JPH0230378B2 - - Google Patents

Description

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

[Prior art and its problems]

When galvanizing a steel strip using continuous hot-dip galvanizing equipment, the steel strip is led into a plating tank containing a galvanizing bath, and its direction of travel is changed by a sink roll installed in the plating tank. be pulled upwards. 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 out by the gas, thereby controlling the amount of zinc deposited on the surface of the steel strip to a constant value. .

FIG. 5 is a schematic longitudinal sectional view of a conventional gas wiping nozzle. As shown in the drawing, the gas wiping nozzle consists of an upper nozzle body 1 and a lower nozzle body 2 that are vertically combined with each other through a distance piece 3, which allows high-pressure gas to be blown into the gas. A chamber 4 and a continuous horizontal slot nozzle opening 5 are formed through which high pressure gas is injected towards the steel strip.

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

As shown in the partial schematic front view of FIG. 6, the distance piece 3 has circular gas jet ports 6 of a predetermined diameter arranged at regular intervals, and the surface 3a facing the slit nozzle opening 5 is It is formed in a dogleg shape in cross section. The thickness of the distance piece 3 is approximately the same as the depth of the recess in the horizontal portion 1b formed in the upper nozzle body 1, and a shim of a predetermined thickness is inserted between the lower nozzle body 2 and the lower nozzle body 2. 7 forms a slit nozzle opening 5.

The upper nozzle body 1, distance piece 3, and lower nozzle body 2 are integrally fixed by a plurality of bolts 8 passing through through holes 1c, 3b, and 2c formed at predetermined intervals in each of them. . 9 is a gas outlet 6 of the distance piece 3 in the gas chamber 4;
This is a straightening rod with a circular cross section that is installed horizontally in the vicinity of the rectifying rod.

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. Through the slit nozzle opening 5, the molten zinc is injected in the width direction of the steel strip moving on the front surface thereof, and the molten zinc excessively deposited on the surface of the steel strip is squeezed out.

However, the conventional gas wiping nozzle described above has the following problems. That is, the seventh
As shown in the figure, 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 toward the strip 10 also becomes non-uniform due to the above-mentioned tendency.

In order to correct the above-mentioned dynamic pressure non-uniformity of the gas,
Although a horizontal rectifying rod 9 is arranged within the gas chamber 4, even with such arrangement of the rectifying rod 9, it is not possible to eliminate the non-uniformity of the gas dynamic pressure.

If the dynamic pressure of the high pressure gas injected from the gas wiping nozzle towards the steel strip is non-uniform,
The amount of plating applied in the width direction of the steel strip cannot be made uniform, and as a result, linear marks occur on the plating surface, resulting in poor quality.

[Purpose of the invention]

Therefore, an object of the present invention is to remove excessively adhered molten zinc from the surface of the steel strip pulled up from the plating bath in continuous hot-dip galvanizing equipment.
To provide a gas wiping nozzle capable of producing a hot-dip galvanized steel strip of excellent quality by squeezing it out by spraying high-pressure gas, making the amount of plating uniform in the width direction of the steel strip.

[Summary of the invention]

In this invention, an upper nozzle body having a downward recess formed on the inner surface and a lower nozzle body having an upward recess formed on the inner surface are integrally connected by a bolt through a distance piece having a plurality of gas ejection ports. In a gas wiping nozzle, which has a horizontal slit nozzle opening at its tip and a gas chamber inside the nozzle by joining, flat surfaces arranged at regular intervals on a base are used as the distance pieces. A plurality of rectifying plates each having a streamlined wing-like shape are used, and the rectifying plates are arranged in the recess formed on the inner surface of the upper nozzle body with their horizontal axes directed toward the slit nozzle opening. A gas ejection port is formed between the plurality of rectifying plates, and the inner surface of the upper nozzle body constituting the gas chamber has a first curved surface portion facing downward and continuing to the slit nozzle opening, with a protrusion sandwiched therebetween. , a recessed portion consisting of a second curved surface portion oriented laterally toward the current plate,
A concave portion consisting of an upwardly curved surface portion continuing to the slit nozzle opening is formed on the inner surface of the lower nozzle body, and high-pressure gas is jetted into the gas chamber from the gas jet port formed between the plurality of rectifier plates. By doing so, the dynamic pressure distribution of the high pressure gas is made uniform.

[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. As shown in the drawing, the gas wiping nozzle consists of an upper nozzle body 11 having a downwardly directed concave portion formed on its inner surface, and a lower nozzle body 12 having an upwardly directed concave portion formed on its inner surface. The formation of a gas chamber 14 into which gas is blown and a continuous horizontal slot nozzle opening 15 through which high-pressure gas is injected towards the steel strip.
It is similar to a conventional gas wiping nozzle.

The inner surface of the upper nozzle body 11 is provided with a rectifying plate 1, which will be described later.
3 and the horizontal part 11e following the horizontal part 11a for the slit nozzle opening 15, and the downward first curved part 11b sandwiching the protrusion 11d, and the rectification. A concave portion is formed with a second curved surface portion 11c extending laterally toward the plate 13. A horizontal portion 1 for the slit nozzle opening 15 is provided on the inner surface of the lower nozzle body 12.
A concave portion consisting of an upwardly curved surface portion 12b continuing from 2a is formed.

In the gas wiping nozzle of this invention,
As shown in a partially schematic front view in Fig. 2, a partially schematic plan view in Fig. 3, and a partially schematic perspective view in Fig. 4,
In the recess formed on the inner surface of the upper nozzle body 11, in place of the conventional distance piece, a plurality of wing-shaped baffle plates 13 with a streamlined planar shape are arranged at regular intervals on the base 13a. , with its horizontal axis facing the slit nozzle opening 15 , and a gas jet port 16 is formed between the current plates 13 .

17 is a shim inserted between the lower surface of the base 13a of the rectifying plate 13 and the lower nozzle body 12; 18 is for integrally fixing the upper nozzle body 11, the rectifying plate 13, and the lower nozzle body 12; bolt, 19 is gas chamber 1
This is a rectifier rod with a circular cross section that is installed horizontally within the rectifying rod.

Since the gas wiping nozzle of the present invention is configured as described above, as shown by the arrow in FIG.
The high-pressure gas ejected into the gas chamber 14 through the straightening plate 13 has a uniform dynamic pressure distribution, so that the high-pressure gas flows from the slit nozzle port 15 toward the steel strip with uniform dynamic pressure. Gas is ejected, thereby making it possible to make the amount of plating uniform across the width of the steel strip.

〔Effect of the invention〕

As described above, according to the present invention, in continuous hot-dip galvanizing equipment, the molten zinc excessively attached 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 excellent effect of making it possible to produce hot-dip galvanized steel strips of excellent quality by making the amount of plating coating uniform in the width direction of the steel strips.

[Brief explanation of drawings]

Fig. 1 is a schematic vertical sectional view showing one embodiment of the nozzle of the present invention, Fig. 2 is a schematic front view of the rectifying plate portion, Fig. 3 is a partial schematic plan view thereof, and Fig. 4 is a partial schematic perspective view thereof. , FIG. 5 is a schematic vertical cross-sectional view of a conventional gas wiping nozzle, FIG. 6 is a schematic front view of the distance portion, and FIG. 7 is an explanatory diagram showing the dynamic pressure distribution of the injection gas. In the drawings, 11...upper nozzle body, 11a...horizontal part, 11
b...First curved surface part, 11c...Second curved surface part, 11
d...Protrusion part, 11e...Horizontal part, 12...Lower nozzle body, 12a...Horizontal part, 12b...Curved surface part,
13... rectifying plate, 14... gas chamber, 15... slit nozzle port, 16... gas jet port, 17... shim, 18... bolt, 19... rectifying rod.

Claims (1)

[Claims] 1. An upper nozzle body having a downward recess formed on the inner surface and a lower nozzle body having an upward recess formed on the inner surface are connected by bolts through a distance piece having a plurality of gas ejection ports. By integrally joining, a horizontal slit nozzle opening is formed at the tip,
In a gas wiping nozzle for hot-dip galvanizing which has a gas chamber formed therein, the distance piece includes a plurality of wing-shaped rectifying plates each having a streamlined planar shape and arranged at regular intervals on a base. , the rectifying plate is arranged in the recess formed on the inner surface of the upper nozzle body with its horizontal axis directed toward the slit nozzle opening, and a gas jet port is formed between the plurality of rectifying plates. The upper nozzle body constituting the gas chamber has a first curved surface facing downward, which extends to the slit nozzle opening, and a second curved surface facing laterally toward the current plate, with a protrusion sandwiched between the inner surfaces of the upper nozzle body constituting the gas chamber. A recessed portion consisting of
A concave portion having an upwardly curved surface continuing to the slit nozzle opening is formed on the inner surface of the lower nozzle body, and the high-pressure gas is introduced into the gas chamber from the gas outlet formed between the plurality of rectifier plates. A gas wiping nozzle characterized in that the dynamic pressure distribution of the high-pressure gas is made uniform by spouting the gas.