JPH10309507A - Paint coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and continuously detect the liquid surface of paint housed in a coating head, that is, the housed quantity of the paint during coating work, to replenish the suitable quantity of the paint to a paint housing part based on this detection to always keep the fixed liquid surface and to supply the paint to a sheet to be coated in uniform film thickness and uniform quality, that is, to enable a device to perform paint coating excellent in film quality. SOLUTION: This device is provided with a coating head 4 having a housing part 2 of paint 1 and having a paint take-out part 3 at the lower end part, a paint supplying part for supplying the paint to the coating head through a control valve for controlling the supplied quantity, a float 7 to be floated on the paint housed in the paint housing part 2 of the coating head so that the float is moved with the rising and falling of the liquid surface of the paint, a load cell 10 for outputting an electric signal in connection with the vertical movement of the float, a gas supply source 18 and an electric/pneumatic converter 21 for converting a gas pressure from the gas supply source by the output from the load cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for coating a paint, and more particularly to an apparatus for coating a paint capable of reliably coating a sheet to be applied with a uniform thickness.

[0002]

2. Description of the Related Art A so-called curtain coater is used in the application of various paints, for example, in the application of paint to electrodes of a battery. This curtain coater has a coating head in which a small volume of paint having a relatively shallow depth is contained, and a coating head having a paint outlet formed at a lower end thereof. The coating material flows down on a web to be coated, that is, a sheet to be coated, for example, an Al foil, a Cu foil or the like constituting the above-mentioned electrode, and the coating material is continuously applied onto the sheet to be coated.

By the way, in such a coating apparatus, in order to apply the paint to a uniform thickness, it is necessary to maintain a constant amount of the paint flowing out from the lower end of the coating head by its own weight. In addition, it is necessary that the paint contained in the coating head is always kept in a state of being contained in a constant amount during the coating operation. As described above, various methods have been proposed as a level control method for keeping a certain amount of paint contained. As a general method, there are a continuous capacitance type, a differential pressure type, a float type, and the like. However, as in the above-described curtain coater, a coating head having a small storage capacity of the paint is used, and only a small amount of the stored paint is used. It is not possible to cope with a case where a large change in the liquid level has a great effect on the film quality such as a uniform coating thickness of the paint. This is due to the difficulty in controlling the supply level of the paint to the coating head based on the detection of the fluid level in a short span, for example, 1 mm, for the viscous paint.

There has also been proposed a method of detecting the liquid level of the contained paint by using an ultrasonic or photoelectric sensor to detect the height of the liquid level. For example, when there is a danger of explosion or ignition due to high flammability, there is a problem in explosion-proof measures. Further, in the case of the photoelectric type, there is a problem that it is difficult to appropriately detect the liquid level in response to a slight fluctuation of the liquid level.

[0005] Further, when the on / off control is performed using a point type level switch, for example, a capacitance type level switch, the liquid level changes in a few millimeters, resulting in a continuous level change. There was a problem in performing high-precision liquid level control.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for applying a coating of paint accurately and uniformly to a predetermined thickness. Is accurately and continuously detected during the coating operation, and based on this detection, an appropriate amount of the coating material is supplied to the coating container, and a constant liquid level is constantly maintained, and the coating target sheet is This makes it possible to apply the paint to a uniform film thickness, and thus to perform the coating of the paint uniformly, that is, with excellent film quality.

[0007]

According to the present invention, there is provided an apparatus for coating a coating material, comprising: a coating head having a storage portion for the coating material and having a paint outlet at a lower end portion; A paint supply unit to be supplied via a control valve, a float floated on the paint contained in a paint reservoir of the coating head so as to move up and down with the liquid level of the paint, and a vertical movement of the float , A load cell that outputs an electric signal, a gas supply source, and an electropneumatic converter that converts a gas pressure from the gas supply source according to an output from the load cell. The paint supply control valve is controlled by the gas pressure of the electropneumatic converter, and the paint supply control valve is controlled in accordance with a variation in the liquid level of the paint contained in the paint containing portion of the coating head from a predetermined position. To control the amount of paint contained in the coating head during paint application work.
Always keep it constant.

As described above, according to the present invention, an electric output corresponding to the liquid level is obtained from the load cell by a float that moves up and down with the liquid level of the paint in the coating head, and this is converted into gas pressure. Because the paint supply valve is controlled by this gas pressure to control the paint supply amount, fluctuations in the liquid level can be detected continuously, and the detection is essentially safe. Since it is extracted as a small electric signal through the explosion-proof barrier, for example, as described above, even for paints that have problems with explosion, ignition, etc., it is possible to avoid the occurrence of sparks etc. and to form a highly safe explosion-proof area Becomes Therefore, during the operation of the coating material, a predetermined amount of the coating material can be reliably set in the coating head, so that the amount of the coating material flowing out from the lower end of the coating head can be reliably set to the predetermined two positions. The thickness of the coating applied to the coating sheet can be accurately controlled, and a uniform film can be satisfactorily coated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, a paint coating apparatus according to the present invention has a coating head having a paint storage section and a paint outlet at the lower end thereof.
A paint supply unit that supplies paint to the coating head through a control valve that controls the supply amount, and a paint supply unit that moves along with the paint level above and below the paint stored in the paint storage unit of the coating head. With the float floated,
It has a load cell that outputs an electric signal in connection with the vertical movement of the float, a gas supply source, and an electropneumatic converter that converts gas pressure from the gas supply source according to an output from the load cell. The paint supply control valve is controlled by the gas pressure of the electropneumatic converter, and the paint supply control valve is controlled in accordance with a variation in the liquid level of the paint contained in the paint containing portion of the coating head from a predetermined position. Is controlled so that the amount of paint contained in the coating head is always kept constant during the paint application operation.

FIG. 1 is a schematic diagram showing an example of the apparatus of the present invention. In this paint coating apparatus, for example, when handling dangerous paint having flammability or the like, an area requiring explosion-proof, that is, a spark, etc., is generated on the left side from the position indicated by reference symbol B in FIG. An explosion-proof area that handles weak currents through an intrinsically safe explosion-proof barrier so that no explosion-proof operation is performed, and the left side is a non-explosion-proof area that does not require explosion-proof, that is, allows normal current handling.

In the apparatus according to the present invention, there is provided a coating head 4 having a paint container 2 for containing the paint 1 and having a paint outlet 3 at a lower end. The coating head 4 is provided with a shutter 5 for opening and closing the paint outlet 3 so as to be rotatable at, for example, the upper end of the paint container 2. The rotation of the actuator 6 is controlled to take out the paint. Mouth 3, for example setting of slit spacing,
It is designed to open and close.

Further, for example, a paint supply source 14 is provided on the explosion-proof area side.
The supply amount of the paint is controlled by the control valve 15 so that the paint is supplied from the paint supply port 16 of the paint containing section 2 of the coating head 4 to the paint containing section 2. The paint supply control valve 15 controls the gas pressure,
For example, the opening / closing control is performed by control means 17 controlled by air pressure.

On the paint 1 stored in the paint storage section 2,
The float 7 that can move up and down in accordance with the up and down movement of the liquid surface of the paint 1 is made to float. At least the surface of the float 7 is made of a material that is not eroded by the paint 1, that is, does not react with the paint 1. The float 7 can be formed of a hollow body having a spherical shape, a cylindrical shape, a conical shape, or any other external shape so as to float on the paint 1.

For example, an arm 8 is attached to the float 7 so that the float 7 can move smoothly in accordance with the level of the liquid of the paint 1. It is supported by the arranged shaft 9,
It can be rotated along the plane of FIG.

A load cell 10, for example, a strain gauge for converting the amount of strain into the amount of electricity is disposed above the coating head 4. In this load cell 10, a rod 11 is disposed at a position where it abuts against an arm 8 that supports the float 7 to rotate, and the arm 8 rotates by the movement of the float 7 that moves according to the level of the paint 1 above and below. Depending on the rod 1
When the rod 1 is moved up and down, a stress is applied to the load cell 10 by its positional displacement, and an electrical signal output corresponding to the vertical displacement of the rod 1, that is, the liquid level displacement can be taken out from the load cell 10.

In a region not requiring explosion protection, for example, a zener barrier 12 and an amplifier 13 for intrinsically safe explosion protection are provided, and the position of the float 7 due to the weak current obtained from the load cell 10, that is, the position of the liquid surface of the paint 1 is provided. Is input to the Zener barrier 12 and further amplified to the amplifier 13.

On the other hand, a gas supply source 18 is provided, and a gas such as air from the supply source is supplied to the control means 17 to be driven. Further, a control gas supply path 20 to the control means 17 is provided.
-Pneumatic converter 21 that adjusts gas pressure by output from
Is arranged, and a control gas whose pressure is controlled is supplied to the control means 17 by an electric output from the amplifier 1, that is, a detection signal from the load cell 10.

Below the paint outlet 3 of the coating head 4, there is arranged a sheet 31 to be coated, such as an Al foil or a Cu foil, which constitutes a battery electrode, for example, a so-called web transfer means. . This transfer means is provided with, for example, a backup roll 32 which rotates while maintaining a predetermined interval from the take-out port 3, whereby the paint flowing out from the take-out port 3 is applied to the sheet 31 to be applied to a required thickness. Thus, a coating film 33 of the paint is formed.

Although not shown, the sheet on which the coating film 33 is formed is transferred to a drier and dried.

As described above, when the paint 1 from the coating head 4 is applied onto the sheet 31 to be applied and the paint 1 in the paint containing portion 2 decreases as described above, The float 7 moves in accordance with the decrease in the surface, and the detection signal current from the load cell 10 fluctuates, for example, increases. Accordingly, the detection signal current flows through the Zener barrier 12 and the amplifier 13. Amplified and controls the electropneumatic converter 21, controls the control means 17 with the corresponding air pressure, opens the control valve 15, and supplies the paint from the paint supply source 14 to the paint container 2 from the paint supply port 16. The liquid level rises. When the liquid level rises above a predetermined position, the float 7 rises accordingly, and accordingly, the detection signal current from the load cell 10 conversely decreases, for example, whereby the electropneumatic converter 21 is controlled. The control means 17 is controlled with the air pressure according to the pressure, the control valve 15 is closed, and the paint supply source 14 is closed.
By cutting off or reducing the supply of the paint from the paint container, the liquid level of the paint in the paint container 2 can be constantly and constantly maintained.

As described above, according to the apparatus of the present invention, an electric output corresponding to the liquid level is obtained from the load cell 10 by the float 7 which moves up and down together with the liquid level of the coating material 1 of the coating head 4 and this is output. Convert to gas pressure,
Since the paint supply valve is controlled by this gas pressure and the paint supply amount is controlled, the paint supply valve is reliably controlled by the small electric output obtained by the fine movement of the liquid level. be able to.

Therefore, during the operation of the coating material, a predetermined amount of the coating material can be reliably set in the coating head, so that the fluctuation of the flowing amount of the coating material from the lower end of the coating head due to the fluctuation of the coating amount can be reduced. This can be effectively avoided, whereby the control of the coating thickness of the coating material on the coated sheet can be performed accurately, and a uniform film can be coated well.

For example, even if the paint to be handled has a danger of explosion or the like, in the explosion-proof area, only a very small current can be handled, so that occurrence of an accident due to sparks or the like can be avoided.

The specific configuration of the apparatus of the present invention is, of course, not limited to the above-described example. For example, an arm is provided on the float 7 for a mechanism for transmitting the vertical movement of the float 7 to the load cell 10. The structure is not limited to the structure, and a structure for directly transmitting the force, a method of amplifying a force by the movement of the float 7 using a link mechanism, a method of converting the movement of the float 7 into a pulling force, By applying a stress to the load cell 10 by this tensile force, various deformation changes can be made.

[0025]

As described above, according to the device of the present invention,
Even during the coating operation, the amount of the coating material 1 in the coating head 4 can be constantly and reliably maintained at a constant level, so that the amount of the coating material flowing out from the lower end thereof can be maintained at a constant level. Therefore, even in the case where the amount of the paint in the paint accommodating portion of the coating head is required to apply the paint with high precision to such an extent that it does not even affect the uniformity of the paint film on the coated sheet, it is sufficient. A uniform paint can be applied to the substrate.

According to the structure of the present invention, an electric output corresponding to the liquid level is obtained from the load cell 10 by the float 7 which moves up and down together with the liquid level of the paint 1 and is converted into a gas pressure. Since the paint supply valve is controlled by this gas pressure and the paint supply amount is controlled, the paint supply valve is reliably controlled by the small electric output obtained by the fine movement of the liquid level. be able to. In other words, even if the paint has a danger such as an explosion,
Since a small current or a small voltage is handled, accidents such as sparks can be avoided, and explosion proof can be reliably achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of a paint coating apparatus according to the present invention.

[Explanation of symbols]

1 paint, 2 paint container, 3 paint outlet, 4
Coating head, 5 shutter, 6 actuator, 7 float, 10 load cell, 12 Zener barrier, 13 amplifier, 14 paint supply source, 15 control valve, 16 paint supply port, 17 control means, 21 electropneumatic converter, 31 coated sheet, 32 backup roll, 33 coating

Claims (1)

[Claims] 1. A coating head having a paint storage section and having a paint outlet at a lower end thereof, and a paint supply for supplying the paint to the coating head via a control valve for controlling a supply amount of the paint. A float floated on the paint contained in the paint containing portion of the coating head so as to move up and down with the liquid level of the paint, and an electric signal related to the up and down movement of the float. A load cell for outputting, a gas supply source, and an electropneumatic converter for converting a gas pressure from the gas supply source according to an output from the load cell, and a supply control valve for the paint based on a gas pressure by the electropneumatic converter. And controlling the paint supply control valve in accordance with the fluctuation of the liquid level of the paint contained in the paint containing portion of the coating head from a predetermined position to control the coating. The amount of paint stored in the head
A coating device for paint, characterized in that it is kept constant at all times.