US3644654A - Giant electrode - Google Patents

Abstract

A giant electrode of graphite for high-output operation of electric arc furnaces in which the electrode is provided with an electric arc stabilizing wick.

Description

United States Patent Zollner et al. 1 Feb. 22, 1972 [54] GIANT ELECTRODE [72] Inventors: Dieter Zollner, Erlangen; Bernhard [56] References Re|chelt, Numberg-Laufamholz, both of UNITED STATES PATENTS G many 859,292 7/1907 Harden ..l3/18 X 1 Asslsnw Conrad! Numbers, Germany 3,120,453 2/1964 Fitzer et a]. ..13/18 x [22] "3" Primary Examiner-Remand A. Gilheany [21] Appl. No.: 45,426 Assistant ExaminerR. N. Envall, Jr.

, Attorney-Walter Becker 30 v Foreign Application Priority Data '[57] ABSTMCT June 13, Germany ..P A g electtode of for highoutput operation of electric arc furnaces in which the electrode is provided with [52] US. CL ..13/ 18 an electric arc stabilizing wick [51] Int. Cl. 05b 7/06 [58] Field of Search ..l3/l8; 314/60; 313/354 2Clalms,2Drawlng Figures The present invention relates to a giant electrode of graphite for electric arc furnaces.

The technical requirement to convey extremely high electric power in connection with the melting operation of electric arc furnaces to the material to be melted and heated in the hearth has lead to numerous improvements in graphite electrodes. However, with regard to the extent to which solid graphite electrodes can be subjected to current loads has principally reached a limit. In order, in spite of this limit, still to be able to transmit greater power, resort has been taken to increasing the voltage. The increase in the voltage while retaining the current, however, entails other difficulties in the electric arc furnace operation. Thus, the electric are which, in view of the higher voltages is longer, causes an unsteady burning behavior and, in view of this instability, brings about a considerable turbulence in the surface of the melt. These turbulences bring about that steel and slag particles are thrown against the lateral hearth lining and thus result in an intolerable extreme wear of the furnace lining.

Therefore, it became imperative to stabilize the electric are as far as possible. To this end, hollow electrodes of graphite have been used. In view of the tendency of the foot point of the electric arc to burn in the interior of the central bores, a stabilization was realized which could be improved furtherby the supply of gases, such as argon, for stabilizing the electric arc and by stabilizing additions at the walls of the electrode.

While these methods bring about considerable advantages, very frequently the graphite consumption figures were considerably higher than expected or the operating costs with gasstabilized hollow electrodes became too high.

It is, therefore, an object of the present invention to provide a giant electrode which will overcome the above-mentioned drawbacks.

This object and other objects and advantages of'the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 is a section through an electrode according to the invention, while FIG. 2 is a top view of the electrode of FIG. 1.

The present invention, which concerns a giant electrode of graphite for maximum output operation of electric arc furnaces, is characterized in that it comprises an electric arc stabilizing wick.

Wick electrodes with small diameter are principally known for use in connection with movie projection lamps and for illuminating purposes. In such an instance, synthetic carbon products are involved of a diameter of up to 20 mm. and a length of approximately 50 cm.

The present invention is concerned with the application of this principle of increasing the power of electrodes to giant electrodes for the electric arc furnace. The advantage of this new electrode results from a combination of individual effects. In this connection there are to be mentioned:

We claim:

1. A giant electrode of graphite for maximum power operation of electric light arc furnaces, which comprises a graphite body having an axial central bore of small diameter therethrough compared to total electrode cross section, and a thin wick arranged centrally in said bore, said thin wick specifically assuring stabilization of electric light are furnace operation and simultaneously reducing graphite consumption.

2. An electrodeof electric light are furnaces according to claim 1, in which the mass of the thin wick contains a compound selected from the group consisting of n TiC and TiN in which n is selected from one to four for stabilization at higher current load demand during maximum power operation of electric light are furnaces.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECHON Patent No. 3, 4 Dated February 22, 1972 t Inventor) Dieter Zollner, a a1 It is certified that error appears in the above-ide'ntified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 after line 20, insert the following:

1. m elsamc current loadability. m, while an graphite electrode of diameter can he st lbj'e Cted to an electric current load of SO kA, which by impregnatioh uithmar and pitch prior to the graphiti zing operation can increased to nearly kA, it is possible to sfibject a 20 electrode of graphite according to the ihvention also fi m impregnation to load of kit. The drawbacks of A impregnated electrodes, such as increased tear danger in view of thehigh density and accordingly 'reduced chemo-shock 'v resistance,- are completely-absent v vith wick electrode a according to the invention.. Similar to' the 110110; electrode, the safety of operation is even considerably increased bt acau se in'view-of the-porous:-wickl-structure;flas compared-to the solid t'lectrode, the graphite electrode has also expansion possibil-it:

' with regard to the wick."

FORM PO-O (10-69) USCOMWDC 503764; a u.s. aovznunrm' manna omc! ms o-ue-au,

Patent No. 3,6l .L;.,65) Page 2' 2.- with th-e hollow electrode, the stabil-izing affect is om the. size 0f the bore so that a relatively high war -"w te Waste results from proming a sufficiently large me. In contrast thereto, the wick electrode according to invention gets by with er small bores. Thus with an having a d'mter of 5 00 'm', in: instancje aj bore of 1fiw -wi.ll suffice for pmdficifig stabilizing efifeiit.

3. me uick'electrode-ancosding theinwentiongenemtes a mlmly quiet 1y burning artwhich has almdist idealsine and thus veryl ong arcs :of

4. Finally, the cmtion -of zhem solid 'grapk xit e is" the am aom to the v the Int 1 thgwi k' s-.-

tin -electric a e the; 4

onto" the wick :doszlngi I 1y favorablere- Patent No. 3,6l. .l;,,65l4. Page 3 i .1 which as electric d, such as 1 r 141, The formation of Tit TiN may be ob -zoxaldes'horethertitanium as well Em" i As will be: seen frbw-the cirfliflge chewel'ec-tmfi g gia ph 'i t mew-ickg.-- The mass 6f m at Quayconsist of the referred. ta above,

It is, of course, up be zmderstooci that the present in ma is, by no, means, limited to the specific disclosure m forth above but also eomptises mq difications within KID taupe of the r claims.

' Signed and sealed this 26th day of February 19m.

(mm) Attest:

f C. MARSHALL DANN Commissioner of Patents EDWARD M.FLETCHER,JR. Attesting Officer

Claims (1)

1. 2. An electrode of electric light arc furnaces according to claim 1, in which the mass of the thin wick contains a compound selected from the group consisting of n TiC and TiN in which n is selected from one to four for stabilization at higher current load demand during maximum power operation of electric light arc furnaces.

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