JP2010229509A - Continuous hot dip metal coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous hot dip metal coating apparatus capable of efficiently removing dross in a snout. <P>SOLUTION: The continuous hot dip metal coating apparatus 1 includes: an image processing means 31 of image-processing a contact area of a bath surface 100a of fused metal 100 in a suction port 16a image-picked up by an imaging means 20 disposed in the snout 4; a computing means 32 of computing the area of the contact area of the bath surface 100a of fused metal 100 in the suction port 16a and the height of the suction port 16a for the bath surface 100a of fused metal 100, based on the provided image; a determination means 33 of determining whether vertically moving the suction port 16a or not, based on the computed height; and a control means 30 of operating a position control means 19 to adjust the height of the suction port 16a, based on the determination result of the determination means 33. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a continuous molten metal plating apparatus, and more particularly, to a continuous molten metal plating apparatus that reduces the adhesion of dross to a steel strip.

  As an example of a continuous molten metal plating apparatus, in a continuous molten galvanizing apparatus, generally, the tip of a snout surrounding the steel strip to be conveyed is inserted into the molten zinc in the plating tank. The steel strip is directly carried into the molten zinc through the inside of the snout. The steel strip carried into the molten zinc is designed to be pulled up to the outside of the plating bath after going around the sink roll located in the deep part of the plating bath. Is galvanized.

In such a continuous hot dip galvanizing apparatus, dross is generated in the hot dip zinc in the plating tank due to a reaction with the steel strip to be transported or the like, and it often floats near the liquid surface.
Then, the movement of the steel strip that goes out from the tip of the snout toward the deep part of the plating tank creates a flow of molten zinc from the inside of the snout to the deep part of the plating tank. There is a flow of molten zinc flowing into the inside, and the dross (top dross) drifting near the liquid surface is drawn into the snout by the flowing-in flow, and the possibility of adhering to the steel strip increases.

Therefore, in order to remove the top dross generated in the snout, supply means for supplying molten metal outside the snout into the snout, suction means for sucking the dross in the snout, and the vertical positions of the supply means and the suction means Has been proposed (see Patent Document 1).
According to this removing apparatus, the dross in the snout is moved and accumulated in the vicinity of the suction nozzle of the suction means by the flow of molten metal supplied from the supply means, and then discharged from the suction nozzle. Removal of dross is performed efficiently and reliably.

  In particular, since the liquid level can be observed from the observation windows provided on both side surfaces of the snout, dross can be obtained by independently displacing the vertical position of the supply means and the suction means by the vertical position adjusting means while observing the liquid level. The suction efficiency can be improved.

JP-A-8-269659

As described above, in the removing device described in Patent Document 1, the suction means is moved up and down to a position where dross can be removed based on the liquid level and the suction port visually recognized by the operator from the viewing window.
However, since the position of the suction port with respect to the bath surface is visually confirmed by the operator, there is a problem that the accuracy of the amount of movement when adjusting the position of the suction port is low. In addition, since there is a limit for the operator to constantly monitor the bath surface and the suction port, there has been a problem that it is not possible to cope with the constantly changing bath surface. Due to these problems, the amount of molten metal sucked in the suction port becomes excessive and insufficient, and as a result, there is a possibility that the molten metal is stuck in the suction port, clogged, or the suction means fails. That is, there is a problem that the efficiency of removing dross in the snout depends on the skill of the operator.

  This invention is made | formed in view of the above-mentioned problem, The objective is to provide the continuous molten metal plating apparatus which can remove the dross in a snout efficiently.

In order to achieve the above object, a continuous molten metal plating apparatus according to claim 1 includes a dipping roll disposed in a storage tank in which molten metal is stored, and a snout having a tip inserted into the molten metal. In a continuous molten metal plating apparatus for continuously carrying a steel strip into the molten metal through the inside of the snout, winding the steel strip around the immersion roll, and plating the surface of the steel strip,
A suction means comprising a suction port for sucking dross near the bath surface of the molten metal in the snout;
Position control means for moving the suction port up and down with respect to the bath surface;
Imaging means for imaging the suction port from its opening direction;
Image processing means for image processing the contact area of the molten metal bath surface at the suction port imaged by the imaging means;
Based on the image obtained by the image processing means, computing means for computing the area of the contact area of the molten metal bath surface at the suction port and the height of the suction port with respect to the molten metal bath surface;
Determination means for determining whether or not to move the suction port up and down based on the height of the suction port obtained by the computing means;
Control means for adjusting the height of the suction port by operating the position control means based on the determination result of the determination means.

  Further, the continuous molten metal plating apparatus according to claim 2 is the continuous molten metal plating apparatus according to claim 1, wherein the dimension of the suction port is H and the height of the suction port with respect to the bath surface is h. When the determination means determines that the height h of the suction port with respect to the bath surface, calculated by the calculation means, satisfies h <0 or h> H / 2, the control means controls the position control means. The height of the suction port is controlled so as to satisfy h = H / 2.

  According to the present invention, the height of the suction port relative to the bath surface is determined based on the image captured by the imaging unit, and the suction port is moved up and down based on the determination. It is possible to prevent the amount from being excessive or insufficient. Therefore, dross in the snout can be efficiently removed without depending on the skill of the operator.

It is the schematic which shows the structure of one Embodiment of the continuous molten metal plating apparatus which concerns on this invention. It is a front view which shows the structure of one Embodiment of the continuous molten metal plating apparatus which concerns on this invention. In this embodiment, it is the schematic which shows the position of the suction inlet with respect to a bath surface. It is a flowchart which shows operation | movement of this embodiment. It is a graph which shows the example of a calibration curve.

Hereinafter, an embodiment of a continuous molten metal plating apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a configuration of an embodiment of a continuous molten metal plating apparatus according to the present invention. FIG. 2 is a front view showing a configuration of an embodiment of a continuous molten metal plating apparatus according to the present invention.
As shown in FIG. 1, the continuous molten metal plating apparatus 1 of the present embodiment includes a storage tank 2 in which a molten metal 100 is stored, a dipping roll 3 disposed in a deep portion of the storage tank 2, a snout 4, It includes a dross removing unit 10, an imaging unit 20, a control unit 30, and a notification unit 40.

  The snout 4 is a connecting device for immersing the steel strip S annealed and reduced and cleaned in the reduction annealing furnace 5 in the molten metal 100 while protecting it in a reducing atmosphere. That is, one end 4 a of the snout 4 is connected to the reduction annealing furnace 5, and the other end 4 b is partially immersed in the molten metal 100. Further, the inside of the snout 4 is filled with a reducing atmosphere gas.

The material of the other end 4b of the snout 4 is preferably a material excellent in corrosion resistance to the molten metal 100 such as zinc and aluminum, and examples thereof include ceramics and heat-resistant steel cast steel products. Moreover, the component of the reducing atmosphere gas introduced into the inside of the snout 4 and the reduction annealing furnace 5 is, for example, 50% H ₂ -50% N ₂ . The steel strip S is carried into the snout 4 from the reduction annealing furnace 5 through the bridle roll 5a. The steel strip S whose surface has been cleaned in the snout 4 and the reduction annealing furnace 5 is immersed in the molten metal 100 obliquely from above through the snout 4, and the traveling direction is changed by being wound around the immersion roll 3. Then, after being hot-plated, it is carried out from the molten metal 100 to the atmosphere.

<Dross removal means>
The dross removing unit 10 includes a supplying unit (not shown in FIG. 1), a suction unit 15, and a position adjusting unit 19.
<Supply means>
The supply means is means for supplying the molten metal 100 outside the snout 4 in the storage tank 2 into the snout 4. The supply means includes a supply nozzle 12 (see FIG. 2), a supply conduit 13 (see FIG. 2), and a supply pump (not shown).

The supply nozzle 12 is provided in the vicinity of the bath surface 100a in the snout 4 and on one outer side in the width direction of the steel strip S (right side in FIG. 2), and inward in the width direction of the steel strip S (left side in FIG. 2). Has an opening 12a. Moreover, the supply nozzle 12 is provided near the surface at the side of the immersion roll 3 of the steel strip S to be plated.
One end of the supply line 13 forms the supply nozzle 12, and the other end extends outside the snout 4 and is connected to a supply pump (not shown).

  The supply pump is provided at the other end of the supply pipe 13, pumps the molten metal 100 outside the snout 4 in the storage tank 2, and jets the molten metal 100 from the supply nozzle 12 in the snout 4. Since the supply nozzle 12 is disposed so that the axis of the opening 12a is parallel to the surface of the steel strip S, the flow of the molten metal 100 is close to the surface of the steel strip S on the immersion roll 3 side. It is formed in the direction of the suction nozzle 16 described later along the surface.

<Suction means>
The suction means 15 is means for sucking dross in the snout 4. The suction means 15 includes a suction nozzle 16, a suction pipe line 17, and a suction pump 18.
The suction nozzle 16 is provided in the vicinity of the bath surface 100a in the snout 4 and on the other outer side in the width direction of the steel strip S (left side of the paper surface in FIG. 2), and inward in the width direction of the steel strip S (in FIG. 2). An opening (suction port) 16 a that opens to face the supply nozzle 12 is provided on the right side of the drawing. Moreover, the suction nozzle 16 is provided near the surface on the immersion roll 3 side of the steel strip S to be plated in the same manner as the supply nozzle 12. As shown in FIG. 2, the opening 16a of the suction nozzle 16 has a shape in which one end of a suction pipe 17 that is a cylindrical body extending vertically is inclined. For this reason, the dimension of the height direction of the opening part 16a becomes large, and even if the vertical position of the dross fluctuates, the dross can be reliably sucked. Since the cross-sectional shape of the suction nozzle 16 is circular, the planar shape viewed from the opening direction is an ellipse (see FIGS. 3E to 3H).

One end of the suction pipe 17 forms a suction nozzle 16, and the other end extends to the outside of the snout 4 and is connected to a suction pump 18.
The suction pump 18 is provided at the other end of the suction pipe 17, sucks dross near the bath surface 100 a in the snout 4 from the suction nozzle 16, and discharges it into the storage tank 2 outside the snout 4.

Here, the material of the supply conduit 13 and the suction conduit 17 is stainless steel (SUS316L), and the diameter thereof is, for example, 80 mm. Moreover, the height direction dimension of the opening part 16a of the suction nozzle 16 is 100 mm, for example.
As described above, the opening 16 a of the suction nozzle 16 is provided to be opposed to the opening 12 a of the supply nozzle 12 with a space therebetween. Then, the dross that has moved and accumulated near the suction nozzle 16 along the flow of the molten metal 100 is efficiently sucked through the opening 16 a and discharged and removed outside the snout 4.

<Position adjustment means>
The position adjusting means 19 is a means for adjusting the vertical position by displacing the suction nozzle 16 up and down with respect to the bath surface 100a.
The configuration of the position control means 19 includes, for example, a nut 19b to which a holding means 19a for holding the suction pipe line 17 is connected, and a screw that is rotatably engaged with the nut 19b via a rolling element (not shown). This is a ball screw having a shaft 19c. A driving means 19d for rotating the screw shaft 19c is connected to one end of the screw shaft 19c.

  The drive unit 19d is connected to the control unit 30 and rotates or stops the screw shaft 19c based on a signal transmitted from the control unit 30 to move the suction pipe line 17 up and down via the holding unit 19a. Thus, the height of the opening 16a of the suction nozzle 16 with respect to the bath surface 100a is changed.

(Imaging means)
The imaging unit 20 is a unit that images the opening (suction port) 16a of the suction nozzle 16 from the opening direction. Here, the “direction in which the opening 16a is opened” is a direction parallel to the axis of the suction nozzle 16 in which the opening 16a is provided at the end. The installation position of the imaging means 20 is not particularly limited as long as the opening 16a of the suction nozzle 16 is installed at a position where imaging is performed in a plan view, and is appropriately set according to the purpose, for example, installed in the snout 4.

  The imaging unit 20 is connected to the control unit 30 so as to be communicable. Therefore, an image captured by the imaging unit 20 can be transmitted to the control unit 30. Further, the imaging unit 20 can be controlled according to a predetermined imaging condition by transmitting a command related to imaging from the control unit 30 to the imaging unit 20.

(Control means)
The control unit 30 includes an image processing unit 31, a calculation unit 32, a determination unit 33, and a storage unit 34.
The image processing unit 31 is a unit that performs image processing on the contact area of the bath surface 100 a of the molten metal 100 in the opening 16 a of the suction nozzle 16 imaged by the imaging unit 20. Specifically, on the basis of a preset threshold value, the reflection luminance of the opening 16a of the suction nozzle 16 and the reflection luminance of the bath surface 100a of the molten metal 100 are adjusted so that the end surface 16b of the opening 16a of the suction nozzle 16 has The region and the region of the bath surface 100a of the molten metal 100 are identified.

  Based on the image obtained by the image processing means 31, the calculating means 32 is based on the area of the contact area of the bath surface 100a of the molten metal 100 in the opening 16a of the suction nozzle 16 and the opening of the molten metal 100 with respect to the bath surface 100a. It is a means for calculating the height of 16a. The area of the contact area of the bath surface 100a of the molten metal 100 in the opening 16a of the suction nozzle 16 is determined by the area of the end surface 16b of the opening 16a of the suction nozzle 16 specified from the previously inputted suction nozzle information. It is calculated | required by the difference of the area | region of the bath surface 100a. Moreover, the height of the opening 16a with respect to the bath surface 100a of the molten metal 100 is specified by the area of the contact region obtained as described above, and suction nozzle information and conversion information (described later) of the corresponding suction nozzle.

  The determination means 33 is a means for determining whether or not to move the opening 16a up and down based on the height of the opening 16a with respect to the bath surface 100a obtained by the calculation means 32. Specifically, when the height of the opening 16a is smaller than half the longitudinal dimension of the inclined surface of the suction nozzle, the position of the opening 16a is maintained, and the height of the opening 16a is the height of the suction nozzle. If it is larger than half the longitudinal dimension of the inclined surface, it is moved so as to reduce the height of the opening 16a.

The storage unit 34 is a unit that sequentially stores suction nozzle information and conversion information, which will be described later, information obtained by the image processing unit 31 and the calculation unit 32, and the like.
Further, the notification means 40 is connected to the control means 30 so as to be communicable. The notification means 40 is, for example, a monitor or a sound generator. The control means 30 transmits a signal for notifying the operator of whether the position of the opening 16a determined by the determination means 33 is appropriate or inappropriate to the notification means 40. The notification means 40 that has received this signal notifies the operator by, for example, an image display or a voice saying that “the position of the suction port with respect to the liquid level is appropriate” or “the position of the suction port with respect to the liquid level is inappropriate”. To do.

(Dross removal method)
Next, a dross removal method using the continuous molten metal plating apparatus of the present embodiment will be described below with reference to the drawings. FIG. 3 is a schematic diagram showing the opening of the suction nozzle that is positioned differently with respect to the bath surface in the present embodiment, wherein (a) to (d) are sectional views, and (e) to (h) It is a top view corresponding to (a)-(d), (e) is a top view corresponding to (a), (f) is a top view corresponding to (b), (g) corresponds to (c). (H) is a plan view corresponding to (d). FIG. 4 is a flowchart of an operation for removing dross using the continuous molten metal plating apparatus of the present embodiment. FIG. 5 is a graph showing conversion information used in the present embodiment.

<Input process>
As shown in FIG. 4, first, "suction nozzle information" and "conversion information" are input by an operator using an input means (not shown). Then, triggered by the input of this conversion information, the control means 30 stores the suction nozzle information and the conversion information in the storage means 34 (S1).
The suction nozzle information is information including a total length, an inner diameter dimension, an outer diameter dimension, an inclination angle of the opening, and the like of the suction nozzle used in the continuous molten metal plating apparatus of the present embodiment.
The conversion information is information indicating the relationship between the distance between the bath surface 100a of the molten metal 100 and the tip of the suction nozzle 16 and the area of the contact area of the bath surface 100a of the molten metal 100 at the opening 16a of the suction nozzle 16. is there. Specifically, the viscosity of the molten metal 100, the size of the suction nozzle 16, the area A of the contact area of the molten metal 100 in the opening 16a of the suction nozzle 16, and the high from the bath surface 100a to the tip of the suction nozzle 16 This is information that is specified in advance as a calibration curve (see FIG. 5). This conversion information is actually obtained by moving the suction nozzles of various dimensions in a liquid having the same viscosity as that of various molten metals that can be used in a continuous molten metal plating apparatus, the height h, and the contact area. Collected in association with area.

<Imaging process>
Next, the control unit 30 transmits a command signal for capturing a planar image of the opening 16 a at a predetermined interval and imaging magnification to the imaging unit 20. As a result, image data relating to the captured planar image of the opening 16 a is transmitted to the image processing means 31 in the control means 30. At this time, the image data relating to the captured planar image of the opening 16 a may be stored in the storage unit 34 by the control unit 30.

<Image processing process>
Next, the image processing means 31 identifies the image data relating to the captured planar image of the opening 16a by the end face (surface facing the imaging means 20) 16b of the opening 16a and the bath surface 100a of the molten metal 100. Image processing is performed on the possible image data (see FIGS. 3E to 3H) (S2). The image data subjected to the image processing in this way is transmitted to the calculation means 32 by the image processing means 31. At this time, the image data processed by the image processing unit 31 may be stored in the storage unit 34 by the control unit 30.

<Calculation process>
Next, based on the image data obtained by the image processing means 31, the calculating means 32 is based on the area of the contact area of the bath surface 100 a of the molten metal 100 in the opening 16 a of the nozzle 16 and the bath surface 100 a of the molten metal 100. The height h of the opening 16a with respect to is calculated (S3).

The area A (see FIGS. 3E to 3H) of the contact area of the bath surface 100a of the molten metal 100 in the opening 16a of the suction nozzle 16 is determined by the opening 16a of the suction nozzle 16 identified by the image processing means 31. This is calculated by subtracting the region of the end surface 16b of the metal from the region of the bath surface 100a of the molten metal 100.
Further, the height h of the opening 16a with respect to the bath surface 100a of the molten metal 100 is specified based on the calculated area A of the contact region and the conversion information (see FIG. 5) acquired in step S1. The area A of the contact area of the bath surface 100a of the molten metal 100 in the opening 16a of the suction nozzle 16 calculated by the calculation means 32 may be stored in the storage means 34 by the control means 30.

<Judgment process>
Next, the opening h based on the height h of the opening 16a with respect to the bath surface 100a of the molten metal 100 obtained by the calculation means 32 and the tip of the suction nozzle 16 in the longitudinal direction (opening direction) of the suction nozzle 16 Based on the dimension 16a (hereinafter referred to as the suction effective dimension H), the determination means 33 determines whether or not the suction nozzle 16 is moved up and down (S9).

  The determination by the determination means 33 first determines whether or not the relationship between the height h of the suction nozzle 16 relative to the bath surface 100a and the effective suction dimension H satisfies h> 0 (S4). When h> 0 is not satisfied (S4-No), as shown in FIGS. 3D and 3H, the opening 16a of the suction nozzle 16 is completely immersed in the molten metal 100 bath. In such a state, since the top dross cannot be removed efficiently, the control unit 30 causes the notification unit to display that the position of the suction unit 15 is inappropriate (S8), and the image is displayed again. Return to the processing step (S2).

  On the other hand, if h> 0 is satisfied (S4-Yes), it is further determined whether or not the relationship between the height of the suction nozzle 16 relative to the bath surface 100a and the suction effective dimension H satisfies h ≦ H (S6). When h ≧ H is satisfied (S6-Yes), the opening 16a of the suction nozzle 16 is positioned above the bath surface 100a of the molten metal 100 as shown in FIGS. 3 (a) and 3 (e). Therefore, the control unit 30 causes the notification unit to display that the position of the suction unit 15 is inappropriate (S8), and returns to the image processing step (S2).

  If h ≧ H is not satisfied (S6-No), it is further determined whether or not the relationship between the height of the suction nozzle 16 relative to the bath surface 100a and the suction effective dimension H satisfies h ≧ H / 2 ( S7). When h ≦ H / 2 is not satisfied (S7-No), the opening 16a of the suction nozzle 16 is more than the bath surface 100a of the molten metal 100 as shown in FIGS. 3 (b) and 3 (f). Since it is determined that the position is slightly above, the control unit 30 causes the notification unit to display that the position of the suction unit 15 is inappropriate (S8) and returns to the image processing step (S2) again.

On the other hand, when h ≦ H / 2 is satisfied (S7-Yes), the opening 16a of the suction nozzle 16 is formed on the bath surface 100a of the molten metal 100 as shown in FIGS. 3 (c) and 3 (g). On the other hand, since it is determined that it is properly positioned, the control unit 30 causes the notification unit to display that the position of the suction unit 15 is appropriate (S5), and returns to the image processing step (S2) again.
Here, the determination step (S9) is a step including step S4, step S6, and step S7 as shown in FIG.

<Position adjustment process>
When it is determined by the determination means 33 that the position of the suction nozzle 16 needs to be adjusted (S6-Yes, S7-No), the control means 30 performs an inappropriate notification (S8) in the notification means 40 and opens the opening. The height of the part 16a is adjusted (S10).
Specifically, the control means 30 operates the position control means 19 to adjust the height of the opening 16a so that the height h of the opening 16a obtained by the calculation means 32 becomes h = H / 2. To do. The adjustment of the height of the opening 16a by the control means 30 is controlled so as to be h = H / 2, and then returns to the image processing step (S2) to perform feedback control.

  Thus, according to the continuous molten metal plating apparatus of the present embodiment, the position of the suction nozzle from the suction nozzle information and conversion information acquired in advance, and the plane image identified by the end face of the suction nozzle and the image of the bath surface The suction nozzle position was optimized. Therefore, it is possible to provide a continuous molten metal plating apparatus that can efficiently remove dross in the snout.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.

DESCRIPTION OF SYMBOLS 1 Continuous molten metal plating apparatus 2 Reservoir 3 Immersion roll 4 Snout 5 Reduction annealing furnace 10 Dross removal means 15 Suction means 16 Suction nozzle 17 Suction pipe 18 Suction pump 19 Position adjustment means 20 Imaging means 30 Control means 31 Image processing means 32 Calculation means 33 Judgment means 100 Molten metal S Steel strip

Claims (2)

A dipping roll disposed in a storage tank in which molten metal is stored, and a snout having a tip inserted into the molten metal, and a steel strip is continuously carried into the molten metal through the snout. In a continuous molten metal plating apparatus that winds around the dipping roll and travels, and plating the surface of the steel strip,
A suction means comprising a suction port for sucking dross near the bath surface of the molten metal in the snout;
Position control means for moving the suction port up and down with respect to the bath surface;
Imaging means for imaging the suction port from its opening direction;
Image processing means for image processing the contact area of the molten metal bath surface at the suction port imaged by the imaging means;
Based on the image obtained by the image processing means, computing means for computing the area of the contact area of the molten metal bath surface at the suction port and the height of the suction port with respect to the molten metal bath surface;
Determination means for determining whether or not to move the suction port up and down based on the height of the suction port obtained by the computing means;
A continuous molten metal plating apparatus comprising: control means for adjusting the height of the suction port by operating the position control means based on a determination result of the determination means.   When the dimension of the suction port is H and the height of the suction port with respect to the bath surface is h, the height h of the suction port with respect to the bath surface calculated by the calculation means is h <0 or h>. When the determination unit determines that H / 2 is satisfied, the control unit controls the height of the suction port so that h = H / 2 is satisfied with respect to the position control unit. Item 2. The continuous molten metal plating apparatus according to Item 1.

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