JPS61161172A - Method and device for stripe coating of seam part of small-diameter can from inside - Google Patents

Abstract

PURPOSE:To stabilize spraying and to execute desired stripe coating by providing a pressure regulator into a cylinder which moves relatively in a small- diameter can in proximity to a gun. CONSTITUTION:The pressure regulator R is provided in proximity to the gun 24 as far as possible on a circuit 20 for supplying a paint to the gun 24 in the stage of moving the gun in the small-diameter can and coating the seam part of the can inside from the inside into a stripe shape. The juncture to a circuit 30 for returning the excess paint to the gun 24 is provided directly on the pressure regulator R or on the front or rear circuit 20. The distance between the regulator R and the gun 24 is thereby reduced and therefore the pressure drop therebetween is disturbed. The sensitive dealing with the opening and closing of the valve in the gun 24 is made possible. The desired discharge pressure and temp. are thus obtd. and are stably maintained. The stripe coating is executed under the fine adjustment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method and apparatus for stripe coating the seam of a small diameter can by moving relative to the interior of the can.

Originally, as shown in FIG. 1, metal cans have stripe coach-in grooves applied to the seams 1a and lb of the can body 1 using paint. The reason for this is that the inside surface of metal cans is fully coated with plastic to prevent the metal from leaching into the contents inside the can, but only the seams are welded. , there is no plastic coating and the metal base is exposed. To cover this, the metal base is then painted with plastic paint in stripes. As a device for stripe coating, a cylinder 9 of approximately 8 mrtt96 is used, as shown in Fig. 2, especially when the can diameter is small, approximately 50w1t or less, and a nozzle is installed in the cylinder. 6, a paint supply piping and electric wiring, an electric welding roll 8, and other stored items are used.

To explain the above-mentioned paint supply piping, that is, the paint supply circuit in more detail, as shown in FIG.

It enters the cylinder 19 through the cylinder 19 and is connected to the gun 14 housed in the distal end of the cylinder. The distance "Ll+" from the regulator to the gun is approximately 1 m to 1.
The pipe length is 5 m, and the diameter of these pipes is relatively thin, about 6 m. The reason for this is that in addition to the paint supply piping, inside the cylinder, there are air piping for operating the gun, electrical wiring for operating the solenoid valve, electrical wiring for the welding machine, other welding wires, and piping for cooling water, etc. This is because the diameter of these pipes is naturally limited because many pipes and wiring are housed therein. As the paint flows through a narrow tube of more than 1 meter, a significant pressure drop naturally occurs, and the amount of paint discharged from the gun nozzle also decreases, and the amount becomes unstable, resulting in uneven coating. do. Particularly when the paint has a high viscosity, (1) the amount of paint supplied decreases due to the pressure drop inside the pipe, and at the same time the paint temperature near the nozzle drops below the required temperature. (2) When a nozzle with a large flow rate is used, followability is lacking and the amount of application decreases over time. (6) When increasing the paint supply pressure to solve the above two problems, there were various problems such as the rebound during spraying became excessive and it became difficult to select a nozzle.

An object of the present invention is to provide a method and apparatus for stripe-coating the seam of a small-diameter can from the inside by moving inside a can, in which a pressure regulator on a paint supply pipe to a gun of the apparatus is installed in front of the gun. It is an object of the present invention to provide a method and apparatus for achieving a desired stripe coating by providing a stable spray by close proximity and maintaining the necessary conditions.

The present invention will be described in detail. Please refer to FIGS. 4 and 5. The pressure regulator R is provided on the paint supply circuit (piping) 20 to the gun 24 as close as possible to the gun 24. At the same time, a connection to the excess paint return circuit (piping) 30 to the gun 24 may be provided directly on the pressure regulator R, or alternatively, the paint supply circuit (piping) may be provided in front of or behind the pressure regulator R. Piping) 20.20a or either. By the above-described arrangement method, the distance between the pressure regulator R and the gun 24 can be shortened, and therefore, a pressure drop between them can be prevented. Furthermore, since the return circuit (piping) is also provided directly or close to the pressure regulator R before and after it, in other words, the distance from the gun 24 is small, so it is sensitive to the opening and closing of the valve inside the gun 24. It is possible to make it correspond to the following.

Next, the structure of the device according to the present invention will be explained. Conventionally, as explained previously (see FIG. 3), a pressure regulator R1 was installed outside the cylinder 19 on the paint supply pipe 10.
was established. In the present invention, as shown in FIG. 4, the pressure regulator is provided within the cylinder 29 and as close to the gun 24 as possible, and the distance of the piping 20a is extremely short ( “t′).

A connecting portion 30p to a return pipe 30 into the paint tank is provided on the paint supply pipe 20 slightly before the pressure regulator.

Next, the operation of the above device will be described. The liquid paint in the paint tank T passes through a pump P, a heater H, and a filter F, and its piping enters the cylinder 29, and then the regulator R.
Go inside. Then, the pressure-adjusted paint is sent into the gun 24 through a short paint supply pipe 20a, passes through an on-off valve operated by a solenoid valve provided in the gun, and is sprayed from a nozzle 26 (S ) to be done.

That is, the seam portions 21a and 2 inside the can are created by a nozzle built into a cylinder that moves within the can 21 (“A”).
It is applied (Sl) in stripes on Ib. Incidentally, excess paint relative to the gun or pressure regulator is returned to the paint tank T by return pipes 30a and 30 provided before the pressure regulator. In other words, more paint than is required is circulated under high pressure and constant temperature before being vacuum adjusted. The pressure regulator R then sends the paint, which has been reduced to an appropriate pressure that will not cause rebound during spraying, to the gun 24 and is sprayed from the nozzle 26. Also, since the distance between the pressure regulator and the gun is short, the pressure drop and temperature drop are extremely small, and spray is made at a proper pressure that is very close to the regulated pressure. This also improves the ability to follow the nozzle, which also leads to stability.

In addition, as shown in FIG. 5, the return pipe can be drawn out directly from the pressure regulator (30b), or it can be drawn out by providing a connecting part 30q on the short pipe 20a between the pressure regulator and the gun (30q). You can also do that. Both of these have the same effect as the connection method described above, i.e., the connection 30p to the return pipe is provided just before the pressure regulator. By providing this, it is possible to obtain the desired discharge pressure and discharge temperature, maintain them stably, and apply a constant stripe coating with good followability and fine adjustment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the body of a can. FIG. 2 is a side view of a conventional gun installed in a cylinder. FIG. 6 is a diagram of a paint supply system for the same gun. A side view of the position of the pressure regulator and a diagram of the paint supply system. Figure 5 is a modified view of the return piping connection of the same as above.
b la', Ib'; 21a.

Claims (1)

[Scope of Claims] 1. A pressure regulator R provided on a paint supply circuit (piping) 20 to a gun 24 that moves relative to each other within a small-diameter can and coats the inner surface of the seam portion of the can in stripes. 24 as close as possible, and at the same time, the connection part with the return pipe 30 from the gun 24 is directly connected to the pressure regulator R.
Alternatively, the pressure regulator R provided on the paint supply circuit (piping) is provided as close as possible to the front or rear of the pressure regulator R (30p, 30q), thereby controlling the pressure between the pressure regulator R and the gun 24. To provide a method for stripe coating a seam part of a small diameter can from the inside, which is characterized by suppressing drop to the minimum limit and thereby controlling the amount of paint discharged from a gun 24 accurately and uniformly with good followability. 2. In a device that moves relative to each other inside a small-diameter can and coats the inner surface of the seam portion of the can in stripes, a paint supply pipe (circuit) 20 to a gun 24 housed in a cylinder 29 that moves inside the small-diameter can. A pressure regulator R is provided above and close to the front of the gun 24, and a return pipe 3 from the gun is provided.
0 directly to the pressure regulator R or in front (30p) or behind (30p) of the pressure regulator R.
0q), an apparatus for stripe coating the seam part of a small diameter can from the inside, characterized in that it is provided close to the pressure regulator R.