JPH06299308A - Bottom dross removing device in molten zinc bath cell for galvanizing line - Google Patents

Abstract

PURPOSE:To completely remove the bottom dross in the bottom of a galvanizing cell by providing the bottom of the galvanizing cell with an inclined plate and sucking up the bottom dross accumulating on its front end with a gas lift pump. CONSTITUTION:A steel sheet delivered from a snout 3 is galvanized while this steel sheet is pulled up in a perpendicular direction by a sink roll 1 in the plating cell contg. a galvanizing bath. The inclined plate 2 having about 20 deg. angle of inclination is mounted, below a sink roll 1, on the bottom of the plating cell so that the bottom dross 7 generated in the plating bath is moved and accumulated to the bottom end of the inclined plate 2. A suction port 5 of the gas lift pump 4 is brought near to the front end of the inclined plate 2. The bottom dross 7 is sucked by introducing gas, such as N2, to the gas lift pump 4. The bottom dross is deposited and removed into a static vessel 6 disposed on the outer periphery of the pump 4. The clean galvanizing bath free from the bottom dross is thus maintained over a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom dross removing device in a hot dip galvanizing bath in a hot dip galvanizing line.

[0002]

2. Description of the Related Art In the hot dip galvanizing process, it is known that bottom dross, which is an impurity, adheres to the plated steel sheet in the zinc bath and impairs the appearance of the plated steel sheet.

Conventionally, as opposed to this bottom dross, for example, as shown in Japanese Patent Application Laid-Open No. 4-232235, a bottom dross deposited on the bottom of a molten bath is sucked by a gas lift pump and an opening is formed on a side surface surrounding the gas lift pump. A technique for depositing bottom dross in a fixed tank has been reported.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As in No. 235, only by installing the suction pump in the molten zinc bath, the bottom dross in the vicinity of the suction pump suction port was sucked and the bottom dross of the entire bath bottom was not sucked, and the effect was not sufficient.

[0005]

The present invention has been made in view of the above problems, and the gist of the present invention is to provide a gas lift pump in a molten zinc bath and to open an opening on a side surface so as to surround the gas lift pump. A slanting plate having an inclined upper surface is provided below the sink roll, and a suction port of the gas lift pump is provided in front of the slanting plate. Melting in a hot dip galvanizing line. It is a bottom dross removing device in a zinc bath.

[0006]

[Function] Bottom dross falling on the slant plate moves forward along the slope of the slant plate and gathers below the slant plate. Therefore, by installing a suction port for sucking the bottom dross here, a wide range of bottom dross can be removed. Can be aspirated.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. In the lab test, as shown in Figure 1, Syncroll 1
An inclined plate 2 having an inclination of 20 degrees was installed in the lower part of, and a gas lift pump 4 was installed in the lower part of the snout 3. Further, the suction port 5 of the gas lift pump 4 was guided below the inclined plate 2. At this time, the bottom dross 7 moves downward along the inclined plate 2 and the nitrogen gas is supplied to the gas lift pump 4 by 10 liter / m 2.
When introduced in, as shown in FIG. 2, the bottom dross 7 on the entire bath bottom is sucked by the gas lift pump 4 in about 5 hours,
It was deposited in the static-state tank 6 installed on the outer periphery of the gas lift pump.

Further, Al is added to the static-conditioning tank 6 and the static-conditioning tank 6 is added.
By bubbling the inside with nitrogen gas, the bottom dross 7 accumulated in the static stabilizing tank 6 floated and became top dross, and the bottom dross could be removed from the zinc bath.

[0009]

As described above, according to the present invention, it is possible to carry out hot dip galvanizing with little bottom dross adhesion for a long period of time.

[Brief description of drawings]

FIG. 1 Schematic diagram of bottom dross removing device in hot-dip galvanizing bath in hot-dip galvanizing line

FIG. 2 shows a relationship between a gas lift suction time and a bottom dross recovery rate in a zinc bath when the apparatus shown in FIG. 1 is used.

[Explanation of symbols]

 1 sink roll 2 inclined plate 3 snout 4 gas lift pump 5 suction port of gas lift pump 4 6 stationary tank 7 bottom dross

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yuji Toda 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Corporation Kimitsu Steel Co., Ltd.

Claims (1)

[Claims] 1. A gas lift pump is provided in a molten zinc bath, a stationary tank having an opening on a side surface is provided so as to surround the gas lift pump, and an inclined plate having an inclined upper surface is provided below a sink roll. A bottom dross removing device in a hot-dip galvanizing bath in a hot-dip galvanizing line, characterized in that a suction port of the gas lift pump is provided to face a plate.