JPH052595Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a sealing device that prevents combustion exhaust gas in a direct-fired heating zone from entering the adjacent reduction zone in a continuous heat treatment furnace for heat-treating strips. .

(Prior Art) Generally, in a continuous annealing furnace in which a strip is heat-treated prior to continuous hot-dip galvanizing of a thin steel sheet, a direct-fired heating zone is used in which the strip fed into the furnace is rapidly heated by a direct-fired burner. It is connected to the following reduction zone by a throat for temperature buffering.

(Problem that the invention aims to solve) However, since gas can freely flow through the throat section as well as the strip, the combustion exhaust gas from the direct-fired burner in the direct-fired heating zone diffuses into the reduction zone, and the nitrogen in the reduction zone There is a problem in that the reducing atmosphere gas consisting of hydrogen gas and hydrogen gas is contaminated, and the effect of the atmospheric gas in reducing and removing oxides on the strip surface is reduced. In addition, the amount of intrusion of combustion exhaust gas can be reduced by reducing the vertical space dimensions of the throat section, but if this dimension is made too small, the shape steel that is stuck to the tip of the strip when passing it through the furnace can be reduced. This is inconvenient because the threading bar cannot pass through the throat section.

This invention solves the above-mentioned conventional problems and aims to provide a flue gas sealing device for a continuous heat treatment furnace that suppresses the intrusion of flue gas from the direct heating zone into the reduction zone.

(Means for solving the problem) However, the combustion exhaust gas sealing device of this invention is
A damper rotatable around a horizontal axis perpendicular to the traveling direction of the strip is provided above the strip in the throat section between the direct-fired heating zone and the reduction zone of the continuous strip heat treatment furnace, and when the blades of this damper are in a hanging state, , a continuous heat treatment characterized in that the tip of the blade is in sliding contact with the upper surface of the strip, and the top and both ends of the blade are in sliding contact with the lower surface of the ceiling and the inner wall surface of the side wall of the throat section, respectively. This is a furnace combustion exhaust gas sealing device.

(Function) In the combustion exhaust gas sealing device of this invention,
When the blades of the damper are suspended, the tips of the blades slide against the running strip, the tops of the blades slide against the lower surface of the ceiling of the throat section, and the ends of the blades on both sides slide against the inner wall surfaces of the side walls of the throat section. This prevents the combustion exhaust gas in the open heating zone from entering the reduction zone from the space above the strip in the throat section. By rotating the damper around the horizontal axis and retracting the blade upwards, a space is created on the pass line through which the threading bar can pass, allowing threading of the strip without any hindrance.

(Embodiment) An embodiment of this invention will be described below with reference to FIGS. 1 to 3.

In the figure, 1 is a non-oxidation furnace type continuous annealing furnace for continuous hot-dip galvanizing, 2 is its direct heating zone, 3 is a reduction zone, and 4 is a throat connecting these zones. Further, 5 is a hearth roller that conveys the strip S, 6 is a direct flame burner that burns fuel at an air ratio of less than 1, and 7 is a radiant tube. 10
is a combustion exhaust gas sealing device installed at the throat 4, in which a blade 1 is attached to a shaft 12 having a horizontal axis 11 (see Fig. 2) perpendicular to the traveling direction of the strip S.
A damper 14 to which a roller 3 is fixed is provided directly above the hearth roller 5a. The shaft 12 passes through the side wall 8 of the throat 4, and a handle 12a is fixed to one end thereof.Both ends are supported by a bearing box 15 and a packing box 16, and can be rotated around the horizontal axis 11 by operating the handle 12a. I'm starting to be able to do it. The blade 13 is made by stacking ceramic fibers 18 on both sides of a steel reinforcing plate 17 fixed to the shaft 12, as shown in the third figure, and fixing the ceramic fibers 18 with a stop pin 19. In the hanging state of the blade shown in FIG. 3, it comes into sliding contact with the upper surface of the strip S. Further, the top portion 20 surrounding the shaft 12 of the ceramic fiber 18 and both end portions 21 in the furnace width direction are also connected to the throat 4.
It is in sliding contact with the lower surface of the ceiling 9 and the inner wall surface of the side wall 8. The inside of the shaft 12 is air-cooled or water-cooled by a known method to prevent overheating.

In the continuous annealing furnace 1 having the above configuration, the strip S
During the heat treatment, the combustion exhaust gas generated by combustion in the open burner 6 is prevented from entering the reduction zone 3 through the upper space of the strip S in the throat 4 section by the damper 14 with the blades 13 hanging down. Ru. Also, the damper 14 is moved around the horizontal axis 11 by approximately
By rotating the blade 13 by 90 degrees and retracting the blade 13 upward as shown by the chain line 22 in FIG. 3, a space for passing the threading bar can be formed between the hearth roller 5a and the blade 13.

This invention is not limited to the above embodiment; for example, in the above embodiment, the damper 14 is provided directly above the hearth roller 5a, so that the strip S
In the part outside the width of the blade 13, the tip 13a of the blade 13 is in direct sliding contact with the hearth roller 5a, which has the advantage that the sealing performance for combustion exhaust gas is particularly good. It may be provided at a position slightly shifted back and forth from directly above. Another damper 1
4 may also be provided above the hearth roller 5b to seal the throat 4 portion in two stages, or nitrogen gas may be further introduced into the space between these two dampers to improve sealing performance.

Although the above description has been made regarding a continuous annealing furnace for continuous hot-dip galvanizing, this invention can also be applied to a combustion exhaust gas sealing device for other continuous heat treatment furnaces such as a continuous annealing furnace for silicon steel sheets.

(Effects of the invention) As explained above, according to this invention, the four circumferences of the blades of the damper provided at the throat are in sliding contact with the top surface of the running strip and the inner wall surface of the throat. The intrusion of combustion exhaust gas into the reduction zone is suppressed, promoting the reduction action in the reduction zone and contributing to improving the quality of the strip.The rotation of the damper also allows the threading of the strip using a threading bar. can also be done without any problems.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of essential parts of a continuous annealing furnace showing an embodiment of this invention, Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line B-B in Fig. 2. It is a diagram. 1...Continuous annealing furnace, 2...Direct fire heating zone, 3...
Reduction zone, 4...Throat, 8...Side wall, 9...Ceiling, 10...Combustion exhaust gas sealing device, 11...Horizontal axis, 12...Shaft, 13...Blade, 13a
...Tip, 14...Damper, 20...Top, 2
1...Both ends, S...Strip.

Claims (1)

[Scope of utility model registration request] The direct-fired heating zone of the strip continuous heat treatment furnace is placed above the strip at the throat between the reduction zones.
A damper is provided that is rotatable around a horizontal axis perpendicular to the traveling direction of the strip, and when the blade of this damper is in a hanging state, the tip of this blade is in sliding contact with the upper surface of the strip, and the top and both sides of the blade are 1. A combustion exhaust gas sealing device for a continuous heat treatment furnace, wherein the end portions are configured to come into sliding contact with the lower surface of the ceiling and the inner wall surface of the side wall of the throat portion.