JPH0248419Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a device for removing contaminants in a snout in a continuous molten metal plating line such as a continuous molten galvanizing line.

(Prior art) A steel strip that has been annealed and has its surface reduced and purified by passing through an annealing furnace in a reducing atmosphere is introduced into a plating bath through a snout with the surface not oxidized.
In continuous molten metal plating, in which zinc is deposited on the surface of the steel strip while passing through molten metal (such as molten zinc), the surface of the steel strip is surrounded by a snout that is submerged in the surface of the plating bath. A lot of molten metal adheres to certain parts.

However, the molten metal in this area is mixed with iron eluted from the steel strip, and the iron concentration gradually increases. As described above, when the iron content in the molten metal in the snout gradually increases, variations occur in the plating layer, resulting in a decrease in quality.

In addition, in hot-dip galvanizing, attempts have been made to improve the plating layer by adding an appropriate amount of aluminum to the molten zinc, but when aluminum is added, the iron eluted from the steel strip reacts preferentially with the aluminum, resulting in Fe ₂ A stationary phase of Al ₃ is generated, and this material floats to form dross. Further, the molten metal evaporated from the bath surface in the snout adheres to the inner wall of the snout as metal ash, and a portion of it falls and floats on the bath surface in the snout.

The impurities consisting of the dross and metal ash floating on the bath surface in the snout may adhere to the incoming steel strip or become stuck to the plating surface of the steel strip due to the entrainment phenomenon when entering the snout. decrease. In addition, due to the generation of dross, the amount of aluminum in the molten zinc decreases, causing fluctuations in the plating component and hindering the stabilization of quality.

Therefore, the applicant of the present application has already proposed a device to effectively remove the impurities and improve the quality (Utility Application No. 034677/1983). This idea consists of arranging a duct inside the plating bath surface inside the snout and the plating bath surface outside the snout, and installing a propulsion device or pump inside this duct. It is designed to suck up foreign matter along with molten metal and discharge it out of the snout.

(Problem to be solved by the invention) However, in the conventional foreign matter removal device, foreign matter in the snout is removed into the duct by the flow of the plating bath surface generated by the propulsive force of the propulsion device or the suction force of the pump. Since the snout is designed to be sucked in by the snout, there is a difference in the discharge state of foreign matter between the bath surface area with good fluidity and the bath surface region with poor fluidity, and the foreign matter from the bath surface inside the snout is uniformly and reliably discharged. There are some problems, such as it being somewhat difficult to

The present invention was developed in view of these circumstances, and is a device for removing foreign matter in a snout in a continuous molten metal plating line, which has high efficiency in removing foreign matter and can reliably discharge foreign matter from the bath surface inside the snout. The purpose is to provide

(Means for Solving the Problems) In order to achieve the above object, the present invention has a concave cross-section for attracting contaminants between the plating bath inside the snout, which is immersed in the surface of the plating bath, and the plating bath outside the snout. A duct is provided, and a suction pump is provided in the duct to suck in impurities and molten metal on the bath surface inside the snout through the internal opening of the duct and discharge them to the outside of the snout. a contaminant removing member for scraping up and removing contaminants; a bracket having a distal end connected to the contaminant removing member and having a rear end extending around the lower end of the snout onto the molten metal outside the snout; and a drive mechanism installed outside the snout that is connected to the bracket and moves the foreign matter removal member along the width direction of the steel strip to transfer foreign matter to the internal opening side of the duct. be.

(Function) According to the present invention, the contaminant removal member in the snout is moved in the width direction of the steel strip by the drive mechanism, and the contaminants floating on the steel strip surface are effectively removed by the contaminant suction duct. can be forcibly transferred to the internal opening side. The foreign matter that was forcibly transported was
The foreign matter enters into the duct through the internal opening of the foreign matter suction duct, and the foreign matter can be efficiently discharged out of the snout along with the molten metal by a suction pump provided within the duct.

Further, in the case of the present invention, the foreign matter removal member inside the snout is connected to the drive mechanism installed outside the snout via a bracket that bypasses the lower end of the snout and extends onto the molten metal outside the snout. The drive mechanism can be inspected, maintained, or repaired in case of failure without removing the reducing gas in the snout.

(Example) Fig. 1 is a longitudinal sectional front view of the main part inside the plating bath in a continuous hot-dip galvanizing line for steel strips showing an embodiment of the present invention. Annealing and surface cleaning are performed in an annealing furnace with a reducing atmosphere.

Then, it passes through the snout 2 and is introduced into the plating bath surface 4c inside the snout 2 in the molten metal (for example, molten zinc or molten zinc alloy) 4 of the plating bath 3 with its surface unoxidized, and after being transferred to the back of the page, it is pulled up. Snout 2 External plating bath surface 4
It is derived from d.

The lower end opening of the snout 2 is submerged below the plating bath surface, and the internal opening is located near the bottom of the plating bath surface 4a along both sides of the steel strip 1 in the width direction. A contaminant suction duct 5 with a concave cross section and an external opening protruding above the surface 4b;
51 are provided so as to face each other on both sides of the steel strip in the width direction. Both ducts 5 and 51 are made of corrosion-resistant steel (for example, stainless steel), and the fixing means 9
They are each fixed to the snout 2 so as to be movable up and down via the snout 2.

Both ducts 5, 51 have internal rising passages 5A, 51A with a square cross section, external rising passages 5B, 51B with a round or square cross section, and both these passages 5A,
Communication passages 5D, 51 with a rectangular cross section extending in the horizontal direction and connecting the 51A, 5B, 51B with each other at the lower part.
D, upwardly facing internal openings 5a, 51a are formed at the upper ends of the internal rising passages 5A, 51A, and upwardly facing external openings 5b, 51b are formed at the upper ends of the external rising passages 5B, 51B. and,
The internal openings 5a and 51a are submerged below the plating bath surface 4a inside the snout 2, and the external opening 5
b, 51b are located at positions projecting upward from the plating bath surface 4b outside the snout 2.

The positions of the internal openings 5a and 51a are adjusted to the bath surface 4.
In order to effectively remove impurities, it is desirable to set the depth to about 20 mm from a.

The internal openings 5a, 51a of both ducts 5, 51 are provided with opposing projecting walls 50, 52 which are U-shaped in plan and have three sides, excluding the steel strip side, extending upward and protruding from the bath surface 4a. There is.

External rising passages 5 of both ducts 5 and 51
B, 51B, for example, an air pump, gear pump, or other suction pump 6 has its suction port 6A.
The level h1 is the upper end level of the communication parts 5D and 51D.
It is set above h2 and placed so that it can be taken in and out. The discharge passage 6B of the suction pump 6 is submerged below the bath surface 4b outside the snout 2.

Next, the operation of the above configuration will be explained.

When the suction pump 6 is driven, its suction force causes the molten metal 4 in the ducts 5 and 51 to flow as indicated by arrows A and B in FIG. Therefore, Snout 2
The molten metal 4 near the steel strip in the inner openings 5a, 5
The plating bath surface 4 outside the snout of the plating bathtub 3 is sucked into the ducts 5, 51 from 1a, is sucked in from the suction port 6A of the suction pump 6 in the external rising passages 5b, 51b, and passes through the discharge passage 6B.
b It is discharged downward. In this case, the molten metal 4 in the snout flows in the width direction of the steel strip 1, and as a result, impurities floating near both the front and back surfaces of the steel strip are discharged from the snout.

Furthermore, if the internal openings of the ducts 5 and 51 are located higher than the level of the plating bath surface of the plating bathtub 3,
For example, if the liquid level H of the molten metal 4 unexpectedly drops to the H ₀ position, the molten metal 4 will no longer flow from the plating bath 3 into the internal rising passages 5A, 51A. In this case, the molten metal and impurities in the ducts 5 and 51 are discharged by the suction force of the suction pump 6, and the bath surface level is lowered to a level slightly below the level of the suction port 6A, but it is not lower than that. won't go down. For that purpose, the communication portions 5D, 51D
The inside of the snout 2 can be completely shut off from the outside of the snout 2, so even if the suction pump continues to drive, the inside of the snout will not be reduced. Gas leakage to the outside can be reliably prevented.

By the way, as shown in Figures 1 and 2,
Contaminant removing members 7, 71 are provided opposite to the front and back surfaces of the steel strip 1, and these contaminant removing members 7,
71 is configured to be movable along the width direction of the steel strip 1 by drive mechanisms 8 and 81. That is, the impurity removal members 7 and 71 are rectangular plates made of corrosion-resistant steel, and are perpendicular to the steel strip 1, with their inner ends relatively close to both the front and back sides of the steel strip 1, and their outer ends close to the snout 2. As shown in FIGS. 3 and 4, when the molten metal 4 is maintained at the normal liquid level H, approximately the upper half of the molten metal 4 The upper part is exposed, and approximately the lower half is immersed in the molten metal 4. Then, the tips of the brackets 10A, 10B are connected to the foreign matter removing members 7, 71, and the brackets 10A, 10B bypass the lower end of the snout 2 so that the rear end of the brackets 10A, 10B are connected to the snout 2.
a drive mechanism 8,8 extending over the molten metal 4 outside the snout 2 and having its rear end installed outside the snout 2;
1.

The drive mechanisms 8, 81 include motors 8A, 81A installed before and after the snout 2;
lead screws 8B, 81B extending along the width direction of the snout 2 so as to be able to decelerate and rotate at the same time as the output shaft of A;
It is composed of moving members 8D and 81D that reciprocate left and right by the forward and reverse rotation of the lead screws 8B and 81B, and the rear ends of brackets 10A and 10B are connected to the lower ends of moving members 8D and 81D. . A pair of upper and lower rails 12A are attached so that the upper and lower ends of the movable members 8D, 81D extend to the front and rear of the snout 2 via hangers 11A, 11B,
12B, and is slidably fitted onto the lead screw 8.
B and 81B are both ends of the rails 12A and 12B (however, only one end is shown in FIG. 5).
It is rotatably supported by a bearing member 13 which is bridge-fixed between both 12A and 12B.

Next, the operation of the above configuration will be explained.

When the motors 8A, 81A of the drive mechanisms 8, 81 are driven to rotate the lead screws 8B, 81B in the opposite direction, for example, the foreign matter removing members 7, 71 at the stroke start position in FIG. You will move in the direction of arrow x1 using this as a guide. Therefore, among the contaminants floating on the plating bath surface 4a inside the snout 2, the contaminants on the near side of the steel strip 1 are forcibly gathered toward the right in the drawing by the contaminant removing member 7 and become contaminants. The contaminants are transferred to the internal opening 5a of the contaminant suction duct 5, enter the contaminant suction duct 5 from here, and are fed to the suction pump 6 provided in the duct 5.
is discharged to the outside of the snout 2 along with the molten metal. In addition, the foreign matter on the back side of the steel strip 1 is forcibly gathered toward the left in the drawing by the foreign matter removing member 71, and the foreign matter is forcibly collected in the internal opening 51 of the foreign matter suction duct 51.
a, and is discharged from there to the outside of the snout 2.

When the foreign matter removing members 7, 71 reach the stroke end position (the position indicated by the imaginary line in FIG. 3),
By rotating the lead screws 8B and 81B in the forward direction, the foreign matter removal members 7 and 71 are moved in the direction of arrow x2, returned to the stroke start position shown by the solid line, and placed in a standby state for the next foreign matter removal operation. enter.
By the return movement of the foreign matter removing member 7,
During the above-mentioned forward movement, all of the foreign matter is sucked into the suction duct 5.
Even if the remaining foreign matter remains without being transferred to the suction duct 51, the remaining foreign matter can be transferred to the suction duct 51 and discharged, and the remaining foreign matter can be removed by the return movement of the foreign matter removing member 71. Suction duct 5
It can be transferred to and discharged.

In this way, the foreign matter is removed from the foreign matter removing members 7, 71.
Since the contaminants are transferred to the contaminant suction ducts 5 and 51 by forced scraping, the contaminants can be removed and discharged extremely efficiently.

In addition, as an embodiment other than the above, a configuration may be employed in which only one of the foreign substance suction ducts 5, 51 is used, or a configuration in which the foreign substance suction ducts 5, 51 are provided opposite to each other on both the front and back sides of the steel strip 1. You can also use it as
Furthermore, by appropriately automatically controlling the height adjustment between the duct and the liquid level of the plating bath, and the height adjustment between the duct and the pump, it is possible to adjust the suction efficiency of foreign substances and the amount discharged from the pump.

Furthermore, although the stroke starting positions, that is, the start positions of the contaminant removal members 7 and 71 are set at both outer sides in the width direction of the steel strip 1 in the explanation, they are set at the center position in the width direction of the steel strip 1. It may be configured to move left and right from this position.

(Effects of the invention) As described above, according to the invention, the contaminant removal member in the snout is moved in the width direction of the steel strip by the drive mechanism, and the contaminants floating on the steel strip surface are removed. In order to effectively forcefully transfer the foreign matter to the internal opening side of the foreign matter suction duct, the forcibly transferred foreign matter enters the duct through the internal opening of the foreign matter suction duct, and the foreign matter is placed inside the duct. The molten metal can be efficiently discharged out of the snout together with the molten metal by a suction pump.

Further, in the case of the present invention, the contaminant removal member inside the snout is connected to the drive mechanism installed outside the snout via a bracket that bypasses the lower end of the snout and extends onto the molten metal outside the snout. Therefore, inspection and maintenance of the drive mechanism or repairs in the event of a failure can be performed outside the snout, and there is no danger of the reducing gas inside the snout leaking outside. Therefore, once the Metsuki line is in operation, it will continue to operate for about one to several months with reducing gas in the snout, but without stopping the operation or waiting for the operation to end, Able to inspect, maintain, or repair drive mechanisms.

Moreover, since the drive mechanism installed outside the snout and the dirt removal member inside the snout are connected by a bracket that bypasses the lower end of the snout, the dirt removal member is connected to the drive mechanism outside the snout via the shaft. Therefore, there is no need to drill holes in the wall of the snout, and it is possible to prevent the dangerous reducing gas inside the snout from leaking out through the hole.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. FIG. 2 is a partially longitudinal front view showing the relationship between the drive mechanism and the foreign matter removal member. 1...Steel belt, 2...Snout, 3...Metsuki bathtub, 4
... Molten metal, 4a, 4b... Plating bath surface, 4c... Plating bath inside the snout, 4d... Plating bath outside the snout, 5, 51... Duct, 5B, 51B... External rising passage, 5D, 51D... Lower communication part, 5a, 51
a... Internal opening, 5b, 51b... External opening, 6
...Suction pump, 6A...Suction port, 7,71...Contaminant removal member, 8,81...Drive mechanism, 10A, 10B
...bracket, h1...suction port level, h2...upper end level of communication section.

Claims (1)

[Scope of utility model registration request] A contaminant suction duct with a concave cross section is provided between the plating bath inside the snout, which is immersed in the surface of the plating bath, and the plating bath outside the snout. A contaminant removing member that is provided with a suction pump that sucks in objects and molten metal and discharges them to the outside of the snout, and that scrapes and removes contaminants floating on the steel strip surface side inside the snout, and this contaminant removing member. a bracket whose tip end is connected to the snout and whose rear end extends around the lower end of the snout onto the molten metal outside the snout; A contaminant removal device in a snout in a continuous molten metal plating line, comprising: a drive mechanism installed outside the snout for transferring objects to the internal opening side of the duct.