JPH05125517A - Gas wiping device - Google Patents

Abstract

PURPOSE:To provide a wiping device for stably controlling the film thickness on the surface of a steel sheet. CONSTITUTION:In the gas wiping device for controlling the film thickness of liquid stuck to the surface of the steel sheet by spouting high pressure squeezing gas 16 from a slit nozzle 15 extended to the width direction of the carried steel sheet, a laser beam irradiating device 21, which the laser beam irradiates from the one end of the slit nozzle 15, is arranged and a beam detecting part 26 for receiving the beam is arranged at the other end. In the slit nozzle 15, the laser beam is irradiated to observe the development of the clogged part in this slit and also, in the case the clogged part develops, the output of the laser beam is increased to melt and remove the clogged part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas wiping device provided in, for example, a continuous plating line (CGL) and a pickling line of an iron making machine.

[0002]

2. Description of the Related Art Conventionally, a gas wiping device has been used, for example, which is provided in a continuous plating line and controls the film thickness of a liquid deposited on the surface after plating. An example of this conventional gas wiping device is shown in FIGS.

As shown in these drawings, the plating solution 11 adheres to the surface of a steel strip 13 which has passed through a plating tank 12 filled with a plating solution 11 containing a plating metal.
In order to adjust and control the film thickness of the plating solution 11, the pair of wiping nozzles 1 are arranged so as to face the steel strip 13 being conveyed.
4, 14 are provided. This wiping nozzle 14
Is formed with a slit nozzle 15 extending in the plate width direction of the steel strip, so that the blowing of the throttle gas 16 introduced is uniform in the plate width direction and the plating solution 11 on the surface of the steel strip 13 is formed.
The film thickness of is controlled. In addition, 17 in FIG. 2 shows a sink roll.

[0004]

By the way, when the wiping operation is performed, the splash of the throttle gas 16 or the like causes the splash of the plating metal to occur in the slit nozzle 15.
There is a problem that clogging may occur inside, and a defective drawing portion 18 on the surface of the steel strip 13 due to clogging of the nozzle may occur, resulting in variations in products.

For this reason, early detection and early removal of nozzle clogging have led to the deterioration of quality and the prevention of partial separation. However, when this removing operation is also performed manually, it is very dangerous because it is performed in the vicinity of the liquid metal plating tank 12, and it is desired to establish a simple and safe method for removing the clogged portion.

[0006]

The structure of the gas wiping device according to the present invention which achieves the above object is such that a high pressure gas is ejected from a slit nozzle extending in the plate width direction of a conveyed steel plate and adhered to the surface of the steel plate. A gas wiping device for controlling the film thickness of a liquid, comprising a light emitting section for emitting a laser beam from one end of the slit nozzle into the slit nozzle and a light receiving section for receiving the light at the other end. Characterize.

[0007]

The light is emitted from the light emitting portion to the light receiving portion while looking in the longitudinal direction of the slit nozzle. When a part of the slit nozzle is clogged, the emitted light is reflected, absorbed and scattered by the clogged part, so that the amount of light reaching the light receiving part is reduced. As a result, the occurrence of clogging of the slit nozzle is detected. A laser irradiation device having a high energy density is used as the means for removing the clogging portion, and the clogging portion can be immediately melted and removed. Therefore, it is not necessary to stop the line, and the operation rate of the line is improved. Further, since the conventional work of removing the clogging part in the vicinity of the dangerous molten metal tank is unnecessary, the safety workability of the worker is enhanced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a gas wiping device according to this embodiment. The same members as the members of the apparatus shown in FIGS. 2 and 3 described above are designated by the same reference numerals, and a duplicate description will be omitted. As shown in FIG. 1, a laser beam irradiation device 21 as a light emitting unit is provided at one end of the slit nozzle 15 of the wiping nozzle 14 of the gas wiping device. Here, the laser beam irradiation device 21 includes a laser beam generator 22, an optical path 23 for propagating the laser beam generated here, an output part 24 installed so as to see through the slit nozzle 15, and a laser beam output part. The scanning device 25 is configured to change the emission direction from the scanning device 24. On the other hand, at the other end of the slit nozzle 15, there is provided a photodetection section 26 as a photodetection section for receiving the laser beam emitted from the output section 24, and between the photodetection section 26 and the slit nozzle 15. A shutter plate 28 that opens and closes the optical path by a driving device 27 is installed in the.

In the above structure, the laser output of the laser light generator 21 is operated at a small output in a normal gas wiping device. If there is no abnormality in the slit nozzle 15, the laser beam output from the output unit 24 through the optical path 23 passes through the slit nozzle 15 and passes through the light detection unit 26.
And the amount of light detected is almost constant. When a clogged portion is generated in the slit nozzle 15, the laser beam is reflected / scattered by the clogged portion, and the amount of light entering the photodetection unit 26 is reduced, so that the occurrence of the clogged portion is detected. When the occurrence of this block is detected,
Immediately, the work for removing the block is started. First, the shutter plate 28 closes the optical path by the driving device in order to protect the light detection unit 26. Next, the laser output of the laser light generator 22 is increased. As a result, the clogged portion is irradiated with a high-power laser beam, and the clogged portion is melted. Since the throttle gas 16 is constantly introduced into the wiping nozzle 14, the molten and clogged portion is blown away and removed. At this time, the scanning device 25 is operated to scan the laser beam, thereby effectively cleaning the peripheral portion.

In this manner, when the slit nozzle 15 is clogged, the clogged portion is immediately detected and melted and removed, so that the deterioration of the quality of the product due to the gas wiping unevenness is greatly reduced. Further, the work in the vicinity of the molten metal tank, which is required in the conventional clogging work, becomes unnecessary, so that the safety of the worker is secured and the safety can be improved.

In the present embodiment, the light emitting portion was used as the light emitting means for detecting the portion and the melting means for removing the portion using the laser beam irradiating device. May be improved.

[0012]

As described above in connection with the embodiments, the gas wiping device according to the present invention constantly monitors the inside of the slit nozzle by using laser light, and when the clogged portion occurs in the nozzle, the laser is wiped. Since the light output can be increased and the clogged portion can be removed, for example, stable gas wiping can be always performed in a continuous plating line or an acid line, and quality can be improved.
Further, unlike the conventional case, it is not necessary to manually remove the clogging part by the worker, and the safety of the worker is significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic view of a gas wiping device according to this embodiment.

FIG. 2 is a schematic sectional view of a conventional wiping device.

FIG. 3 is a schematic view showing a defect of a conventional wiping device.

[Explanation of symbols]

 11 Plating Solution 12 Plating Tank 13 Steel Strip 14 Wiping Nozzle 15 Slit Nozzle 16 Diaphragm Gas 17 Syncroll 18 Poor Drawing Part 21 Laser Beam Irradiator 22 Laser Light Generator 23 Optical Path 24 Output 25 Scanning Device 26 Photodetector 27 Drive Device 28 Shutter plate

Claims (1)

[Claims] 1. A gas wiping device for ejecting a high-pressure gas from a slit nozzle extending in the plate width direction of a conveyed steel plate to control the film thickness of a liquid adhering to the surface of the steel plate, wherein one end of the slit nozzle is provided. A gas wiping device, characterized in that a light emitting part for emitting a laser beam is provided in the slit nozzle, and a light receiving part for receiving the light is provided at the other end.