US979663A

US979663A - Electric furnace.

Info

Publication number: US979663A
Application number: US48189509A
Authority: US
Inventors: Bayard Guthrie; Joseph P Karch
Original assignee: Individual
Current assignee: Individual
Priority date: 1909-03-08
Filing date: 1909-03-08
Publication date: 1910-12-27
Anticipated expiration: 1927-12-27

Description

Patented Dec.27,1910.

3 SHEEN-SHEET 2.

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B. GUTHRIE & J. P. KARGH. ELECTRIC FURNACE.

APPLICATION FILED HA3. 8, 1909. 979,663;

ll fl""' INVENTORS Bayard G'uibrl'e. k/J05? b P K r:/:.

sa a V///////////// /////4 WITNESSES B. GUTHRIE & J. P. KARGH.

ELECTRIC FURNACE. APPLICATION mum MAB. a, 1909.

Patented Dec. 27, 1910.

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b P Kare/1.

UNITED STATES PATENT OFFICE.

- t I BAYARD GUTHRIE, OF PITTSBURG, PENNSYLVANIA, AND JOSEPH P. KARCH, OF PLAIN- VILLE, CONNECTICUT.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Dec. 27, 1910.

To all whom it may concern:

Be it known that we, BAYARD GUTHRIE and JOSEPH P. KARGH, citizens of the United States, residing at Pittsburg, Allegheny county, Pennsylvania, and Plainville, 1n the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

This invention relates particularly to the melting of metals by the heat of the electric arc. i

The main object is to provide a simple and reliable construction W iich is efiicient and durable.

It is also desired to facilitate pouring and to produce a clean solid ingot without loss of metal.

The complete invention in its preferred form comprises a crucible and four radially movable electrodes in a tiltable casing which carries a swinging mold. The melting may be carried on in a neutral or reducing atmosphere. i 3

The details will be more clearly understood from the following specification and the accompanying three sheets of drawings.

Figure 1 is furnace. Fig. 2 is a plan view of the same with the top removed and showing a circuit diagram. Fig. 3is an enlarged fragmentary plan view of one electrode and its operating mechanism. Fig. 4 is a side view and vertical section of the same. Fig. 5 is an end view and partial section of the same. Fig. 6 is a vertical section of the furnace showing the crucible and the casing tilted for pouring. Fig. 7 is an enlarged vertical section of the casing and crucible showing one of the trunnions. i CuWent.-The crucible ,1, for containing the metal, the flux and other materials of a charge is, located between the electrodes 2,. 3, 4; and 5 which are arranged in pairs and supplied with current from the generator 6. This is of the quarter phase alternating .current type. Two direct current machines might be used however if desired.

Uasing.-The shell 7 of the casing is riveted or otherwise secured to the bottom plate 8 and reinforced by the hoop Two brackets such as 10 are riveted or otherwise secured to the bottom and side of the casing and each carries a trunnion 11. The two

trunnions

11, 11 are journaled in the standa front View of one form of.

Fig.

ards

12, 12. A gear wheel 13 on one of the trunnions meshes with pinion 14 and the hand wheel 15 is provided for rotating pinion 14 and thus tilting the casing and crucible for pouring. The interior wall and the bottom of the casin is lined with a plastic composition 16 suc as clay and asbestos fiber. A fire brick floor and piers such as 17 are provided to support the crucible be tween the electrodes. A perforated fire clay stand 18 is provided when a neutral or reducing atmosphere is desired, the gas being admitted through the pipe 19.

OmcibZe.The crucible is made of a suitable composition such as plumbago, clay and sand in proper proportions and sufiiciently free of oxid of iron so as to prevent the format-ion of carbid of silicon in the openation of the furnace so far as possible. The lower or melting part of the crucible is of the usual shape such for instance as is used "in melting steel. mouth is preferably funnel shaped as at 20 to increase its capacity and for convenience in filling. The cap 21 fits into this mouth portion and when new sits at the top and gradually sinks lower as it wears away in use. The cover 22 of the casing is held down by stay bolts such as 23, 23. A discharge spout or pipe 24, for instance of plumbago, fits over the outlet lip 25 in the side of the crucible near the top and extends out through the wall of the casing. v

zllolcL-From a pair of hooks 26 secured to the top 22 is suspended the ingot mold 27 by means of the

eye bolts

28, 28. The mold rests on the cross plate 29 and is wedged into the

clamps

30, 30; A plumbago funnel 31 or phosphorizer is provided at the upper end of the mold. The axis on which the mold swings is just in front of the discharge end .of the crucible spout 24 so that as the crucible is tilted up the stream .of metal pouring from the spout always falls straight down into the mold without splashing against the cold sides or spilling. This uniform flow insures a perfectly sound ingot.

Electrodes-Each of the four electrodes is radially movable to and from the crucible (see Figs. 3, at and 5). The face of the electrode is shaped to correspondwith the external contour of the crucible, the arc of its horizontal sect-ion being about (see The rear end is dove tailed and fits'vertically into the spring jaws of the The 'ing continued until thecrucible is empty. The furnace is then returned to its horizonholder 32 whose shaft 33 extends through the stufling box or 'land 34 and is secured in the clamp 35. The latter is mounted on a carriage 36 which slides on the guide bracket 37. -A rotatable screw '38 carried by this bracket is engaged by the interiorly threaded half nut 39, which is secured to or formed as a part of the carriage 36. By rotating the screw 38, for instance by a bandle 40, the nut 39 travels along the screw and moves the carriage 36, clamp 35 and the holder 32 and its electrode in or out as desired. In order to move all the electrodes simultaneously a bevel pinion 41 is mounted on the end of each screw 38 and all of them mesh with the bevel gear wheel 42. This is supported by a grooved wheel or shive 43 adjacent each pinion.-. Rotation ,of any one of the four screws and its pinion rotates the big gear and all the other pinions and screws so that all the electrodes are moved at the same time. Current is led to each electrode for instance by conductors such as 44. The holder is of course insulated properly from the carriage 36 and. from the casing at the stuffing box 34/ The electrodes and holders are coppered where they are in electrical engagement. The glands 34 should of course be properly packed to prevent leakage.

Operation-The casing being horizontal as shown in Fig. 1, the crucible 1, is charged and the car placed on top and the

electrodes

2,3, 4 and 5 are all moved up into contact with the crucible. Current is then turned on and the crucible and its contents are in the circuits. This warms up the crucible and contents but as the electrodes are purposely made large and as the crucible and contents are relatively good conductors the heatis not great. The handle 40 is then applied to the end of one of the screws 38 and the electrodes are slowly withdrawn from contact with thecrucible. Arcs immediately form between the pair of electrodes 2 and 3 and the pair t and 5 with the crucible in the center of intense heat. The great heat soon melts the contents of the crucible. The electrodes are then closed into contact with the crucible, the arcs gradually decrease and the current is turned off. The mold 27 being hung on the

hooks

26, 26, the hand wheel 15 is rotated so as to tilt the furnace as shown in Fig. 6 and pour the. contents of the crucible into the mold. The electrodes hold the crucible while pouring. Vhen one mold is filled it can be quickly removed and another substituted and pour tal position of Fig. 1 and recharged and the operation repeated. I

WVhen it is particularly desired to avoid oxidation of the contents of the crucible a neutral orinert gas may be supplied through the pipe 19 and which will pass through the perforated stand 18, up around the crucible 1, and out through the opening in the top of the casing surrounding the crucible mouth. This will prevent the air from reaching the contents of the crucible. Similarly a combustible gas may be supplied and burned as it escapes'from the ning in the top of the casing. This wil have a tendency to withdraw oxy en from the contents of the crucible and thus actas a reducin agent.

Each electrode is vertically a justable in the jaws of the holder 32 so as to properly fitthe crucible when moved up to it. Each electrode and its holder is horizontally adjustable in the clan ipl35 inde ndently of all other electrodes. is enab es the operator to properly adjust the electrodes so that they will all engage the crucible when it is in the center of the casing and so-that when the arcs are formed by-retracting the electrodes, each electrode will be the same distance from the crucible as all the others. The carriages and gear connections cause the electrodes to all move simultaneously and through the same distance and at equal speeds so as to maintain equal arcs on all sides.

Changes in details of construction and substitutions of equivalents are of course contemplated and considered to be within thescope of the claims hereinafter set forth as will be understood by those familiar with theart of metal working.

-What We claim is:

1. .In an electric furnace, a tiltable casing, a crucible therein, a supporting said cruci means for retracting said electrodes to form an arc.

2. In an electric furnace, a crucible, a plurality of electrodes having their faces shaped to fit the sides of the crucible and holders and from the crucible said. electrodes being vertically removable from said holder.

3. In an electric furnace, pairs of radially movable 3 ring jaws hav-. ing vertical openings and e ectrodes having wedge sha posterior portions adapted to be insert in the openings in said jaws and removable therefrom by vertical movement.

t. In an electric furnace, a crucible having a funnel shaped mouth and an outlet. below the mouth electrodes arranged at the sides of the crucible and means for tilting said crucible to pour fromsaid outlet.

5. In an electric furnace, a casing, a crucible therein, means for producing an are, a spout leading from said crucible, a mold swinging from the casing and means for tilting the crucible and easing.

6. In an electric furnace, a tiltable casing, a crucible therein, a spout from the crucible leading beyond the edge of the casing, a small mouthed and relatively deep ingot plurality of electrodes le when pouring and for said electrodes movable toward a a plurality of 7. In an electric furnace, a tiltable cas-.

ing, a crucible therein, a spout leading therefrom, a pair of .hooks carried by'the casing, afi'ording an axis immediately in front of the outlet from said spout and a mold hav- 7 ing eye bolts adapted to be hung on said hooks for the purposespecified.

8. In an electric furnace, a casing, a plurality of horizontally movable jaws and a vertically removable electrode carried by each jaw.

9. In an electric furnace, a casing, a mu.

cible therein, a plurality of holders extending through said casing, an electrode carried by each holder inside said casing and removable vertically therefrom and means outside said casing for moving said holders.

10. In air electric furnace, a crucible and a plurality of electrodes arranged around the sides of the crucible and each extending substantially from the top to the bottom thereof.

holders therefor, means for radially adjusting the holders'independently and means for moving all the holders together.

12. In an electric furnace, a crucible, a plurality of holders, an electrode vertically insertible in each holder and means for moving said holders.

13. In an electric furnace, a crucible, a

plurality of holders an elect-rode vertically insertible in each holder, and means for moving said holder radially.

14. In an electric furnace, a crucible, a plurality of independently adjustable holders, an electrode vertically insertible in each. holder and means for moving said holders.

15. In an electric furnace, a casing comprising, a shell, a bottom therefor, a lining therein, a reinforcing hoop about the lower part of the shell, trunnion brackets secured to the bottom and shell and means for tilting the casing.

In testimony whereof we have afiixed our signatures in presence of Witnesses.

BAYARD GUTHRIE. JOSEPH P. KARCH. Witnesses for B. Guthrie:

LoUIs MARR, ANDRE SCHMIIT. VVit-nesses for J. P. Karch:

A. V. BROOK, D. G. CLARK.