US935937A - Electric furnace. - Google Patents

Description

W. A, SMITH. ELECTRIC FURNAGE. APPLICATION FILED JUNE 15, 19.09-

93519372 Patented 0cm, 1909.

v2 SHEETS-SHEET 1.

W. A. SMITH. ELECTRIC FURNACE. APPLIOATION FILED JUNI: 15, 1909.

Patentedoet. 5, 1909.

2 SHEETS-SHEET 2.

WILLIAM ACHESON SMITH, 0l? NIAGARA FALLS, NEW YORK, ASSGNOR T0 INTER- .NATIONAL ACHESON GRAPHXTE COMPANY, OF NIAGARA FALLS, NEW YORK.

ELECTRIC FURNACE.

Specification of Letters Patent.

rateatea oet. s, ieee.

T o all whom it may concern.'

-Bc it known that l, WTILLXAM Aoi-riesen Siurrir, a `citizen of the United States, residing at Niagara Falls, in the county of Niagara and State of New York, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

.This invention relates to electric furnaces, and consists essentially in the provision in a furnace having walls which are permeable to the gaseous reaction products, of means for effecting the combustion of such reaction products under conditions which will effectively check or reduce heat loss from the charge.

For a full understanding of the invention the saine will be described by reference to certain specific embodiments thereof as illustrated in the accompanying drawings,

wherein:

Figure l is a transverse vertical section of an electric furnace of the resistance type embodying the invention; Figs. 2, 3, l and '5 are similar views of cert-ain modified constructions.

Referring to the drawings, the furnace is shown as comprising a base l and lateral charge-retaining walls 2, carried by the base, the walls 2 being preferably simply constructed of one or more courses of brick and readily taken down at the conclusion of each run of an intermittently operated furnace to facilitate removal of the product. A As illustrated, the base is provided with transverse air passages 3,'serving both to cool the base and to equalize conditions. onl opposite sides of the furnace.

d represents the charge and 5 the heating resister en'ibedded therein, the ends of the resister heilig in electrical connection with the respectiveterminals of thc electric eircuit as is well understood in the art. The charge is assumed to be one yielding a combustible gas as a reaction product, carbon monoxid, hydrogen, hydrocarbon vapors, or. the like, examples'of charges of this character being the mixture containing` .sand and carbon employed in the nninutacture of silicide of carbon, the petroleum coke.y anthracite coal or other formof carbon used in the production of graphite and graphite sage for the gaseous reaction products from all portions of the charge; these interspaces are indicated at C, and for clearness are shown lon a somewhat exaggerated scale, For the purposes of the invention it is essential merely that the walls 2 should be so con structed as to afford free passage for the entire volume of react-ion gases. I

In furnaces constructed above described the is found to burn freely at the points of escape, but to be con'iparativelyineiectiye in heating the wallv of the furnace or in reducing the loss of heat from the charge. l have found however that if the burning gases, and the heated products of combustion thereof, be confined in or in proximity to the permeable walls, the temperature of these walls becomes comparati velyhhigh with a corresponding diminution of the rate of flow of heat from the charge, the result being that a very considerable economy of current is effected in maintaining any given temperature' or range of temperature in the charge. A further result is that inthe product-ion of materials requiring more or less definite teinivierat-ure conditions, as for eX- ample silicide of carbon, the productive .Zone of the :furnace is greatly extended; that is to say, with any given temperature iny and adjacent the heat-ing resister, the temperature conditions which are suitable for the reaction and which are therefore productive are extended much farther into the body of the charge. lt follows from this lhatthe provision of such spaced walls or equivalent means.for'contining.thc burning in ory adjacent the walls efl'ccts a double economy,

'in that it economizes the current required to' manita 1n a given temperature range, and.

also increases the product of the furnace by widening the limits within which a reacting temperature isxinairuained.

The foregoing results are secured in the furnace illustrated in Fig. l. by the provision of limit-retained walls 7, spaced from the pern'ieable walls. These heatret-aining walls may-be of sheet metal, preferably interiorly faced with material of low' heat conductivity Si, and provided with supports 9 the construction being of a character permitting the ready removal of the heatretaining wall at the close ofthe operation in case it is desired to take down the brick walls 2 to give access to the product. A' in ex cess is admitted to the spaces lbetween the or closed as may be desired. To further retain the heated gases plates 1l ofany suitable non-combustible material may be arranged to close, either wholly or partially, the top of the intermediate space.v A further economy of heat and cur-rent may be secured by extending the heat-retainino' wall over the top of the charge, at a suit; 'le distance therefrom as indicated at 7', S in 4t: in this case the products of combustion may he nei-mitten. to escape through suitable ori- .trein the upper portion of the heat-restructure, or they may be led eli' rough a tine indicated' at i3.

modified construction is illustrated in E2, wherein a vertical layer7 bed or wall t2 Icoarse material., as coke, broken tirebriclr cr the like is disposed between the charge and the permeable wall 2, in which position it serves asan interior extension of this wall, supported between the charge and the wall 2. This material is highly permeableeand owing to its coarse or granular character it contains a comparatively large volune of heated gas, and acts therefore a very eitective heat insulator` Air may enter this layer or wall either through the outer walls 2, which then perform also the functions of theheat-retaining walls 7, or through v fines iti". and ei'cct, the combustion of gases in and around the granular material l2, thus providinga highly heated zone adjacent the charge.; or in case the gases are not permitted to escape freely from the upper surfaces of the layers 0r interior Wal-ls l2, for example in case the charge et be extended over these as indicated in Fig. 3, or in case these are. made of comparatively linely subdivided material, the gases may loe burned outside the permeable walls 2, or between these and the heat-retaining walls precisely i as described in connection with Fig. t and as further illustrated in Fig. 3. lhus in the construction illustrated in Fig. 2, according' to the particular conditions, the air may either pass inwardly through the permeable walls :2, ellecting combustion of the gases in the layer 1Q, or these gases may pass outward through the walls 2, burning` on their outer vfaces. ln the latter case spaced heatretaining walls are preferably provided shown in Fig. The specific conditions must be chosen in any particular case, with reference lo the character and volume of the reaction gases, to ctl'ect the greatest. degree of ceonomyof heat consistent willi the avoidance of all danger of explosions from accuniulations of unburned gases. 'Obviously the construction may be otherwise modiiled to ctl'cct the purposes of the invention: for example, the charge-retaining walls may be of 'a hollow or checkered construction as illustrated by way of example at 2 in Fig'. 5, whereby the gases are burned Within these walls, the outer or heat-retaining walls being used or not as may be desired. ln this construction air may be admitted to the interior of the wall, or to the intersticcs'thereof, as by lines l0.

I claim:

l. iin electric furnace comprising a arnace chamber having aI Wall construct to atford free passage for reaction gasei and means for confining the burninggases in proximity to said permeable Wall.

i2. iin electric furnace comprisingr a furnace cliiimbcr haring a wall constructed to altord free passage for reaction gases, a heat-retaining wall outside said permeable wall, and means for effecting combustion of the furnace `gases between said heat-retaining wall and the charge.

iin electric furnace comprising a furnace chamber having a wall constructed to alford free passage for reaction gases, a heat-retainingwall outside said permeable wall and spaced therefrom, and means for effecting combustion of the furnace gases between said heat retainingl wall .and the charge.

Al. An electric furnace comprising a furnace chamber having` a wall constructed to all'ord free passage for reaction gases, a heat-retainiin; wall outside said permeable wall7 and means for4 ell'ecting` combustion of 'the furnace gases between said heat-retainino' wall and the permeable Wall, I

o. An electric furnace comprisinga furnace chamber havinga permeable Wall, a removable heat-retaining wall disposed in proximity to said permeable wall, and means for admitting air to etl'ectcoinlnistion of 2gases traversing said permeable wall.

t3. An electric furnace comprising a furnace chamber having` a permeable wall, and a wall or layer of broken or granular material interposed between said permeable wall and the charge.

'7. An electric furnace comprising a furnace chamber havingr a permeable wall, a wall or layer of broken or granular material interposed between said permeable wall and the charge, and means for effecting` combustion of `gaseous reaction products traversing; Isaid interior wall.

8. An electric furnace comprising a furnace chamber hai/'ing ay permeable wall, a wall or layer of brolcen or lgranular material interposed between said permeable wall und the charge. and means 'for eli'ceting combustion ol' gaseous reaction products within said interior wall.

lllfi Correction in Letters Patent No. 935,937.

An electric furnace comprising e. urheat-retaining wall, said heat-retaining Walt nace chamber having u 'permeable Wall, and extending above the furnace charge: 3.0 means for effecting combustion of gaseous In testimony whereo, l aix my slgnature products of r action Within the interstices of in presence ot' two Witnesses. t 5 said Wall. f WILLIAM ACH-'ESN Sit/HTH.

10. An electric furnace comprising a Lt'ur- Wvitnesses: i 'mice chamber having at Well constructed to VILLIAM H. ARtsoN.

afford free passage of reaction gases, and u EBEN C. Serment.

.i lt is hereby certfied that in Letters Patent No. 93.5.93?. granted (lccober V 1909, upon the application of William cheson Smith. of Nizig'uru Falls, New York, for un improvement in "i Electric Furnaces" un error appears in the printed specification requiring' correction as follows: Paget. line 100. the compound Word herstretaned" should read hef/-rezfte'nfn g: and that the said Lettere Patent slnoul be read-With this correction therein that the salme may conform toWtlxe record of' the -cuse in the Patent Qtice.

'Signed und seulefl'this Tth rlzty ot' Ilvcember. A. D.. '1909.

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