JPH10183318A - Zinc pot for hot dip galvanizing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zinc pot having a durable bath circulating mechanism. SOLUTION: A groove shaped passage 3, in which both ends are connected to different positions of a zinc pot 2 and its bath surface has a height equal to a bath surface of the zinc pot, is arranged on a side face of the zinc pot for hot dip galvanizing. The passage 3 is divided into two parts 32, 34 respectively including connecting parts 31, 35 of the zinc pot 2 by a partition wall 3, an further, a vertical type pump 4, which transfers a zinc bath B from one side part 32 to the other side part 34, is arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zinc pot for accommodating a zinc bath in a hot-dip galvanizing facility for a steel strip or the like.

[0002]

2. Description of the Related Art In a hot-dip galvanizing facility in which a steel strip is immersed in a hot-dip zinc pot and then pulled up, gas wiping is used to adjust the amount of zinc applied. It has been a problem to cause defects in products by adhering to the surface. The dross that causes the dross floats on the bath surface because it has a slightly lower specific gravity than zinc, but it is agitated due to the flow of the bath in the pot and is partially present inside the bath.

In order to prevent defects caused by dross, a zinc bath containing a large amount of dross is led out of the pot without stirring the bath surface as much as possible, and the bath is circulated such that the dross is removed and the bath is gently returned to the pot. Is effective. For example, JP
JP-A-5-255828 describes a combination of dross removing means using a filling tank and bath circulation.
No. 171386 describes a combination of heating and cooling means and bath circulation. Various other proposals have been made, but none of them have been considered with regard to durability, and they have been basically improved in principle.

[0004]

According to the experience of the present inventors, the circulation of the bath using the pump and the piping described in these prior arts causes the piping to be broken in one to two weeks. There is a problem in terms of durability, and the utility is poor. This is due to the fact that the fluid to be handled is not only a high-temperature molten metal but also zinc, which is extremely reactive with various materials. Further, it is extremely difficult to take measures when the circulation is temporarily stopped, which is an obstacle to the stable operation of the apparatus. Although the dross defect has been a subject for many years, it is the durability problem that has hindered the realization of various proposals, and the development of a stable bath circulation means has been strongly desired.

An object of the present invention is to solve the problem of durability and realize a stable bath circulation.

[0006]

SUMMARY OF THE INVENTION The present inventors have found that the problem of insufficient durability in the conventional proposal is that the bath circulation is to be flowed by applying pressure to a small pipe similar to a normal fluid. Focusing on what is happening, instead of pumping the bath with a pump, connect two places of the pot with a groove-shaped flow path, and move the bath from one side of the partition provided in the flow path to the other by the pump. By creating a level difference between the baths on both sides of the partition, a natural circulation flow was created.

[0007] That is, the present invention provides a zinc pot for hot-dip galvanizing, wherein both ends are connected to different positions of the zinc pot, and the height of the bath is the same as that of the zinc pot. A grooved flow path is provided, and the flow path is divided by a partition wall into two portions each including at least one connection portion with the pot, and the zinc bath is transferred from one portion to the other portion. A zinc pot for hot-dip galvanizing, characterized by comprising zinc bath cleaning means, preferably at least one part of a flow path partitioned by a partition wall. A zinc pot for hot-dip galvanizing as described above.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the vicinity of a zinc pot of this embodiment, FIG. 2 is a sectional view of a channel portion, 1 is a snout, 2 is a zinc pot, 3 is a channel, 31 is a downstream opening, and 32 is a suction port. Side flow path, 33 is a partition wall, 34 is a discharge side flow path, 35 is an upstream opening, 4 is a vertical pump (not shown in FIG. 1), B
Is a zinc bath, D is dross, and S is a steel strip.

The steel strip S enters the zinc pot 2 directly from the atmosphere gas through the snout 1 and is wound around the sink roll in the bath, and turns its traveling direction vertically upward toward the bath. A channel 3 is provided on a side surface of the zinc pot 2. The channel 3 is in the form of a groove having an open circular or square cross section at the top. The zinc pot 2 has connecting portions at two different positions, that is, openings at both ends. The downstream opening 31 is near the rising portion of the steel strip S, and the upstream opening 35 is near the snout. Since the flow of dross on the bath surface accompanies the steel strip S and goes from the upstream side to the downstream side of the steel strip S, the flow path 3 draws the bath from the downstream opening 31 in the opposite manner, and the upstream opening
Return to 35. A partition wall 33 is provided at a position close to the upstream opening 35 in the middle of the flow path 3 and connected to one part, that is, the suction side flow path 32 following the downstream opening 31 and the other part, that is, the upstream opening 35. The discharge-side flow path 34 is divided. The suction side flow path 32 is made longer to promote the floating of the dross.

[0010] The downstream opening 31 is opened at the upper side of the flow path section to facilitate the flow of floating dross, and the upstream opening 35 is opened at the lower side of the flow path section to make it difficult for the dross to flow into the pot. The area near the surface is closed. The vertical pump 4 as a means for transferring the zinc bath is installed near the partition wall 33, the suction port is in the suction side flow path 32, and the discharge port is in the discharge side flow path.
Open at 34. When the pump is stopped, the bath surface of the suction side flow path 32 and the discharge side flow path 34
At the same level because there is no circulating flow. When the pump is started, the level of the suction side flow path 32 decreases, so that the zinc bath flows from the zinc pot 2, and the level of the discharge side flow path 34 increases, so that the bath returns to the zinc pot 2. Therefore, the bath circulates through this flow path as long as the pump is operating.

As compared with the case where the bath is directly sucked in and discharged from the zinc pot 2, the bath surface changes naturally due to the inflow into the flow path and the outflow from the flow path, and the dross is not agitated. The dross can be easily separated and floated in the middle of the flow path without affecting the bath level. Since the transfer of the bath is carried out between flow paths of almost the same level, the vertical pump 4
A small pressure and capacity is sufficient, and a simple structure and excellent durability can be selected.

The dross floating and accumulating on the bath surface is easy to be scraped out by human power, but a known automatic dross separation device shown in phantom lines in FIG. 5 may be installed. Although the example in which the flow path 3 is provided on one side of the zinc pot 2 has been described, it goes without saying that the flow path 3 may be provided on the opposite side to the steel strip S, that is, on both sides of the zinc pot 2.

[0013]

According to the present invention, compared to the conventional piping type dross separation apparatus, the durability is excellent, and not only can it be stably operated for more than three months, but also the bath surface fluctuation due to bath circulation is small. Therefore, there is no quality defect due to dross entrainment, and an excellent effect that the quality is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of the vicinity of a zinc pot showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a flow path portion showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Snout 2 Zinc pot 3 Flow path 4 Vertical pump (Zinc bath transfer means) 5 Automatic dross separation device (Purification means) 31 Downstream opening (Connection part) 32 Suction side flow path (part) 33 Partition wall 34 Discharge side Flow path (part) 35 Upstream opening (connection) B Zinc bath D Dross S Steel strip

Claims (2)

[Claims] At least one side of a zinc pot for hot-dip galvanizing is connected to different positions of the zinc pot, and a bath surface of the zinc pot is common to a bath surface of the zinc pot. And a connecting wall (31, 35) for connecting to the zinc pot (2) at least at one location by a partition wall (33). Split into two parts (32, 34)
A zinc pot for hot dip galvanizing, comprising a zinc bath transfer means (4) for transferring a zinc bath from one part (32) to the other part (34). 2. A zinc bath cleaning means (5) is provided in at least one part (32) of the flow path partitioned by the partition wall (33).
The zinc pot for hot-dip galvanizing according to claim 1, comprising: