US1242275A - Electric furnace. - Google Patents

Description

l. R. VALENTINE.

ELECTRIC FURNACE.

APPLICATION FILED MAY 12. 19!].

Patented 0% 9,1917.

Inventor W? n L m w a ..T.. m R .m M .H .W W

UNITED srrarns PATENT oumon.

IRVING R. VALENTINE, OF SCI-IENECTADY, NEW YORK, ASSIGNOR TOE ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

ELECTRIC FURNACE.

Application and May 12, 1917.- Serial No. 168,254.

To all whom it may concern:

. Be it known that L'lnvine R. VALENTINE,

a citizen of the United States, residing at Schenectady, in the county of Schenectady,

State of'New York, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a speci- .ficatlon.

The present invention comprises an apparatus for the heating of metals and other materials which is partlcularly useful 1n 1ndustrialapplications requiring that excessively high temperatures should be avoided,

for example, the melting of brass, the annealing and tempering of steel, and the heat:

ing of metalsfor the purpose of forging.

In'accordance with my invention, heat is generated by means ,of an electric arc in an inclosedspace in which the materials to be heated. are located but I said articles are shielded from the direct heat radiation from said are.

My-invention will be set forth with greater particularity in the appended'claims and a complete understanding of my invention may behad from the following description taken in connection with the accompanying drawings of which Figure 1 1s a perspective view 'ofsthe furnace' with one end partly broken away, and Fig. 2 is a longitudinal sectional 'view.

I As shown in both these figures, the furnace comprises a container 1v consisting of refractory material, such as fire brick and reinforced by steel plates 2. As shown n Fig.

"2, the material to be heated, such .as the charge 3,.is contained within a crucible constituted by the base 4 of the furnace and re- ;fractory walls 5, 6 extending upwardly from the base-part way to the arched roof 7. The walls 5., 6 pre ferably consist of suitable heat conductive refractory material, such as carborundu'm brick. Upon opposite sides of the crucible and clbsely adjacent are paired prisinatic rods 8, Sland 9, 9,'respectively, con- -sisting of carbon, graphite or other suitablev conductive material. Cooperating-with the rods 8, 8" and 9, 9 respectively, are carbon. or graphite electrodes 10, 10 and 11, 11',

projecting through the roof 7 of'the furnace, so that onv each side of the crucible containing thecharge two arcs may be mamtained in series. The current passes, for'example, from the electrode 11120 the rods 9,

9', and returns by way of electrode 11'. To.

' Specification of Letters Patent.

Patented Oct. 1917.

prolong the life of the horizontal conductor To prevent the arc injuring the furnace,

as well as the charge whichis'be'ing heated,

the arc preferably is partially smothered by surrounding the arcing electrodes'with granular carbon 13. The supports'l4,, for the electrode and the electrical connections 15 have been indicated as broken away'for the sake of simplicity. Although the furnace has been illustrated with two sets of paired electrodes located on opposite sides of the baflie walls 5, 6, it is obvious that one of the sets may be omitted if desired, likewise others may be added if desired without departing from my invention.

The voltage across the. arcing electrodes may be measured by connecting suitable instruments across the respective upright electrodes, and the electrodes 16, 17, passing through the base of the furnace making electrical contact with the horizontal conductors. The charge in the furnace may be removed through a spout 18 and by tilting the furnace with suitable tilting apparatus, which is wellknown, and which therefore, has not been shown in the drawing.

By means of the construction shown a charge of brass, or any other material, with in the central heating space is protected from the direct heat radiations from the arcs. Heat is conveyed to the charge both by conduction through the supporting walls and as the walls do not extend materially above said arcs heat is conveyed to the charge by reflection from the walls of the furnace, particularly by the arched roof. Convection currents of the gas within the furnace also assist in distributing the heat. I have found that in this way the temper 'ature may be maintained below a value "which would endanger the charge, for ex-. fample, in the case of brass byvolatilizing zinc. On the other hand the use of arcs for heating possesess the advantage of flexibility and ease of control and enables currents of lower amperage and higher voltage to be used than in a resistance furnace.

What I claim as new and desire to secure 1 by Letters Patent of the United States is:

1'. 'An electric furnace comprising a con: tainer providing a support for materials to be heated, a stationary electrode resting on the base of said container, one or more movable are-supporting electrodes cooperating therewith, shielding means between materials to be heated and an-arc between said electrodes." j 2. An electric furnace comprising a container providing a centrally located hearth: vfor materials to be heated and having an arched roof, means for operating electric arcs on opposite sides of said hearth, refractory walls located between said hearth and said arcs but not extending materially above said arcs to cut off direct heatradi- .ation only from said arcs to the material to be heated but permitting a maximum radiation from the arcs to the sides and roof of said co tainer.

.3. An el ctric furnace comprising a container, providing a hearth for'materials to be heated, an electrical conductor located closely adjacent said hearth, one or more 'movable electrodes projecting through said container and operatingin arcing relation to said'conductor and shielding means 10- cated between materials to be heated and an are or arcs between said conductor and said electrodes.

4. An electric furnace comprising the combinationof a container, awall consisting of heat conductive refractory material .in part dividing the space inclosed by said container,=-co5perating are electrodes located on oneside of said wall, materials to be heated located on the opposite side of said wall being shieldedby said Wall from the direct heating action of an are between said electrodes, and a mass of granularconducbetween said electrodes.

5. An electric furnace comprising the combination of a container, a refractory wall extending upward from the base of said container part way to the upper wall of said container a conductor located on the base of said container adjacentone side ofsaid wall, one or more electrodes roject- 'IRVING R. VALENTINE.

" tive material surroundingan arcing space

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