JPH0474857A - Gas wiping device for hot dip metal coating - Google Patents

Abstract

PURPOSE:To stably and uniformly control the deposition of molten 2n on a steel sheet by constituting the gas ejection nozzles of the gas wiping device of a galvanizing device of main nozzles and auxiliary nozzles and disposing inclined end plates and end plates at both ends in the transverse direction of the plated steel sheet. CONSTITUTION:A pair of the main slit nozzles 2 are disposed to face the front and rear surfaces of the steel sheet 6 to be plated above a plating bath cell 13 contg. a galvanizing bath 14 and the auxiliary nozzles 3 are provided in combination in the parts above and below these nozzles. The inclined end plates 7 having cylinders (e) at ends are disposed near both ends in the transverse direction of the steel sheet 6 and shielding plates 10 are erected at the side ends thereof. Gas jet flow 11 is sprayed in a band form to the galvanized steel sheet 6 under the gaseous pressure Pm from the slits 4 of the main slit nozzles 2 and under the pressure Pa smaller than the Pm from the slits 5 of the auxiliary nozzles 3. The control of the deposition of the molten Zn by the gas jet flow 11 is easy and the flow of the gas to the end sides on the steel sheet surface near the ends of the steel sheet 6 is controlled by the presence of the shielding plates 10. The formation of splashes and edge build-ups based on the flow of the gas to the end sides is thus prevented.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a gas wiping device for hot-dip metal plating, and more particularly, in hot-dip metal plating such as hot-dip galvanizing, a gas wiping device is used to remove gas wiping from a hot-dip metal plating bath. This invention relates to a gas wiping device for molten metal plating, which sprays gas onto the front and back surfaces of a metal plate and squeezes out excess molten metal with a gas jet knife.

(Prior art) In order to control the amount of molten metal deposited in hot-dip metal plating on a metal plate, the metal plate is immersed in a hot-dip metal plating bath and when pulled out of the bath, excess molten metal is squeezed out. be exposed. The squeezing method includes a roll method in which two grooved rolls are installed above the bathtub to squeeze out the water, and a gas wiping method in which high-pressure gas is blown on and the resulting liquid is squeezed out using a gas jet knife. In recent years, as the speed of pulling metal plates has increased, gas wiping methods have come into widespread use in order to improve productivity.

A conventional gas wiping method and gas wiping device will be described below based on a perspective view of the gas wiping device shown in FIG.

fi+ is a metal plate such as a steel plate, which is immersed in molten metal 091 such as molten zinc in the plating bath Ca, and is pulled up approximately vertically above the plating bath holder. The gas wiping device is
Disposed above the plating bath CO and on the front and back sides of the metal plate (1), a belt-shaped gas jet stream wider than the width of the metal plate (1) is directed horizontally and toward the front and back sides of the metal plate (11). This gas jet has a slit nozzle which ejects water, and an end plate GG which is erected near the end of the metal plate and collides with the end of the band-shaped gas shet flow.

When the above-mentioned slit nozzle blows out a band-shaped gas jet flow onto the front and back surfaces of the metal plate (1),
Excess molten metal can be squeezed out by the action of the gas et knife produced upon collision with the surface of the metal plate (1).

The end of the band-shaped gas jet flow collides with the end plate q6, thereby preventing the generation of noise due to collision of opposing gas jet flows.

(Problem to be Solved by the Invention) Incidentally, in order to improve the productivity of hot-dip metal plating, there has been a demand for increasing the rate of pulling up metal sheets.

If the metal plate pulling speed is increased, it is necessary to correspondingly increase the flow rate of the band-shaped gas shet stream for squeezing out excess molten metal.

However, in the conventional gas wiping device, when the flow rate of the band-shaped gas jet stream ejected from the nozzle 4 is increased by increasing the angle of the nozzle tip of the slit nozzle, the band-shaped gas jet stream is ) After colliding with the metal plate (1) surface, the downward flow becomes unstable in the gas flow such as upward flow or downward flow flowing along the metal plate (1) surface,
Therefore, there is a problem that the molten metal may be squeezed out too much, making it impossible to control the amount of molten metal deposited (and also encouraging the generation of splashes from the squeezed molten metal. There is a problem in that it is not possible to increase the plate pulling speed or to improve the productivity of hot-dip metal plating.

In addition, in the metal plate (11) near both ends of the metal plate (1) in the width direction, most of the gas that collides there escapes in the width direction, that is, toward the ends of the metal plate, so the squeezing effect is weakened. Therefore, there is a problem that the metal plate (1) has a thicker weight than the center part, and an edge buildup is formed.This occurs even when the metal plate pulling speed is not increased.

Furthermore, there is also the problem that splash occurs due to the gas flow in the width direction.

The present invention has been made with attention to such circumstances, and its purpose is to solve the above-mentioned problems of the conventional method, and to reduce the amount of damage to the end side of the metal plate surface near the end of the metal plate. The gas flow can be suppressed to prevent the generation of soot and edge build-up, and even when the flow rate of the band-shaped gas jet flow is increased, the downward flow of gas after collision with the metal plate surface can be stabilized. The present invention aims to provide a gas wiping device for molten metal plating that can control the amount of molten metal deposited.

(Means for Solving the Problems) In order to achieve the above object, a gas wiping device for molten metal plating according to the present invention has the following configuration.

That is, the apparatus according to claim I is a molten metal plating gas that blows gas onto the front and back surfaces of a metal plate pulled up substantially vertically from a molten metal plating bath and squeezes out excess molten metal with a gas-on-et knife. In the wiping device, main slits are arranged above the plating bath and on the front and back sides of the metal plate, and eject a band-shaped gas jet stream wider than the width of the metal plate horizontally toward the front and back sides of the metal plate. A nozzle, a sub-nozzle that is attached to the upper and/or lower part of the main slit nozzle and ejects a band-shaped gas jet stream wider than the width of the metal plate horizontally and toward the front and back surfaces of the metal plate, and the width of the metal plate. An inclined end plate is arranged near both ends of the gas jet stream and collides with the end of the band-shaped gas jet stream, and an inclined end plate is arranged near the metal plate at the end of the inclined end plate, which is perpendicular to the width direction of the metal plate. This gas wiping device for molten metal plating is characterized in that it has a shielding plate that is erected to receive and shield a gas jet flow that collides with a metal plate and flows toward an end of the metal plate.

In the device according to claim 2, the end of the inclined end plate is formed into a truncated conical cylinder, and the receiving port for the gas shet flow that collides with the inclined end plate and flows along the inclined end plate surface is connected to the cylinder of the cylinder. provided on the surface, with the small diameter opening bottom of the cylinder on the side near the metal plate,
2. The gas wiping device for molten metal plating according to claim 1, wherein the large-diameter bottom portion is disposed on the far side of the metal plate, and a filter is stretched over the large-diameter bottom portion.

(Function) The gas wiping device for molten metal plating according to the present invention has the following features:
As the slit nozzle is equipped with the main slit nozzle and sub-nozzle as described above, when gas is ejected from these nozzles, a band-shaped gas jet stream is blown onto the front and back surfaces of the metal plate, mainly from the main slit nozzle. The gas allowed to squeeze out excess molten metal. At this time, the gas ejected from the sub-nozzle acts on the potential core of the gas ejected from the main slit nozzle, making the potential core longer than the case of only the slit core or the main nozzle, increasing the nozzle distance accordingly, resulting in splashes, etc. Adhesion to the nozzle is reduced. Furthermore, even when the flow rate of the belt-shaped gas shet flow from the main slit nozzle is increased, the downward flow of gas after collision with the metal plate surface can be stabilized, and the amount of molten metal deposited can be well controlled. The squeezing effect also increases.

Also, since the inclined end plate as described above is grown, the ends of the band-shaped gas shet flow obliquely impinge on the inclined end plate. Therefore, it is possible to prevent the generation of noise due to the collision of opposing gas jet flows, and it is also possible to make the noise generated when the end plate collides smaller than in the case of the conventional device.

Furthermore, since the above-described shielding plate is provided upright, the gas jet flow that collides with the metal plate and flows toward the end of the metal plate is received and blocked by the shielding plate. Therefore, it is possible to suppress the flow of gas toward the edge side on the metal plate surface near the edge of the metal plate, thereby preventing the generation of splash and the formation of edge buildup due to the gas flow toward the edge side. become.

The end of the inclined end plate is formed into a truncated conical cylinder, and an inlet for a gas jet flow that collides with the inclined end plate and flows along the inclined end plate surface is provided in the cylindrical surface of the cylinder. It is preferable that the small-diameter opening bottom be placed near the metal plate, the large-diameter bottom be placed far from the metal plate, and furthermore, the filter may be stretched over the large-diameter bottom. In this way, the gas flow that collides with the inclined end plate and flows along the inclined end plate surface enters the inside of the truncated conical cylinder from the above-mentioned intake port, and becomes a high-speed rotating flow on the small diameter side or on the large diameter side. The pressure becomes higher than the center of the low-speed rotating flow, and the gas flow does not suck in the outside air on the small diameter side, but is discharged to the outside through the filter on the large diameter bottom. At this time, fumes in the outside air sucked in from the small diameter side can be captured by the filter. Therefore, the metal fume evaporating from the molten metal plating bath can be captured and recovered.

(Example) A gas wiping device according to an example of the present invention is shown in FIG. 1, an enlarged view of the main part of the device is shown in FIG. 2, and an enlarged view of the nozzle part is shown in FIG. 3. The device is located above the hot-dip galvanizing bath 03,
A pair of main slit nozzles (2) are arranged facing the front and back sides of the steel plate (6), respectively, and sub-nozzles (3) are provided above and below the nozzles (2). An inclined end plate having a cylinder as described below near both ends in the width direction (
7), and a shielding plate 00) is erected at the side end of the inclined end plate (7). The end of the inclined end plate (7) is formed into a truncated conical cylinder (e), and an inlet tm for the gas flow 0z flowing along the surface of the inclined end plate (7) is provided on the cylindrical surface of the cylinder tel. , the small-diameter opening bottom α & of the cylinder (el) is placed near the steel plate (6), and the large-diameter bottom (8) is placed on the far side of the steel plate (6), and the large-diameter bottom (8) is provided with a filter (9). ) is installed.

The steel plate (6) was immersed in molten zinc C141 in a plating bath σ3 while running, and lifted out of the bath σ3, and excess molten metal was squeezed out above the plating bath α3 using the gas wiping device as described below.

That is, from the slit (4) of the main slit nozzle (2) to P
A belt-shaped gas jet stream is ejected horizontally at a pressure of m, and a steel plate (
6) At the same time, a band-shaped gas jet stream was ejected from the slit (5) of the sub-nozzle (3) at a pressure of Pa lower than Pm. Then, due to the action of the gas ejected from the sub nozzle (3), the above Pm is increased and the main slit nozzle (2)
) Even if the gas flow rate from the nozzle (2) was increased, either the gas jet flow from the nozzle (2) or the downward flow of the gas after colliding with the steel plate (6) was stabilized, and the amount of molten metal deposited could be well controlled. . It was also confirmed that the squeezing effect also increased.

The gas flow that collides with the surface of the steel plate (6) near the widthwise end of the steel plate (6) and flows toward the end of the steel plate (6) is caused by the shielding plate αO)
It is received and shielded by. Therefore, it was possible to prevent the occurrence of soot and pilt-up due to the flow of gas toward the end side of the steel plate (6).

The ends of the band-shaped gas shet flow, ie, the portions that do not collide with the steel plate (6), obliquely collide with the inclined end plate (7). Therefore,
No noise was generated due to the collision of opposing gas jet streams, and the noise generated when the end plates collided was smaller than in the case of the conventional device.

The gas that collided with the inclined end plate (7) then flows along the flat part of the inclined end plate (7), and the gas flow 0z flows into the truncated conical cylinder (8) from its intake port 071. The large diameter bottom (
8) was discharged to the outside through the filter (9). Therefore, it was confirmed that zinc fume in the outside air could be captured by the filter and that the working environment could be improved.

(Effects of the Invention) According to the gas wiping device for molten metal plating according to the present invention, a band-shaped gas jet flow is blown onto the front and back surfaces of a metal plate pulled up substantially vertically from a molten metal plating bath to remove excess molten metal. At this time, it is possible to suppress the flow of gas toward the end at the surface near the end of the metal plate, thereby preventing the generation of splash and the formation of edge build-up.

Further, even when the flow rate of the band-shaped gas jet stream is increased, the downward flow of the gas after colliding with the metal plate surface can be stabilized, and the amount of molten metal deposited can be well controlled. Therefore, even if the metal plate is pulled up at a high speed, excess molten metal can be squeezed out and the amount of molten metal deposited can be controlled without causing problems such as squeezing out too much molten metal or promoting splash generation. Therefore, it becomes possible to improve the productivity of hot-dip metal plating.

Furthermore, an inclined end plate is provided as an end plate to prevent the ends of the band-shaped gas jet streams from directly colliding with each other, and since the ends of the band-shaped gas jet stream obliquely collide with the end plate, the ends of the opposing gas jet streams collide with each other obliquely. It is possible to prevent the generation of noise due to collision, and to make the noise generated when the end plate collides smaller than in the case of the conventional device.

When the end of the inclined end plate is formed into a truncated conical cylinder having a gas jet flow inlet, a filter, etc. as described above, metal fumes in the outside air near the molten metal plating bath can be captured by the filter. , it will be possible to improve the working environment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an outline of a gas wiping device according to an embodiment of the present invention, FIG. 2 is a perspective view showing main parts of the device,
FIG. 3 is a side sectional view showing the nozzle portion of the device, and FIG. 4 is a perspective view showing a conventional gas wiping device. (1) Metal plate, (2) Main slit nozzle, (3) Sub nozzle, (41 (51 slits), (6) Steel plate, (7) Slanted end plate, (8) Large diameter bottom, (9) - Filter, σ0) Shielding plate, UaZ gas flow, α3 Hot dip galvanized bathtub, σ4
Molten zinc, α9 slit nozzle, qf5 end plate,
G7) Gas flow inlet, Gg small diameter opening bottom, 091
Molten metal, ■ Plating bath, (el truncated conical cylinder, ridge) - flat part of inclined end plate. Patent applicant: Kobe Steel, Ltd. Agent: Patent attorney: Akira Kanekichi - Figure 2, Figure 3, Figure 4

Claims (2)

[Claims] (1) In a gas wiping device for molten metal plating, which blows gas onto the front and back surfaces of a metal plate pulled up approximately vertically from a molten metal plating bath and squeezes out excess molten metal with a gas jet knife, above the plating bath. and a main slit nozzle disposed on the front and back sides of the metal plate and ejecting a band-shaped gas jet stream wider than the width of the metal plate horizontally toward the front and back sides of the metal plate; /or a sub-nozzle installed at the bottom that ejects a band-shaped gas jet stream wider than the width of the metal plate horizontally toward the front and back surfaces of the metal plate; and a gas jet stream near both ends of the metal plate in the width direction. An inclined end plate is arranged to be inclined in the ejection direction and collides with the end of the band-shaped gas jet stream, and an inclined end plate is arranged perpendicular to the width direction of the metal plate at the end near the metal plate of the inclined end plate, and A gas wiping device for molten metal plating, comprising a shielding plate that receives and shields a gas jet flow that collides and flows toward the end of a metal plate. (2) The end of the inclined end plate is formed into a truncated conical cylinder, and the cylindrical surface of the cylinder is provided with an inlet for a gas jet flow that collides with the inclined end plate and flows along the inclined end plate surface. The gas for molten metal plating according to claim 1, wherein the small-diameter opening bottom of the cylinder is placed near the metal plate, the large-diameter bottom is placed far from the metal plate, and a filter is stretched over the large-diameter bottom. Wiping device.