US1543695A - Brass-melting furnace - Google Patents

Description

June; 30, 1925. 1,543,695

0. A. COLBY BRASS MELTING'F'URNACE Filed Jan. 12, 1923 WITNESSES: INVENTOR WW Ova A. Colby.

f Furnaces,

Patented June 30, 1925.

, unlrsn srsrss 1,543,695 A'rsn'r .QFFICE.

oaa A. COLBY, OF'IBWIH, rxnnsynvamn, assmnon TO wns'rmsnons'amacrrarc a MANUFACTURING comm, aoonromnon or .rznnsrnvanm Buss-maniac summon.

Application ileflianuary 12, 1923. Serlalh'c, 612,204.

To all lbkpm it may-;lconcem;; Be itkno'w'n that; I, (lanai, -Co1';1 ir,' a Oil zen-'of -tlie"United States, an 'a-resident of Irwin, in the county of Viestm'oreland and Stateof' Pennsylvania, haveinvented a new and useful Improvement in Brass-Melting of'n hic-h the following is a specification."'"

My invention relates to electric furnaces and" particularly to electric' resistance tur- I The object of my-inventionis to provide a relatively simple, compact and symmetrical refractory heating element for an ricet-ric'furnaoe;

In practicing my invention, I provide a plurality of radially extending, relatively thin, flat, refractory resistor plates located in spaced relation in a SIXbStzilitlflll) circulaf'p'ath, with granular electric-conducting material located.- thercbetween. Paus of oppositely bereled, refractory end blocks located in symmetrically spaces positions (hride the plates into group-r, .the number thereof bemgin accordance with the number of'phascs of an alternating current supply circuitfleleotrically connected thereto. Resilient means are provided to press a plurality of refractory terminal members min close operative engagement with the pairs of beveledend blocks to maintain the plates and the granular material in close operative engagement.

The heating element may be located in a suitable electric-insulating and hcat'insulating casing adapted to the work to be dope in the furnace. In the single sheet of drawings, I Figi'ure 1 is a view, in vertical section, of an electric furnace comprising the device embodying my invention,

Fig. 2- is a view, in horizontal section thereof, talgen on the. line lL-II cf Fig. 1, and

3 and 4- are diagrammatic top plan views of heating elements arranged for energization from a two-phase and a three-phase supply circuitrespectively.

An electric furnace 11 comprises an outer metallic casing 12 of any suitable or desired contour end dimension, huthcrc shown as substantially circular in contour. An outer layer 13 comprises either a plurality of bricks onblorks ora mass of a suitable heat-insulating refractory material. An

inner layer 14 comprises a lining of asuitable .ihigbvte-mperature resisting refractory material.- A: third inner linin" andmuflle 15 may comprise a relatively 61in layer of a refractory material which is particular-l adapted to withstand the relatively high temperatures encountered in the operation of the furnace;- The hereinbefore described layers oftefractory material define or sur rounda chamber 16 which, as it is; desi red to employ-a substantially circular crucible 17 therein, is also made substantially circular in horizontal contour. A cover member 18 of sheet metal may be provided to substan-. tially close the top.of the chamber '16 to prevent heat loss therefrom or toprevent objects falling therein.

A heating element, which is supported on the floor of the furnace, comprises alurality of radially extending, relatively t in, flat. refractory, electric-conducting plates 19 which may consist-of graphite, carbon, or other similar material. The plates 19 are located in spaced relation in a substantially circular path, their outer edges being located close to, or operatively engaging, the inner surface of the. mufiie 15. Relatively small masses 21, of a granular electric conducting material, such as comminuted carbon, "are located between the adjacent spaced plates, the mass extending to within a short distance of the outer edge of the plates. The plates 19 and the interposed mass of granular material are divided into a plurality of. synnnetrically spaced groups by a plurality of pairs of oppositely beveled refractory end blocks 22 and 23 which are located in spaced relation in substantially the same path as are the plates 19. n

A plurality of refractory terminal mem- A, of wedge shape. are located between and operativcly engage the opposing beveled surfaces of the pairs of end blocks 22 and 23. the dimensions of the blocks 24 being such that. the blocks are notlocated in the same horizontal plane as are the plates 19, but extend thereabove in order that they may be moved in a direction at right angles to the plane of the circular path in which the plates 19 are located. to maintain them in close operative engagement with the end blocks 22 and 2 to maintain these in close operative engagementwith the adjacent plates 19 and also to maintain the plates 19 and the masses 21 in close operative engage- 'jacent terminals is,

ment with each other during the operation of the furnace.

Each of the members 24 is provided with an opening 25 extending therethrough and a water cooled, electric-circuit terminal member 26 of a suitable material, such as copper. has its upper end located inand extending through the opening 25. A helical spring 27 surroumlsthe rod 26 over a portion of its length, laterally extending flange portion 28 being provided on the member 26 against which the outer end of the spring 27 may rest. The inner end of the spring 27 rests against an insulating portion of the casing, suitable provision being. of course, necessary-to prevent current flowing through the furnace structure from one of the terminal membersto the other. As this construction is no part of the present invention, I have not illustrated it in detail. An inlet'conduit 29 and an outlet conduit 31 is provided with terminal members 26 to pern'htpf water cooling the same.

If it is desired phase alternating only one pair of refractory terminal blocks 24 and the (so-operating pairs of end blocks 22 and 23 will be provided substantially as illustrated in Figs. 1 and 2 of the drawing. The current path is, in this case, from one of the terminal members 26 and then through the two sets of plates and masses of granular material in parallel-circuit relation, to the other and diametrically opposed terminal members. If it is desired to em loy a heating element of the above descri d t pe, on a two-phase circuit, two pairs of books 24 are located 90" a art, substantially as illustrated in Fig. 3 o the drawing, and a current ath between adthere ore, only through one A of the periphery of a circle. In case it is'desired to energize the heating element from a three-phase source of supply, the terminal members 24 will be three in number and located 120 9. art, substantially as illustrated in Fig. 4 o the drawing.

If it is desired to employ a heating element of the hereinbefore described type in a brass rmelting furnace, the construction is such that the. crucible 17 may be placed within the furnace chamber 16 and the heat ing element is placed adjacent to the surrounding bottom of the crucible. Suitable means, such as short shafts 32, may be secured to the metallic casing 12 in order that the entire furnace structure may be tilted in a suitable mechanism (not shown) to permit of emptying the crucible as desired.

While I have illustrated my improved heating element in a furnace particularly adapted to the melting of brass in a crucible, it is not limited thereto and may be located to operate from a direct. current source of supply or from a single current source of supply in a suitable furnace construction, which is adapted to the work to be performed in a chamber constituted by refractory walls.

Various changes in ctail and arrangement may be made without departing from the spirit and scope of the invention and such modifications are intended to be covered by the appended claims.

I claim as my invention:

1. An electric resistance furnace comprising a plurality of radially extending, relatively thin, flat, refractory resistor )lates, located in a substantially circular pat 1, and a plurality of refractory terminal members, of wedge shape, interposed between certain of said plates and symmetrically spaced circumferentially thereof.

2. An electric resistance furnace comprising a plurality of radially extending, relatively thin, flat, refractory resistor plates,

located in spaced relation in a substantially circular path, electric-conducting material connecting adjacent lates, airs of oppositely' beveled space end b ocks divi mg said plates into symmetrical groups, refractory terminal members, of wed e shape, located between said pairs of en blocks, and resilient means operatively engaging said terminal members for forcing them laterally of said plates to compress the same.

4. An electric resistance furnace comprising a plurality of radially extending, relatively thin, flat, refractory resistor plates, locatedin spaced relation 1n a substantially circular path, granular refractory electricconducting material located between and connecting adjacent plates, and resiliently actuated means movable in a plane substantially parallel to the flat surfaces of said plates for compressing said granular electric-eonducting material between said plates and for conducting current to and from said plates and said granular material.

5. An electric resistance furnace com rising a substantially circular wall of re ractory electric-insulating material, a plurality of radially extendin relatively thin, flat carbonaceous plates coated in spaced relation in a substantially circular path, granular electric-conducting material located between and connecting adjacent plates, a plurality of pairs of o positely beveled, spaced carbonaceous end b ocks dividing said plates and interposed granular material into sym- .terial is connected,

ber of said groups being in accordance with the number of phases of a supply circuit to which said sets of plates and granular maand nefractory electriccircuit terminal members, of wedge shape 0 ratively engaging-said respective pairs .0 beveled end blocks;

plates locatei stantially 6. In an electric resistancefurnace, in combination, a plurality of radially extending,relatively'thin, flat, refractory resistor in spaced relation m a subcircular path, granular electriceonducting,material between said platcs,a

veled refractnrand blocks dividing said plates and interposed plurality of pairs of.spaeed and oppositely granular material into a'pluralityo'f symmetrical groups, and a plurality of refractory terminal members, of wedge shape, movable. in a dire tion at right angles to the plane of said circular path for operatively engaging said pairs of end blocks and for compressing said granular material and plates.

7. In an electric resistance furnace, in combination. a plurality of radially extending, relatively thin, ltat refractory resistor plates located in spaced relation in asubstantially circular path, granular ell-(triccouduetiug material hetweeu said plates, a plurality of pairs of spaced amtop positely beveled refractory cud blocks dividing said plates and interposcrl granular material into a plurality of s \-'|umetrical groups, a pluralitynf refractory terminal uu-uihers,of wedge end blocks. and resilient means for moving Silltl terminal members in a direction at right angles to the. plane ot said circular path to closely engage said end hlucks and granular material between ORA A. 001.1; 12

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