JPH0525552A - Gas-sealing device at outlet and inlet of strip heat-treating furnace - Google Patents

Abstract

PURPOSE:To improve the quality of a metallic strip and to save energy and resources by using a gas-sealing device at the outlet and inlet for the strip in the continuous heat-treating furnace for the strip with the sealing performance improved and preventing the diffusing of the external air into the furnace. CONSTITUTION:Pressure pads 8 and 8 are arranged at the opening of a heat- treating furnace and opposed to both sides of a strip 1, the inside of the pads 8 and 8 is divided into two chambers, and an atmospheric gas is blown out of a slit nozzle 10 on the furnace side between a couple of inclined slit nozzles 9 and 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for gas-sealing an inlet / outlet portion of a strip heat treatment furnace in which a metal strip is penetrated into the furnace to be heat-treated.

[0002]

2. Description of the Related Art In order to prevent atmospheric gas in the furnace from being blown out from the inlet / outlet portion of a strip heat treatment furnace, or to prevent outside air from entering the furnace, a seal is conventionally provided at the inlet / outlet portion so as to sandwich the strip from both sides. There has been provided a contact-type sealing device such as one provided with rolls or one in which felt is pressed against both sides of the strip.

[0003]

Although these contact type sealing devices have high sealing performance, they may damage the strip surface. In particular, in the strip immediately after being extracted from the galvanizing bath, the zinc layer adhering to the strip surface was in a molten state, and zinc could not be used as a sealing device because zinc adhered and solidified to the above contact type sealing device.

Therefore, conventionally, a method of spraying a sealing gas on both sides of the strip to seal them in a non-contact manner has been adopted. However, the conventional gas sealing device generally does not have sufficient sealing property and allows outside air to enter the furnace. There was a problem that it was easy.

[0005]

DISCLOSURE OF THE INVENTION An inlet / outlet gas sealing device for a strip heat treatment furnace according to the present invention is intended to solve the above-mentioned problems. A pressure pad is arranged in the opening of the heat treatment furnace so as to face both sides of the strip. The inside of the pressure pad is divided into two chambers, and the atmospheric gas sucked from the inside of the furnace is blown out from the slit nozzle inside the furnace of the pair of inclined slit nozzles. Further, the inlet / outlet part gas sealing device of the strip heat treatment furnace of the present invention is set so that the amount of atmospheric gas blown out from the slit nozzle inside the furnace is larger than the amount of gas blown out from the slit nozzle outside the furnace. Is a further feature.

[0006]

Function: The atmosphere gas in the furnace is blown out from the slit gas inside the furnace to form a static pressure region by the pressure pad, so that the sealing property is improved even in the non-contact state.

[0007]

An embodiment of the present invention will be described with reference to the drawings.
Fig. 1 shows a metal strip extracted from a galvanizing tank which is heated and soaked through this vertical heat treatment furnace. In Fig. 1, 1 is a vertical roll from a galvanizing tank 4 through a turning roll 2 and a submerged roll 3. Strips to be extracted into 5 are heating zones, 6
Is a soaking zone, and 7 is a cooling zone. The strip 1 is conveyed to the cooling zone 7 through the series of heating zones 5 and soaking zone 6. The heating zone 5 and the soaking zone 6 are provided with a heat source such as a radiant tube.

At the inlet (lower end) of the heating zone 5, pressure pads 8 are arranged so as to face both sides of the strip 1. The pressure pads 8, 8
As shown in FIGS. 2 and 3, the pair of slit nozzles 9 and 10 are provided so as to be inclined inward with respect to each other, and the pressure plate 11 between the slit nozzles 9 and 10 has A large number of small fumaroles 12, 12, ... Are opened. In the pressure pads 8 and 8, a partition plate 15 is provided for a chamber 13 communicating with one slit nozzle 9 and a chamber 14 communicating with the other slit nozzle 10.
It is divided by. Reference numerals 19 and 19 denote cover plates provided at both ends of the slit nozzles 9 and 10 so as to prevent gas from flowing out to the side. In addition, such pressure pads 16 and 16 are also provided at the outlet (upper end) of the soaking zone 6.
The pressure pads 16 and 16 are also partitioned into a chamber 17 and a chamber 18 by a partition plate as described above.

Reference numeral 20 denotes an air supply pipe connected to a source of an atmospheric gas such as nitrogen gas. The air supply pipe supplies the atmospheric gas to the soaking zone 6 via a pipe 21 and also supplies the atmospheric gas to the pressure via the pipe 22. The pads 8 and 8 are supplied to the chamber 13 outside the furnace, and the atmospheric gas can be further supplied to the chamber 18 outside the furnace of the pressure pads 16 and 16 through the pipe 23.

Reference numeral 24 denotes a furnace atmosphere gas of the pressure pads 8 and 8 and a furnace inside chamber 14 of the pressure pads 8 and 8 and a furnace inside gas of the pressure pads 16 and 16 inside the furnace. It is a circulation fan that supplies the chamber 17.

In this gas seal device, the operation of one of the pressure pads 8 will be described. The atmosphere gas of high temperature sucked from the inside of the furnace is blown out from one slit nozzle 10 located inside the furnace. , Ambient temperature atmospheric gas blows out from the other slit nozzle 9,
An atmospheric gas static pressure region 30 is formed between the pressure plate 11 and the strip surface. Therefore, the slit nozzle 10
The high-temperature atmospheric gas blown out of the chamber mainly inverts upward due to its static pressure and flows upward along the strip surface.
Further, ambient temperature atmospheric gas blown out from the slit nozzle 9 is inverted downward due to its static pressure and flows downward along the strip surface. Therefore, the ambient gas at room temperature blown out from the slit nozzle 9 can be prevented from entering the furnace very much.

The amount of the atmospheric gas blown out from the slit nozzle 10 inside the furnace is made slightly larger than the amount of the atmospheric gas blown out from the slit nozzle 9 outside the furnace so that the gas is blown out from the slit nozzle 9. Atmosphere gas can be effectively prevented from entering the furnace, and low-temperature atmosphere gas can be prevented from entering the furnace, so that the temperature inside the furnace is prevented from lowering and it is effective in saving energy.

Note that air or other gas may be blown out from the slit nozzle 9 instead of the atmospheric gas. In short, in this gas seal device, gases having different temperatures and components may be blown out from both nozzles. Since the degree to which both gases are mixed can be reduced, the consumption of expensive atmosphere gas can be suppressed and energy can be saved.

Although not shown, a heater is provided in the middle of the pipe 21 so that the atmospheric gas supplied to the soaking zone 6 is preheated, so that the temperature inside the soaking zone 6 decreases due to the supply of this atmosphere gas. To be prevented.

[0015]

As described above, the inlet / outlet gas sealing device of the strip heat treatment furnace of the present invention can exhibit high sealing performance without contacting the strip and prevent outside air from entering the furnace. It is a valuable thing that can contribute to improvement, energy saving, and resource saving.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an entire strip heat treatment furnace according to the present invention.

FIG. 2 is a vertical cross-sectional view of a gas sealing device according to the present invention.

3 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 strip 5 heating zones 6 soaking 8,8 pressure pad 9,10 slit nozzle 13, 14 rooms 15 dividers 24 Circulation fan

Claims (2)

[Claims] 1. A pressure nozzle is arranged in an opening of a heat treatment furnace so as to face both sides of the strip, and the pressure pad is divided into two chambers, and a slit nozzle inside the furnace among a pair of inclined slit nozzles. A gas sealing device for the inlet and outlet of the strip heat treatment furnace, characterized in that the atmospheric gas sucked from the furnace is blown out. 2. The strip according to claim 1, wherein the amount of atmospheric gas blown out from the slit nozzle inside the furnace is set to be larger than the amount of gas blown out from the slit nozzle outside the furnace. Gas sealing device for inlet and outlet of heat treatment furnace.