RU2818159C1 - Ladle furnace unit - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to three-phase arc melting and ladle electric furnaces. Furnace-ladle installation consists of a column with one electrode holder with three electrodes located on it, which is connected by a short circuit to a furnace transformer, an automated control system (ACS). Column is made with possibility of moving electrodes in ladle and providing specified heating of metal to required temperature. Furnace-ladle installation is equipped with a power source consisting of a step-down transformer connected to the supply network, and low-frequency thyristor unit installed on the secondary side, connected to the electrode holder connected to the furnace transformer through the low-frequency thyristor unit.

EFFECT: reduction of furnace transformer power and provision of uniform consumption of electrodes and thus uniform wear of lining in the furnace-ladle installation.

3 cl, 3 dwg

Description

The invention relates to electrometallurgy, namely to three-phase arc melting and ladle electric furnaces.

A known ladle furnace installation (patent RU 2305915, priority 02.16.2005), consisting of an automated control system (ACS), a steel truck with a ladle, a shaft with three electrode holders located in it with graphite electrodes fixed in them, which are connected to furnace transformer. The disadvantage of this design is the close location of the electrodes to the ladle lining, which leads to increased wear of the lining.

A ladle furnace installation is known, adopted as a prototype (“Unit for complex processing of steel with increased reliability.” Authors: Bershitsky I.M., Nikulin A.A., Savalyk N.A., Tarakanov S.A. Publishing house “Electrometallurgy”, 2008 year, No. 7, pp. 25-28), consisting of an automated control system, a steel truck with a ladle, a shaft with one electrode holder located in it with graphite electrodes fixed in them, which are connected through a short network to a three-phase furnace transformer. The disadvantage of this design is the impossibility of regulating power by phase and low cos ϕ, which requires the installation of a reactive power compensation device and a high-power furnace transformer.

The proposed design of the ladle furnace installation consists of a column (Fig. 1, item 1) with one electrode holder located on it (Fig. 1 and 2, item 2) with three electrodes (Fig. 1 and 2, item 3), short network (Fig. 1, item 4), a furnace transformer (Fig. 1, item 5) and an automatic control system, characterized in that it is equipped with a power source consisting of a step-down transformer (Fig. 2, item 6) connected to the supply network, and a low-frequency thyristor unit installed on the secondary side (Fig. 2, item 7), connected to the electrode holder (Fig. 1 and 2, item 2). The column (Fig. 1, item 1) with the electrode holder fixed on it (Fig. 1, item 2) moves in the shaft (Fig. 1, item 8), due to this the electrodes (Fig. 1, item 2) move in the shaft (Fig. 1, item 8). 3) move in the ladle (Fig. 1, item 9), providing the specified electrical mode for heating the metal (Fig. 1, item 10) to the required temperature. The thyristor unit (Fig. 3, item 7) can be equipped with a voltage regulator in each phase separately. The installation can be equipped with two step-down transformers (Fig. 3, item 6), connected in parallel, to which one low-frequency thyristor unit is connected (Fig. 3, item 7).

The proposed installation eliminates the following shortcomings of the patents listed above:

- it is known that cos ϕ of most ladle furnace units is 0.7. Because of this, it is necessary to use a furnace transformer, 30% of the power of which is not used. By powering the ladle furnace from a source with a reduced frequency, it is possible to reduce the power of the furnace transformer;

- in addition, during the operation of the ladle furnace installation, due to the operation of the metal blowing system with argon, uneven wear (waste) of the graphite electrodes occurs. By changing the power distribution across phases using a thyristor power supply unit, it is possible to ensure uniform consumption of the electrodes and, thereby, achieve uniform wear of the lining.

The technical result of the proposed installation is to reduce the power of the furnace transformer and ensure uniform consumption of electrodes and, thereby, uniform wear of the lining in the ladle furnace installation.

Claims (3)

1. Installation of a ladle furnace, consisting of a column with one electrode holder with three electrodes located on it, connected by a short network to a furnace transformer, an automated control system (ACS), characterized in that the column is designed to move the electrodes in the ladle and provide the specified heating metal to the required temperature, in addition, the ladle furnace installation is equipped with a power source consisting of a step-down transformer connected to the supply network, and a low-frequency thyristor unit installed on the secondary side, connected to an electrode holder connected to the furnace transformer through a low-frequency thyristor unit. 2. Installation according to claim 1, characterized in that the thyristor unit is equipped with a voltage regulator in each phase separately. 3. Installation according to paragraphs. 1 and 2, characterized in that it is equipped with two step-down transformers connected in parallel, to which one step-down frequency thyristor unit is connected.

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