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CA2023993A1 - Replacement electrode - Google Patents

Replacement electrode

Info

Publication number
CA2023993A1
CA2023993A1 CA 2023993 CA2023993A CA2023993A1 CA 2023993 A1 CA2023993 A1 CA 2023993A1 CA 2023993 CA2023993 CA 2023993 CA 2023993 A CA2023993 A CA 2023993A CA 2023993 A1 CA2023993 A1 CA 2023993A1
Authority
CA
Canada
Prior art keywords
electrode
furnace
worn
bottom wall
electrodes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA 2023993
Other languages
French (fr)
Inventor
Joseph A. Mulcahy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
J Mulcahy Enterprises Inc
Original Assignee
J Mulcahy Enterprises Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by J Mulcahy Enterprises Inc filed Critical J Mulcahy Enterprises Inc
Priority to CA 2023993 priority Critical patent/CA2023993A1/en
Publication of CA2023993A1 publication Critical patent/CA2023993A1/en
Abandoned legal-status Critical Current

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  • Vertical, Hearth, Or Arc Furnaces (AREA)

Abstract

ABSTRACT OF THE DISCLOSURE
Instead of being replaced completely, worn bottom electrodes in an arc furnace are renewed by connecting a new electrode section at the lower end and then projecting the renewed electrode into engagement with a fresh charge of scrape metal to be melted in the furnace. Any recess formed in the refractory material of the bottom wall of the furnace by a mushroom head on the worn electrode may be filled with fresh refractory material.

Description

-` 20239~3 TITLE OF INV~TION
RI~PLI~CEMENT ELEClq~ODE

FIELD OF INV~TION
The present invention relates to replacing electrodes in a D.C. arc furnace.
~CRGROUND TO THE INVENTION
Arc furnaces with bottom electrodes possess two different types of design. In a first design, large current values from a point source are spread through a bath of liquid metal and then through a refractory hearth to a spread out conducting base. This arrangement has several disadvantages, including local wear under the electrode, which has to be detected by thermocouple, the snowball effect of local wear, with the current taking the path of least resistance, and the tendency o~ high current to be attracted together, so that the current i5 not naturally dissipated through the spread electrode.
In a second design, metal conducting elements protrude through the hearth from a bottom, generally water-cooled, connector and make contact with the liquid metal or scrap, as described, for example, in U.S.
Patent No. 4,646,316. This arrangement also has disadvantages, including a tendency for the upper portion of the electrode in contact with the liquid metal to become extended into a mushroom or cauliflower form and, when the extension becomes too severe, the electrode must be changed, requiring considerable downtime. In addition, the furnace may be periodically emptied, leaving little or no metallic contact between the electrodes and the next scrap charge for the furnace. This problem generally is overcome by placing a large metal spider into the furnace prior to changing, with feet penetrating into the electrode caps.
SUMMARY OF INVENTION
The present invention is concerned with the second ,.` '.`' ~ ~;
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type of arrangement and provides an improvement with respect thereto. In the present invention, when the furnace is emptied, the bottom electrodes are raised -hydraulically through the hearth, such that the top of electrode is in contact with the next scrap charge.
After raising the electrode through the hearth, refractory material may be gunned around the new portion of the electrode, filling in the cavity in the lower closure left by the mushroom head.
10Accordingly, in one aspect, the present invention -provides a method of processing worn electrodes in an electric arc furnace, which comprises providing an electric arc furnace having at least one power-carrying electrode pro~ecting through a bottom wall into a heating zone, ~oining an electrode section to the lower end of a worn electrode, and raising the worn electrode within the furnace.
BRIEF DESCRIPTION OF DRA~INGS
Figure 1 is a sectional view of a new electrode in a DC-powered arc furnace;
Figure 2 is a sectional view of a used electrodes in the arc furnace with the head distorted to a mushroom shape; and Figure 3 i~ a sectional view of the arc furnace illustrating the addition of a further electrode unit in accordance with one embodiment of the invention.
DFSCRIPTION OF PREFOR~ED EMBODIMENT
Referring to the drawings, there is shown therein the lower portion of an arc furnace 10 for melting metals, such as scrap metal, by employing at least one and usually a plurality of electrodes 12 projecting through the lower closure 14 of suitable refractory material or other material of construction into engagement wlth the material to be melted. The electrodes 12 are surrounded externally of the furnace by a water-cooled electrode holder 16. ~ ;

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As the melting operation proceeds, the electrodes ~;~
12 become worn and spread out at their upper ends, ~ -forming a mushroom shaped head 18, which produces a correspondingly-shaped recess 20 in the refractory 5 material of the lower closure. ~ ~
In the present invention, rather than replace the ~ ;
worn electrodes completely, as in the prior art, a new olectrode section 22, or two or more new electrode sections, is ~oined to the lower end of the old electrode 12 and the lengthened electrode is raised, such as by suitable hydraulic equipment 24, into the body of the furnace 10 and into engagement with the next charge of scrap metal to be melted. The recess 20 in ~ i-the furnace wall 14 then is filled in with refractory ;,~
material.
By using the procedure of the present invention, ~ ;;
bottom electrodes are added as required with a downtime of approximately 15 to 20 minutes. During thisi period, ;~ -other bottom wall repair also may be made. ~;~
8UMMARY OF DI8CL0SnRB
In summary of this disclosure, the present invention provides a much improved means for replacing worn leotrode~ in electrio aro furnaoes. Modifications are po~sible within the soope o$ this invention. ;
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Claims (4)

1. A method of processing worn electrodes in an electric arc furnace, which comprises:
providing an electric arc furnace having at least one power-carrying electrode projecting through a bottom wall into a heating zone, joining an electrode section to the lower end of a worn electrode, and raising the worn electrode within the furnace.
2. The method of claim 1 wherein said worn electrode has an enlarged head which forms a correspondingly-shaped recess in the bottom wall, and, following the raising of the worn electrode within the furnace, the recess is filled in with material of construction of the bottom wall.
3. The method of claim 2 wherein said material of construction of bottom wall is refractory material.
4. The method of claim 2 wherein said the worn electrode is raised within the furnace into engagement with a charge of scrap metal to be melted in the furnace.
CA 2023993 1990-08-24 1990-08-24 Replacement electrode Abandoned CA2023993A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA 2023993 CA2023993A1 (en) 1990-08-24 1990-08-24 Replacement electrode

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA 2023993 CA2023993A1 (en) 1990-08-24 1990-08-24 Replacement electrode

Publications (1)

Publication Number Publication Date
CA2023993A1 true CA2023993A1 (en) 1992-02-25

Family

ID=4145815

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2023993 Abandoned CA2023993A1 (en) 1990-08-24 1990-08-24 Replacement electrode

Country Status (1)

Country Link
CA (1) CA2023993A1 (en)

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