JPH1072654A - Method for preventing sticking of dross around in-bath synchronizing roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the sticking of dross around a synchronizing roll by detecting the dross from the in-bath synchronizing roll surface and to stabilize operation over a long period of time by bringing a contact roll into point-to- point contact with the synchronizing roll and reversely rotating this contact roll. SOLUTION: The contact roll 10 is brought into point-to-point contact with the synchronizing roll 3 in the bath of a plating line in a position where the roll does not come into contact with a strip 2. The contact roll 10 is held freely rotatably at the synchronizing roll 3 and is reversely rotated with respect to the rotating direction of the synchronizing roll 3. The contact roll 10 comes into uniform contact with the synchronizing roll 3 and detaches the dross from the synchronizing roll surface at all times and, therefore, the dross does not grow. The contact roll does not give rise to thermal deformation and allows molten metal to flow in the direction parting from the surface of the synchronizing roll 3. The molten metal is further detached by centrifugal force. Then, the phenomenon that the dross is included into the contact surfaces between the strip 2 and the synchronizing roll 3 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved technique for stabilizing the operation of a continuous hot-dip galvanizing line and extending the life of an apparatus.

[0002]

2. Description of the Related Art An example of a conventional method for preventing dross from winding around a sink roll will be described with reference to FIG. Molten zinc bath 1
The strip 2 enters the inside, is wound around the sink roll 3, changes direction, is guided by the support roll 4, rises, is adjusted in plating thickness by the wiping nozzle 5, is guided by the guide roll 6, and is guided to the next step. I will Since the dross adheres and grows on the surface of the sink roll and deteriorates the product quality, in order to prevent the dross, the doctor blade 7 whose tip is sharpened over the entire length of the sink roll is brought into close contact with and pressed against the dross to remove the dross. This pressing force is given by the air cylinder 8 from outside the bath.

[0003] This technique also has the effect of preventing dross wrapping around the sink roll for a short period of time, but the life of the bath equipment has been extended by various operational improvements.
There has been a problem that thermal deformation of the blade 7 deteriorates the contact state with the roll, causing partial dross winding or damaging the roll surface. As a countermeasure, a technique of moving the blade left and right by shortening the blade length has been proposed. However, it has been difficult to keep the contact state uniform, and the wear has been large, so that the blade cannot be used for a long time.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a method for preventing dross from being wound around a sink roll in a bath, which has a long-term stable effect. Aim.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in view of the problem that the conventional doctor blade system has a problem of uniform contact state, a conventional doctor blade system is replaced with a doctor blade. A linear contact is made using a contact roll having a low possibility of deformation, and the contact roll is reversely rotated with respect to the rotation of the sink roll, thereby effectively preventing dross from adhering to the sink roll.

[0006] Since the contact roll is immersed in the bath and reversely rotated to contact the sink roll, not only the uniformity of the contact state is maintained, but also the dross is constantly removed from the surface of the sink roll regardless of the inside or outside of the plate path. Because they are separated, dross does not grow. The effect of this contact roll is
The surface of the sink roll is cleaned stably by line contact with the sink roll without causing thermal deformation, etc., and the molten metal entrained with the rotation of the sink roll is removed from the sink roll surface by the reverse rotation of the contact roll. Since the fluid flows in the direction away from each other and is further separated by the centrifugal force, the phenomenon that the rotating floating dross of the sink roll approaches the strip and is caught in the contact surface between the strip and the sink roll is prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS. 1 is a side view of the embodiment, FIG. 2 is a front view thereof, and FIG.
Is a drive gear train arrangement diagram. The contact roll 10 is rotatably held by a sink roll arm 9 by a bearing 11. The rotational force of the contact roll 10 is transmitted from a drive gear 12 attached to the shaft end of the sink roll to a driven gear 14 attached to the shaft end of the contact roll 10 via an intermediate gear 13 attached to the arm 9. By the action of the intermediate gear 13, the contact roll reversely rotates in the rotation direction of the sink roll.
Although the gear ratio of the gears can be selected in a wide range, according to the experiments performed by the inventor, in the reverse rotation state, the influence of the rotation speed is small, and it seems that there is no significant difference in the dross winding prevention effect.

In this embodiment, a φ200 mm contact roll was used for a φ800 mm sink roll. The gear ratio was 2: 1: 1. It is not preferable to increase the pressing force between the sink roll and the contact roll, because this causes a rotational resistance of the sink roll and causes a slip with the strip. In the embodiment, the contact is made only by the roll's own weight. Needless to say, the drive of the contact roll can be performed from another drive device using a universal joint. In the example apparatus, dross wrapping around the sink roll could be prevented more stably for a longer period of time as compared with the conventional doctor blade, and the bath equipment replacement cycle was extended.

[0009]

According to the present invention, since the contact roll is rotated and contacted instead of the conventional doctor blade,
The effect of preventing dross wrapping was maintained for a long time, and the replacement cycle of bath equipment was extended, so that production capacity was improved and maintenance costs could be reduced. In addition, by rotating the roll in reverse, the dross winding prevention effect can be obtained only by light contact, and the dross defect reduction effect is obtained because the approach of the floating dross to the strip is reduced.

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2 is a front view of the embodiment of the present invention.

FIG. 3 is a gear train arrangement diagram showing an arrangement of contact roll driving gears.

FIG. 4 is a side view of a conventional dross wrap prevention method using a blade.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 molten zinc 2 strip 3 sink roll 4 support roll 5 wiping nozzle 6 guide roll 7 doctor blade 8 pressing air cylinder 9 sink roll arm 10 contact roll 11 contact roll bearing 12 drive gear 13 intermediate gear 14 driven gear

Claims (2)

[Claims] 1. A contact roll line-contacted with a sink roll and immersed in a bath is reverse-rotated to a position in a continuous hot-dip galvanizing line not in contact with a strip of a sink roll, so that dross is removed from the sink roll surface in the bath. A method for preventing dross from winding around a sink roll in a bath, characterized in that the roll is separated. 2. The method according to claim 1, wherein the rotation of the contact roll is provided from a sink roll in the bath.