US360144A - Electric furnace - Google Patents

Description

(No Model.)

B. H. & A. H. OOWLES.

ELECTRIC FURNACE.

No. 360,144. Patented M21129, 1887.

1,0120% ass/2S:

UNITED STATES PATENT OFFICE.

EUGENE H. 'COXVLES AND ALFRED H. COVLES, OF CLEVELAND, OHIO.

ELECTRIC FURNACE.

SPECIFICATION forming part of Letters Patent No. 360,144, dated March 29, 1887.

Application filed October 16, 1855. Serial No.180,035. (No model.)

To all whom; it may concern.-

Be it known that we, EUGENE H. OowLEs and ALFRED H. COWLEs, citizens o f the United States, residing at Cleveland, in the county of Guyahoga and State of Ohio, have invented certain new and useful Improvements in Electric Furnaces; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being bad to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to furnaces in which the reduction of ores and chemical compounds, the production of alloys, the refining of metals, and like metallurgical operations are carried 011 by means of electricity.

This invention consists in the means by which the varying electrical resistance of the charge in the furnace is made the primary agency in actuating and controlling the feeding of the material to be smelted or reduced.

This invent-ion also consists in the means for automatically regulating and controlling the charging, feeding, and discharging of a furnace of the type hereinafter described through the agency of the electrical resistance of the charge in the said furnace.

This invention further consists in the construction of the furnace, and in the combination therewith of the feeding, discharging, and resistance regulating apparatus, as hereinafter fully described and claimed, whereby the va rying electrical resistance of the charge in the furnace is made the primary agency in actuating and controlling the feeding of the material to be smelted and discharging the products.

Figure l in the drawings shows a furnace embodying our invention in vertical section through the center, with the automatic feedregulating apparatus attached thereto. Fig. 2 is a modification of the mechanism for regulating the downward feed of the charge. Fig. 3 is a side view of the automatic feed mechanism.

' By means of our invention a desirable regularity and uniformity of feeding or charging the furnace is effectually accomplished, and this is important for many reasons, prominent among which may be mentioned that the fluctuations of the current are governed and controlled within definite limits, the draft upon the motive power is made more constant and uniform, and'the dynamo is relieved from the risks attendant upon sudden or undue variations in the resistance of the external or work ing circuit.

We will now proceed to more particularly describe our invention with reference to the accompanying drawings, in which similar letters of reference indicate corresponding parts in allthe figures.

A is the positive electrode, preferably made of electric-light carbon in the form of a pipe or hollow cylinder.

B is the feed-hopper, preferably made conical in form, and having its lower end attached to the top of the positive electrode.

(1 is the negative electrode, also made of electric-light carbon in the form of a hollow cylinder and fastened to the plate D, which is built into the lower portion of the furnace, and to which plate the negative wire of the circuit is connected.

E are the furnace-walls, formed of fire-brick, silica, lime, or other refractory material.

F is a lining or filling of fine charcoal, pnr verized lime, and carbon, or other suitable ma terial. This lining surrounds the negative electrode 0 and insulates it, and being a bad conductor of heat, as well as of electricity, it prevents the destruction of the lower part of the walls and the bottom of the furnace when the furnace is in operation.

G is also a lining of charcoal, lime, and carbon, or other suitable material. This lining surrounds the zone of fusion between the positive and negative electrodes, and extends upward around the said positive electrode. This lining G is similar in function and character to the lining F, but is made of coarser material to provide for the escape of the gases given off from the charge at the zone of fusion when heated by the current. Thelining of materiahwhich is a bad conductor of heat and electricity and which surrounds the zone of fusion, prevents the atmosphere from having access to the charge at this point and combining with and destroying the combustible constituents of the charge, instead. of allowing them to remain in contact, when rendered incandescent by their resistance to the electric current, with the material to be reduced.

T is an escape-pipe, through which the aforesaid fumes and gases pass from the upper part of the furnace into the condenser t.

H is a plate covering the top of the furnace, and having a hole, 71, in the top of it, through which the positive electrode can slide freely.

I isa lever pivoted in the bracket i, attached to the plate H.

J is a screw passing through. a screwthreaded hole in the opposite end of lever I and bearing upon the plate H. The lever I is attached to thefeed-hopper B, and by means of the screw J the said hopper, together with the positive electrode A, attached to it, may be raised or lowered to increase or decrease the width of the zone of fusion, as required, or to compensate for the wear of the electrode.

K is a poker or plunger of carbon placed within the hopper B, and extending downward through the electrode A nearly as far as the zone of fusion. This poker is provided with projections for better acting upon the charge, and is attached at its upper end to the crank 6 of the driving-shaft L by means of the connecting-rod 7c. The d riving-shaft L is sup ported in any suitable bearings, l, and is providedwith a gear-wheel, Z which engages with a similar gear-wheel, m, of a motor.

As herein shown, the motor consists of a weight, in, hung by the cord at", carried by the drum m the latter being secured to the shaft M, and transmits the power to the gearl' through the gear m. A brake-wheel, m, is

- carried by the motor-shaft, and a crank-handle, m is provided for winding up the weight when the cord is run down.

Instead of a weight and cord, a coiled spring or any other equivalent mechanism may be used to operate the feed mechanism.

N is a brake-lever pivoted at one end in the support a, and supported at the other end, a, by means of the spring 0 and screw 0, which screw passes through ascrew-threaded hole in any suitable fixed support, 0. By means of the screw 0 the tension of the spring 0 can be regulated. The brake-lever N is provided with a projection, a", which engages with the serrations of the brake-wheel m when the brake-lever is in its raised position and locks the motor.

P is the elcctro-magnet placed beneath the outer end of the brake-lever.

R and S are the circuit-wires attached, respectively, to the positive and negative electrodes and the magnet P placed within the circuit.

The essential feature of this furnace is that the resistance is regulated and preserved constant by the movement of the charge itself, and not by the movement of the electrodes as at present practiced. The action of the furnace is rendered continuous for a long period, and the time lost in charging and emptying the furnace as hitherto constructed is saved. The electrodes act as conductors only for conveying the current to the charge, and the heat is generated in the charge itself by its electri cal resistance, the carbon constituents of the charge becoming incandescent.

The practical operation of the furnace is as follows: The feed-hopper is filled with the material to be reduced, and the current is passed through the wires. This causes an intense heat at the zone of fusion between the electrodes, the material is there reduced, and falls through the lower electrode into the lower part of the furnace. The electro-magnct l is made of just such a power that when the re sistance at the zone of fusion becomes less and more than the normal amount of current flows through the said magnet the end a of the brake-lever will be drawn down against the tension of the spring which supports it. This movement of the brake-lever sets free the brake-whecl, and the motor-shaft is free to turn and by means of the driving shalt and crank to operate the poker in the furnace.

The movement of. the poker up and down forces more of the charge in the hopper to de scend into the zone of fusion, and when the resistance is thereby increased to the normal amount the current, which is proportionately decreased, 'allows the eleetro-magnct to let go the brake-lever, which then stops the movement of the poker. This operation is again repeated upon fresh portions of he charge of material to be reduced, which may consist of ore and carbon mixed together, or other equivalent resistance material, being fed downward from the hopper and the reduced metal withdrawn from the bottom.

it will be seen that with this form of furnace the charcoal or carbon immediately surrounding the zone of fusion renews itself as fast as it becomes graphitized. It then falls down. into the lower part of the furnace, or it may be knocked down by moving the upper electrode, as it is desirable to get rid of it as soon as it becomes a good conductor of electricity.

lVe do not limit or confine our invention to any specific form or construction of mechanism to be employed, inasmuch as any mechanical devices may be used which can be actuated and controlled primarily by the electrical resistance of the charge in the furnace, and which will operate through such agency to control and govern the feeding of said furnace.

We are aware that an electric lamp has been patented abroad in which it was proposed to obtain light from a stream of pulverized ma terial, caused to flow from a reservoir through one pole of an electric circuit, and thence to the other pole, in contact with the atmosphere, and that it was proposed to regulate the exitvalve of the reservoir by means of an electro-' magnet placed in the circuit.

lVe do not broadly claim the system of automatically regulating-the supply of resistance material between the poles of an electric circuit by means of an electromagnetic device inserted in the circuit.

We are also aware that an electric furnace has been constructed in which the length of the are and the distance between the electrodes is automatically regulated by the resistance of the arc.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is

1. In an electric furnace, the combination of two stationary electrodes of opposite polarity, a body of material which is a bad conductor of heat and electricity surrounding the zone of fusion, a feed-hopper for the charge to be reduced, and means for automatically moving the charge between the said electrodes when the normal resistance is diminished, substantiall y as and for the purpose set forth.

2. In an electricfurnace, the combination of two stationary electrodes of opposite polarity, a body of material which is a bad condoctor of heat and electricity surrounding the zone of fusion, a feed-hopper for the chargeto be reduced, a device for moving the charge between the said electrodes, mechanism for actuating the said charge-moving device, and an electro-magnet placed -in the circuit and ada 'lted to start the said actuating mechanism when the normal amount of the current is increased, snbstantially as and for the purpose set forth.

3. In an electric furnace, a hollow cylindrical electrode, a feed-hopper attached to one end of the said electrode, a lever pivoted to the stationary top portion of the furnace for supporting the said feed-hopper and electrode, and a screw for regulating the position of the lever and causing the said electrode to project more or lesswithin the furnace, substantially as and for the purpose set forth.

4. In an electric furnace, the combination of two vertical electrodes of opposite polarity, alining of fine charcoal surrounding the lower electrode, a lining of coarse charcoal surrou nding the zone of fusion between the electrodes and extending upward around the upper electrode, and the furnace-walls for retaining the said charcoal linings in position, substantially .as and for the purpose set forth.

In an electric furnace, the combination of the electrodes A and C, the feed-hopper at tached to electrode A, the poker working back and forth within the said hopper and electrode, the driving-shaft provided with a crank for actuating the said poker and with the gearwheel 1*, the motorshaft M, provided with the means for rotating it, the gear-wheel m, and a brake-wheel, the brake-lever having the projection or", engaging with the brake-wheel, the spring 0, attached to the said brake-lever at its free end, and the electro-magnet P, for disengagingthe brake lever when the normal amount of current passing through the mag netis increased, substantially as and for the purpose set forth.

6. In an electric furnace, the combination of the retaining-walls, the electrode 0, the fine charcoal lining F, the electrode A, the feedhopper B, the lining of coarse charcoal G, the condenser t, the lever I, pivoted at the top of the furnace for supporting the said feed-hopper and electrode A, and the screw J, for adjusting the position of the electrode A within the furnace, substantially as and for the purpose set forth.

7. An electric furnace provided with a body of material which is a bad conductor of heat and electricity surrounding the zone of fusion, and wherein the electrical resistance of the charge while in the zone of fusion constitutes the primary agency whereby the feeding mechanism of the said furnace is actuated and controlled, substantially as and for the purpose set forth.

8. An electric furnace provided with a body of material which is a bad conductor of heat and electricity surrounding the zone of fusion, and wherein the charge forms part of an electric circuit and is in contact with the terminals of the electric circuit, and wherein the varying electrical resistance of the said charge due to its temperature and condition is the agency whereby the action of said furnace feeding or charging mechanism is actuated and controlled, substantially as and for the purpose set forth.

9. In an electric furnace wherein the charge fills the space between the electrodes and is in contact therewith, the combination, with suitable charging or feeding apparatus, of a body of material which is a bad conductor of heat and electricity surrounding the zone of fusion,- and an electromagnetic device actuated and controlled by a current dependent for its strength and variations upon the varying electrical resistance of the charge in said zone of fusion, substantially as and for the purpose specified.

10. In an electric furnace provided with a body of material which is a bad conductor of heat and electricity surrounding the zone of fusion, and wherein the charge fills the space between the electrodes and is in contact therewith, an electric circuit which includes the charge insaid furnace, and-also includes suit able feeding or charging apparatus or mechanism for controlling the same, whereby the electrical resistance of the charge shall influence and govern the feeding or charging of said furnace, substantially as and for the purpose specified.

In testimony whereof we afiix our signatures in presence of two witnesses.

EUGENE H. OOWLES. ALFRED H. COWLES. Witnesses:

ROMAINE 0. Corn, E. H. PERDUE.

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