Asea Aktiebolag

Asea Ab

Allmanna Svenska Elektriska Aktiebolaget

Asea Brown Boveri Ab

Sven-Einar Stenkvist

Bo Vesteras Rappinger

Bjorn Widell

Erik Lassander

Kjell Bergman

Conny Andersson

Bengt Fredrickson

A new method of making an electrically conductive hearth in a d.c. furnace is effected by first heating bricks such as magnesite-graphite bricks and the like, from their new commercially available form to high temperatures decresing the normal resistivity of the bricks and thereafter laying the bricks to form the hearth from top to bottom with the heat treated bricks.

D.C. arc furnace having electrically conductive hearth and method for

Electrically conductive refractory bricks, containing particles (e.g. flakes) of graphite or other electrically conductive material are pressed into the desired final shape but include a plurality of passages, none of which passes completely through the brick. The passages each extend substantially perpendicularly to the predominant direction of the conducting particles.

Electrically conductive bricks

A DC arc furnace having an electrically conductive hearth adapted to contain a melt, and at least one arcing electrode above the hearth and adapted to form a heating arc with the melt when the hearth and electrode are supplied with DC power; the hearth having a wear lining directly contacted by the melt and formed by refractory material through which electrical conductors extend from the bottom of the wear lining to its top. A metal plate under the wear lining electrically connects with the conductors and is supported by one or more electrically non-conductive layers of refractory. Power connection to the wear lining is via the plate and a connection with the periphery of the plate.

Direct current arc furnace

A DC arc furnace comprising a furnace vessel having a hearth and a side wall extending upwardly from the hearth, conductive means for conducting DC through the hearth from its outside to a melt in the hearth, an arcing electrode, a substantially horizontal arm having a holder holding the electrode substantially vertically above the hearth, a substantially vertical mast from which the arm extends, and means for connecting DC positively to the conductive means and negatively to the electrode so as to form an arc between the electrode and the melt and producing an arc flare to which the side wall is exposed; wherein the improvement comprises means for connecting the arm to the mast so as to permit the arm to be adjustably moved longitudinally to different positions and means for mounting the mast so it can be adjustably rotated to different positions about its axis, whereby the electrode and its arc can be located at different positions horizontally to the side wall.

DC arc furnace

A DC arc furnace including a hearth adapted to contain a melt and having a melt electrode which is only effective when covered by the melt, an enclosure for the hearth including a roof over the hearth, at least one arcing electrode depending downwardly through the roof and adapted to initially melt a charge of solid metal on the hearth and thereafter the resulting melt, and at least one starting electrode through which electric power is transmitted to the charge of solid metal until it is melted down by the arcing electrode to enough melt to cover the melt electrode; the starting electrode or electrodes depending downwardly through the roof at a position horizontally offset from the arcing electrode and being adapted to be moved downwardly so as to press on the charge of solid scrap on the hearth until the charge is melted down by the arcing electrode so as to cover the melt electrode and thereafter to be moved upwardly free from the charge.

DC arc furnace having starting equipment

A DC arc furnace having a vertical arcing electrode adapted to be connected with a negative current lead and a hearth adapted to contain a melt below the electrode and having a hearth electrode, the hearth electrode extending laterally from the axis of the arcing electrode symmetrically with respect to the axis and having a plurality of electrical connections extending to the outside of the hearth and spaced laterally from the arcing electrode's axis symmetrically with respect to the axis, the connections being adapted for connection with a positive current lead and application of DC to the electrodes powering an arc between the arcing electrode and melt; wherein the improvement comprises a positive current lead below the bottom of the hearth and having an upper end positioned on the arcing electrode's axis below the hearth's bottom and extending from the positive current lead's upper end vertically downwardly on the axis to a low position where the magnetic field of the positive current lead cannot appreciably affect the arc, the positive current lead extending substantially horizontally from its low position offset from the hearth, the positive current lead's upper end having electrical conductors extending from it to the electrical connections of the hearth electrode and which are symmetrical with respect to the arcing electrode's axis.

DC Arc furnace hearth connection

A DC arc furnace has an electrically conductive hearth adapted to contain a melt, and at least one arcing electrode above the hearth and adapted to form a heating arc with the melt when the hearth and electrode are supplied with DC power. The hearth has a wear lining directly contacted by the melt through which electrical conductors extend from the bottom of the wear lining to its top. Layers of electrically conductive bricks are under the wear lining and have a top layer electrically connecting with the electrical conductors, and a melt plate under the layers of the electrically conductive bricks is connected to DC power. The layers of conductive bricks have a bottom layer in electrical connection with the melt plate. The improvement comprises a layer of mixed bricks between the top and bottom layers of the electrically conductive bricks and formed by alternating electrically conductive and non-conductive bricks.

DC Arc furnace improved hearth construction

A metallurgical ladle furnace has a ladle for containing the melt, an arcing electrode positioned on the ladle's axis, and a melt electrode in the ladle's lower portion and substantially symmetric with respect to the arcing electrode. DC power applied to the electrodes results in an arc between the arcing electrode and the melt for heating the melt and incidentally causing the melt to stir in vertical directions, the melt moving downwardly in the middle below the arc, upwardly along the walls of the melt and inwardly towards the arc. A DC powered coil surrounds the ladle horizontally at half the ladle's height or higher, around the upper portions of the melt. The field of this coil in cooperation with a DC flow in the melt caused by the current flow between the electrodes, provides a substantially tangential stirring force on the melt which is in addition to the stirring force of the electrode current in the melt. This additional force results in the surface of the melt acquiring a concave shape surrounding the arc and protecting the ladle's wall from the arc flare while increasing the melt's energy absorption from the arc.

Ladle furnace with DC heating

The present invention relates to a method and a device for operating a DC arc furnace with a bottom in the furnace vat consisting of rammed compound (8) or bricks with metallic elements (7) which are in electrically conductive contact, directly or via electrically conductive bricks (10) such as carbon bricks, with a hearth connection (11). The method is characterized in that, after melting and possibly further treatment of a charge (15), when tapping said melt such a quantity thereof is left that said remainder, the sump (17), may serve as part of a starting electrode for the next melting operation.

Method and device for operating a DC arc furnace

An electric arc furnace has an electrically conductive roof with an electrode opening through which an arcing electrode depends with the opening closed around the electrode by an upstanding tubular electrically insulating refractory column surrounding the electrode and mounting on its top an electrically conductive electrode seal.

Electric arc furnace arcing electrode seal

A DC arc furnace hearth directly contacted by the melt is made from partially metal cased bricks which provide metal-to-metal intercontact while exposed portions of the bricks provide brick-to-brick intercontact.

DC Arc furnace component

A metal oxide reduction furnace has a shaft holding a verticle column of coke. An electric arc on the side of the lower portion of the column burns a cavity in the coke column and the arc is surrounded by the side wall and inner closed end of the cavity so that high temperatures are obtained. A stream of the metal oxide in particulated form mixed with a reducing agent is projected into the cavity to react endothermically within the cavity and lower the high temperature while reducing the oxide to its metal.

Metal oxide reduction furnace

A DC arc furnace has power lines arranged completely symmetrically with respect to the arc so as to prevent the arc from bending angularly.

DC Arc furnace power connection system

A DC arc furnace has shielding between the arc and its power lines preventing or retarding the magnetic field created by the power lines from deflecting the arc.

DC Arc furnace having a shielded arc

A DC arc furnace hearth is formed by brickwork having electric conductors extending through it, the conductors at their bottoms connecting with an electrically conductive layer on which the brickwork is layed and having top ends contacted by a melt contained by the brickwork. Arcing power can be transmitted via the conductive layer and conductors to the melt.

Growing community of inventors

Vaster.ang.s, Sweden

Sven-Einar Stenkvist