SU52319A1 - Electrode holder for meadow furnaces - Google Patents

Description

Graphite or carbon conductors, called electrodes, are used to supply a current to a bath of an electric arc furnace and to get a volt arc in it. The electrode is fixed with a special clamping device of the furnace - the electrode holder.

At the beginning of operation of the furnace, the nipple rolls two electrodes. When during operation the lower electrode burns so much that the length of the candle is insufficient for operation, then the candle is supplemented with a new electrode, screwing it up from the top each time.

In modern conditions, when the use of coal electrodes in electric furnaces prevails, in the process of exploitation one has to face a number of difficulties. Carbon electrodes, when used in 8-ton and 15-ton Hera-type furnaces, are highly heated and as a result are rapidly oxidized in air. This circumstance leads to a reduction in the cross section of the electrodes in the course of work, not only in the furnace bath, but also above it, up to the electrode holders, and the candles, in the form of their own gravity, break and fall off; most often it happens in place

nipple connections. The consumption of electrodes, at the same time, per 1 ton of suitable metal is excessively high. In addition, frequent breakdowns of the electrodes significantly increase the downtime of electric furnaces due to the need to replace the carbon electrodes.

The rapid oxidation of carbon electrodes is also facilitated by the presence of streams of hot gases from the furnace through the gaps in the roof, which serve for the passage of electrodes. Despite a number of appropriate protection methods by sealing gaps, the results are far from positive.

Heating the red electrode up to the clamping device leads to the heating of the latter and, as a result, there is a rapid combustion of the inserts, sliders and flexible copper bars (current-carrying parts) with all the unpleasant consequences resulting from this, even if there are water-cooled heads.

In order to eliminate these drawbacks, it was proposed to perform the electrode holder in the form of a hollow cylinder, fitted at the end with a nipple screwed into the body of the electrode.

In this case, the cylinder and the nipple are cooled with water washing them from the inside. However, such electrode holders turned out to be imperfect. When an inappropriate assembly of a spark plug occurs, a volt arc arises in the socket of the carbon electrode, which burns out the nipple threads.

The proposed transitional electrode holder with cooling eliminates all these drawbacks and makes it possible to work more efficiently on an electric furnace with a minimum consumption of electrodes.

The proposed electrode holder consists of a metal (iron) hollow cylinder, fitted at the end with a nipple, to which an electrode is screwed. The cylinder and the nipple are cooled with water, air, etc. With a sufficient length of the cylinder, it is found that the clamping device is transferred closer to the arc, as the area of the destructive oxidizing effect on the electrode is reduced. In this case, according to the invention, the nipple is electrically insulated from the parts of the electrode holder which are intended to supply current to the electrode. Such isolation of the nipple prevents the occurrence of electric arcs between the cutting of the hyppel and the electrode.

The invention is illustrated in the drawing; in FIG. 1 of which the proposed electrode holder is shown in longitudinal section, and in FIG. 2 is a cross-section along the line AB in FIG. one.

The proposed electrode holder is made in the form of a hollow iron cylinder 7 with a nipple 2, to which a carbon or graphite electrode is screwed. The upper part of the cylinder 7 is closed by a flange tightly welded to the edge of the cylinder. A tube 3 is passed through this flange, passing along the axis of the cylinder and not reaching the bottom of the nipple 2 by the diameter of the tube itself. The tube 3 serves to supply cooling water (air, etc.) flowing through the second tube 77, the end of which is welded to the flange covering the upper part of the cylinder /.

The nipple 2 is welded into the flange 5, having a diameter smaller than the inner diameter of the cylinder 2. Then the nipple flange is attached to the flange 4 of the cylinder 7 with six pin 9, which are fixed by nuts 10. The studs are insulated from the flange 5 with micanite bushings 8 and washers 7; In addition, a Klingerite washer 6 is laid between the flanges 4 and 5. Flange 4 has an internal boring that is larger than the diameter of the nipple body. After pre-assembling the nipple, the flange 4 is welded into cylinder 7.

The gap between the body of the nipple 2 and the flange 4 must be filled with an insulating material (asbestos cord or micanite tape).

Before putting the electrode holder into operation, the nipple is screwed tightly to the failure, the electrode, the socket of which is previously well lubricated with the electrode mass. Then, the electrode holder is lifted by a crane by the transport ring, inserted into the furnace head, lowered the candle to the required height and secured with a clamping mechanism. Aluminum (or copper) plates are fastened to the head liners with screws, which contribute to a greater contact density between the transition electrode holder and the head liners. Corresponding flexible hoses are attached to tubes 3 and 77, cooling (water, air, etc.) of the electrode holder is turned on and the furnace can be put into operation.

After the electrode has burned and reduced in length so that it does not reach the bottom of the furnace, it is necessary to remove the candle and install a backup. At the same time, regardless of the operation of the furnace, the remaining piece of the electrode should be unscrewed on the side, a new electrode should be added to it from above and again screw this bundle tightly onto the nipple of the electrode holder. Thus, the next reserve will be prepared.

Melting, carried out with the proposed transitional electrode holder with water cooling, revealed the advantages awaited by the authors:

1. The consumption of electrodes is abruptly eliminated in the first phase and intensive oxidation is eliminated. The carbon electrode, even after several heats, is very well preserved.

2. There are no downtime for replacing the electrodes.

3. Inserts, rams and tires are not hot, as the first ones have cooling from two sides (head and cylinder).

The use of the proposed electrode holder with graphite electrodes should reduce their consumption, since the electrode holder makes it possible to work on a short candlestick, which reduces the continuous absorption of graphite electrodes even in the presence of good compaction.

The proposed design of the electrode holder can make it possible to work on coal electrodes on large furnaces and thus free from the import of graphite electrodes.

Fears of using a water-cooled transition electrode holder should be considered completely unfounded - this is confirmed by the work of experienced electrode holders.

The presence of water above in the metal and electric furnace is already present both in the heads and in the cooling rings. Even if the electrode burns and gives a leak, it will be noticeable (the jet will be visible and the slag will blacken under this place) and can be replaced immediately.

The design of the electrode holder is designed so that at the lowest position of the electrode holder, the nipple is 150 mm higher than the upper level of the slag in the furnace. Therefore, the transition of the transition electrode holder into the slag or metal is completely excluded.

The subject matter of the invention.

Cooled electrode holder for arc furnaces, having a cooled metal nipple screwed into the electrode body, characterized in that, in order to prevent electric arcs between cutting the nipple and the electrode, the nipple is electrically insulated from the parts of the electrode holder that are designed to supply current to the electrode.

to the author's testimony of A. V. Abramov V. F. Bondar and V. D. Oschepkova No. 52319

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