JPS62133058A - Gas wiping nozzle - Google Patents

Abstract

PURPOSE:To exert uniform dynamic pressure to a high pressure gas and to make plating deposition uniform in the transverse direction of a steel strip by fixing the rear surfaces of upper and lower nozzle bodies to a nozzle spacer and providing many rows of specifically shaped gas ejection ports to the spacer. CONSTITUTION:The upper nozzle body 1 of which the inside surface consists of a sloped part 1a and a horizontal part 1b and the lower nozzle body 2 of which the inside surface consists of a sloped part 2a and a horizontal part 2b are combined above and below. The nozzle spacer 11 is bolted to the rear surfaces of the upper and lower nozzle bodies 1, 2 and flow regulating bars 9a, 9b are provided to a gas chamber 4 to constitute a gas wiping nozzle. The plural gas ejection ports 12 are provided to such nozzle spacer 11. Each ejection port 12 is formed to the rhombic shape of the same area consisting of the top side 12a and bottom side 12b parallel with each other and the diagonal left side 12c and right side 12d. The total size of the vertical lengths (a) and (b) of the adjacent ejection ports 12, 12' is made approximately the same as the vertical length A of the ports 12, 12'. The uniform dynamic pressure is thereby exerted to the high pressure gas and such gas is ejected from a slit nozzle port 5.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention provides a method for squeezing out excessive molten zinc on the surface of a steel strip pulled up from a plating tank in continuous hot-dip galvanizing equipment by spraying high-pressure gas.
This invention relates to a gas wiping nozzle for controlling the amount of zinc deposited.

[Prior art and its problems]

When galvanizing IJ tubes using continuous hot-dip galvanizing equipment, the steel strip is guided into the plating bath containing the galvanizing bath, and the steel strip is progressed by a zinc roll installed in the plating facility. The direction is changed and you are pulled up in the opposite direction. In this way, the surface of the steel strip immediately after being pulled up from the plating tank has an excessive amount of molten zinc attached to it. High-pressure gas is sprayed onto the surface of the steel strip from a pair of gas wiping nozzles, and the excessively deposited molten zinc is squeezed off by the gas, thereby controlling the amount of zinc deposited on the surface of the steel strip to a constant value. ing.

FIG. 3 is a schematic longitudinal sectional view of a conventional gas wiping nozzle. As shown in the drawing, the gas wiping nozzle is
It consists of an upper nozzle body 1 and a lower nozzle body 2 that are vertically combined via a distance piece 3, which creates a gas chamber 4 into which high-pressure gas is blown, and a gas chamber 4 in which high-pressure gas is directed toward the IJ tag. A continuous horizontal slit nozzle opening 5 is formed to eject water.

A downward recess consisting of a horizontal part 1b and an inclined part 1a for mounting the distance piece 3 is formed on the inner surface of the upper nozzle body 1, and the tip thereof is connected to the slit nozzle opening 5.
It is a horizontal part for Inside the lower nozzle body 2, a shallow upward concave portion consisting of an inclined portion 2a and a horizontal portion 2b is formed following a horizontal portion at the tip of the lower nozzle body 2 for the slit nozzle opening 5.

As shown in the schematic front view of part 5 in FIG. 4, the distance piece 3 has circular gas ejection ports 6 of a predetermined diameter arranged at regular intervals, and has a surface 3aid facing the slit nozzle opening 5. It is shaped like a letter in cross section. The thickness of the distance piece 3 is equal to the thickness of the horizontal portion 1 formed on the upper nozzle body 1.
The slit nozzle opening 5 is formed on the lower surface by a shim 7 having a predetermined thickness and inserted between the lower nozzle body 2 and the lower nozzle body 2.

The upper nozzle body 1, the distance piece 3, and the lower nozzle body 2 each have a through hole 1c formed at a predetermined interval.
, 3b and 2c are integrally fixed by a plurality of bolts 8 passing through them. Reference numeral 9 denotes a rectifying rod with a circular cross section that is horizontally provided in the gas chamber 4 in the vicinity of the gas jet port 6 of the distance piece 3 .

Since the conventional gas wiping nozzle is configured as described above, the high pressure gas blown from the back side of the distance piece 3 is ejected into the gas chamber 4 through the gas ejection port 6 of the distance piece 3. The steel sinter that passes through the slit nozzle opening 5 and moves in front of the IJ stub is injected in the width direction of the IJ stub, squeezing off the molten zinc that has adhered excessively to the surface of the IJ stub.

However, the conventional gas wiping nozzle described above has the following problems. That is, as shown in FIG. 5, the dynamic pressure of the gas ejected from the circular gas ejection port 6 of the distance piece 3 into the gas chamber 4 tends to be high at the center and weak at the periphery. The dynamic pressure of the gas injected from the port 5 toward the steel strip 1o also becomes non-uniform due to the above-mentioned tendency.

In order to correct the above-mentioned non-uniform dynamic pressure of the gas, the gas chamber 4
Although a horizontal rectifying rod 9 is disposed inside, even this arrangement of the rectifying rod 9 does not solve the non-uniformity of the gas dynamic pressure.

If the dynamic pressure of the high-pressure gas injected from the gas wiping nozzle toward the steel strip is uneven, it is not possible to make the coating amount uniform in the width direction of the steel strip, and as a result, lines appear on the plated surface. Marks occur, leading to quality defects.

[Purpose of the invention]

Therefore, an object of the present invention is to use a continuous hot-dip galvanizing equipment to remove excessively adhered molten zinc from the surface of a steel strip pulled up from a plating tank by spraying high-pressure gas, and to remove the excess molten zinc from the surface of the steel strip in the width direction of the steel strip. An object of the present invention is to provide a gas wiping nozzle that can produce hot-dip galvanized steel strip with a uniform coating amount and excellent quality.

[Summary of the invention]

This invention includes an upper nozzle body having a downwardly directed recess formed on its inner surface and a lower nozzle body having an upwardly directed recessed portion formed on its inner surface.
In a gas wiping nozzle for hot-dip galvanizing, which has a horizontal slit nozzle opening at its tip and a gas chamber formed inside thereof by integrally joining the upper nozzle body and the lower nozzle body, The upper nozzle body and the lower nozzle body are fixed by nozzle spacers provided on the back surfaces thereof, and the nozzle spacer is provided with a plurality of oblique gas ejection ports at regular intervals along its length, and the oblique The gas ejection port is characterized in that the total vertical length of adjacent portions of the gas ejection port is approximately constant at any location.

[Structure of the invention]

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic vertical sectional view showing one embodiment of the present invention, and FIG. 2 is a partially schematic front view of a nozzle spacer. As shown in the drawing, the gas wiping nozzle includes an upper nozzle body 1 having a downward recess formed on the inner surface with an inclined part 1a and a horizontal part 1b, and a shallow upward recessed part with an inclined part 2a and a horizontal part 2b formed on the inner surface. A gas chamber 4 and a slit nozzle opening 5 are formed by vertically combining the upper nozzle body 1 and the lower nozzle body 2 with the lower nozzle body 2 having a recess formed therein. This is similar to a conventional gas wiping nozzle.

In the gas wiping nozzle of the present invention, the upper nozzle body 1 and the lower nozzle body 2 are fixed to a rear nozzle baser 11 with bolts so as to form slit nozzle ports 5 at predetermined intervals. has been done.

As shown in FIG. 2, a plurality of gas ejection ports 12 are formed in the nozzle spacer 11 at regular intervals. The gas outlet 12 has horizontal upper sides 12a and lower sides 12b that are parallel to each other, and an oblique left side 12c that is parallel to each other.
and the right side 12d, and are formed in an orthorhombic shape with the same area, and the adjacent gas ejection ports 12, l2'
The sum of the vertical lengths a and b at any location is the vertical length A of one gas outlet 12 or 12'.
is formed almost the same way.

9a and 9b are rectifying rods with a circular cross section that are horizontally provided in the gas chamber 4.

Since the gas wiping nozzle of the present invention is configured as described above, the gas ejection port 1 of the nozzle spacer 11
The dynamic pressure distribution of the high-pressure gas ejected into the gas chamber 4 through 2 should be such that the total dimension of vertical lengths a and b at adjacent gas ejection ports 12° and 12' is approximately constant at any location. This results in uniformity.

As a result, high-pressure gas is ejected from the slit nozzle port 5 toward the steel strip with uniform dynamic pressure.
The amount of plating deposited in the width direction of the steel strip can be made uniform.

〔Effect of the invention〕

As described above, according to the present invention, in continuous hot-dip galvanizing equipment, excessive molten zinc adhering to the surface of the steel strip pulled up from the plating tank is squeezed by spraying high-pressure gas with uniform dynamic pressure distribution. This provides an industrially useful effect of making it possible to produce a hot-dip galvanized steel strip of excellent quality by making the amount of coating coating uniform in the width direction of the steel strip.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view showing one embodiment of the present invention;
Figure 2 is a partial schematic front view of a part of the nozzle spacer, Figure 3
The figure is a schematic vertical cross-sectional view of a conventional gas wiping nozzle.
The figure is a schematic front view of the distance piece portion, and FIG. 5 is an explanatory diagram showing the dynamic pressure distribution of the injection gas. In the drawing, ■... Upper nozzle body 2... Lower nozzle body 3...
Distance piece 4...Gas chamber 5...Slit nozzle port 6...Gas jet lower...Shim
8... Bolts 9.9a, 9b... Rectifier rod 10.
・・Steel strip 11・・Nozzle spacer 12・
...Gas outlet 12a...Top side 12b...
・Bottom side 12c...Left side 12d...Right side.

Claims (1)

[Claims] By integrally joining an upper nozzle body with a downward recess formed on its inner surface and a lower nozzle body with an upward recess formed on its inner surface, a horizontal slit nozzle is formed at the tip of the upper nozzle body. In a gas wiping nozzle having a mouth and a gas chamber formed therein, the upper nozzle body and the lower nozzle body are fixed by nozzle spacers provided on the back surfaces of the upper nozzle body and the lower nozzle body. At the same time, the nozzle spacer is provided with a plurality of oblique-shaped gas outlets at regular intervals along its length, and the oblique-shaped gas outlets are arranged so that the vertical length of the adjacent portions of the oblique-shaped gas outlets are equal to each other. A gas wiping nozzle characterized in that the total dimension is approximately constant at any location.