US2662104A

US2662104A - Feed and current supply apparatus for consumable electrodes and method of operating furnaces using the same

Info

Publication number: US2662104A
Application number: US211887A
Authority: US
Inventors: Raymond L Southern
Original assignee: Allegheny Ludlum Steel Corp
Current assignee: Allegheny Ludlum Steel Corp
Priority date: 1951-02-20
Filing date: 1951-02-20
Publication date: 1953-12-08
Anticipated expiration: 1970-12-08

Description

Dec. 8, 1953 Filed Feb. 20, 1951 R. L. SOUTHERN FEED AND CURRENT SUPPLY APPARATUS FOR CONSUMABLE ELECTRODES AND METHOD OF OPERATING FURNACES USING THE SAME 3 Sheets-Sheet l Fig.

Ill

INVENTOR. Raymond L. Southern uh? HIS ATTORNEYS Dec. 8. 1953 R. SOUTHERN FEED AND CURRENT SUPPLY APPARATUS FOR CONSUMABLE ELECTRODES AND METHOD OF OPERATING FURNACES USING THE SAME 3 Sheets-Sheet 2 Filed Feb. 20, 1951 INVENTOR. Raymond L. Sou/hem BYj %ma4d% HIS ATTORNEYS Dec. 8, 1953 R. L. SOUTHERN 2,662,104

FEED AND CUR R SUPPLY APPARATUS FOR CONSUMABLE E DE ND METHOD OF OPERATING FURN S NG THE SAME Filed Feb. 20, 1951 3 Sheets-Sheet 3 IN VEN TOR. Raymond L. Sou/hem 48 BY imiliem Mm L 450 HIS ATTORNEYS Patented Dec. 8, 1953 ED STATES PATENT orricr.

2,662,104 FEED AND CURRENT sUi'PLi liirAith'riJs FOR CONSUMABLE ELECTRODES METHOD OF OPERATING FURNACES USING THE SAME This invention relates to apparatus for progressively advancing a consumable metal elee-- trode into an arc melting furnace or crucible and to means for supplying energizing current to such electrode. 7

In employing a consumable electrode of a metal such as titanium, the electrode is fed into the crucible of an arc-melting furnace and an arc is set up between the tip of the electrode and metal in the furnace to heat the electrode up to a melting temperature. The electrode is thus progressively melted down to form an ingot within the crucible. A metal such as titanium can be pressed into sticks which are somewhat porous. Metal powder or sponge, thus compacted, will still retain some residual impurities, depending upon theparticula-r process by which the metal is separated from its compounds. That is, the metal may contain some residual halides such as chlorine, iodine etc, and some residual reducing material such as hydrogen, potassium, magnesium etc.-, which if not properly eliminated will tend to contaminate the melt. More volatile impuritiessuch as moisture, oxygen or nitrogen may also be present. I

The sticks produced by this pressing method may be somewhat irregular in surface contour; they are relatively frangible and somewhat porous; As a result, considerabledifficulty has been encountered in effecting an efficient electric contact with the electrode stick as it is being fed. Further, the feed must be positive, but must be accomplished without damaging the relatively frangible stick. I

It has thus been an object of my invention to provide new and improved apparatus for feeding and conducting current to a consumable electrode employed in an arc melting operation;

Another object of my invention has been to provide a relatively simple but practical arrangement for feeding relatively frangible, pressedout sticks of a metal such as titanium.

A still further object has been to devise an effective arrangement for feeding arc-producing current to a consumable electrode while it is being advanced into a melting crucible or furnace; v I 7 These and many other objects of my inven tion will appear to those skilled in the art from the illustrated embodiments and from the de pending claims. 7

In the drawings; Figure 1 is a vertical sectional view in elevation taken through a complete apparatus assembly constructed in accordance with my invention and as applied to an arc melting furnace or crucible; I k

Figures 2,- 3 and 5 to '7 inclusive; are sectional views taken respectively along" th'e'lines II" II,

111, v-v, VI-VI, and VII-VII of Figure l; N I 1 Figure 3A is a sidesectional view in elevation taken along the line IIIA- -IIIA of Figure '3; V

Figure 4 is an emargeqsecuonn detail taken along the line IV IV' of Figure 3; Figures 8 and 9 are enlargedsectional details of the current applying apparatus disclosed particularly inFigure 2; Figure 8 is taken at a right angle to Figures 2 9; v Figures 10 and are enlarged sectional .details of a modified form of construction used applying current to the electrode stick; Figure 10 is taken at a right angle to Figure 11;

In carrying out my invention, I employ a redtangular stick ll of substantially square crosssection, pressed out into a suitable length, for example feet I have found that a cross-section of two in ches s duare satisfactory. The stick 3 i is positioned an enclosure that is sealed ofi" from the atmosphereand within which a set of feed rolls and a set of electric contact rolls are operativelypositioned., The lower end of the electrode stick extends into an arc-melt ing crucible or furnace l 0 and current of opposite potential is supplied to such furnace to thereby form an are I) witustam charge of metal or with previously. meltedmetal a to progressively build ups, pure metal ingot. r

The progressive rate of feed of the electrode stick Ii maybe automatically controlled by a commercial amblidyne or other suitable device to actu'atethe feed roll's at a rate depending upon therate of melting of the stick and as governed by the current consumed by thearc b. Referring particularly to Figure 1, it will be noted that due to spacelimitations, the view" is broken way through the crucible In. aswell as through anup per or stick-carrying enclosure l2. The fullleinfgth o f the stick I! is sealed off from the atmosphere by the vertically-extending en closure l2 whic'h' maybe a pipe or tube of an internal d ameterpf about as? to 3 inche'slif a 2 inch square stick i l' isv employed (has a diag} onal dimension rap er 2.82") so that the stick is guided i'n its iiiovjeim e nt aridsupptrtga by the inner wall cr me nc'iosui {in (see Fi ure 6), The enc'losure lz at a nular bottom flange portion v inland In ,enclo s i'ng portion 12b] securedltlie'reto b wield n qlflbwtb form a mtggrareqnstru i0 ,T he enclosure 12 has a gas inlet lib tO its Chamber, the purpose (if which will be er e a n d- 1 Y A second or stick feeder enclosure it has a rectangularbott'om flange l fic for securing it to third em} cure at, v A to' mduntiiig late meniber it of the enclosure (6 positioned beneath theencldstir' l2 and carries a'pair of

feed rolls

22 and 32. It Will be fibtdthat the member l5 and the flange Hill are secured to the enclosure l6 by weld metal w. The flange |2a of the first or upper enclosure I2 is mounted on the top member |5 of the second enclosure l5 by bolts l3; the joint is sealed off by an annular gasket I4. As shown, the chamber defined by the second enclosure 5 is open to chamber defined by the upper or first enclosure l2. When one stick I I has been advanced, so that its upper end He reaches a position near the bottom of the enclosure l2, a new stick is introduced and its lower end is welded to the upper end of the old stick to form a continuous electrode. For this purpose, the bolts |3 may be removed and the enclosure |2 lifted off the enclosure IS.

A feed roll mounting base member l! is secured to the top mounting plate member i5 to project downwardly therefrom by bolts l8. As shown particularly. in Figure 1, 2 and 3, a pair of transversely spaceC-wapart vertical support members I9 extend downwardly from the base member I! and carry bearings for the shaft 2| of a knurled feed roll 22. The feed roll 22 has end flanges 22a which project on either side of the stick H to guide it during its movement. The shaft 2| at one end extends through a sealing gland 23 in the enclosure l6 and has a chain sprocket 24 secured on such extending end by a key 2 la. The sprocket 24 is driven by a chain 24a through a sprocket 25a mounted on a motor 25 which may, in turn,

be controlled in its operation by an amplidyne device 26.

As also shown in Figures 1 to 4, inclusive, the spaced-apart support members I9 are at one end slotted out at 33 to receive sleeve bearings 3| n which carry a shaft 3|! of a second knurled feed roll 32. The outer contour of the bearings 3| is square (as contrasted to the annular contour of bearings 20), in order to guide them in their sliding movement within the slots 33. The second roll 32 which is mounted in an opposed position with respect to the roll 22, also ha a pair of end flanges 32a to guide the stick The full lines of Figure 3 show the roll 32 as an idler or backup roll and the dot and dash lines indicate that it may be a drive roll. In any event, its sleeve bearings 3! are slidably mounted in the slots 33 by adjustable screw-downs. Each screwdown, as shown in these figures, has a clamping piece or face plate 34 which is secured on an end of each support I!) over the slot 33 therein by bolts 34a. A screw-down bolt 35 is adiustably positioned to extend inwardly from the piece or face plate 34 into the slot 33, and has a pin end 35a extending into and slidably carrying a spring supporting washer 36a. A compression spring 36 is mounted over the shank of the washer 36a and over a shank 3|b of the bearing 3|. The springs 36 yieldably press opposite ends of the shaft 33 of the roll 32 inwardly. Thus, the roll is yieldably held in a contacting relationship with one side of the electrode I. The screw-down 35 may be moved inwardly and outwardly, after its lock nut 351) has been loosened, to adjust the tension or the spring 36. In this manner, the yieldable engagement of the roll 32 with respect to side of the stick [I i controlled and a positive feed of the stick H is effected Without any danger of breaking it.

As shown by the dot and dash lines of Figure 3, the roll 32 may also be driven. If this is desired, a pair of sprockets 21 are mounted adjacent opposite ends of the main shaft 2| and a pair of similar sprockets 23 are mounted on extending end portions of the secondary shaft 323.

Iii

Chains 23 mesh with the

sprockets

21 and 29 on each side of the assembly. As shown in Figure to obtain the same direction of feed of the two

rollers

22 and 32, I provide an idler sprocket 25s on each end of an idler shaft 291) over which the chain 25 run. The shaft 292) is positioned beneath and to one side of the shaft 30 and is journaled within the support members 9 by bearings 290. In this manner, the roll 32 still has a yieldably mounted relationship, but may be driven from the primary shaft 2| in a timed relationship with the roll 22.

The third or contact roll enclosure or housing 40 is mounted beneath the second enclosure or housing It and its chamber is open thereto and carries sets or opposed pairs of electric contact rolls 55. Inert gas may be introduced to the chamber of the enclosure 40 through the inlet 2c of the upper enclosure l2. An upper annular flange 40a is secured by weld metal 111 and proiects from the top of the third enclosure 4|) to receive a sealing-in gasket 43 and the bottom flange I50. of the second enclosure. Bolt and nut assemblies 4| extend through the flange lBa, the gasket 43, and the flange 40a to secure the second enclosure It in a iluid-sealed-olf relationship to the third enclosure 40.

At its lower end, the enclosure 49 has a bottom closure plate or member 44 which is secured thereto by weld metal to and serves as a support for a mounting base member 45 of the contact rolls 55. The mounting base member 45 rests on an insulating and heat-resistant separator 46 and is secured to the bottom closure member 44 by bolts All. The bolts 41 are insulated from the mounting member 45 and the closure member 44 by heat-resistant sleeves 41a. It will thus be apparent that the enclosure 40 is electrically insulated from the current-carrying, mounting base member 45.

The mounting base member 45 has two pairs of oppositely-positioned, semi-circular, bearingcontact bores or sockets 4511. Each socket 45a receives a ball end 5| of each contact roll mounting bracket 53. The call end 5| of each bracket 53 i removably positioned in one of the sockets bearing 45a by a plate member 42 which is secured thereto by bolts 49. Plate member 48 also has rounded cavities or contact bores therein to receive the ball ends 5| and hold them in position within the bearing-contact sockets 45a.

Each bracket 55, as shown particularly in Figures l, 8 and 9, has a pair of contact arms 52 extending upwardly therefrom and defining a bifurcated portion within which a contact roll 55 is rotatively mounted by mean of its integral shaft 54. As will be noted, current is carried by the arms 52 through the shaft 54 which rotates therein, as well as through endwise contact of the roll 55 with the arms 52. This provides a maximum path for current flow and eliminates sparking and excessive heating. Each contact roll 55 i adapted, as shown, to ride along one side of the four sides of the electrode stick and by reason of its ball and socket mounting, Y

is free to pivot and move transversely in and out with respect to the stick That is, the axial plane of the roll 55 or the transverse plane of the bracket 52 may be pivoted as well as the longitudinal plane of the bracket to move the roll in and out with respect to the surface contour of the stick II. This is important in view of the somewhat irregular surface presented by the sides of the electrode stick I I; it avoids arcing between the rolls 55 and the stick.

r The arms. 52 or each bracket sc- (see Figures 1', 2, 8 and 9) have an intermediate offset or groove 52a to receive and position an annular, compression-spring helix 53 to yieldably hold the rolls in surface contact with the sides of the electrode stick l l'. Thati's', the spring 5'3i's positioned about all four brackets 50. to yieldably hold their rolls 55 in contact and in surface conformance with the. sides ofthestick ll. Current 01' one poten tial' (negative) is supplied to the base member 45 by a supply line 5? which is connected: to a projecting lug 45b. The line 5T is insulated from the enclosure 40 andia fluid-tight, hermetic seal is provided byan insulating sleeve 56. The parts $5,181,511; 54* and 55 are all of. a highlyconductive metal, such as. copper, acopperalloy; or bronze.

The third enclosure 40 is mounted on. the furnace of crucible m by a fourth, cooling fluid or water j'acketed enclosure 58'. The. fourth enclosure 58 has an inner metal. wall 58a of square design which. is spaced from the electrode stick ill, so as tobe out of electric contact therewith, see Figure '7'. The longitudinal, restrictive, elecnode-passageway defined by the wall. 58a is: conne'cted'. between the chamber of the enclosure 40 and the crucible to, see. Figure 1'. In this manner, a continuous, hermetically-sealed enclosure isprovided for the feeding and energizingmechanism of the electrode stick H.

The fourth or'mounting" enclosure 5'13 has a top closure plate 59' which is secured thereto by weld metal wand closes oil the upper end of its'coolin'g chamber. The plate 59 is secured to' the bottom plate E4 of the. enclosure do by bolt and nut assemblies 611' whose heads are inset in the member #4,, seeF-igure I. An annular insulating "and heat-resistant gasket 61 seals off the joint between these enclosures from the atmosphere. An annular bottom' plate 62 projects outwardly from the enclosure 58' to close oil the lower. end of it's cooling chamber and to provide an end closure for and mount it on the furnace orcrucible i0. As will be noted,. the enclosure 58 has a cooling'fluid' inlet 58b and outlet 58c.

The crucible or furnace It has a copper flange lUb projecting from its copper inner wall orliner IOa" and. has a steel flange 9a projecting from its outer steel wall 9. Bolt: and nut assemblies 63 extend through the bottom plate 62 of the enclosure 58' and through the flanges Illb and 9a,

and are insulated from. these parts by a heatresistant, insulating sleeves 64. Heat resistant gaskets 65. and 66 seal off and insulate these parts with respect to each other when they are in a secured relationship. It will thus be noted that the enclosure 58 is electrically insulated from the furnace l0 and that metal spatter from the melt,- ing operation cannot. short circuit the electrode with respect to the furnace. As will be noted, currentof.oppositepotential (positive) issupplied to the flange Iflb and thus, .to the liner. Illa. The fourth or connecting. and cooling, enclosure 58 is thusv insulated from the third enclosure 41).

Asshown in Figure 1. of. the drawings, theinner wallv Illa; of the crucible l-O is open to the top of the furnace and has a bottom portion of. greater thickness which is removably secured to. its side portions by bolt and nutassemblies, so that a formed ingot. can be readily removed therefrom after the. outer steelwall 9. has been dropped by removing the bolt and nut assemblies 63. Cooling water may be introduced to the wallsv of the furnace a through a. bottom outlet and. discharged through a top outlet to maintain its inner wall a at a proper operating temperature.

the compression spring 531 A gas that is inert to the metal of the electrode, such as argon, helium, or neon, is introduoed through inlet I'Zc and flows downwardly through the chambers'of the enclosures it, as and 58 into the crucible I'O and'out-throughan outlet 8 in thebottonr plate-62'. In thismannenthe more readily volatil-izable impurities are swept downwardly at a much faster rate than the advance of the electrode. Impurities are prevented from collecting on the rolls and causing damage to the bearing surfaces. The flow also helps to cool. the contact rolls and to prevent appreciable furnace heat'from rising intothe chamberot the. enclosure fill. The inert gas is also employed to flush out theapparatus after the top-enclosure l2: has been replaced and vacuum evacuate'd following the in.- sertion of a new electrode stick. The inert gas will also carry off volatile or gaseous impurities fromthe crucible I301. The water-jacketing' of the enclosure 58 maintains portions of the stick ti above: it at a relatively low temperature, so that the current contact rolls 55' and the feed rolls '22 and 32' are protected. from the intense heat of the crucible H)- As shown in Figure 1', the water-cooled, inner-wall 58a 1a heat baille)v which is positioned closely adjacent to and. which has a shapecorresponding to that: of the. electrode l'l, thus serves as a heat. insulating or segregating means between the relatively hot chamber of the furnace is and the: chamber of the enclosure. which: contains the feed andicontact: roll mechanisms. Thus, the contactroll mechanism 5'0 may be positioned adjacent: the bottom of the enclosure it: without dan'gerot being? damagedby the heat of the furnace.

In Figures 10 and. 11,1 have shown a. slightly modified form of contact roll construction. In this arrangement the bottom-base member is mounted in the same: manner: as the: member 45, but has nosockets. Each bracket member 617 has a slightly different form: of mounting and is provided with a transverse-connector portion 61b. The connector portion filbt is provided with an enlarged: slot ill-c thereinwithin which a pivot pin or goose neck Ellis-loosely positioned. Each pivot pin extends upw-ardlyfrom a base portion 68a that issecured on: the base member 45' by' bolts 69. The upper end of the pin $82 is provided with a Washer 68?) and a cotter pin 680 to somewhat loosely mount the bracket member 6'! thereon and permit the desired pivot action thereabout; The construction ofthebrackets t lis otherwise substantially' the same as the construction of the brackets 59; Each: has a groove Bid to receive In view of the somewhat loosely mounted: relationship of the-brackets 6:7, I additionally providea braided (flexible) electric: connector cable-- to between: them and the base portion: sca This construction: also permits the brackets 61 to" y ieldably move in and out on a transverse plane as 'well as on a longitudinal plane, so that the rolls will always make a contact of maximum effectiveness with the elect'rodestick I i.

What I claim is:

1. In melting'down' a press-formed consumable metal electrode containing readily volatilizable impuritiessuch as halidesand reo'l'ucing material, wherein the electrode-ismechanically fed" into an electric arc-melting furnace from within a hermetically sealed-off closure positioned above the furnace and having a: bottom end connection therewith; wherein electric current is mechanically; applied to the electrode within a bottom portion 'of'the'enclosure, andwherein electriccurrent of opposite potential is applied to metal within the furnace, the method which comprises, establishing and maintaining an electric are between a lower end portion of the electrode within the furnace and the metal within the furnace, volatilizing the readily volatilizable impurities adj acent a top portion of the furnace, flowing agas that is inert to the metal of the electrode from the enclosure downwardly along sides of the electrode into the furnace and sweeping the volatilized impurities out of the top portion of the furnace, heat insulating and segregating the atmosphere of the closure from the atmosphere of the furnace while feeding the electrode into the furnace, and effecting the heat insulating by providing an actively-cooled atmosphere about the electrode during its movement from the closure into the furnace.

2. An apparatus for feeding and electrically energizing a consumable metal electrode being introduced into an electrically-energized arcmelting furnace to produce ingots therein which comprises, an enclosure positioned adjacent the furnace and defining a chamber for containing a longitudinal length of the electrode, a second enclosure defining a restrictive electrode-passageway therealong, said second enclosure connecting the chamber of said first-mentioned enclosure to the furnace and defining an end closure portion for the furnace, feeding means positively engaging the electrode to advance it from said firstmentioned enclosure through the passageway of said second enclosure into the furnace, at least a pair of rider contacts operatively positioned within said first-mentioned enclosure to engage the d electrode and apply energizing current thereto during its advance into the furnace, said ider contacts having means to yieldably hold them in engagement with the electrode, and said second enclosure being electrically insulated from the furnace to prevent metal spatter from short-cir cuiting the electrode with respect to the furnace during an arc melting operation therein.

3. An apparatus for feeding and energizing a consumable electrode being introduced into an electric arc melting furnace which comprises, an enclosure positioned on the furnace and defining an electrode-receiving chamber, means connecting the chamber of said enclosure to one end of the furnace, feeding means positively engaging the electrode to advance it into the furnace, at least a pair of electric current-supplying rider contacts operatively positioned within said enclosure to engage the electrode, a positioning part operatively mounting each of said rider contacts for movement transversely of and towards the electrode, and a force-equalizing spring operatively connected between each of said positioning parts to yieldably hold each of said rider contacts in an effective force-equalized electrical contact with the electrode While it is being advanced into the furnace.

4. An apparatus for feeding and energizing a consumable electrode being introduced into an electric arc melting furnace which comprises, an enclosure positioned on the furnace and defining an electrode-receiving chamber, said enclosure having a restrictive electrode-passageway defining means connecting its chamber to the furnace, feeding means positively engaging the electrode to advance it into the furnace, at least a pair of electric current-supplying rider contacts operatively positioned within said enclosure and ad- ,jacent the furnace to engage the electrode, a positioning part operatively mounting each of said 'tudinally thereah rider contacts for movement transversely of and towards the electrode, and a spring helix operatively engaging each of said positioning parts to yieldably hold each of said rider contacts in an effective force-equalized electrical contact with the electrode while it is being advanced into the furnace.

5. An apparatus for feeding and electrically energizing a relatively frangible metal electrode of irregular surface contour which is to be introduce-zi into an. electric arc melting furnace to produce ingots therein which comprises, an enclosure positioned in a spaced-apart relationship from the furnace and connected at one end thereto, said enclosure being of suflicient length to contain a longitudinal length of the electrode therein, a pair of fed rolls operatively positioned within said enclosure adjacent one end thereof and engaging opposite sides of the electrode, at least one of rolls being operatively driven to progressively advance the electrode into the furnace, means holding at least one of said feed rolls in yieldable engagement with said electrode to positively advance the electrode without breakage; a set of rider contacts, a positioning member operati'vely-movably mounting each of said rider contacts within said enclosure between said feed rolls and the furnace, said set of rider contacts having at least a pair of electrically-energized contacts engaging opposed sides of the electrode, and a force-equalizing spring operatively positioned about said positioning members and holding each of rider contacts with an equalized force in yieldable contact with opposite sides of the electrode irrespective of irregularities in the sur ace contour of the electrode to provide an eilic t electrical contact with the electrode all times without breaking it.

in pparatus for feeding and energizing a un'iacle electrode being introduced into an electric arc melting furnace which comprises, an enclosure above the furnace and defining a chamber, encl-osu being of sufficient length to contain a long length of the electrode therein, a ed rolls cperatively positioned within said en; .re adjacent an upper end portion thereto to e igage the electrode and advance it into the i so, yieldable rider contacts operatively positioned within lower portion of said enclosure to the electrode and supply electrical current thereto during its advance into the furnace, a heat bailiing enclosure connecting the lower aortion of first-mentioned enclosure to an upper end portion of the furnace having means to heat insulate said firstmentioned. enclosure from the furnace, and said bailing enclosurrhaving an inner wall longide ding an electrode passing chamber that is rest ficted transversely to provide a cle rance between said. inner wall and. side portions of the electrode during its advance into the furnace.

*1. An apparatus as defined in claim 6 wherein, said drive rolls are knurled and have end flanges to guide the electrode, and said rider contacts are positioned in an opposed relationship with respect to each other.

8. An apparatus as defined in claim 6 wherein, a mechanical drive is connected to one of said feed rolls, and the other of said feed rolls is mounted in yieldai'le engagement with the electrode.

9. An apparatus defined in claim 6 wherein, a conductive base member is mounted on said enclosure, at least a pair of conductive brackets are pivotally mounted on said base member, and each conductive bracket of said pair rotatably carries one of said rider contacts.

10. An apparatus as defined in claim 9 wherein, each said bracket carries a ball portion, said conductive base member has a socket thereon to receive said ball portion, and means is secured to said base member to pivotally mount said ball portion within said socket.

11. An apparatus as defined in claim 9 wherein, pivot pins are mounted to project from said base member, and each said bracket is pivotally mounted on one of said pivot pins.

12. An apparatus for feeding and energizing a consumable electrode being introduced into an electric arc melting furnace which comprises, a hermetically sealed-off enclosure positioned to extend above the furnace and defining a chamher, said enclosure being of a suflicient length to contain a longitudinal length of the electrode therein, a pair of feed rolls operatively positioned within said enclosure and engaging the electrode, means positively actuating at least one of said feed rolls to progressively advance the electrode into the furnace, a set of opposed pairs of contact rolls operatively positioned within said enclosure between said feed rolls and the furnace, means supplying electric energy to said contact rolls, means holding said contact rolls in flexible yieldable engagement with the electrode during its advance into the furnace, and a waterjacketed enclosure connected between said firstmentioned enclosure and the furnace and having an inner enclosing wall therealong defining an electrode passageway therethrough of substantially transversely limited extent sufficient to provide a minimum clearance between it and the electrode and to heat insulate said first-men tioned enclosure with respect to the furnace.

13. An apparatus for feeding and energizing a a consumable electrode being introduced into an electric arc melting furnace which comprises, an enclosure above the furnace and defining a chamher, said enclosure being of sufficient length to contain a longitudinal length of the electrode therein, a pair of feed rolls operatively positioned within said enclosure adjacent an upper end portion thereof to engage the electrode and advance it into the furnace, yieldable contact rolls operatively positioned within a lower end portion of said enclosure to engage the electrode and supply electrical current thereto during its advance into the furnace, a heat baffling enclosure connecting the lower end portion of said first-mentioned enclosure to an upper end portion of the furnace and having means to heat insulate said firstmentioned enclosure from the furnace, said baffiing enclosure having an inner wall longitudinally therealong defining an electrode passing chamber that is restricted transversely to provide a minimum clearance between said inner wall and side portions of the electrode during its advance into the furnace, a conductive base member positioned within said first-mentioned enclosure, contact roll mounting brackets pivotally mounted on said base member to extend therefrom and carry said contact rolls, and yieldable means operatively engaging said brackets to hold said contact rolls in yieldable engagement with the electrodes.

14. An apparatus for feeding and energizing a consumable electrode having four substantially planar sides that is to be introduced into an electric arc melting furnace which comprises, an enclosure above the furnace end defining a cham- 10 her, said enclosure being of sufficient length to contain a longitudinal length of the electrode therein, a pair of feed rolls operatively positioned within said enclosure adjacent an upper end portion thereof to engage the electrode and advance it into the furnace, yieldable contact rolls operatively positioned within a lower end portion of said enclosure to engage the electrode and supply electrical current thereto during its advance into the furnace, a heat baffling enclosure connecting the lower end portion of said firstmentioned enclosure to an upper end portion of the furnace and having means to heat insulate said first-mentioned enclosure from the furnace,

' said bafiiing enclosure having an inner wall longitudinally therealong defining an electrode passing chamber that is restricted transversely to provide a minimum clearance between said inner wall and side portions of the electrode during its advance into the furnace, said contact rolls having two opposed pairs, one of said opposed pairs being in engagement with two of the planar sides and the other of said opposed pairs being in engagement with the other two of the planar sides of the electrode, and flexible means positioned to force said contact rolls into engagement with the planar sides of the electrode.

15. An apparatus for feeding and energizing a consumable electrode being introduced into an electric arc melting furnace which comprises, an enclosure above the furnace and defining a chamber, said enclosure being of sufficient length to contain a longitudinal length of the electrode therein, a pair of feed rolls operatively positioned Within said enclosure adjacent an upper end portion thereof to engage the electrode and advance it into the furnace, yieldable contact rolls operatively positioned within a lower end portion of said enclosure to engage the electrode and supply electrical current thereto during its advance into the furnace, a heat baffling enclosure connecting the lower end portion of said first-mentioned enclosure to an upper end portion of the furnace and having means to heat insulate said first-mentioned enclosure from the furnace, said baflling enclosure having an inner wall longitudinally therealong defining an electrode passing chamber that is restricted transversely to provide a minimum clearance between said inner wall and side portions of the electrode during its advance into the furnace, pivotally mounted brackets carrying said contact rolls, and a yield able compression spring positioned about said brackets.

RAYMOND L. SOUTHERN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,169,384 Dwight Jan. 25, 1916 2,097,502 Southgate Nov. 2, 1937 2,541,764 Herres et al Feb. 13, 1951 2,564,337 Maddey Aug. 14, 1951 OTHER REFERENCES R. M. Parke & J. L. Ham: The Melting of Molybdenum in the Vacuum Arc, Metals Technology Technical Publication No. 2052, v. 13, No. 6, Sept. 1946 (12 pages).

Browne: Steel, Jan. 19, 1948 (pp. 74-76, 78).

Clauser: Materials and Methods, Jan. 1948 (pp. 57-62).

Herres 8; Davies, Steel, May 2, 1949 (pp. 82-86.