JP3775966B2 - Masking equipment for pipe inner surface coating - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a masking device for pipe inner surface coating.
[0002]
[Prior art]
When ductile cast iron pipes are centrifugally cast, it is common to paint the inner and outer surfaces of this pipe, and in particular, the inner surface of the pipe is a powder produced by spraying paint from the tip of a lance inserted into the pipe. Body painting is often performed. By the way, in general, a cast iron pipe has a receiving port on one end side, and the inner surface of this receiving port is coated with a different specification from the powder coating of the tube body, so that powder coating of the tube body is not performed. When this occurs, the film thickness becomes too large. For this reason, in order to prevent the paint sprayed from the tip of the lance from splashing and adhering to the inner surface of the receiving port, a cylindrical masking member inserted into the receiving port and the inside of the masking member are communicated. 2. Description of the Related Art A masking device for painting an inner surface of a pipe provided with an exhaust passage is conventionally known.
[0003]
FIG. 4 shows the configuration of such a conventional masking apparatus. Here, reference numeral 1 denotes a ductile cast iron pipe whose inner surface is to be painted, and is configured to be supported in the horizontal direction and to be rotationally driven around its axis. A receptacle 2 is formed at the end of the tube 1. Reference numeral 11 denotes a masking device, which has a cylindrical support portion 12 in the horizontal direction orthogonal to the axis of the tube 1. A rotating cylindrical body 13 is fitted on the support portion 12.
[0004]
An opening 15 having a connection flange 14 is formed in the rotary cylindrical body 13 at even positions along the circumferential direction. The pair of openings 15 and 15 are provided at an interval of 180 degrees in the circumferential direction. That is, the pair of openings 15 and 15 provided at an interval of 180 degrees are provided on a straight line. The support portion 12 is provided with a radial communication passage 16 for communicating the pair of openings 15 and 15 with each other.
[0005]
Each connecting flange 14 is connected to a masking member 17 having a pipe-shaped water-cooled jacket structure having a different diameter depending on the type of the pipe 1 to be coated on the inner surface. As shown in the figure, the masking member 17 is configured such that its outer diameter is substantially equal to the inner diameter of the receiving port 2 of the pipe 1, and between the inner surface of the receiving port 2 when inserted into the receiving port 2. A gap is not generated as much as possible, so that reliable masking can be performed. Then, the masking member 17 that has reached the position where it can be inserted into the receiving port 2 of the tube 1 by the rotation of the cylindrical body 13 communicates with the communication passage 16 and the masking member 17 on the opposite side spaced 180 degrees in the circumferential direction. It is configured. The masking member 17 on the opposite side is communicated with a dust collector (not shown) when it is in the illustrated position.
[0006]
In such a configuration, when the inner surface of the tube 1 is painted, the tube 1 that has been annealed after centrifugal casting and is still under a predetermined temperature is supported in the horizontal direction as shown in the figure, and the cylindrical body 13 is rotated. Then, the masking member 17 corresponding to the type, that is, the diameter of the tube 1 is made to face the receiving port 2 of the tube 1. Then, by moving the masking device 11 or the tube 1, the masking member 17 is inserted into the receiving port 2 of the tube 1 as shown in the figure.
[0007]
In this state, the tube 1 is rotated around the axis while operating the dust collector (not shown), and the coating lance 4 is inserted into the tube 1, and the dust is directed from the tip of the lance 4 toward the inner surface of the tube 1. Body paint 19 is ejected. The powder coating 19 is welded to the inner surface over the entire length and the entire circumference of the tube 1 except for the inner surface of the receiving port 2 into which the masking member 17 is inserted by the heat of the tube 1.
[0008]
Of the sprayed paint 19, the portion that does not adhere to the inner surface of the tube 1 enters the masking member 17 on the airflow 20 generated by the operation of the dust collector and masks on the side opposite to the communication path 16. It is sent to the dust collector through the member 17.
[0009]
At this time, the temperature of the masking member 17 itself also rises, and a part of the powder coating material 19 adheres to the inner peripheral surface of the masking member 17 and is left as it is to coat the inner surfaces of many pipes 1. As shown in FIG. 5, the adhering paint 21 grows on the inner periphery of the opening end of the masking member 17.
[0010]
Therefore, in order to prevent the adhesion paint 21 from growing, the nozzle 22 is brought close to the opening end of the masking member 17 for each cycle in which the inner surface of one pipe 1 is coated, as shown in FIG. Air 23 from the nozzle 22 is blown to the inner periphery of the end to remove the adhering paint and prevent its growth.
[0011]
[Problems to be solved by the invention]
However, the nozzle 22 blows the air 23 locally on the masking member 17, and therefore, a portion where the air 23 does not hit is generated, and the growth of the adhering paint is inevitable over time.
[0012]
Further, as shown in the figure, when the masking member 17 on the opposite side spaced 180 degrees in the circumferential direction from the masking member 17 inserted into the tube 1 corresponds to a small diameter tube, the communication path 16 This masking member 17 has a smaller diameter and a smaller passage sectional area. In that case, a step is formed in the flange 14 which is a connecting portion between the communication passage 16 and the masking member 17, and the airflow 20 is stagnate at the step, and the adhered paint 21 is likely to grow. In this case, if the air 23 is blown from the nozzle 22 close to the opening end of the masking member 17 as described above, the adhered paint cannot be sufficiently removed, and the adhered paint grows over time. Inevitable.
[0013]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such problems and to reliably prevent adhesion of paint in a masking device.
[0014]
[Means for Solving the Problems]
In order to achieve this object, the present invention provides a cylindrical masking member inserted into the interior of the tube receiving port, an exhaust passage communicating with the inside of the masking member, and an inner periphery of the opening at the tip of the masking member. And a nozzle that blows air in an annular shape.
[0015]
In such a configuration, since the nozzle is configured to blow air in an annular shape over the inner circumference of the opening at the tip of the masking member, the masking member is uniformly blown with air on the entire inner surface, and therefore It is possible to prevent the occurrence of a situation where a location where air does not hit locally occurs and the adhered paint grows at that location.
[0016]
The present invention also provides a cylindrical masking member inserted into the interior of the tube receiving port, an exhaust passage communicating with the interior of the masking member, and a nozzle that blows air onto a portion of the exhaust passage where the cross-sectional area of the passage changes. It is equipped with.
[0017]
With such a configuration, the air is blown to a place where stagnation may occur in the airflow based on the change in the passage cross-sectional area in the exhaust passage, so that the growth of the adhering paint at that place is reliably prevented.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the masking apparatus for pipe inner surface coating according to the embodiment of the present invention is based on FIGS. 1 to 3, and the same members as those shown in FIGS. 4 to 5 are denoted by the same reference numerals. This will be described in detail.
[0019]
As shown in FIG. 1, an air nozzle 31 is provided on the support portion 12 of the masking device 11. The air nozzle 31 is provided so as to project annularly along the inner periphery of the communication passage 16 as an exhaust passage, and is connected to the masking member 17 on the side opposite to the masking member 17 inserted into the pipe 1. The air 32 can be blown in an annular shape toward the flange 14.
[0020]
FIG. 2 shows that an air nozzle 34 capable of blowing air 33 against the masking member 17 to be inserted into the tube 1 is located inside the opening of the masking member 17 when the masking member 17 is not inserted into the tube. A state where air 33 is blown around the circumference is shown. The air nozzle 34 has a nozzle body 35 and a support member 36 integrally. The support member 36 is composed of, for example, a pipe and has a function of supporting and moving the nozzle body 35 and a function of supplying pressurized air to the nozzle body 35.
[0021]
FIG. 3 shows the detailed structure of the nozzle body 35. The nozzle body 35 is formed in a hollow truncated cone shape corresponding to the diameter of the masking member 17 to which the air 33 is blown, and is moved by the support member 36 so that the hypotenuse 37 of the truncated cone faces the inner periphery of the masking member 17. It is supported. A plurality of through holes 38 for ejecting the air 33 are formed along the circumferential direction of the oblique side 37. Thereby, the air 33 can be blown in an annular shape over the inner periphery of the opening of the masking member 17. A plurality of air nozzles 34 having different dimensions corresponding to the diameter of the masking member 17 are prepared.
[0022]
In such a configuration, when the inner surface of the pipe 1 is painted as shown in FIG. 1, a plurality of dust collecting devices are operated as described above, and the air inside the masking device 11 is sucked and exhausted. During the painting operation on the pipe 1, the air 32 is constantly ejected from the air nozzle 31, and the air 32 is blown in an annular shape toward the connection flange 14. This reliably prevents the adhesion paint from growing in the portion where the connection flange 14 is provided and the cross-sectional area of the exhaust passage changes.
[0023]
About opening of the front-end | tip of the masking member 17, air is sprayed as follows. That is, when the painting of the pipe 1 is completed and the pipe 1 is carried out of the apparatus, the air nozzle 34 corresponding to the diameter of the masking member 17 is used to support the air nozzle 34 as shown in FIG. Thus, the nozzle body 35 faces the opening of the masking member 17. In this state, air 33 is blown annularly from the nozzle body 35 over the inner periphery of the opening at the tip of the masking member 17. Thereby, the growth of the adhering paint is prevented on the entire inner periphery of the opening at the tip of the masking member 17.
[0024]
【The invention's effect】
As described above, according to the present invention, the cylindrical masking member inserted into the tube receiving port, the exhaust passage communicating with the masking member, and the inner periphery of the opening at the tip of the masking member The air nozzle is equipped with a nozzle that blows air on the entire surface of the masking member, so that air can be uniformly blown around the inner surface of the masking member. Occurrence can be prevented.
[0025]
Further, according to the present invention, a cylindrical masking member inserted into the tube receiving port, an exhaust passage communicating with the masking member, and air is blown to a portion of the exhaust passage where the passage cross-sectional area changes. Since the nozzle is provided, air can be blown to a portion where the airflow may stagnate based on the change in the cross-sectional area of the exhaust passage, and the growth of the adhering paint at that portion can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is an overall cross-sectional view of a masking apparatus for pipe inner surface coating according to an embodiment of the present invention.
2 is a view showing a state in which air is blown from the nozzle to the inner periphery of the opening end of the masking member in FIG. 1. FIG.
FIG. 3 is a detailed view of the nozzle of FIG.
FIG. 4 is an overall cross-sectional view of a conventional masking apparatus for pipe inner surface coating.
5 is a view showing a state in which air is blown from the nozzle into the opening end of the masking member in FIG. 4;
[Explanation of symbols]
1 Pipe 16 Communication path 17 Masking member 31 Air nozzle 34 Air nozzle

Claims (2)

A cylindrical masking member inserted into the interior of the tube receiving port, an exhaust passage communicating with the inside of the masking member, and a nozzle for blowing air in an annular shape over the inner periphery of the opening at the tip of the masking member A masking device for painting the inside of tubes. A cylindrical masking member inserted into the tube receiving port, an exhaust passage communicating with the inside of the masking member, and a nozzle for blowing air to a portion of the exhaust passage where the cross-sectional area of the passage changes are provided. A masking device for pipe inner surface painting.

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