JPS6345671Y2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a seal structure around an electrode of a melting furnace, particularly an electric arc furnace for steelmaking.

(Prior art and its problems) Since three electrodes are normally used in an arc furnace, there are three openings in the center of the lid of the arc furnace for the electrodes to pass through. Therefore, since the exhaust gas generated during melting blows out from the annular gap between the opening and the electrode, a dust collection hood has come to be provided around the electrode to collect dust from the exhaust gas. However, as shown in the cross section in Figure 4, three electrode openings are also provided in the center of the hood with sufficient radial clearance so that the electrodes do not interfere with the electrodes. As a result, exhaust gas blows out from this annular gap between the electrode hole and the electrode, and the heat generated in the furnace is released.At the same time, when the amount of exhaust gas blown out is small, a large amount of surrounding air is sucked in through this annular gap. This tended to increase oxidation loss of the electrode.

Furthermore, a method is known in which an air curtain is provided in the annular gap in order to prevent exhaust gas from blowing out from the annular gap. This is considered to be an effective method in terms of reducing the amount of exhaust gas blowing out, but
In addition to promoting the oxidation loss phenomenon of the electrode and increasing the amount of oxidation loss, it also had the drawbacks of using a considerable amount of gas even when N ₂ gas etc. was used, making it extremely difficult to control the gas amount. .

(Means for solving the problems) In order to solve these problems, the present invention
By installing a seal ring made of refractory running material above the annular gap between the electrode and the furnace lid, and between the electrode and the dust collection hood, the amount of heat removed from the arc furnace is minimized and the amount of dust collection air is reduced. The present invention provides a sealing structure around the electrodes of an arc furnace that makes it possible to do this.

That is, the gist of the present invention is to provide an electrode hood aperture through which the electrode passes through the dust collection hood around the electrode on the upper part of the furnace lid of an arc furnace, and to form an annular hood aperture formed between the electrode hood aperture and the electrode. At the top of the gap, the inner diameter D is limited to D = d + 10 mm to 50 mm for the electrode diameter d.
A seal ring is mounted so that it can slide in the horizontal direction, and the inner diameter D' is set relative to the electrode diameter d at the top of the annular gap formed between the electrode hole and the electrode opening provided in the lid of the arc furnace. This is a sealing structure around the electrode of an arc furnace in which a second seal ring having a diameter of =d+10 mm to 100 mm is placed on top of the second seal ring so as to be slidable in the horizontal direction.

(Operation, Example) Next, the operation of the present invention will be explained based on the example shown in FIGS. 1 to 3.

As shown in FIG. 1, three electrode openings 5 through which electrodes 4 pass are provided in a small ceiling portion 3 located at the center of a furnace lid 2 provided above an arc furnace body 1. As shown in FIG. 2, a second
A seal ring 13 is mounted on the upper part of the small ceiling part 3 so as to be horizontally slidable to form an annular gap 9 smaller than the annular gap 8. Second seal ring 13
In this example, a steel plate 10 is lined with a refractory material 12 using studs 11. Above the small ceiling part 3 are three electrode hood openings 5' through which the electrodes 4 pass.
A first sealing ring 15 is installed horizontally at the top of the dust collecting hood 14 in an annular gap 8' between the electrode outer surface 6 and the inner vertical surface 7' of the opening of the dust collecting hood 14. The annular gap 9' is smaller than the annular gap 8'.
The first seal ring 15 is also a steel plate 10' lined with a refractory material 12' by studs 11'.

Usually, the annular gap 8 and the annular gap 8' are determined by the degree of concentricity between the electrode 4 and the electrode aperture 5 and the electrode hood aperture 5', the degree of concentricity between the electrode 4, the electrode aperture 5, and the electrode hood aperture 5', the amount of splash that adheres to the electrode outer surface 6, the time when the electrode penetrates, and the time when the furnace cover rotates. In consideration of fluctuations, etc., in a 20t nominal arc furnace, the
The diameter is 30 to 50 mm, and 100 mm or more in large furnaces. According to the present invention, even if the outer surface 6 of the electrode comes into contact with the inner vertical surfaces 7 and 7' of the opening due to concentric deflection between the electrode and the opening or vibration when the electrode penetrates or when the furnace lid is rotated, the second and Since the seal ring 1 is only placed on the small ceiling part 3 and the dust collection hood 14, it is in a state where it can move in the direction of the shake, and only the amount of splash adhering to the electrode outer surface 6 should be considered. It's a good thing.
In a 20 t nominal arc furnace, the annular gap 9 is 10 to 30 mm per diameter, and the annular gap 9' is 10 to 20 mm, while in a furnace of 20 t or more, the annular gap 9 is 10 to 100 mm.
mm, the annular gap 9' can be reduced to 10 to 50 mm.

FIG. 3 shows another embodiment, which is of a compact storage type so that it does not protrude from the upper surface of the furnace lid and dust collection hood.

(Effect of the invention) According to the invention, the opening area of the annular gap 8 is reduced to 1/4 or less compared to the conventional one, so the amount of exhaust gas blown out from inside the furnace is suppressed and the amount of heat removed by exhaust gas discharge etc. is minimized. At the same time, the amount of air sucked from the annular gap 8' is also reduced, making it possible to reduce the amount of electrode oxidation loss and the amount of dust-collecting air. It is a very effective means of reducing the electric power consumption of arc furnace operation and as a countermeasure for environmental dust collection.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing one embodiment of the present invention, Fig. 2 is an enlarged view showing details of the seal structure of one embodiment of the present invention, and Fig. 3 is a detailed view of the seal structure of another embodiment of the present invention. The enlarged view shown in FIG. 4 is a diagram showing a dust collecting device around an electrode of an arc furnace equipped with a conventional dust collecting hood. 1...Furnace body, 2...Furnace cover, 3...Small ceiling part,
4... Electrode, 5... Electrode aperture, 5'... Electrode hood aperture, 6... Electrode outer surface, 7, 7'... Opening inner vertical surface, 8, 8'... Annular gap, 9, 9'... annular gap, 10, 10'... steel plate, 11, 11'...
Stud, 12, 12'... Refractory, 13... Second seal ring, 14... Dust collection hood, 15...
...First seal ring.

Claims (1)

[Scope of utility model registration request] An electrode hood opening through which the electrode passes is provided in the dust collection hood around the electrode at the top of the furnace lid of the arc furnace, and the inner diameter D is set at the top of the annular gap formed between the electrode hood opening and the electrode diameter. D=d+10mm~ for d
A first seal ring with a diameter limited to 50 mm is placed on top so that it can slide horizontally, and the inner diameter D' is attached to the electrode at the top of the annular gap formed between the electrode opening provided in the lid of the arc furnace and the electrode. D′=d+10 for diameter d
A seal structure around the electrode of an arc furnace in which a second seal ring limited to mm to 100 mm is placed on top so that it can slide horizontally.