzle portion 17 is provided in two stages, but it is also possible to provide the holding device 14 in multiple stages. Furthermore, even when painting large-diameter pipes that do not require the holding device 14, the work process can be streamlined by using the nozzle 13 of the present invention and changing back-and-forth painting to one-way painting. The thickness of the target coating film 25 is usually about 50μ, but the amount of powder 16 applied to the inner surface of the tube 11 is adjusted according to the inner diameter of the target tube 11.
The amount of spray from the nozzle 13 and the degree of diffusion are controlled by the flow pressure and pumping pressure of powder supply. Ru.

Effects of the invention As described above, according to the invention, by providing the nozzle with multiple spray ports, powder can be applied multiple times to the inner surface of the tube during one-way painting, and pinholes can be eliminated. It is possible to form a target coating film while preventing the occurrence of spiral patterns and without reducing the gloss of the coating film.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view showing an embodiment of the nozzle of the present invention, and FIG. 3 is a view taken along arrow A-A in FIG. Figure 4 is a view taken along arrow B-B in Figure 2, and Figure 5 is a view taken along arrow D- in Figure 2.
D arrow view, Figure 6 is a C-C arrow view in Figure 2, Figure 7
The figure is an operational diagram of an embodiment of the present invention, FIG. 8 is an operational diagram of a conventional nozzle, and FIG. 9 is an overall configuration diagram using a conventional nozzle. DESCRIPTION OF SYMBOLS 11...Pipe, 12...Lance, 13...Nozzle, 14...Holding device, 16...Powder, 17a...
...first spray nozzle section, 17b...second spray nozzle section.

Claims (1)

[Scope of utility model registration request] A nozzle that applies powder to the inner surface of a tube while being pulled out in one direction in the axial direction of the tube,
It has spray nozzles for spraying powder on the distal end side and the proximal end side, and the one located on the proximal end side of the spray nozzle parts is used as a first spray nozzle for applying a mist coat to the inner surface of the tube.
The spray nozzle is formed as a spray nozzle, and the one located on the tip side is formed as a second spray nozzle for applying a target coating film to the inner surface of the tube, and the first spray opening opens at the first spray nozzle. A spray nozzle characterized in that a hole and a second injection hole opening at a second spray port are provided in communication with each other at a base end thereof.