JPS62176568A - Method for heating gun for stripe coating in small caliber can and said gun - Google Patents

Abstract

PURPOSE:To always form a good pattern at the time of initial start-up by preventing the falling in the temp. of residual paint, by allowing supplied paint to bypass even at the closure time of the opening and closing valve in a gun to heat the periphery of a jet passage from a valve to a nozzle. CONSTITUTION:An opening and closing valve 3 is opened and closed by ON/OFF of operation air or a current and, at the time of an open state, supplied paint passes through the opening and closing valve 3 and a jet passage 6 to be inject ed from the nozzle 9 provided to the leading end of the jet passage 6. Next, the passage of the supplied paint is stopped by the closure of the opening and closing valve 3 and the injection of the paint is stopped but paint having the same temp. as the supplied paint always passes through the paint passage 2D of a bypass regardless of the opening and closing of the valve 3 and is recycling. Therefore, the temp. of the paint not injected remaining in the jet passage 6 is kept when the opening and closing valve 3 is closed to make it possible to keep temp. suitable for the next injection and normal spraying can be performed at proper viscosity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and gun for heating a gun for stripe coating the inside seam of small diameter cans.

Conventional technology In the first place, inside small diameter cans, stripe coating (1,
S, S) are being constructed. A system diagram of the system is shown in FIG. 4, and a side cross-sectional view of the conventional basic structure of the above-mentioned gun, which is the object of the present invention, is shown in FIG.

First, the system diagram (FIG. 4) will be explained. tank 4
The paint in 1 is suctioned and pressure-fed by a pump 42 through piping, passed through a heater 43 and heated appropriately, then passed through a filter 44 and a reginator 45, and after being adjusted to an appropriate pressure, it is transferred to the paint supply piping. It is connected via 46 to gun 48 . Paint is sprayed (SP) by a nozzle 49 mounted on the gun 48, but even if spraying is interrupted, the paint is returned to the tank 41 through a return pipe 47. In other words, we are always recycling. Naha the above gun 4
8 is made small in size to accommodate the movement of the small diameter can C on the outside thereof.

Next, the structure of the above-mentioned conventional gun will also be explained. Fifth
Please refer to the figure. Inside the gun body 51, there is provided a paint passage 52A connected to the paint supply pipe 46, an on-off valve 53 on the passage, and a return paint passage 52B after the on-off valve 53. is connected to the return pipe 47. Further, the opening/closing valve 53 and subsequent parts in the body 51 are connected to a jetting passage 56 in an intermediate adapter 55 coupled to the body 51, and a nozzle 59 is connected to the end of the passage.

Next, the operation of the above gun will be explained. The supplied paint passes through the supply passage 52A and reaches the on-off valve 53 for ejection. When the opening/closing valve is "closed," the water returns to the tank through the return passage 52B and is constantly recycled. When the opening/closing valve is "open," it passes through the jetting passage 56 in the intermediate adapter 55 and is ejected from the nozzle 59. do. Needless to say, when the ejection is interrupted, the opening/closing pulp 53 is closed. Then, the supplied paint enters the return passage in front of the on-off valve 53. That is, since the paint is recycled, the temperature near the paint passage inside the body 51 is maintained at the temperature of the paint. However, after the on-off valve 53 is closed, the paint remaining in the ejection passage 56 from before the ejection was interrupted remains stagnant. Over time its temperature will drop with the adapter. Therefore, the viscosity of the paint also increases. At that point, when the opening/closing pulp 53 is opened to resume ejection, the supplied paint enters the ejection passage 56 in the intermediate adapter 55, so that the remaining stagnant paint is pushed out. However, as mentioned above, the temperature of the paint has decreased and the viscosity has increased, so the ejection speed becomes slower than before. That is, the amount of spray is smaller, the spray pattern is smaller than before, and the width of the previously set stripe is narrower. Therefore, it is unsuitable for use. Furthermore, even if a new supply of paint from which the remaining paint has been extruded enters, the temperature of the intermediate adapter 53 itself has decreased, so the temperature of the paint passing through the jetting passage 56 also decreases, and the viscosity also increases. Then, as above, the spray pattern is reduced and the stripe application width becomes narrower. The regular spray pattern is set only after a certain period of time has passed and the temperature of the intermediate adapter 55 itself increases due to subsequent paint passing through, and the temperature of the jetting paint passing through the jetting passage 56 does not drop. reaches the width of Therefore, the ejected paint is wasted until then. In other words, the yield was poor, time was wasted, and production efficiency was low.

PROBLEM TO BE SOLVED BY THE INVENTION The motivation for the present invention is to eliminate the waste of paint and time during stripe coating operations in small diameter cans, particularly in the initial stages of intermittent operations.

As mentioned above, in conventional stripe coating guns in small-diameter cans, (a) When paint jetting is interrupted, paint remains in the paint jetting passage inside the gun, its temperature drops, and its viscosity increases. rises.

((To) In the case of restarting the ejection, the high viscosity paint whose viscosity has increased passes through the ejection passage, so the amount of ejection decreases.

(c) Due to the decrease in the amount of ejection, the spray pattern from the nozzle is reduced.

2) Reduced spray patterns cannot be used because they deviate from the regular application pattern.

(e) Therefore, it is necessary to release the paint for a certain period of time and wait until the temperature of the paint returns to normal and the normal application pattern is restored.

(f) The above-mentioned release of paint and waste of time are problems in terms of production efficiency.

The root of the above problem is that when the paint jetting is interrupted, the temperature of the paint remaining on the jetting passage drops together with the adapter. If this temperature drop is prevented, this problem will be completely solved.

Means to be Solved by the Invention An object of the present invention is to maintain the temperature of the paint remaining in the jetting passage in the gun at approximately the same temperature as the jetting paint when the jetting of the gun for stripe coating inside small diameter cans is interrupted. It is to be.

In order to achieve the above object, the present invention heats the supplied paint at an appropriate temperature to recycle the area around the ejection passage even when ejection is interrupted.

That is, the gist of the present invention is to provide a method and apparatus for heating and insulating the area around the ejection passage between the on-off valve 3 and the nozzle 9 using supplied paint that is recycled even when the coating operation is interrupted in stripe coating inside a small-diameter can. It is.

As a method of heating the area between the ejection passage from the valve to the nozzle in the above gun, automatic temperature adjustment using an electric heater is a possible method, but the setting of such a device is limited to the extremely small space inside a small-diameter can. Therefore, it is extremely difficult to implement. The present invention does not use any separate equipment as described above, but uses the supplied paint itself.
That is, even when the on-off valve in the gun is opened, the supplied paint is bypassed to heat the area around the ejection passage between the on-off valve and the nozzle.

The basic structure for carrying out the above method is shown below. Please refer to FIG. The gun for stripe coating inside a small diameter can is connected to a suitably heated paint supply pipe 2A and its return pipe 2B. These connections are connected to both ends of a supply passage 2C in the gun body 1, and an on-off valve 3 is provided on the supply passage 2C. The on-off valve 3 is directly connected to the rod 12, and the other end is directly connected to an air pinstone or solenoid. Above opening/closing valve 3
Thereafter, a bypass paint passage 2D is provided around the ejection passage 6 up to the nozzle 9, and this passage is connected to the supply piping 2A and return piping 2B of the parent piping in parallel with the above-mentioned supply passage 2C. Ru.

Action Please refer to Figure 1. Operation air or current ON, O
The on-off valve 3 is opened and closed by the FF. Open/close valve 3
When "opened", the supplied paint passes through the opening/closing valve 3, passes through the jetting passage 6, and is jetted out from the nozzle 9 at the tip thereof.

Next, by opening the on-off valve 3, the passage of the supplied paint is closed and the spraying of the paint is stopped. On the other hand, in the bypass paint passage 2D, regardless of whether the on-off valve 3 is opened or closed,
Paint at the same temperature as the supplied paint always passes through and is recycled. Thereby, by closing the on-off valve 3,
The unsprayed paint remaining in the jetting passage 6 is kept warm,
The temperature does not drop and remains at the appropriate temperature for eruption. Therefore, even at the next time of ejection, since it has an appropriate viscosity, a normal spray can be performed. A predetermined coating pattern can be obtained.

Additionally, as a derivative benefit, the temperature of the paint as it passes through the ejection passage is maintained at a higher temperature than in the conventional case. This provides the following benefits:

■ The supply pressure of paint can be lower than that of conventional systems.

■ Can handle higher viscosity paints.

■ Spray pattern can be further expanded.

As a result of the experiment, it was found that there was almost no change in the spray pattern even if the spray was restarted 10 minutes after the spray was stopped.

Comparative data for the temperature of the ejected paint upon restart between a gun according to the invention and a conventional gun is shown in FIG.

Embodiment 1 Please refer to FIG. 2. Gun body 21 is open/close valve 2
3 and its seat 24, and thereafter an intermediate adapter 25 is attached with a bolt 28 or the like. A jet passage 26 communicating with the on-off valve 23 is provided inside the intermediate adapter 25, and a nozzle 29 is attached to the tip of the passage. A bypass paint passage 22D is provided in the intermediate adapter 25, and this passage is connected to the paint supply passage 22A in the body 21 and its return passage 22B.

The effect is almost the same as that in the basic structure mentioned above. Since it is the same, it will be omitted.

Part 2: Please refer to Figure 3. Principal term 1. In the above, the bypass paint passage was built into the intermediate adapter, but in this example, a conduit 32E is wound around the outside of the intermediate adapter 35. In this example, even the outer periphery of the nozzle 39 can be kept warm.

Effects of the Invention According to the method and gun of the present invention, the coating pattern of the stripe coating does not change even when the stripe coating work inside small diameter cans is interrupted, or even during the intermittent work, and the stripe coating pattern always maintains the regular width. It is possible to coat stripes.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the operation of a gun for stripe coating inside small-diameter cans according to the method of the present invention. FIG. 2 is a first embodiment of the present invention. Figure 3 is a side sectional view of the gun shown in Figure 2. Figure 4 is a system diagram of a small diameter can stripe coating system Figure 5 is a conventional gun for the same type of gun Figure 6 is a temperature comparison data graph of sprayed paint between the gun according to the present invention and the conventional gun Explanation of main symbols I, 21.31... Gun body 2 cooking...
...Paint supply pipe 2B...Return pipe
2C, 22C.

Claims (1)

[Claims] 1. A small-diameter device characterized by heating the space between the on-off valve 3 and the nozzle 9 in the body 1 of the gun with paint having approximately the same temperature as the paint supplied to the body 1 of the gun. How to heat a gun for stripe coating inside a can. 2. Branch the paint supply pipe 2A to the gun or the paint passage 2A in the gun body 1 to a paint passage 2C to the on-off valve 3 in the body 1, and the tip of the on-off valve 3 and the body 1. A gun for stripe coating inside a small-diameter can, characterized in that a paint passage 2D is provided in parallel with a nozzle 9 attached to the can. 3. The gun for stripe coating inside small diameter cans according to claim 1, wherein an intermediate adapter 25 is provided between the on-off valve 23 and the nozzle 29, and a paint passage 22E is provided inside the intermediate adapter 25. 4. Remove the paint passage 22D in the intermediate adapter and replace it with a paint pipe 32 on the outer periphery of the intermediate adapter 35.
A gun for stripe coating inside small diameter cans according to claim 3, wherein D is provided. 5. The gun for stripe coating inside small diameter cans according to claim 4, wherein the paint pipe 32D is provided extending to the outer periphery of the nozzle 39.