JP3499042B2 - Atmospheric gas leakage prevention device for continuous annealing furnace - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous annealing furnace, in which the atmosphere gas in the furnace at the inlet and outlet of a strip-shaped plate material (strip or the like, hereinafter simply referred to as a steel strip) is reduced. The present invention relates to an atmosphere gas leakage prevention device for preventing leakage to the outside. 2. Description of the Related Art Conventionally, continuous annealing furnaces have been operated in an inert gas atmosphere such as nitrogen gas for preventing the generation of scale. In order to prevent atmospheric gas from leaking from the entrance side and the exit side of the steel strip, a sealing device is provided.As such a sealing device, for example, a facing roll type that sandwiches a passing steel strip from above and below, A curtain type is known. [0003] However, in the case of the opposed roll type, it is difficult to adjust the roll pressure, and furthermore, there is a drawback that the steel strip passing through tends to be flawed.
5-10 because the sealing property is poor as in the case of the curtain type
It is difficult to prevent the furnace atmosphere gas from leaking to a positive pressure of about mmAq. Furthermore, when the thickness of the steel strip passing therethrough changes or when the pressure in the annealing furnace changes, it is difficult to immediately secure the sealing performance and prevent the leakage of the atmospheric gas. was there. The present invention has been made in view of such circumstances, and has a good sealing effect, and furthermore, an atmosphere gas leakage prevention device for a continuous annealing furnace that can be finely adjusted even if the thickness, width, and pressure in the annealing furnace fluctuate. The purpose is to provide. [0004] A first aspect of the present invention is to meet the above object.
The atmosphere gas leak prevention device of the continuous annealing furnace according to the present invention is an atmosphere gas leak prevention device arranged on the entrance side and the exit side of the steel strip of the continuous annealing furnace that heats and cools a continuously running steel strip, A gas-tight tube that includes a supply path and an exhaust path for a supply gas, and is capable of expanding and contracting by the pressure of the supply gas.
A pressure regulating valve for regulating the internal pressure of the hermetic tube is provided on the exhaust path side of the hermetic tube. It should be noted that, in addition to performing sealing by directly contacting the passing steel strip and the airtight tube, in order to prevent the abrasion of the airtight tube, another sealing material may be adhered to make contact with the steel strip and perform sealing. The present invention applies. According to the first aspect of the present invention, there is provided an atmosphere gas leakage prevention device for a continuous annealing furnace, wherein a continuous annealing furnace for heating and cooling a continuously running steel strip has an inlet side and an outlet side of the steel strip. Since the airtight tube is provided with a supply path and an exhaust path for the supply gas and is capable of expanding and contracting by the pressure of the supply gas, facing the front and back surfaces of the continuously running steel strip, the pressure of the airtight tube is reduced. By performing the adjustment, the airtight tube comes into contact with the front and back surfaces of the steel strip, thereby preventing leakage of the atmospheric gas in the furnace. Further, since the pressure adjusting valve for adjusting the internal pressure of the airtight tube is provided on the exhaust path side of the airtight tube, it is possible to gradually remove the gas once put in the airtight tube, thereby making it possible to reduce the thickness of the steel strip. ,
The pressure in the hermetic tube corresponding to the width or the like can be finely reduced, whereby the pressure in the hermetic tube can be finely controlled. An embodiment of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is a schematic explanatory view of an apparatus for preventing atmospheric gas leakage of a continuous annealing furnace according to one embodiment of the present invention, and FIG. 2 is a partial front view of the same. FIGS. 1 and 2 show an apparatus 10 for preventing atmospheric gas leakage in a continuous annealing furnace according to an embodiment of the present invention. The airtight tubes 13 and 14 are housed in holding boxes 15 and 16 and installed vertically. This airtight tube 13,
Numeral 14 is a rubber bag or other bag made of a synthetic resin having no air permeability and the like, and a supply gas such as nitrogen is supplied to the source pressure regulating valve 1.
7 and the direction switching valve 18. Further, pressure regulating valves 19 and 20 and pressure gauges 21 and 22 are respectively attached to the airtight tubes 13 and 14, and the supplied gas is discharged into the furnace, and the pressure in the airtight tubes 13 and 14 is reduced. Can be changed to The airtight tubes 13 and 14 and the steel strip 12
In order to reduce wear of the airtight tubes 13 and 14, seal members 23 and 24 are provided. [0008] The amount of expansion and contraction of the airtight tubes 13 and 14 is uniquely related to the internal pressure of the airtight tubes 13 and 14.
By adjusting the internal pressure of the steel strip 12 with the pressure adjusting valves 19 and 20, it is possible to set the gap between the steel strip 12 and the airtight tubes 13, 14 or the sealing members 23, 24 to a required optimum value. Here, advantages of the case where the pressure regulating valves 19 and 20 are provided will be described below in comparison with the case where the pressure regulating valves 19 and 20 are not provided. In the continuous annealing furnace 11, the size of the steel strip 12 changes continuously according to the passing schedule, and the thickness (t) of the steel strip 12 also changes frequently. It is important to keep If the internal pressure of the airtight tubes 13 and 14 is too high, the pressing force against the steel strip 12 becomes excessive, and not only the airtight tubes 13 and 14 or the sealing materials 23 and 24 are remarkably worn, but also the surface of the steel strip 12 is scratched and formed. It becomes a defect.
The airtight tubes 13 and 14 are provided while the steel strip 12 is flat.
The steel strip 12 may pass through the sealing portion in a state where the steel strip 12 is warped in a gutter shape. In this case as well, the internal pressure of the airtight tubes 13 and 14 is adjusted to adjust the steel strip 1.
It is important to prevent the surface flaw 2 above. When the pressure regulating valves 19 and 20 are not provided, it is difficult to adjust the internal pressure of the airtight tubes 13 and 14 to an appropriate range only by turning on and off the direction switching valve 18. That is, in order to reduce the internal pressure of the airtight tubes 13 and 14, the directional control valve 18 is operated to shut off the supply gas on the original side and exhaust the gas in the airtight tubes 13 and 14, or the directional control valve 18 is operated. It is conceivable to reduce the set pressure of the source pressure regulating valve 17 while keeping the flow to the source pressure side. However, if the supply gas is shut off by the direction switching valve 18, the airtight tubes 13 and 14 contract rapidly, so that the atmosphere gas in the furnace is reduced. Will be leaked in large quantities. Even if the set pressure of the source pressure adjusting valve 17 is lowered, the airtight tubes 13 and 14 are kept in a state where the source pressure of the supply gas is still applied.
Will hardly change. Therefore, when the pressure adjusting valves 19 and 20 are not used, the internal pressure of the airtight tubes 13 and 14 cannot be adjusted to an appropriate range while preventing leakage of the atmospheric gas. By adjusting the pressure in the airtight tubes 13 and 14 by finely adjusting the pressure of the airtight tubes 13 and 14 (the airtight tubes 13 and 14 may be connected to each other because only the airtight tubes 13 and 14 communicate with each other), the thickness (t) and the width of the (W) or fine airtight tubes 13 and 14 corresponding to various conditions such as when the steel strip is curved.
Can be adjusted. When a combustible gas or a reducing gas is used as an atmosphere gas in the continuous annealing furnace 11, an inert gas such as nitrogen is used as a supply gas, and the supply gas leaks from the airtight tube. We take care to be safe. In this case, the nitrogen exhausted from the airtight tube is supplied again into the furnace and used as an atmosphere gas in the furnace, so that the gas intensity does not deteriorate. Although the exhaust ports of the pressure regulating valves 19 and 20 are directed to the inside of the furnace, the released supply gas (for example, nitrogen) can be effectively used. According to the first aspect of the present invention, the internal pressure of the hermetic tube is adjusted by a pressure regulating valve provided on the exhaust side of the hermetic tube to expand and contract the hermetic tube. The amount can be controlled freely, and even when the thickness of the steel strip changes or when the steel strip passes in a gutter-like warped shape, the appropriate expansion and contraction amount can always be set, so that the steel strip surface flaws are prevented, and Also, it is possible to reliably prevent the atmosphere gas in the furnace from leaking without fear of abrasion of the airtight tube or the sealing material. In addition, the amount of expansion and contraction of the airtight tube has a unique relationship with the internal pressure, and by automatically setting the internal pressure according to the change in the thickness of the steel strip using this characteristic function, the amount of expansion of the airtight tube is adjusted to a predetermined optimal amount. It can be changed, and the gap between the steel strip and the airtight tube can be easily controlled automatically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view of an atmosphere gas leakage prevention device of a continuous annealing furnace according to one embodiment of the present invention. FIG. 2 is a partial front view of the same. DESCRIPTION OF SYMBOLS 10 Atmospheric gas leakage prevention device of continuous annealing furnace 11 Continuous annealing furnace 12 Steel strip 13 Airtight tube 14 Airtight tube 15 Holding box 16 Holding box 17 Original pressure regulating valve 18 Direction switching valve 19 Pressure regulating valve 20 Pressure regulation Valve 21 Pressure gauge 22 Pressure gauge 23 Seal material 24 Seal material

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C21D 9/56 C21D 1/74 F27D 7/06

Claims (1)

(57) [Claim 1] An atmosphere gas leakage prevention device disposed on the inlet side and the outlet side of a steel strip of a continuous annealing furnace for heating and cooling a continuously running steel strip, An airtight tube that is provided with a supply path and an exhaust path for supply gas, and that can be expanded and contracted by the pressure of the supply gas so as to face the front and back surfaces of the continuously running steel strip; and an exhaust path for the airtight tube. A pressure regulating valve for regulating the internal pressure of the hermetic tube is provided on the side of the atmosphere gas leakage preventing device for a continuous annealing furnace.