JPS61130479A - Method for inhibiting penetration of air into plated steel strip alloying furnace - Google Patents

Abstract

PURPOSE:To inhibit the penetration of air into an alloying furnace and to prevent reduction in the temp. of the furnace by placing shutters at the inlet and outlet of the furnace and keeping the internal pressure of the furnace slightly higher than atmospheric pressure. CONSTITUTION:Shutters 8a, 8b are placed at the inlet and outlet of an alloying furnace 6. The internal pressure of the furnace 6 is measured with a pressure gauge 10, and an exhaust gas regulating valve 13 in an exhaust duct 12 is regulated on the basis of the measured value so as to keep the internal pressure of the furnace 6 slightly higher than atmospheric pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for suppressing air intrusion into a plated copper strip alloying furnace.

(Prior art and its problems) As is well known, the alloying process for plated steel strips generally involves guiding the copper strip into a plating bath, pulling it up directly above the plated layer, and then leading it directly to an alloying furnace installed directly above it. It is heated to form an alloy between the plated metal and the copper strip (iron).

In such an alloying treatment method, due to the passage (advancement) of the plated steel strip, the chimney effect of F, etc., air is sucked in from the inlet side of F, and the furnace temperature decreases, so it is maintained at the alloying temperature. However, energy is also required to compensate for the decrease in furnace temperature, which significantly reduces energy efficiency.

In order to prevent such difficulties, for example, as in Japanese Utility Model Application Publication No. 58-172460, a shielding plate is placed between the furnace entry side and the coating amount control nozzle, and one of the gases injected from the nozzle is Although it has been disclosed to prevent air from reaching the inlet side of the furnace, this method also cannot completely prevent air from entering, and is accompanied by the above-mentioned difficulties.

(Object of the Invention) The present invention has been made in order to advantageously solve these difficulties, prevent air from entering, and improve the energy saving effect.

(Means for solving the problem) The present invention is characterized by arranging shutters on the entry and exit sides of the alloying furnace, detecting the furnace internal pressure, and adjusting the exhaust gas regulating valve of the furnace exhaust gas duct based on this. The present invention provides a method for suppressing air intrusion into a plated steel strip alloying furnace, which is characterized by controlling the furnace internal pressure to be higher than atmospheric pressure.

That is, in the present invention, a shutter is placed on the inlet side of the furnace to minimize intruding air, and a shutter is also placed on the outlet side so that the pressure inside the furnace can be easily adjusted. Slight openings are required on the furnace entry and exit sides for the plated steel strip to pass through, and for the widthwise direction of the copper strip. The outlet shutter should be placed as close to the plated steel strip as possible to minimize intruding air, and the outlet shutter should also be placed as close to the plated steel strip as possible to minimize the blow-out of furnace exhaust gas and reduce the amount of furnace exhaust gas discharged. By adjusting the , the pressure inside the furnace can be easily controlled to above atmospheric pressure (approximately 1.0 W Aq or above), and the intrusion of air can be reliably suppressed.
By connecting the static pressure pad to the shutter, the shutter can be easily brought close to the plated steel strip.

(Example〕 Next, examples of the present invention will be described.

In FIG. 1, a steel strip 2 is subjected to surface cleaning etc. in a pre-treatment furnace 1 of hot-dip galvanizing equipment, guided to a molten zinc bath 3, and after plating, an alloy consisting of a direct firing section 4 consisting of a group of burners and a retention section 5 is shown. The plated steel strip 2t is introduced into the alloying furnace 6 and alloyed, and then cooled in the cooler 7 to produce an alloyed galvanized steel sheet. Deploy. The shutter 8b is connected to a static pressure pad 9, the shutters ga and gb are placed as close as possible to the plated steel strip 2, and the inlet and outlet of the alloying furnace 6 are closed.
Minimize air intrusion from the inlet side and minimize exhaust gas emissions from the outlet side.

10,000, a furnace pressure detector 10t is installed in the furnace 6, detects the furnace internal pressure, guides it to the furnace pressure regulator 11, and adjusts the furnace pressure control valve 13 provided in the exhaust gas duct 12 based on the detection result, This is to control the internal pressure of the furnace to be higher than atmospheric pressure at all times by adjusting the amount of exhaust gas discharged, thereby suppressing the intrusion of air.

Next, an example of the shutter operating mechanism will be described. In FIG. 2, a drive shaft 14t'' is attached to the shutter 8a at the entrance end of the furnace 6.
A driving device 15 (such as a motor or an air cylinder) is installed through the opening, and the operation of the driving device 15 moves the shutter 13a'i back and forth to close the entrance.

In FIG. 3, a drive machine 15 is installed at the outlet end of the furnace 6 through a drive shaft 14 to a shutter 8b,
A static pressure pad 9 is provided at the plated steel strip 2 from the discharge nozzle 16, and air is blown onto the plated steel strip 2 to maintain static pressure on the steel strip 2 and prevent vibration of the steel strip 2. The exit is closed by operating the shutter 8 and bringing it as close to the plated steel strip 2 as possible.

(Effects of the invention) It is possible to almost prevent air from entering the alloying furnace, reliably preventing a drop in furnace temperature, and saving energy.Also, the amount of exhaust gas blown out on the exit side of the alloying furnace is reduced, and the cooler on the alloying furnace Excellent effects such as reliable cooling of the plated steel strip after alloying can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing an example of the operating mechanism of the alloying furnace entry side shutter, and Fig. 3
The figure is an explanatory diagram showing an example of an alloying furnace exit side d-shutter operating mechanism. 2... Steel strip, 3... Molten zinc bath, 6... Alloying furnace, ga, gb --- shutter, 10... Furnace pressure detector, 12... Exhaust gas duct, 13...・Furnace pressure control valve.

Claims (1)

[Claims] Shutters are placed on the entry and exit sides of the alloying furnace, and the furnace internal pressure is detected, and based on this, the exhaust gas regulating valve of the furnace exhaust gas duct is adjusted to control the furnace internal pressure to be higher than atmospheric pressure. A method for suppressing air intrusion into a plated steel strip alloying furnace.