JP7619307B2 - Coating Equipment - Google Patents

Description

The present invention relates to a coating device that forms a coating film.

As a conventional technique in this field, for example, Patent Document 1 discloses a coating device that forms a coating film by ejecting a coating material from a die. This coating device is equipped with a first pipe that connects the die and a tank, and a second pipe that branches off from the first pipe and connects to the tank, and the coating material can be ejected from the die by operating the valves installed in these pipes.

JP 2019-98203 A

However, the coating material sent from the tank to the die may contain air (air bubbles), which may prevent the coating material from being discharged properly.

The present invention was made in consideration of such problems, and aims to provide a coating device that can effectively discharge and coat the coating material while preventing air bubbles from being included in the coating material discharged from the die during coating.

In view of the above problem, the coating device according to the present invention includes a tank for storing a coating material, a die for discharging the coating material, a first pipe connecting the die and the tank, a second pipe branching from the first pipe and connecting to the tank, a branching portion between the first pipe and the second pipe, a coating valve disposed between the die, a circulation valve disposed on the second pipe, a branching portion between the first pipe and the second pipe, and a pump disposed between the tank, and is characterized in that the portion of the first pipe from the branching portion to the coating valve extends downward in a vertical direction from the branching portion, and the portion of the second pipe from the branching portion to the circulation valve extends upward in a vertical direction from the branching portion and serves as an air reservoir for accumulating air contained in the coating material flowing from the branching portion to the coating valve.

According to the coating device of the present invention, during coating, the circulation valve is closed, the coating valve is open, and the pump is driven to flow the coating liquid from the tank to the die. At this time, since the section of the first piping from the branching part to the coating valve extends downward in the vertical direction from the branching part, the coating material flowing in this section of the first piping flows downward from the branching part, but the air (air bubbles) contained in this coating material moves toward the branching part due to buoyancy.

Furthermore, the section of the second pipe from the branch to the circulation valve extends vertically upward from the branch and serves as an air reservoir that stores air contained in the coating material traveling from the branch to the coating valve. This allows air (air bubbles) that has moved from the first pipe to the branch to be stored in the air reservoir.

In this way, according to the present invention, the coating material discharged from the die during coating can be discharged well and then coated while preventing air bubbles from being included in the coating material. Furthermore, after coating is completed, the air that has accumulated in the air reservoir can be returned to the tank together with the coating material by opening the circulation valve and driving the pump with the coating valve closed.

FIG. 1 is a schematic diagram of a coating device according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the operation of discharging a coating material from a die in the coating device shown in FIG. 1 . FIG. 2 is a schematic diagram for explaining an operation of circulating a coating material in a tank in the coating device shown in FIG. 1 .

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The coating device 1 according to the present embodiment is a device for coating a liquid or paste-like coating material. As shown in Fig. 1, the coating device 1 includes a tank 11 for storing the coating material, a die 12 for discharging the coating material, a first pipe 13 for connecting the tank 11 and the die 12, and a second pipe 14 for branching off from the first pipe 13 and connecting to the tank 11.

The coating device 1 includes a branching portion 19 between the first pipe 13 and the second pipe 14, a coating valve 15 arranged between the die 12, and a circulation valve 16 arranged in the second pipe 14. The coating device 1 further includes a pump 17 arranged between the branching portion 19 and the tank 11, and a suck-back valve 18 arranged between the die 12 and the coating valve 15. In FIG. 1, the operating directions of the coating valve 15, the circulation valve 16, and the suck-back valve 18 are indicated by arrows.

The tank 11 stores a fluid or paste-like coating material to be discharged from the die 12. The pump 17 is provided in the first pipe 13. Typically, the pump 17 is disposed near the tank 11, and the operation of the pump 17 causes the coating material to be discharged from the tank 11 into the first pipe 13.

The coating material stored in the tank 11 flows out of the tank 11 into the first pipe 13 by the operation of the pump 17, and then flows from the tank 11 through the first pipe 13 to the branch point 19 of the first pipe 13 and the second pipe 14.

Here, when the coating material is discharged from the die 12 (discharge state), the coating material flows through the first pipe 13 toward the die 12. On the other hand, when the coating material is not discharged from the die 12 (circulation state), the coating material flows through the second pipe 14 and returns to the tank 11.

The first pipe 13 is a pipe that connects the tank 11 and the die 12. The coating material to be coated by the die 12 flows through the first pipe 13. In the flow path of the coating material in the first pipe 13, a pump 17, a coating valve 15, and a suck-back valve 18 are arranged in this order from the tank 11 side. A branch section 19 to the second pipe 14 is provided between the coating valve 15 and the pump 17. Furthermore, the first pipe 13 has a larger diameter at the location where the suck-back valve 18 is provided than at other locations so that the suck-back valve 18 can move radially when inserted into the first pipe 13.

One end of the second pipe 14 is connected between the coating valve 15 of the first pipe 13 and the pump 17, which is the branching section 19, and the other end of the second pipe 14 is connected to the tank 11. In addition, a circulation valve 16 is disposed on the path of the coating material flowing through the second pipe 14.

The coating valve 15 is generally cylindrical, and as shown in FIG. 1, a hole 15a is provided that passes through the outer periphery of the generally cylindrical shape, passing through the central axis, and penetrating to its end face, and the hole 15a is connected to the first pipe 13. The coating valve 15 rotates around the central axis of the generally cylindrical shape as the rotation axis center by power generated by a first motor 21 connected to the coating valve 15. The first motor 21 receives power from, for example, an external power source (not shown), and generates a rotational force for rotating the coating valve 15.

Here, the coating valve 15 rotates due to the power of the first motor 21, and when the position of the upstream opening of the hole 15a coincides with the position of the first pipe 13, the valve is opened to allow the coating material to pass through the hole 15a. As a result, the coating material flows toward the die 12, and the die 12 is in an ejection state in which the coating material is ejected.

On the other hand, when the coating valve 15 is rotated by the power of the first motor 21 and is not positioned at the upstream opening of the hole 15a or the position of the first pipe 13, the coating valve 15 is in a closed state in which the coating material cannot pass through.

The circulation valve 16 is disposed above the coating valve 15. The circulation valve 16 is generally cylindrical like the coating valve 15, and has a hole 16a that penetrates from the outer circumferential surface of the generally cylindrical cylinder through the central axis of the generally cylindrical cylinder to the diagonal outer circumferential surface. The circulation valve 16 is disposed such that the outer circumferential surface of the generally cylindrical cylinder is sandwiched diagonally by the piping used for the second piping 14. The circulation valve 16 rotates around the central axis of the generally cylindrical cylinder by the power generated by the second motor 22 connected to the circulation valve 16. The second motor 22 receives power from, for example, an external power source (not shown) and generates a rotational force for rotating the circulation valve 16.

Here, when the circulation valve 16 rotates due to the power of the second motor 22 and the position of the opening of the hole 16a coincides with the position of the second pipe 14, the circulation valve 16 is in an open state in which the coating material can pass through the hole 16a. This allows the coating material to flow through the second pipe 14.

On the other hand, when the circulation valve 16 rotates due to the power of the second motor 22 and the position of the opening of the hole 16a does not match the position of the second pipe 14, the circulation valve 16 is in a closed state, preventing the coating material from passing through.

The suck-back valve 18 is a generally cylindrical piston disposed between the die 12 and the coating valve 15, and is inserted from the outer diameter side of the first pipe 13 toward the inside. A third motor 23 is connected to the suck-back valve 18. The suck-back valve 18 is driven by the power received from the third motor 23 from the outside to the inside of the first pipe 13 (pushing) or from the inside to the outside (retracting). The third motor 23 receives power, for example, from an external power source (not shown), and generates a force to cause the suck-back valve 18 to perform pushing and retracting operations.

As a result, when the suck-back valve 18 is driven in the pushing direction, the suck-back valve 18 enters the first pipe 13, causing the flow rate of the coating material discharged from the die 12 to suddenly increase. On the other hand, when the suck-back valve 18 is driven in the retracting direction, the flow rate of the coating material to suddenly decrease.

The die 12 is a member with a slit formed at the tip for discharge, and is connected to the first pipe 13. The tip of the die 12 is positioned to face the roll-shaped object to be coated (not shown). The die 12 discharges the coating material flowing in through the first pipe 13 from the tip side, and forms a coating film on the object to be coated, which rotates in a position opposite the tip of the die 12.

In this embodiment, the coating valve 15 is disposed below the branching portion 19, and the portion 13a of the first pipe 13 from the branching portion 19 to the coating valve 15 extends downward in the vertical direction from the branching portion 19.

Furthermore, the coating valve 15 is disposed above the branching portion 19, and the portion 14a of the second pipe 14 from the branching portion 19 to the circulation valve 16 extends upward in the vertical direction from the branching portion 19. This portion 14a of the second pipe 14 serves as an air reservoir 14A that stores the air contained in the coating material flowing from the branching portion 19 to the coating valve 15.

Next, referring to Figures 2 and 3, we will explain the operation of the coating device 1 when coating starts and when coating ends. First, we will explain the start of coating.

As shown in FIG. 3, in the initial state, the coating valve 15 is closed and the circulation valve 16 is open. The coating material discharged from the tank 11 and reaching the branching point 19 of the first pipe 13 and the second pipe 14 flows through the second pipe 14 and returns to the tank 11, so that the coating material can be circulated. Note that since the coating valve 15 is closed, the coating material does not flow from the branching point 19 of the first pipe 13 and the second pipe 14 toward the die 12. Note that the suck-back valve 18 is in the retracted state.

Next, the second motor 22 is operated to rotate the circulation valve 16 into a closed state. At this point, the pump 17 is operating, so the coating material is pressurized near the branch point of the first pipe 13 and the second pipe 14. Next, the first motor 21 is operated to rotate the coating valve 15 into an open state. This causes the coating material to flow from the branch point 19 of the first pipe 13 and the second pipe 14 through the coating valve 15 toward the die 12.

Next, the third motor 23 is operated to put the suck-back valve 18 into a pushed-in state. This causes the flow rate of the coating material discharged from the die 12 to rise sharply. In this state, the coating material is discharged from the die 12. Note that since the circulation valve 16 is closed, the coating material does not flow from the branching point 19 of the first pipe 13 and the second pipe 14 toward the tank 11.

Thus, according to the coating device 1 of this embodiment, during coating, the coating liquid can be made to flow from the tank 11 to the die 12 by driving the pump 17 with the circulation valve 16 closed and the coating valve 15 open. Here, the portion 13a of the first pipe 13 from the branching portion 19 to the coating valve 15 extends downward in the vertical direction from the branching portion 19. Therefore, the coating material flowing through the portion 13a of the first pipe 13 flows downward from the branching portion 19, but the air (air bubbles) contained in the coating material move toward the branching portion 19 due to buoyancy.

Furthermore, as shown in FIG. 2(b), the portion 14a of the second pipe 14 from the branch 19 to the circulation valve 16 extends vertically upward from the branch and serves as an air reservoir 14A that stores air contained in the coating material flowing from the branch 19 to the coating valve 15. This allows air (air bubbles) that has moved from the portion of the first pipe 13 toward the branch 19 to be stored in the air reservoir 14A.

In this way, during coating, the coating material discharged from the die 12 can be effectively discharged and applied while preventing air bubbles from being included in the coating material. Furthermore, because air does not remain inside the die 12 or in the portion of the first pipe 13 that houses the suck-back valve 18, the appropriate amount of coating material can be discharged.

Next, the first motor 21 is operated to rotate the coating valve 15 and close it. Specifically, the coating valve 15 is closed while the coating material is being discharged from the die 12. The second motor 22 is operated to rotate the circulation valve 16 and open it. Finally, the third motor 23 is operated to retract the suck-back valve 18.

As a result, the coating material passes from the branching point 19 of the first pipe 13 and the second pipe 14, through the second pipe 14 equipped with the circulation valve 16, and returns to the tank 11. Furthermore, after coating is completed, the air accumulated in the air reservoir 14A can be returned to the tank 11 together with the coating material by opening the circulation valve 16 and driving the pump with the coating valve 15 closed.

In this way, by performing intermittent coating operations, the coated and uncoated states are repeated, so air does not continue to accumulate in the path of the second piping 14, and air can be prevented from flowing into the die 12.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design modifications can be made without departing from the spirit of the present invention as described in the claims.

In this embodiment, the air stored in the air reservoir is returned to the tank, but for example, a valve or the like may be provided to allow the air to escape to the outside through the second pipe before the coating material is returned to the tank.

1: Coating device, 11: Tank, 12: Die, 13: First pipe, 13a: Part of first pipe 13, 14: Second pipe, 14a: Part of second pipe 14, 14A: Air reservoir, 15: Coating valve, 16: Circulation valve

Claims (1)

A tank for storing a coating material;
A die for discharging the coating material;
A first pipe connecting the die and the tank;
A second pipe branched from the first pipe and connected to the tank;
a coating valve disposed between a branch portion of the first pipe and the second pipe and the die;
A circulation valve disposed in the second pipe;
a pump disposed between the branch portion of the first pipe and the second pipe and the tank,
a portion of the first pipe from the branching portion to the coating valve extends downward in a vertical direction from the branching portion,
A coating device characterized in that the portion of the second piping from the branching portion to the circulation valve extends upward in a vertical direction from the branching portion and serves as an air reservoir for storing air contained in the coating material flowing from the branching portion to the coating valve.

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