JPH0730673Y2 - Seal box for metal strip surface treatment equipment - Google Patents

Description

[Detailed Description of the Invention] <Industrial field of application> The present invention is a coating solution used for hot metal plating of metal strips or coating of various paints, and a surplus of the paint by gas wiping, that is, a coating amount, that is, a coating thickness. The present invention relates to a wiping device for adjusting, and particularly to a seal box for hot metal plating or painting.

<Prior Art> Conventionally, in the gas wiping method which is widely used in the hot-dip galvanizing line, as shown in FIG. 6, the steel strip 1 is sandwiched and the wiping nozzles 2 and 2'are arranged to face each other in the width direction. The surplus plating solution 3 on the steel strip 1 is wiped by a wiping nozzle 2, 2'having a uniform slit gap and spraying a uniform jet gas at a right angle or a substantially right angle to the steel strip 1.

In such a wiping apparatus, in the conventional technique, as means for reducing the amount of plating solution deposited, (1) the wiping gas nozzle angle relative to the steel strip surface is higher than the reaching point of the wiping gas jet flow to the steel strip surface. A method of displaying at an angle formed by and making an acute angle.

(2) A method of increasing the temperature of the wiping gas to reduce the viscosity of the plating metal on the surface of the steel strip.

(3) A method of increasing the ejection speed of the wiping gas.

Etc.

However, the above method (1) in which the angle of the wiping gas nozzle with respect to the surface of the steel strip is set to an acute angle causes a large amount of splash of molten metal and causes frequent nozzle clogging.
In the method (2) of increasing the temperature of the wiping gas to reduce the viscosity of the plating metal on the surface of the steel strip, the wiping is difficult under a non-oxidizing atmosphere such as combustion exhaust gas, and the temperature of the wiping gas is increased. However, the viscosity of the plating metal on the surface of the steel strip cannot be reduced for the amount of heat required for this, and the effect on the control of the amount of plating solution adhered is small. The method (3) of increasing the jetting speed of the wiping gas is the most effective in controlling the amount of plating metal deposited on the surface of the steel strip, but the jetting amount of the wiping gas collides with the surface of the steel strip and the side edge of the steel strip. High frequency sound is generated by the mutual collision of the wiping gases.
Further, there are frequent occurrences of splashes of plated metal and the drawing of the atmosphere by the wiping gas jet flow, which results in the oxidation of the hot-dip metal on the surface of the steel strip, resulting in a decrease in the kettle yield. However, the method (3) is the most effective as a method for increasing the plating treatment speed and reducing the amount of plating metal deposited.

Therefore, in order to solve the problem in the method (3),
A technique has already been proposed in which a plating box is adhered to a steel strip and a deposition box is controlled by gas wiping to provide a wiping nozzle and a seal box surrounding the wiping nozzle to make a non-oxidizing atmosphere in the seal box.

However, in order to prevent the ingress of oxygen by the secondary vortices created by the flow of wiping gas flowing along the steel strip surface, the outlet opening through which the steel strip of the seal box passes must be extremely narrow. Therefore, when there is flapping of the steel strip or passage of a poorly shaped steel strip, there is a problem in that the opening of the seal box and the steel strip having the molten plating metal on its surface come into contact with each other and spoil the plated product.

Therefore, the present inventors have provided a seal gas jet nozzle so that the seal gas flows from the inside to the outside in the vicinity of both ends in the width direction of the seal box opening, and the seal box opening can be made larger than before, and the seal box Japanese Patent Application Sho 63-21234 for a sealed box that can prevent oxygen from entering inside
No. 4 (JP-A-2-61048).

However, the plating solution that can be wiped only by the wiping nozzle as described above cannot secure the uniformity of the amount of adhesion in the width direction of the steel strip. That is, the phenomenon that it is difficult to wipe the vicinity of the width end of the normal steel strip occurs and the amount of the plating solution 3 deposited becomes larger than that in the central part. Therefore, the present inventors have already developed this improvement method as a baffle plate with an edge wiping nozzle (hereinafter A baffle plate with EWN) is proposed in Japanese Patent Application No. 63-33749 (JP-A-1-208441).

<Problems to be Solved by the Invention> An object of the present invention is to provide a gas wiping device that employs a baffle plate, and a sealing box for hot-dip galvanizing or painting, the opening of which is sufficiently wide. An object of the present invention is to provide a seal box capable of preventing the invasion of oxygen from a skimmer and filling the inside of the seal box with a sufficient concentration of inert gas.

Another object is to provide a seal box in which the gap between the gas wiping nozzle and the metal strip can be freely changed.

Further, the present invention provides a seal box capable of arranging a baffle plate with EWN that is effective for ensuring the uniformity of the amount of plating solution deposited in the strip width direction.

<Means for Solving the Problems> The present invention integrally mounts a plated or painted metal strip and a wiping nozzle for ejecting a gas toward a baffle plate arranged in the vicinity of the edge of the metal strip,
Left and right upper seal boxes that can adjust the gap with the metal strip, and lower seal boxes that surround the lower and side surfaces of the left and right upper seal boxes and have their lower ends immersed in a molten metal plating tank or a paint tank. A seal box of a surface treatment equipment for a metal band consisting of, wherein a seal gas supply box is provided at an upper portion of the lower seal box and at a position facing the side surfaces of the left and right upper seal boxes,
Nozzles for ejecting seal gas are provided on the surface of the seal gas supply box facing the baffle plate, the surface of the upper seal box facing the side surface, and the surface of the upper seal box facing the upper end edge. Surface treatment equipment for metal strips, characterized in that the lower seal box is provided with nozzles for ejecting seal gas from both ends of the openings of the left and right upper seal boxes toward the downstream side in the traveling direction of the metal strip. It is a sealed box.

<Operation> As a result of various experiments and observations conducted by the present inventors in order to understand the inflow path of oxygen that enters the seal box, the following facts were found.

(1) Steel strip 1 plated as shown in FIG.
Excluding the central part of the steel strip plate width of the opening that passes through,
That is, oxygen enters the seal box 4 through the opening outside the vicinity of the edge. The arrow A indicates the gas flow ejected from the wiping nozzle, and the arrow B indicates the inflowing oxygen flow.

Further, as shown in FIG. 8, if the baffle plate 6 with EWN8 is arranged on the extension of the width of the steel strip and near the edge of the steel strip, penetrating the side wall of the seal box 4, the inside of the oxygen seal box 4 is The inflow location can be only at both ends of the opening through which the steel strip 1 passes.

(2) The inflow of oxygen occurs from the opening through which the baffle plate 6 with EWN8, which penetrates the side wall of the seal box 4 and is arranged close to the steel strip edge, passes.

From the above, the nozzles that eject the sealing gas from the inside of the seal box toward the downstream side of the traveling direction of the steel strip at the both ends of the opening through which the plated steel strip passes, and the opening through which the baffle plate with EWN passes By providing a seal gas supply box having a nozzle for ejecting the seal gas toward the baffle plate, and confirming the effect, it becomes possible not only to make the plating solution adhered to the steel strip uniform, It is possible to completely prevent the inflow of oxygen from the section into the seal box,
It has been found that the inside of the seal box is filled with the desired inert gas, and it is effective in preventing the oxidation of the plated metal and suppressing the generation of dross.

The present invention has been constructed on the basis of the above findings. Next, a more specific configuration will be described.

Generally, the range of steel strip plate width to be plated is considerably large, about 600 to 1800 mm, and the baffle plate with EWN must be arranged corresponding to the varying plate width. In addition, the amount of plating solution deposited varies, and as a method of controlling the amount deposited, the spacing between the steel strip and the wiping nozzle is often changed. The configuration of the present invention under such operating conditions will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing a seal box of the present invention. Here, 10, 10 'are left and right upper seal boxes, and the wiping nozzles 2, 2'are integrally attached to the left and right upper seal boxes 10, 10', respectively. 10-1 and 10'-1 are side surfaces of the upper seal boxes 10 and 10 ', and 10-2 and 10'-2 are upper edge ears of the upper seal boxes 10 and 10'.

Reference numeral 9 denotes a lower seal box, the lower end of which is immersed in the plating solution 3 in a molten metal plating bath, for example. Further, at the upper part of the lower seal box 9, the seal gas supply box 1 is provided at a position facing the left and right upper seal boxes 10, 10 '.
3 is provided, and on the surface of the seal gas supply box 13 facing the baffle plate 6, the nozzle 16 for ejecting the seal gas or the side surface portion 10- of the upper seal box is provided.
Nozzles 15 for ejecting seal gas are provided on the surface facing 1,10'-1, and upper edge ears 10-2,10 'of the upper seal box.
A nozzle 14 for ejecting a sealing gas is provided on the surface facing -2.

Furthermore, the lower seal box 9 is provided with nozzles 12 for ejecting the seal gas from the vicinity of both ends in the width direction of the upper opening of the seal box toward the downstream side in the traveling direction of the steel strip 1.

FIG. 2 is a side sectional view when FIG. 1 is assembled, showing an arrangement of an upper seal box 10, 10 ′ integrally attached with wiping nozzles 2, 2 ′ and a lower seal box 9 located therebelow. The configuration is shown, and the wiping gas ejected from the wiping nozzles 2, 2 ′ has openings 5,1.
It is a diagram schematically showing how the material is discharged from the seal box from 1. The wiping gas flow after impacting the steel strip is a very fast flow along the steel strip at the seal box opening ((a)) through which the steel strip after plating passes, while the sealing box opening
The gas flow discharged from 11 becomes a fairly slow flow, and it is possible to keep all the pressure in (a) at a positive pressure and prevent oxygen from entering through the opening 11.

FIG. 3 is a side view of the seal box, FIG. 4 is a cross section of the front part of the seal box, and FIG. 5 is a plan view of the end part on the seal box side. Here, the 12 nozzles are for ejecting seal gas to prevent oxygen from entering from both ends of the opening through which the plated steel strip passes, and the seal gas is directed toward the downstream side in the traveling direction of the steel strip. Gush out. Seal gas supply box 13
Includes a gap Δ1 between the upper edge portion 10-2 of the upper seal box and the seal gas supply box 13, a gap Δ2 between the side surface portion 10-1 of the upper seal box 10 and the seal gas supply box 13,
And nozzles 14, 15 and 16 for ejecting the seal gas for blocking the flow of oxygen which is trying to enter the seal box from each part of the gap Δ3 between the baffle plate with EWN 6 and the seal gas supply box 13 are provided. There is. The arrow here indicates the flow direction of the seal gas.

With such a structure, not only the amount of the plating solution attached to the steel strip 1 can be made uniform, but also the plating solution can be prevented from being oxidized and dross can be suppressed. Although the baffle plate with EWN is used as a specific configuration example of the present invention, it is obvious that the present invention can be applied to the case where only the baffle plate is used. If the gap between the steel strip 1 and the wiping nozzles 2, 2'is not changed, the gap Δ
It goes without saying that the seal box can be configured with 1 and Δ2 set to zero.

Next, an example of measuring the effect of the seal box by measuring the oxygen concentration in the seal box using the seal box equipped with the seal gas ejection nozzle of the present invention will be shown.

N ₂ gas was used as the wiping gas and the seal gas.
As a result, the oxygen concentration in the seal box is Therefore, the sealing effect by the injection of the sealing gas is clear, and it is effective in suppressing the oxidation of the plating metal and the generation of dross.

<Effect of the Invention> Oxygen that enters the seal box can be prevented by using the seal gas jet nozzle, and the seal box can be filled with a high-concentration inert gas, and the following effects are obtained.

It is possible to prevent deterioration of the plating surface properties due to oxidation immediately after wiping and to make the plating thickness uniform,
It is possible to obtain high quality and beautiful plated products.

The generation of dross of plated metal is reduced, the yield of zinc can be improved, and the cost can be reduced.

Since the gap between the metal strip and the wiping nozzle can be freely changed, an extremely thin basis weight can be achieved.

[Brief description of drawings]

1 is an exploded perspective view of the seal box of the present invention, FIG. 2 is a side sectional view of the seal box of the present invention, FIG. 3 is a side view of the seal box of the present invention, and FIG. 4 is a partial front sectional view. FIG. 5 is a plan view of a side end portion of the seal box of the present invention, FIG. 6 is an explanatory view showing a typical example of a conventional gas wiping method, and FIG. 7 is a schematic view of an oxygen intrusion route in the conventional seal box. FIGS. 8A and 8B are diagrams showing the invasion route of oxygen into the seal box when the EWN baffle plate is used. 1 …… Steel strip, 2,2 ′ …… Wiping nozzle, 3
... plating solution, 4 ... seal box, 5 ... opening through which plated steel strip passes, 6 ... baffle plate, 7 ... opening through which baffle plate passes, 8
…… Edge wiping nozzle (EWN), 9 …… Lower seal box, 10,10 ′ …… Upper seal box, 10-1,1
0'-1 ... Side part of the upper seal box, 10-2, 10 '
-2 ... the upper edge of the upper seal box, 11 ... seal box opening, 12 ... nozzle, 13 ... seal gas supply box, 14 ... nozzle, 15 ... nozzle, 16 ... nozzle,

Claims (1)

[Scope of utility model registration request] 1. A wiping nozzle for ejecting a gas toward a plated or painted metal strip and a baffle plate arranged in proximity to the edge of the metal strip is integrally attached, and a gap between the strip and the metal strip can be adjusted. A surface treatment facility for a metal strip comprising left and right upper seal boxes and a lower seal box that surrounds lower and side surfaces of the left and right upper seal boxes and has its lower end immersed in a molten metal plating tank or a paint tank. A seal box, wherein a seal gas supply box is provided at an upper portion of the lower seal box and at a position facing the side surfaces of the left and right upper seal boxes, the seal gas supply box facing a baffle plate, and the upper portion. The seal gas is jetted to the surface facing the side surface of the seal box and the surface facing the upper edge of the upper seal box. And a nozzle for ejecting a sealing gas from both ends of the openings of the left and right upper seal boxes toward the downstream side in the traveling direction of the metal strip. Seal box for metal belt surface treatment equipment.