JPH1150129A - Device for sealing lance inserting hole in vacuum degassing vessel and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new sealing device of an insertion hole, which can change a lance while continuing a refining work, and a using method thereof. SOLUTION: In a sealing device for lance insertion hole in a vacuum degassing vessel, a ball valve 9 is arranged between an upper cover 1 and a mechanical sealing device. The using method is composed of a process in which the lance 3 whose tip part is positioned in the vacuum degassing vessel is raised until the tip part reaches the upper part of the ball valve 9, a process in which the ball valve is closed, and a process in which the lance is taken out from the sealing device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal device for a lance insertion hole of a vacuum degassing container, which can replace the lance even during refining.

[0002]

2. Description of the Related Art A lance insertion method in a vacuum degassing apparatus such as an RH method generally includes an upper blowing method in which a vacuum degassing tank is inserted from an upper lid and an oblique blowing method in which the lance is inserted from an upper tank.

FIG. 5 is a schematic vertical sectional view of a vacuum degassing tank for refining molten steel by inserting a lance through an insertion hole of an upper lid into a vacuum degassing tank. The gas generated in the vacuum degassing tank is sucked from an exhaust pipe 20a of the upper tank 20 into an exhaust device (not shown), and the inside of the vacuum degassing tank is maintained at a vacuum of about 0.1 Torr. On the other hand, the molten steel M in the molten steel pot 23
2 into the lower tank 21, and is degassed by degassing and oxygen blown from the lance 3.
2 and return to the molten steel pot 23. The repetition of this increases the degree of refining of the molten steel. In such a refining process,
If the airtightness between the insertion hole 2 of the upper lid 1 and the lance 3 is not sufficient, the degree of vacuum in the vacuum degassing tank is reduced, and refining cannot be performed.

Conventionally, the above-mentioned airtightness has been performed by a gland packing. However, when metal is adhered to the outer peripheral wall of the lance during refining due to molten steel splash, and the lance in this state is reciprocated through the gland packing, the gland packing is obtained. However, it wears out in a short period of time, and the degree of vacuum in the tank cannot be maintained.
For this reason, the gland packing was frequently replaced.

[0005] An apparatus for solving this problem is disclosed in
No. 158967 and Japanese Utility Model Laid-Open No. 2-118746. FIG. 4 shows this device, in which a lance 3
A hollow elastic body 5 which expands due to gas pressure and closely adheres to the lance 3 at the time of expansion is provided outside the gland packing 7 provided in the insertion hole 2 to improve the sealing performance. Reference numeral 4 denotes a casing on which the hollow elastic body 5 is mounted, and reference numeral 6 denotes a sleeve on which the gland packing 7 is mounted. Reference numeral 8 denotes an inlet for Ar gas blown into the insertion hole 2 to prevent the molten steel splash from entering the insertion hole 2.

[0006]

However, the lance sometimes leaks water due to melting or cracking of the water cooling tube during use. When this water leak occurs, there is a danger of steam explosion in the tank. Further, the amount of oxygen to be blown may be reduced or blown out due to deformation or blockage of the lance nozzle portion. In such a case, the lance will be replaced, but in the device provided with the hollow elastic body,
When the lance is removed from the insertion hole, the vacuum cannot be maintained because the atmosphere flows through the hole of the hollow elastic body. For this reason, the refining operation is suspended, the remaining hot water in the tank is extracted, a new lance is attached, and then the inside of the tank is evacuated to resume refining.

For this reason, the work has to be suspended for a long time when replacing the lance, which hinders the improvement of the operation rate.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a new insertion hole sealing device capable of replacing a lance while continuing a refining operation, and a method of using the same.

[0009]

The present invention achieves the above objects by the following apparatus and method of use.

The apparatus is a lance insertion hole seal device for a vacuum degassing container, in which a ball valve is provided between an upper lid and a mechanical seal device. Device.

The method of use is as follows: (a) a step of raising a lance positioned at the tip in the vacuum degassing container until the tip is located above the ball valve; Closing step (c) removing the lance from the seal device.

[Operation] Since a ball valve is provided between the upper lid and the mechanical seal device, when replacing the lance, the ball valve can be opened and closed to replace the lance. .
Since the opening and closing of the ball valve can be performed in a short time, the degree of vacuum in the degassing tank does not decrease. That is, the lance can be replaced while continuing the refining operation.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic longitudinal sectional view of a lance insertion hole sealing device according to an embodiment of the present invention. 4 that are the same as those described in FIG. 4 mean the same members, and a description thereof will be omitted. The lance insertion hole sealing device is configured as follows. A ball valve 9 is mounted on the insertion hole 2 of the upper lid 1. This ball valve 9 is
A valve body 10 having a spherical body having a through hole 10a through which it passes, a valve box 11 accommodating the same, a valve shaft 12 for rotating the valve body 10, a torque actuator as a rotating means of the valve shaft 12 not shown, and the like. I have. And 90 ° in the direction of arrow R
When rotated, the insertion hole 2 is closed airtightly and further 90 °.
When rotated, the lance 3 communicates with the insertion hole 2 so that the lance 3 can pass therethrough. If a torque actuator or an electric motor with a speed reducer is used as the rotating means, the insertion hole 2 can be quickly closed and opened.

A gland packing means including a sleeve 6 as a mechanical seal device and a gland packing 7 mounted on the ball valve 9 is provided above the ball valve 9, and the hollow elastic body 5 and the hollow elastic body 5 are accommodated thereon. A gas expansion seal means comprising a casing 4 is provided. This sealing means
A gas or liquid, such as compressed air, is injected into the hollow elastic body 5 to expand the seal, the seal is brought into close contact with the outer periphery of the lance 3, and the gas or liquid is discharged to release the seal.

Next, a method of replacing a lance using the above-mentioned insertion hole sealing device will be described. (1) Discharge the gas from the gas expansion seal means and release the seal. (2) The lance 3 used is pulled up, and when its tip comes off the through hole 10a of the valve body 10 of the ball valve, the valve shaft 1
2 is rotated 90 ° to either side to close the insertion hole. (3) The used lance and the new lance are exchanged, and the new lance is lowered into the valve box of the ball valve 9 through the gas expansion seal means and the gland packing means. Stop descent when you reach it; see FIG. (4) The valve shaft 12 of the ball valve is rotated 90 ° to either side to release it into the insertion hole 2, and the lance is lowered to a predetermined position in the degassing tank (see FIG. 3) and stopped. (5) A compressed gas is injected into the hollow elastic body 5 of the gas expansion seal means to expand the hollow gas, thereby making the space between the lance 3 and the hollow elastic body 5 airtight.

[0017] In the above steps, the steps (2) and (4)-(5) have the opportunity for the air to enter the degassing tank. The total time of these steps is 30 seconds. Yes, very short, and the vacuum in the degassing tank does not drop.

[0018]

According to the present invention, a ball valve is provided between the upper lid and the mechanical seal device.
The lance can be replaced by opening and closing the ball valve. Further, since the opening and closing of the ball valve can be performed in a short time, the degree of vacuum in the degassing tank does not decrease, and the lance can be replaced while continuing the refining operation.

[Brief description of the drawings]

FIG. 1 is a lance insertion hole seal according to an embodiment of the present invention.
FIG. 2 is a schematic vertical sectional view of a screw device.

FIG. 2 is a schematic vertical sectional view of a lance insertion hole sealing device in a state where a new lance is stopped immediately above a valve body.

FIG. 3 is a schematic longitudinal sectional view of a lance insertion hole sealing device in a state where a new lance is lowered through a ball valve.

FIG. 4 is a schematic longitudinal sectional view of a conventional lance insertion hole sealing device.

FIG. 5 is a schematic longitudinal sectional view of an RH degassing tank.

[Explanation of symbols]

 1 upper lid 2 insertion hole 3 lance 4 casing 5 hollow elastic body 6 sleeve 7 gland packing 8 Ar gas introduction hole

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyuki Hiji 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd.

Claims (2)

[Claims] 1. A lance insertion hole seal device for a vacuum degassing container, wherein a ball is provided between an upper lid and a mechanical seal device.
A sealing device for a lance insertion hole of a vacuum degassing container, wherein a sealing valve is provided. 2. A method of using a lance insertion hole sealing device for a vacuum degassing container having the following steps. (A) a step of raising and lowering the lance positioned at the tip in the vacuum degassing container until the tip is located above the ball valve; (b) a step of closing the ball valve; Step to remove from seal device