SU2129A1 - Electric arc furnace - Google Patents

Description

The present invention aims at a device for an electric arc furnace in which a volt arc heating a metal rotates under the influence of a magnetic field created by an electric current passing through a coil surrounding the furnace. The presence of a coil that is included in the circuit with alternating current in series with a voltaic blow, and with a constant current in parallel or in series, gives the arc the shape of a rotating helical spiral. The rotation of the arc arc has the following objectives; uniform heating of the melting space, better heat transfer from the arc to the metal and stability of the long arc.

In FIG. 1 shows a vertical section of a furnace with electric arcs between the metal and the movable electrode; FIG. 2 - the same with the arc above the metal, and FIG. 3 - the same with arcs above the metal at three-phase current.

The melting space / proposed furnace is made of any refractory material (dolomite, magnesite, etc.). Arcs are formed between the processed metal 3 and the moving carbon electrode 4 and under the influence of the magnetic field of the excitation coil 5 rotate along the metal surface (Fig. 1).

In a furnace with one rotating volt arc, the current is supplied to the metal by means of the bottom electrode 2, but in the furnaces with several rotating arcs, the latter can be connected in parallel (the presence of the bottom electrode is necessary) or in series (the bottom electrode is absent). The excitation coil can be placed outside, or embedded in the laying of the furnace.

The furnace can operate on constant and alternating current, in the latter case, single-phase, two-phase (Fig. 1) or three-phase current is applicable; when operating the furnace at a constant current

the coil can be connected in series or in parallel with the volt arc, while operating on alternating current the coil is always connected in series with the arc.

The furnace can be used for remelting, refining steel and other metals, as well as for the production of special steel grades.

In the case of remelting of easily oxidizing and volatile metals under the direct action of a volt arc on them, the furnace device is modified as follows. The metal is placed in a conductive crucible 7 (graphite, coal, etc.), which is surrounded by refractory masonry 2 (Fig. 2). The crucible serves as one of the volt arc electrodes, which burns between the side wall of this crucible and the moving carbon electrode 3. Under the influence of the vertical magnetic field created by the coil 4, the volt arc is in rotational motion above the metal surface, forming a flame cone. The stove can work on. constant or single phase overcurrent; The way to turn on the coil is the same. The proposed option can replace a crucible furnace for remelting various metals.

In order to obtain very high temperatures, the following modification of the furnace with voltaic arcs above the metal is proposed.

The modified furnace consists of a melting space and, at three-phase current, three cavities (for forming rotating volt arcs), made in block 7 of TO / V conductive refractory material (coal, graphite, etc.) enclosed in refractory masonry 2 (Fig 3). The second electrodes for the formation of volt arcs are three moving carbon electrodes 3 connected in a three-phase circuit. The surrounding electrodes of the coil 4, which serve to create magnetic fields causing the rotation of volt arcs, with alternating current are connected through current transformers 6 in one phase with the corresponding electrode 3. This variant of the furnace can be used as a laboratory and industrial furnace to obtain a very high temperatures.

SUBJECT OF THE PATENT.

1. Electric arc furnace with one or several electric arcs rotating under the influence of a magnetic field around movable carbon electrodes, which is used with the purpose of creating a magnetic field, coil 5 (Fig. 1), placed either outside or embedded in 1 furnace which coil is connected to the circuit when operating on direct current in series or in parallel, when operating on alternating current in series with electric arcs burning between the metal of the bath 3 and the movable electrodes 4 (Fig. 1).

2. Variation of the furnace described in paragraph 1, characterized by the use of crucibles (Fig. 2) from an electrically conductive material in order to form an arc above the metal surface between the walls of the crucibles and the movable electrode 3 (Fig. 2).

3. Variation of the electric furnace described in paragraph 2, in the case of three-phase current, characterized in that the melting space is made in a conductive refractory block 7 enclosed in a refractory masonry 2 and equipped with three cavities 5 with three movable electrodes 3 placed in them, included in the three-phase circuit, wherein each electrode is surrounded, respectively, by a coil 4 connected via a transformer 6 in one phase with electrode 3 (Fig. 3).

Tipo-lithograph “Red Pechatnik, Leningrad, International, 75. FIG. one.