JP2003239020A - Horizontal type furnace for continuously annealing strip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce leakage amount of reducing atmospheric gas such as expensive hydrogen gas to the outside of a furnace and to reduce a running cost by making more perfect gas sealing in an inlet and/or an outlet. <P>SOLUTION: In a horizontal type furnace for continuously annealing a strip, in which the metal strip 2 is continuously carried in the furnace, and a bright annealing is applied in the reducing atmosphere such as the hydrogen gas, downward bending state sealing chambers 10, 16 are formed in the inlet part and/or the outlet part of the metal strip to carry in and/or carry out the metal strip through these sealing chambers. Further inert gas such as nitrogen gas having larger specific gravity than that of the reducing atmospheric gas is blown into the sealing chambers. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a horizontal furnace for continuously annealing a metal strip in an atmosphere gas.

[0002]

2. Description of the Related Art A strip continuous annealing furnace in which metal strips are continuously conveyed in a furnace and heated and cooled in a reducing atmosphere gas such as hydrogen gas to cool and anneal the metal strips substantially horizontally 2. Description of the Related Art Conventionally, a horizontal furnace that conveys inside and a vertical furnace that conveys a metal strip substantially vertically are known. Further, as shown in, for example, Japanese Unexamined Patent Publication No. 10-226824, Japanese Unexamined Patent Publication No. 10-280053, etc., a sealing device is provided at the inlet and the outlet of the metal strip to prevent the reducing atmosphere gas from leaking out of the furnace.

[0003]

By the way, in the conventional vertical furnace, there is a drawback that the sealing device does not function sufficiently because the draft action of the gas in the furnace works strongly and the outside gas easily leaks to leak the atmospheric gas. In addition, there is a problem that the facility construction cost is generally higher than that of the horizontal furnace. Therefore, the present invention provides a more complete gas seal at the inlet and / or the outlet in a horizontal furnace with less problems as described above, and reduces the amount of expensive reducing atmosphere gas such as hydrogen gas leaking out of the furnace. An object of the present invention is to provide a horizontal furnace for continuous strip annealing, which can reduce the running cost by reducing the running cost.

[0004]

To this end, the present invention provides a horizontal strip furnace for continuous strip annealing in which a metal strip is continuously conveyed in the furnace and brightly annealed in a reducing atmosphere gas such as hydrogen gas. It is characterized in that a downwardly bent seal chamber is formed at an inlet portion and / or an outlet portion of the strip, and the metal strip is carried in and / or carried out through the sealing chamber. Further, the present invention is characterized in that, in the horizontal furnace for continuous strip annealing, an inert gas such as nitrogen gas having a specific weight larger than that of the reducing atmosphere gas is blown into the sealing chamber.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 is a horizontal furnace body, and 2 is a metal strip that is horizontally conveyed inside in the direction of the arrow. The horizontal furnace body 1 is provided with a plurality of burners 4 for heating the outside of a cylindrical muffle 3 through which the metal strips 2 pass, thereby indirectly heating the metal strips 2 using the burners as heat sources, and It consists of a cooling zone for cooling the metal strip 2 by jetting a cooling gas from a plenum chamber 5 provided so as to face the upper and lower surfaces of the strip 2, and by supplying hydrogen gas from an air supply port 6, the horizontal type The inside of the furnace body 1 is held in a reducing atmosphere gas.
A blower 7 sucks the reducing atmosphere gas from the inside of the horizontal furnace body 1, cools it with a cooler 8, and then circulates it through the plenum chamber 5.

Therefore, a seal chamber 10 is formed in a downwardly bent shape at the end of the horizontal furnace body 1 on the inlet side, and turning rolls 11 and 12 are provided at the upper and lower portions of the seal chamber, respectively. An inlet 13 is provided on the side wall of the seal chamber, a pair of seal rolls 14 is provided at the inlet, and the metal strip 2 carried in from the inlet is hung on the deflecting roll 12 and the deflecting roll 11 to pass through the seal chamber. The metal strip 2 is brought into the furnace body. And the seal chamber 1
An inert gas such as nitrogen gas is blown into the inlet 0 from the air supply port 15 to fill the sealing chamber 10 with the nitrogen gas. Since the nitrogen gas has a larger specific weight than the hydrogen gas, it stays in the seal chamber 10 formed in the downwardly bent shape and acts as a seal gas. Therefore, a reducing gas such as hydrogen gas is introduced into the inlet 1.
Prevent from leaking from 3.

A seal chamber 16 is formed in a downwardly bent shape at the end of the horizontal furnace body 1 on the outlet side, and deflection rolls 17 and 18 are provided at the upper and lower portions of the seal chamber, respectively. An outlet 19 is provided on the side wall of the seal chamber, a pair of seal rolls 20 is provided at the outlet, and the metal strip 2 is hung on the deflecting roll 17 and the deflecting roll 18. Allow it to be carried out of the main unit. Then, an inert gas such as nitrogen gas is blown into the sealing chamber 16 from the air supply port 21 to fill the sealing chamber 16 with the nitrogen gas so that the reducing gas is discharged from the outlet 1.
Preventing leaks from 9.

Therefore, only the inert gas such as nitrogen gas filling the sealing chamber leaks from the inlet 13 or the outlet 19, and there is a risk that dangerous and expensive reducing gas such as hydrogen gas may leak to the outside of the furnace. It can be lost. Further, the ratio of the inert gas having a large molecular weight passing through the gap formed around the seal roll can be reduced as compared with the gas having a small molecular weight. Further, since the seal chamber is formed in the downward bent shape, there is no possibility that the inert gas in the seal chamber flows into the horizontal furnace main body 1 to reduce the concentration of reducing gas of hydrogen gas.

In this embodiment, hydrogen gas was used as the reducing gas and nitrogen gas was used as the inert gas. However, an inert gas having a specific weight larger than that of the reducing atmosphere gas should always be blown into the sealing chamber. If so, other gas such as argon gas can also be used. Further, in this embodiment, the downwardly bent seal chamber is formed at both the inlet portion and the outlet portion of the metal strip, but either the inlet portion or the outlet portion may be provided at only one.

[0010]

As described above, the horizontal furnace for continuous strip annealing according to the present invention forms a downwardly bent seal chamber at the inlet and / or outlet of the metal strip, and the metal strip passes through the seal chamber. Since it is carried in and / or out, the amount of leaking reducing atmosphere gas such as expensive hydrogen gas outside the furnace is significantly reduced, and there is a beneficial effect such as running cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a horizontal furnace for continuous strip annealing showing an embodiment of the present invention.

[Explanation of symbols]

1 Horizontal furnace body 2 metal strip 6 Air supply port 10 seal room 11,12 Turning roll 13 entrance 14 seal roll 15 Air supply port 16 seal room 17,18 Turning roll 19 exit 20 seal roll 21 Air inlet

Claims (2)

[Claims] 1. A horizontal furnace for continuous strip annealing, in which metal strips are continuously conveyed in a furnace and brightly annealed in a reducing atmosphere gas such as hydrogen gas, the inlet and / or the outlet of the metal strips. A horizontal furnace for continuous strip annealing, characterized in that a downwardly bent seal chamber is formed, and a metal strip is carried in and / or carried out through the seal chamber. 2. The horizontal furnace for continuous strip annealing according to claim 1, wherein an inert gas such as nitrogen gas having a specific weight larger than that of the reducing atmosphere gas is blown into the sealing chamber.