JPS6386853A - Gas wiping device - Google Patents

Abstract

PURPOSE:To prevent generation of splashes, edge overcoats, noise, etc., by installing edge plates which have adequate sizes and are provided with holes in adequate positions to both ends in the transverse direction of a steel strip moving between opposite wiping nozzles. CONSTITUTION:A wiping gas is blown from the opposite wiping nozzles 12 to the steel sheet 14 moving therebetween to control the plating deposition of a molten metal and further, the edge plates 13 having the adequate sizes are installed to both end faces in the transverse direction of the sheet 14 apart therefrom. The sizes of the plates 13 of a gas wiping device constituted in the above-mentioned manner are specified to W+2w>=L, p2>=p1, q2>=q1 and further >=1 holes or notches are provided to the plates 13 in the position O<p1 (where, W; the width of the sheet 14, w; the width of the plates 13, L; the width of the nozzles 12, p1; the difference between a nozzle blow off line 16 and the top surface of the nozzles 12, q1; the difference between the line 16 and the bottom surface of the nozzles 12, p2; the difference between the line 16 and the top surface of the plates 13, q2; the difference between the line 16 and the bottom surfaces of the edge plate, O; the position of the line 16).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gas wiping device for controlling the amount of deposited molten metal plating. In particular, the present invention relates to a gas wiping device that prevents excessive adhesion on both ends of steel plates, splashes, and noise.

(Conventional technology and 3 points in between) When performing fusion metal plating on steel (reverse) in a continuous, volume fusion metal plating line, conventionally, the steel sheet that has been pretreated is heated in a heat treatment furnace, and the pretreated steel plate is The steel plate was immersed in a metal plating bath through the interior of the steel plate, and then lifted out. At that time, a wiping gas was blown from a wiping nozzle toward the plated steel sheet to control the amount of metal plating deposited in the bath.

In this method of adjusting the area weight by spraying wiping gas, the gases from the opposing wiping nozzles collide with each other, especially at both ends of the steel plate, causing gas turbulence, and causing A so-called edge overcoat phenomenon in which excessive molten metal adhered was observed.

This is because the nozzle width of the gas wiping device is wider than the fence plate, so the wiping gas flows outward from both ends of the steel plate.

Other problems include the generation of splash from both ends of the steel plate and the generation of noise due to the collision of the wiping gas blown out from both opposing nozzles.

This phenomenon occurs when a gas wiping device is used to adjust the size of molten metal plating: The wiping gas that is blown toward the steel plate blows off the excess metal that has adhered to both ends of the steel plate. Therefore,
This spheronite phenomenon has caused clogging of nozzles and other deposition control devices, and adhesion of molten metal.

Preventing edge overcoat on both ends of these steel plates 1
Conventionally, the nozzle slit gap has been widened toward both ends of the steel plate to increase the gas flow rate, thereby improving the squeezing force, and auxiliary nozzles have been installed at both ends of the steel plate to locally narrow the gap at both ends. Attempts have been made to improve the squeezing force.

However, in this way, the gas flow rate is locally controlled at both ends of the steel plate.
: In the cooling method, the cooling at both ends of the steel sheet is accelerated, and the solidification of the molten metal becomes uneven in the width direction of the steel sheet. The solidification line of molten metal is high near the center of the steel plate, and conversely, it drops sharply at both ends.

・Also, because the nozzles are usually placed facing each other on the front and back sides of the steel plate, collisions of the wiping gas occur where the nozzles protrude from the width of the steel plate, causing intense noise.

At present, edge plates are provided to avoid such problems.

By the way, Fig. 3 is a schematic explanatory diagram showing the flow direction of the wiping gas blown out from the nozzle around the wiping nozzle. can be seen. A negative pressure VA region indicated by the (-) portion as shown in FIG. 3 was present. Note that at this time, a positive pressure (+) region is generated in the direction of the nozzle blowout line.

Therefore, while spraying the wiping gas, BjE
Since a large force is applied to the nozzle by this negative pressure, if the steel plate is thin or the tension applied to the steel plate is small, the steel plate may be drawn toward the nozzle. However, normally, a fairly large bow length force is applied to the steel strip, so a single strip of steel will not be drawn to the nozzle, but if you envy the edge plate as mentioned above,
Edge plates were often attracted to the nozzle due to such negative pressure.

In order to overcome this negative pressure, a supporting device with a fairly rigid structure is required to secure the edge plate, which makes the gibrate support mechanism heavy and difficult to use. j! It had turned into a pheasant.

Even if such a strong fixing device were provided, many of these edge plates have a mechanism that cannot follow changes in the steel plate width or nozzle height, and the operability is very faithful. Ta.

For example, the one-edge overcoat prevention device disclosed in Japanese Patent Publication No. 52W43457 installs an edge plate as a baffle plate that can be finely adjusted in the width direction of the steel plate or in the direction in which the steel plate advances. Or, even if horizontal vibration occurs, the distance between the steel plate and the baffle plate should be set to 11
It was of a structure that automatically tried to keep it constantly below 11M.

However, when 'b<1, the prevention effect of the edge overcoat is insufficient, and there are many other problems such as the inability to reduce the weight to 1, and the inability to follow changes in steel sheet width and nozzle height.

Therefore, it is an object of the present invention to provide an apparatus that solves the problems of conventional gas wiping apparatuses, such as splash generation from both ends of the mouth plate, geo-barcode generation, noise generation, etc.

(Means to Solve the Problem) Therefore, as a result of intensive studies on this problem, the edge plate completely covers the nozzle part that protrudes from the nozzle elevation range and the date plate width direction range. I tried to improve the mechanism of the edge plate to make it possible.

However, even if such edge plates are provided at both ends of the battens, instability during operation due to wiping gas cannot be avoided. Therefore, by further providing holes or notches in these plates, the stability of the edge plates is improved. Knowing this, he completed the present invention.

Here, the gist of the present invention is a gas wiping device comprising opposing wiping nozzles and edge plates spaced by ^1 on both end faces in the width direction of a steel plate that moves between the wiping nozzles. , the edge plate has dimensions W+2w≧L1 P2≧PQz≧Q+, and the edge plate is further provided with one or more holes or notches at positions where 0<PI. It is a device.

However, W: steel plate width, -2 plate width, L: nozzle width Pl: difference between nozzle blowout line and nozzle top surface, q:: difference between nozzle blowout line and nozzle bottom surface, P2: nozzle blowout line and edge plate top surface q2: Difference between the nozzle blowout line and the bottom surface of the edge plate, 0: Nozzle blowout line.

Further, the present invention provides a gas wiping device characterized in that the edge plate is supported in the width direction of the steel plate so as to be able to follow the width of the steel plate, and is also supported on both end faces in the width direction of E+H so as to be able to rise and fall freely. It is a device.

Note that the edge plate may be configured to be supported by the upper surface of the wiping nozzle.

(Operation) Next, the present invention will be explained in more detail using the accompanying drawings.

FIG. 1 is a partial explanatory diagram showing the installation relationship between the edge plate and the wiping nozzle according to the present invention, FIG. 2 is a partial explanatory diagram of the gas flow when wiping gas is sprayed onto a steel plate, and FIG. Figure 4 is a partial explanatory diagram showing the pressure distribution on the steel plate surface when wiping gas is blown onto the F4 plate.
Fig. 5 is a partial explanatory diagram showing how the edge plate vibrates when wiping gas is sprayed. Fig. 5 is a partial explanatory diagram showing how the edge plate and steel sheet are stable in the same line. , a partial explanatory diagram showing the positions of holes or notches of the edge play 1 according to the present invention, and FIG. 7 are partial explanatory diagrams showing the positional relationship of opposing wiping nozzles.

In the present invention, as shown in FIG. 1, the edge plate 13 is preferably made to be movable in the width direction of the steel plate by bringing the edge plate 3 into contact with both ends of the steel plate and the ground surface of the nozzle 12 by means of a support device 15. One steel plate can be moved up and down in the direction of travel.

Moreover, the nozzle itself can also be freely lowered four times in the direction in which the steel plate advances. And this edge plate support device 15
is driven by an appropriate driving means such as a motor or an air cylinder.

It should be noted that the details and mounting manner of such drive means are already clear to those skilled in the art from the above description, and further description thereof will be omitted for the sake of brevity.

FIG. 2 shows the wiping gas flow from the nozzle 12 toward the steel plate 14 in the case of FIG. 01 board 1
The pressure distribution on 4 is as shown in FIG.

By the way, when the edge plate is not provided with holes or notches like this, as shown in FIG.
2, the wiping nozzle center line 1
It rotates around 6 and becomes extremely unstable.

The present invention provides a hole or notch in the edge plate 13 to relieve the negative pressure area.
This prevents the particles from being attracted to the nozzle 12 and stabilizes it.

This is because when the wiping gas is blown out from the nozzle port, its dynamic pressure becomes self-sustaining and stable at the equilibrium point of the dynamic pressure of the edge plate.

Therefore, the shape of the cutout or hole is not particularly limited as long as such effects can be obtained.

Thus, according to the invention, 14+5. Even if the pressure and flow rate of the gas blown out from the nozzles located opposite to each other on the front and back sides are different, the effect of the holes and notches makes the pressure distribution as uniform as possible on the front and back sides of the edge plate, and the edge plate is placed in the specified position. It stabilizes.

The manner in which the edge plate is balanced between both nozzles is shown in FIG.

The wiping gas from the nozzle 12 is sent to the edge plate 13.
The front and back sides of the edge plate are connected through a common hole 18.

The position of the hole or notch in the edge plate mentioned above should be above the blowout line of the Wibin Crizzle as shown in Figure 6, and the hole or notch should not be located even partially on the top surface of the nozzle. .

This is because the presence of these holes or notches on the nozzle air outlet is similar to the situation without the edge plate, which is undesirable from the standpoint of noise reduction.

Therefore, the position of the hole or cutout provided according to the invention is such that O<PL. In other words, the hole or notch is provided at a position higher than the nozzle blowout line and between the nozzle blowout line and the second surface of the nozzle. At this time, in order to avoid direct collision with the wiping gas blowout flow and the formation of a negative pressure area as shown in Figure 3, there is a step between the nozzle blowout line and the hole or notch, that is, the hole or notch is located between the lower end of the nozzle and the nozzle blowout line. The distance from the blowout line shall be at least 10 mm or more. However, the position of the hole or notch shall not exceed P, that is, the upper surface of the nozzle.

At least a portion of the hole or notch does not extend beyond the position P, and is therefore inside the nozzle top surface.

This is because if it is separated from the upper surface of the nozzle, there is no point in providing a hole or notch.

In order to satisfy these conditions, in the l aspect,
The edge plate is supported on the upper surface of the nozzle to maintain a constant positional relationship in the height direction between the edge plate and the nozzle, and a support mechanism as shown in Figure 7 is used to maintain the relationship at the height of the nozzle, even if only one nozzle is used. It is preferable to keep it constant.

However, in this case, the level difference between the front and back sides of the nozzle is controlled by the position of the hole or notch in the edge plate. In addition, in order to control the amount of coating to be uniform, it is preferable that the step of the nozzle blowout line be within 10 mm.

Next, the reason why the size of the edge plate is limited in the present invention will be explained.

Even if edge plates are installed at intervals on both ends of the steel plate, W+2
If w<L, that is, the sum of the width of the steel plate and the width of both edge plates is shorter than the nozzle width, the gas blown out from the front and back nozzles will directly collide, causing noise. Therefore, in order to prevent the gases blown from the front and back nozzles from colliding, the first
As shown in the figure, the edge plate width must be large enough to completely cover the nozzle width, that is, W+2w≧L.

Here, W: @plate width, -2 plate width, and L: nozzle width.

Next, as shown in Fig. 1, the reason why P2≧P1%q2≧ is customary is that if the edge plate is not provided at a height that completely covers the wiping gas blowout flow, the gas may collide directly with the wiping gas. The height of the edge plate is greater than the height of the nozzle Pf ≥ PI% so that the edge plate completely covers the nozzle.
It was assumed that Qz≧q.

Here, P: Distance from the nozzle blow line to the top surface of the nozzle, P2: Distance from the nozzle blow line to the top surface of the edge plate, q, Distance from the nozzle blow line to the bottom surface of the nozzle, q2: Distance from the nozzle blow line to the bottom surface of the edge plate is the distance.

Therefore, the reason why the size of the edge plate and the position of the hole or notch are limited as described above in the present invention is to stabilize the edge plate on its own, make the basis weight uniform, and further prevent noise.

FIG. 8 shows a preferred arrangement example of the gas wiping device according to the present invention. What is particularly important is the size, position, and number of holes (cutouts) per day, and in the illustrated example, the holes are 50 mm in diameter. 4 pieces - arranged in a row, the distance from the nozzle blowout line 16 is 50
I am taking IIIm.

Note that this arrangement is just one example, and it is clear to those skilled in the art that many modifications can be made taking other processing conditions into consideration.

(Effects of the Invention) In this way, the present invention prevents the generation of negative pressure due to air entrainment from the surroundings of the steel plate or edge plate by attaching the edge plate 1 provided with holes or notches to the gas wiping device. This improves the self-supporting stability of the edge plate, thereby eliminating the vibration of the FA plate surface and making the amount of plating uniform, thereby achieving the effect of preventing soot coating, edge overcoat, and noise generation.

In addition, the present invention has a mechanism that allows the edge plate to move in the width direction of the steel plate, that is, along the top surface of the nozzle, and also allows the edge plate to move in the upward and downward direction of the nozzle, that is, in the direction of temporary movement of the ¥A. By reducing the size and making the edge plate lighter, the equipment used or! It can be designed functionally according to the size of 21 temporary width.

Therefore, according to the present invention, a reliable mechanism is provided to eliminate the coating amount difference in the width direction of the steel plate, which is one of the weaknesses of conventional hot-dip plating, and improves workability and functionality. Its utility value is high as a gas wiping device that can excellently adjust the basis weight of molten metal plating.

[Brief explanation of the drawing]

FIG. 1 is a partial explanatory view showing the arrangement relationship between the edge plate and the wiping nozzle in the present invention; FIG. 2 is a partial side view showing the direction in which air flows when wiping gas is blown onto a steel plate; The figure is a partial explanatory diagram showing the pressure distribution on the steel plate surface when wiping gas is blown onto the steel plate; Figure 4 is a partial explanatory diagram showing how the edge plate vibrates when wiping gas is blown onto the steel plate. Figure; Figure 5 is a partial explanatory view showing how the edge plate and mouth plate are stably held; Figure 6 is a partial explanatory view showing the positions of holes or notches in the edge plate according to the present invention FIG. 7 is a partial explanatory diagram showing the positional relationship between opposing wiping nozzles; and FIG. 8 is a schematic explanatory diagram showing a preferred arrangement example of the device of the present invention.

Claims (3)

[Claims] (1) A gas wiping device equipped with opposing wiping nozzles and edge plates spaced apart from each other on both end faces in the width direction of a steel plate that moves between the wiping nozzles, where the dimensions of the edge plates are W+2w≧L, P_2 ≧P_1, q_2≧q_1, and the edge plate is further provided with one or more holes or notches at positions where 0<P_1. However, W: Steel plate width, w: Plate width, L: Nozzle width P_1: Difference between the nozzle blowout line and the nozzle top surface, q_1: Difference between the nozzle blowout line and the nozzle bottom surface, P_2: Between the nozzle blowout line and the top surface of the edge plate. q_2: Difference between the nozzle blowout line and the bottom surface of the edge plate, 0: Nozzle blowout line. (2) The edge plate according to claim 1, wherein the edge plate is supported in the width direction of the steel plate so as to be able to follow the width of the steel plate, and is also supported so that it can be raised and lowered along both end faces of the steel plate in the width direction. Gas wiping device. (3) The gas wiping device according to claim 2, wherein the edge plate is supported by the upper surface of the wiping nozzle.