JP2006206936A - Device for removing foreign matters from roll in bath for hot-dip metal coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for removing foreign matters from a roll in a bath for hot-dip metal coating bath capable of effectively removing foreign matters deposited on the roll in the bath with a simple mechanism. <P>SOLUTION: The device for removing foreign matters from the roll in the bath for hot-dip metal coating comprises a blade 6 to abut a tip thereof on a roll surface in the roll 4 in the bath, a float 7 which is sunk in the bath 3 to give the buoyancy, and a shaft 9 to rotatably support the float and the blade, and the blade tip is pressed against the roll surface with the buoyancy. The blade 6 is formed of an arc-shaped bent plate, the shaft 9 is located at the center of curvature, and/or the shaft 9 preferably supports a blade rear end side via a link 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a foreign matter removing apparatus for a roll in a molten metal plating bath.

Regarding the foreign matter removal device for the roll in the molten metal plating bath, the arm that supports the blade (doctor blade) that scrapes off the foreign matter adhering to the roll in the bath has been lifted to adjust the pressing force of the blade to the roll in the bath. And what attached the weight is known (patent document 1). Also, the rod that supports the doctor blade is supported by a guide that can be moved up and down via a screw shaft, and the buoyancy of the floating box attached to the rod is adjusted so that the doctor blade stably contacts the roll in the bath. Is known (Patent Document 2).
Japanese Patent No. 3452017 JP 2002-309357 A

  The foreign matter adhering to the roll in the bath used in the state of being immersed in the molten metal plating bath is mainly dross, especially the top dross, and in normal operation, a metal band is formed on the roll surface of the bath roll. It tends to adhere to portions other than the portion that passes around (the plate path portion), and the amount of adhesion increases with time, and eventually adheres. In this case, when the plate width of the metal band to be passed next becomes wider than the present, the metal band has a portion on the edge side of the plate width outside the plate path portion of the metal band that has passed previously, that is, the foreign material. Passing through the fixed roll surface portion and coming into contact with the foreign material fixed to the roll surface portion, a surface roughening phenomenon is caused and the possibility of quality deterioration is increased. In order to prevent this, it is effective to remove the foreign matter such as dross before adhering to the roll surface, and there is a case where the blade is used as a means for removing the foreign matter such as dross attached to the roll in the bath. Many. Many proposals have been made regarding the method of attaching the blade, the pressing method, the operation method, and the like.

  However, in the conventional technology, for example, as shown in Patent Documents 1 and 2 above, a mechanism that adjusts the pressing force of the blade by the buoyancy of the floating box and the load from above is adopted. Therefore, there is a problem in that the apparatus configuration is complicated, equipment cost is high, and installation space is required. Further, in order to maintain the pressing force within an appropriate range, both the load from above and the buoyancy of the floating box must be adjusted, which causes a problem that requires cost and manpower.

  The object of the present invention is to solve the above-mentioned problems of the prior art and to provide a foreign matter removing apparatus for a roll in a molten metal plating bath that can effectively remove foreign matter adhering to the roll in the bath with a simple mechanism. To do.

  The present inventors diligently studied to achieve the above object, and as a result, came up with a mechanism for pressing the blade against the roll surface of the roll in the bath using the buoyancy unique to the molten metal bath. In this mechanism, a blade that abuts the tip side of the roll in the bath is rotatably supported with the shaft as a fulcrum, and the rear end side of the blade is urged upward by the buoyancy of the float submerged in the bath. This urging force creates a rotational force on the blade, and this rotational force presses the blade tip side against the roll surface of the roll in the bath.

That is, the present invention has a blade whose tip abuts against the roll surface of the roll in the bath, a float that is submerged in the bath and imparts buoyancy, and a shaft that rotatably supports the float and the blade. The tip of the blade is pressed against the roll surface by the buoyancy, and the foreign substance removing device for the roll in the molten metal plating bath is characterized by the above.
In the present invention, it is preferable that the blade is an arcuate curved plate and the axis is positioned at the center of curvature of the arc.

  In the present invention, it is preferable that the shaft supports a rear end side of the blade via a link.

  According to the present invention, the pressing force of the blade to the roll in the bath is provided only by the buoyancy from the float that is submerged in the bath, and by setting the buoyancy to a value corresponding to the desired pressing force, sufficient foreign matter can be obtained. Since the removal performance can be ensured, the foreign matter adhering to the roll in the bath can be effectively removed with a simple mechanism.

  FIG. 1 is a cross-sectional view showing an example of the present invention. The in-bath roll 4 located on the left side of the metal strip 1 conveyed from the bath 3 to the outside 2 of the bath contacts the metal strip 1 and rotates counterclockwise. The tip end side of the blade 6 is in contact with the roll surface of the roll 4 in the bath. The blade 6 is supported by a shaft 9 via a link 8 attached to the rear end side thereof, and can rotate around the shaft 9. The shaft 9 is fixed to a bath equipment support frame (not shown). A float 7 is attached to the rear end side of the blade 6, and a buoyancy F of the float 7 acts. The blade 6 is formed of an arcuate curved plate, and the shaft 9 is located at the center of curvature of the arc.

In this configuration, the distance between the rear end position and the front end position of the blade 6 from the shaft 9 is r0 and r1, and the angles with respect to the half line extending vertically upward are θ and α, and the roll 4 in the bath at the blade 6 contact point position. The angle with respect to the half line extending vertically upward from the roll center 5 is β, the force exerted by the blade 6 on the roll 4 in the bath is F2, and the counter reaction force is F1 and F2 in the roll radial direction component (the pressing force). If F3 is applicable, the following equation is established from the balance of moments about the shaft 9 about the blade 6 and the balance of forces at the contact point of the blade 6.
F × r0 × sin θ = F1 × r1 × sin α (1)
F1 = F2 (2)
F3 = F2 × cosβ (3)
From these equations, the following equation representing the relationship between the buoyancy F and the pressing force F3 is derived.
F = F3 × (r1 / r0) × sin α / cos β / sin θ (4)
In this example, since the blade 6 is an arcuate curved plate and the shaft 9 is located at the center of curvature of the arc, the position of the contact point does not move during use. That is, r1 = r0 is always satisfied, and α and β do not vary. On the other hand, the angle θ changes from the angle θ1 at the start of use given as the design condition of the blade 6 to the angle θ2 at the end of use as the wear progresses. The change in the value of sin θ during the process of changing the angle θ from θ 1 to θ 2 can be easily calculated, and the minimum value of sin θ can be easily calculated. Further, the desired value of the pressing force F3 is determined from the past operation results. Therefore, by setting the buoyancy F to a value equal to or greater than the calculated value of the equation (4) in the case of F3 = desired value and the minimum value of sin θ obtained from θ1 and θ2, a desired pressing force is ensured and sufficient foreign matter is obtained. Removal performance is obtained.

Needless to say, when θ ≦ 0 ° or θ ≧ 180 °, sin θ becomes zero or a negative value, and the force from the blade 6 does not act on the contact point, so θ1 and θ2 exceed 0 °. It is determined to be within a range of less than 180 °.
If the blade 6 is not an arcuate curved plate, or if the shaft 9 is not located at the center of curvature of the arc of the arcuate curved plate, the position of the abutment point will fluctuate during use, and generally r1 ≠ r0, and , Α and β also vary. However, since these fluctuation ranges are determined from the design conditions of the blade 6, the maximum value of (r1 / r0) × sin α / cos β / sin θ is obtained. Therefore, the desired pressing force is secured by setting the buoyancy F to a value equal to or greater than the calculated value of the equation (4) when F3 = desired value and (r1 / r0) × sinα / cosβ / sinθ = maximum value. And sufficient foreign matter removal performance can be obtained.

The link 8 may be attached to a position other than the rearmost end portion of the blade 6. In this case, the blade 6 portion on the rear end side of the link 8 attachment position cannot contact the roll 4 in the bath. The link 8 is preferably attached to the rearmost end of the blade 6 because the usable length of the blade 6 is shortened.
The float 7 is preferably constituted by a pipe having both ends closed. In such a case, assuming that the outer diameter of the pipe is d, the length is L, the dead weight is W, the molten metal bath density is ρ, and the gravitational acceleration is g, the buoyancy F that the rear end side of the blade 6 receives from the pipe is
F = π × (d / 2) ² × L × ρ × g−W × g (5)
Therefore, the design of the float 7 for obtaining the set buoyancy F can be very easily performed.

It is sectional drawing which shows an example of this invention.

Explanation of symbols

1 Metal band 2 Outside bath 3 In bath 4 Roll in bath 5 Roll center 6 Blade 7 Float 8 Link 9 Axis

Claims (3)

  A blade whose tip abuts against the roll surface of the roll in the bath, a float that is submerged in the bath to give buoyancy, and a shaft that rotatably supports the float and the blade. An apparatus for removing foreign matter from a roll in a molten metal plating bath, wherein a tip of a blade is pressed against the roll surface.   The apparatus for removing foreign matter from a roll in a molten metal plating bath according to claim 1, wherein the blade is an arcuate curved plate, and the shaft is positioned at the center of curvature of the arc.   The apparatus for removing foreign matter from a roll in a molten metal plating bath according to claim 1 or 2, wherein the shaft supports a rear end side of the blade via a link.