US2942046A

US2942046A - Electrode cooling means for electric arc furnace

Info

Publication number: US2942046A
Application number: US749977A
Authority: US
Inventors: Lloyd W Johnson; David J Klee
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1958-07-21
Filing date: 1958-07-21
Publication date: 1960-06-21
Anticipated expiration: 1977-06-21

Description

June'Zl, 1960 L. w. JOHNSON ETAL 2,942,046

ELECTRODE COOLING MEANS FOR ELECTRIC ARC FURNACE Filed July 21, 1958 3 Sheets-Sheet l INVENTORS Lloyd W. Johnson David J. Klee BY Theli r Anomey June 21, 1960 L. w. JOHNSON ETAL 2,942,046

zuacmoos coounc MEANS FOR ELECTRIC ARC FURNACE Filed July 21, 1958 3 Sheets-Sheet 2 I INVENTORS Fig. 2 Lloyd W. Johnson David J. Kleg Their AH'orney June 21, 1960 w. JOHNSON ET AL 2,942,046 ELECTRODE COOLING MEANS FOR ELECTRIC ARC FURNACE Filed Jul 21, 1958 s Sheets-Sheet 5 INVENTORS Lloyd W. Johnson David J. Klee m av /M The ir AHorney ELECTRODE COOLING MEANS FOR ELECTRIC ARC FURNACE Lloyd w. Johnson, Acton, and David J. Klee, Shelbyville, Ind., assignors to General Electric Company, a corporation of New York Filed July 21, 1958, Ser. No. 749,977

9 Claims. (CI. 13-14) This invention relates to electric arc furnaces and more particularly to novel and improved means for fluid cooling a non-consumable electrode of a vacuum arc furnace.

The invention is primarily concerned with electric arc furnaces ofthe type wherein a metal melting operation is performed within a hermetically sealed enclosure utilizing either a non-consumable or a consumable electrode. In furnaces of this type the sealed enclosure may comprise a crucible or mold in which the melted metal is collected and an electrode housing extending upwardly of the mold in which an electrode is mounted for movement longitudinally of the housing and relative to the mold. During the melting operation, the electrode housing and crucible may be evacuated or in certain cases may be pressurized, and at other times the melting opera- Un ted swtespatemp provided with a passage or conduit for'the circulation of cooling fluid therewithin and into heat exchange relationship with an electrode carried by the supporting means. In accordance with the invention, cooling fluid is circulated through the passage of the electrode supporting means from a source externally of the furnace by means of a pair of expansible members formed by a pair of coiled tubes disposed entirely within the electrode housing and substantially concentrically arranged about the electrode supporting means. One end of each tube is fixed relative to the furnace housing while the other ends of the tubes are connected to the cooling fluid passage of the electrode supporting means, so that as the electrode supporting means is moved alternately in opposite directions relative to the electrode housing the coils will expand and contract in coil spring-like fashion.

The details of the invention will be best understood by reference to the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a fragmentary side elevational view, partlyin section, of an electric arc furnace embodying this invention; 1

Fig. 2 is an enlarged fragmentary side elevational view, partly in section, ofthe electrode support and cool ing means of the furnace of Fig. l; and p Fig. 3 is anenlarged top cross sectional view substantially along the line 3 3 of Fig. 1.

tion may take place at atmospheric pressure in the presit is necessary to provide means for cooling the electrode. The location of a movable electrode within a hermetically sealed enclosure obviously complicates the problem of supplying cooling fluid to the electrode. A previously known solution to this problem includes the use of an array of long flexible hoses or tubes supported externally of the furnace and connected to sliding tubes extending through sliding seals in the electrode housing. The sliding tubes are connected to the electrode support for movement therewith and provide for the circulation of cooling fluid within the support to cool the electrode carried thereby. This so-called stinger type furnace of course requires a facility of considerable height to house it inasmuch as when the electrode is fully retracted or raised to its upper position the sliding tubes and flexible hoses attached thereto will projcctfrom the top of the electrode housing a distance at least equal to the full range of electrode travel.

It is the primary object of this invention to provide novel and improved means for cooling an electrode mounted for movement in a sealed enclosure of an electric arc furnace which will obviate the necessity for sliding tubes projecting upwardly from the furnace, expensive sliding seals for the tubes, and an array of long flexible hoses externally of the furnace, thus effecting a substantial reduction in the height of the furnace and improving the over-all economy of fabrication and upkeep of the furnace.

Other objects and advantages of this invention will be in part made obvious and in part pointed out in detail hereinafter. V

In one aspect of our invention, we provide as a portion of a hermetically sealed furnace enclosure an elongated vertically arranged electrode housing in which electrode supporting means is mounted for movement longi-' tudinally thereof. The electrode supporting means; is

With reference to the drawings and particularly Figs. 1 and 3, van electric are-furnace of the type with which this invention is concerned comprises a supporting frame 10 of structural metal including hollow up-

right columns

12 and 14 which respectively form inlet and outlet cooling fluid manifolds. Supported on the frame by brackets 16 is a vertically arranged electrode housing 18 comprising an elongated metal cylinder 20. Fixedly supported on the bottom of the cylinder 20 is a substantially cylindrical furnace body 22 the underside of-which isin registry with a water-cooled crucible 24. A hopper26 sup-v ported on the frame 10 is connected to the body 22 for feeding a charge of granular or pulverized metal into the body for melting thereof by an are between a pool of molten metal in the crucible and a non-consumable electrode 28 shown in its retracted inoperative position.

The electrode is supported by an electrode supporting means 30 suspended vertically within the electrode housing by means of a chain 32 engaged over a sprocket 34 which is mounted on a shaft 36 extending outwardly through the housing in sealed relation thereto. The shaft 36-mounts at its outer end the sprocket 38 carrying a chain 40 engaged with a sprocket 42 on a shaft 44 of a gear box 46 mounted on the electrtode housing and drivingly connected to a-rnotor 48 for raising and lowering the electrode. Means for guiding the electrode supporting means in its vertical movement is provided -by tubular guide posts '50, 52, and 54 arranged equiangu larly and equidistant about the longitudinal ,axis of the electrode housing. T-he free end of the chain 32 is dis-, posed within the hollow guide post 50, as shown in Fig. 3, and if desired maybe providedwith a counterweight to. reduce the power required for movement of the electrode; Electrical current forthe electrode is supplied bysuitable connection, notshown, to the cylinder 20 and thence through a current collector including a plurality of flexible contacts 56 carried by a Y- shaped block 58 mounted on the upper'end of the electrode supporting means .30 with the contacts extending chordally of the sh ul he e-she mu .-12at@ h. s i sms ne one.

. intimate contact with the electrode.

electrode supporting means 30 as well as the current collector for'the electrode supporting means are not a part of our present invention.

Cooling fluid is 'directed along the outer wall of the cylinder 20 by means of a pair of channel members 60 and '62 closed at both ends which, as is most clearly shown in Fig. 3, extend longitudinally of the exterior of the cylinder on opposite sides thereof. The channel 60 is provided with a fitting 64 at its lower end which is adapted to be connected by a hose 66 to the inlet manifold 12. The

channels

60 and 62 are connected at their upper ends by a suitable conduit, not shown, and the channel 62 is provided with a fitting 68 at its lower end adapted to be connected to a hose 70 fitting to the outlet manifold 14.

As most clearly shown in Fig. 2 the electrode supporting means 30 comprises a'pair of metal

tubular members

72 and 74 concentrically arranged one within the other in radially spaced relation so as to provide an annular passage 76 between the outer tube 72 and inner tube 74 and a central passage 78 within the inner tube 74. The electrode supporting means further in cludes an electrode clamp 80 supporting the electrode 28 independing fashion from the lower end of the electrode supporting means. As most clearly shown in Fig. 2, the

passages

76 and 78 are connected adjacent the top of the electrode so as to circulate cooling fluid in In accordance with the invention, a pair of expansible fluid conducting members in the form of helically wound

metal tubes

82 and 84 are disposed substantially concentrically about the electrode supporting means with the inner coil 82 being of lesser diameter than the outer coil The lower end of the coil 82 is connected to a litmg 100 extending outwardly of the furnace body 22 for connection to a hose 86 leading to the inlet manifold 12. The upper end of the tube 82 is connected to an L-shaped fitting 88 extending inward-1y of the electrode supporting means in communication with the outer annular passage 76. The upper end of the center passage 78 m the electrode supporting means is connected to the upper end of the outer tube 84 through an L-shaped fitting 90 extending outwardly of the electrode supporting means. The lower end of the outer tube 84 is fixed to a fitting 92 on the furnace body communicating with theinterior of an internal annular cooling fluid chamber 94 in the furnace body which is connected by suitable means, not shown, to a hose 96 which is in turn connected to the outlet manifold 14. A pair of

alignment plates

98 and 99 extending substantially radially of the upper end; of the electrode supporting means are provided with notches engaging the upper end portions of the inner and outer tubes, respectively, to maintain the tubes'in alignmeat-with the electrode supporting means.

D ring operation of the furnace, cooling fluid is in-' troduced through the inner tube 82 into the outer passage 76' of the electrode supporting means and circulated into heat exchange relationship with the electrode 28 and thence passed through the center passage 78-of the electrode supporting means and outer tube 84to-the outlet manifold 14. During" movement of the electrode supporting means relative to the furnace, the

coils

82 and 84 will elongate and shorten in a manner similar to a coil spring thus providing-extensible fluid conduits for thepas'sage of cooling fluid to and from the electrode supporting means with the extensible conduits being disposed entirely within the sealed furnace structure thus eliminating the necessity of any outwardly projecting members extending through sliding seals or the like as well as the need for my extensive array of long flexible hoses which complicates the furnaceinstallation and increases the maintenance on the furnace.

It is preferred that the coils 82 and 84- be woundin the opposite sense,- as shown most clearly in Fig;- 3, wherein theinner'coil sz exte'ndsin" a clockwise dime 4 tion from its fitting 88 while the coil 84 extends in a counterclockwise direction from its upper fitting 90. In this manner when the coils are contracted and the inner coil is nested within the outer coil, there will be no tendency for the coils to jam and lock, but to the contrary upon subsequent movement of the coils in an extending direction the coils will be cammed apart by their oppositely inclined engaging surfaces. The

coils

82 and 84 while oflering decided advantages when used in connection with a non-consumable electrode furnace also may be used with a consumable electrode to provide cooling of the electrode supporting means. As will be apparent the electrode cooling means of this invention results in a substantial reduction in over-all height of the furnace installation over the use of stringer type arrangements. The

coils

82 and 84 require only occasional inspection and the maintenance problems involved are at a minimum. Additionally, while not primarily intended for this purpose, the coils provide a certain amount of radiant cooling of the cylinder 20 of the electrode housing.

It will be understood that many changes could be made in the construction heretofore shown and described and that different embodiments of the invention could be made without departing from the scope thereof. Accordingly, the foregoing description and drawing should be taken only in an illustrative sense and not as limiting the invention, it being our intention that the invention herein described shall be limited only by the terms of the appended claims which shall include within their scope a-ll structure which logically falls within the language of the claims.

What we claimas new and desire to secure by Letters Patent of the United States is:

1. In an electric arc furnace, a housing, electrode sup porting means disposed at least partially within the hous-' ing mounted for movement in opposite directions rela tive to the housing and having a cooling fluid passage, and a resilient member disposed within the housing with one end thereof connected for movement with the electrode. supporting means relative to the housing and with its other end fixed relative to the housing, said resilient member being provided with a cooling fluid passage extending between its ends connected and arranged to conduct cooling fluid with the end of the passage-corresponding to said one end of said member being in fluid flow communication with the passage of the electrode supporting means, and said resilient member further being subjected to tensile and compressive forces upon changes inthe distance between its ends.

2. In an electric arc furnace, a housing, electrode supporting meansdisposed at least partially within the housing mounted for movement in opposite directions relative to the housing and having a passage for the circulation of cooling fluid including an inlet and an outlet for the passage, and a pair of resilient metal members disposed within the housing with one end of each of said members being connected to the electrode supporting means for movement therewith relative to the housing and with the other end of each of said members being fixed relative to the housing, each of said members being provided with a cooling fluid passage extending between the ends thereof with the ends of' the passages in said members corresponding to said one end thereof being in flow communication respectively with the inlet and outlet of the passage in the electrode supporting means, each of said members being'subjected to tensile and compressive forces upon changes in the distance" between its ends.

3. In an electric arc furnace, a housing, electrode supporting means at least partially disposed within the housing mounted for movement in opposite directions relative to the housing and having a passage connected and arranged to conduct cooling fluid, and an elongated helically arranged cooling fluid conducting hollow member disp'osed abouttheelectrode supporting: means= ahd:

extending longitudinally thereof, one end of said member being fixed relative to the housing, the other end of said member being mounted for movement with the electrode supporting means and in fluid flow communication with the passage of the electrode supporting means so that upon movement of the electrode supporting means in opposite directions relative to the housing said member will expand and contract in spring-like fashion in the direction of movement of the electrode supporting means.

4. In an electric arc furnace, a housing, electrode supporting means disposed at least partially within the housing mounted for movement in opposite directions relative to the housing and including a passage for the circulation of cooling fluid having an inlet and an outlet, and a pair of expansible and contractible cooling fluid conducting hollow members disposed about the electrode supporting means and extending in the direction of movement of the electrode supporting means, one of said members being received within the other, the members being connected at one end to the electrode supporting means for movement therewith and in flow communication with the inlet and outlet respectively of the passage of the electrode supporting means, the other ends of said members being fixed relative to the housing.

5. In an electric arc furnace, a housing, electrode supporting means disposed at least partially within the housing mounted for movement in opposite directions relative to the housing and including a cooling fluid passage having an inlet and an outlet, a pair of helically arranged tubular elements disposed entirely within the housing, said elements being arranged about the electrode supporting means with the axes of the helixes formed thereby extending in the direction of movement of the electrode supporting means, said tubular members further being arranged substantially concentrically one within the other and being connected at one end to the electrode supporting means for movement therewith and in fluid flow communication with said inlet and outlet respectively, the other ends of said tubular members being fixed relative to the housing.

6. In an electric arc furnace, a housing, electrode supporting means disposed at least partially within the housing and including a passage having an inlet and an outlet for the circulation of cooling fluid, a helically wound tubular member disposed about the electrode supporting means in spaced relation with its axis extending in the direction or" movement of the electrode supporting means, and a second helically wound tubular member disposed substantially concentrically within the first tubular member in radially outwardly spaced relation, the members being connected at one end to the electrode supporting means in fluid flow communication with said inlet and outlet respectively, the other ends of the tubular members being fixed relative to the housing.

7. In an electric arc furnace, a housing, electrode supporting means disposed at least partially within the housing and having a passage constructed to conduct cooling fluid including an inlet and an outlet, and a pair of helically arranged tubular elements disposed in the housing and arranged about the electrode supporting means with the axes of the helixes formed by said elements extending in the direction of movement of the electrode supporting means, said elements being arranged substantially concentrically one within the other with one element being spaced intermediate the other element and the electrode supporting means and being helically wound in a sense opposite that of the other element, the elements being connected at one end to the electrode supporting means for movement therewith and in fluid flow communication with said inlet and outlet respectively, the other ends of said elements being fixed relative to the housing.

8. In combination, electrode supporting means constructed to be disposed entirely within a sealed furnace enclosure for movement in opposite directions relative to the stationary portions of the furnace; the electrode supporting means including a cur-rent collector portion, means for suspending an electrode, and a passage having an inlet and an outlet and constructed to conduct cooling fluid to cool the electrode; and means for conducting cooling fluid to and from said passage from externally of a furnace housing to the electrode supporting means including a pair of helically arranged tubular members arranged substantially concentrically of each other and disposed about the electrode supporting means with the axes of the helixes formed thereby extending in the direction of movement of said supporting means, the members being connected at one end to the electrode supporting means and in fluid flow communication with said inlet and outlet respectively, the other ends of the members being constructed for connection to a fluid source and outlet, respectively, on the stationary portion of the furnace.

9. In combination with electrode supporting means constructed and arranged for moving an electrode relative to the housing of an electric arc furnace and having a passage for conducting cooling fluid to cool the electrode, a pair of resilient metal hollow members, and means mounting one end of said hollow members for movement with the electrode supporting means and in fluid flow communication with the passage of the electrode supporting means, the other end of said members being constructed to be fixedly mounted on the furnace housing, the hollow members being subjected to tensile and compressive forces in response to movement of the electrode supporting means relative to the furnace housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,671,461 Bagley May 29, 1928 2,726,278 Southern Dec. 6, 1955 2,771,498 Bredtschneider et a1. Nov. 20, 1956 FOREIGN PATENTS 727,341 Germany Oct. 31, 1942