US1103309A - Electric furnace. - Google Patents

Description

UNITED STATES PATENT OFFICE.

ADOLPHE MINET AND ENRI' LOUIS noncn LUCAS, or PARIS, FRANCE.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented July 14, 1914.

Application filed December so, 1913. Serial No. 809,487.

To all whom it may] concern.

- Be it known that we, ADOLPHE MiNET, of

which the required temperature is generated.

This resistance is constituted by the combination ,of two resistances, viz., a principal resistance and a secondary resistance. The

former generates the greater portion of the heat set. up by Joule effect and is consti tuted by'a mass of granulated carbon which is maintained in shape by the pressure of the secondaryresistance which restsupon 'it, so that the constancy of the values of the current (voltage and amperage) during the whole reaction is insured. The secondary resistance, which ls'shunted relatively to the principal resistance, is constituted by pieces or blocks of material which have a conductivity considerably less than that of the principal resistance so that only a small part of the current passes through it. These blocks are heated mainly by .thermal conductivity and distribute the heat, to the retorts which are inclosed in suitably shaped cavities.

Another essential feature of the furnace is the electrodes each of which consists of a metal plate connected with the current is to prevent such heating of the electrodes as woulchrendcr them practically useless.

The invention is illustrated in the ac companying drawings wh.erein Figure 1 is a longitudinal section and Fig. 2 a transverseisection of the improved furnace.

a is the body of the furnace built of very refractory bricks covered by. plates b of similar refractory material.

c are walls dividing the interior of the furnace, made of carbonaceous substances through the resistances d 01 sufiiciently light that the pressure exerted by the walls shall not exceed 11.025 lbs.

per 15.5 square inches. The interior of the furnace is of a size just suiiicient to conta1n the heat generating resistances and the distillation retorts.

The resistances comprise two distinct elements, via, a principalresistance d and a' secondary resistance constituted by a plurality of elements (Z (Z (Z5. The principal resistance d is constituted by a mass of granulated carbon of perfectly regular geometrical configuration having the form of astraightprism rectangular in cross section. The constant pressure to which it is submitted owing to the fact that it supports the resistances d d ll and the retorts e e 6, prevents it from changing shape. Its conductivity is such that it .receives 90 per cent. of the current which passes through the furnace.

The resistances (Z ...(Z are consti- .g ood conductors of heat but their electrical conductivity is ten times smaller than that of the resistance (Z, so that only ten percent. of the current passes through them. his to be understood, however, that ninety and ten per cent. are not abs lute values but are values given by way of example only.

As only a small'quantity of current passes (i they generate only a small amount. of heat by Joule efi'ect, but they transmit by thermal conductivity the heat generated by d,- this heat distributes itself throughout the mass of the resistances J, (Z d and, during the duration of the reaction, the temperatures' distributed within the furnace remain in perfect equilibrium.

"he retorts e 0 are similar to those usually employed in the metallurgy of Zinc and are provided with a condensation pocket f and a nozzle 9. Current is led to the principal resistance (Z by means of electrodes each. of which comprises a metal sheet h (usually of steel) to which the current leadthese conditions only a small amount of heat is generated in the column 2' by Joule efi'ect. Owing to this arrangement, while the temperature of the resistance d reaches from 1500 to 1600 degrees when the furnace is in terioration of adjustable electrodes.

, the current during the reaction, perfect ad- In addition to the. advantages above set forth (viz. continuous working and long duration,'invariability of the constants of justment and distribution of the temperature at different points within the furnace, indestructible electrodes and very high efliciency) the new furnace possesses numerous other advantages. For lnstance, owing to the fact that the interior capacity of the furoace'is just suflicient to containthe resist-- ances and the retorts heat losses through the walls are reduced to a minimum and the thermal efiiciency is very high. The retorts c being surrounded by the blocks 1/, (Z cannot become subjected to excessive heat and the heat is evenly distributed around their periphery. As they are supported, throughout their length. their thicknessmay notably decreased, thus increasing their permeability to heat.

' In the construction illustrated the resistance d is constituted by a single mass of carbon but when the furnace must have a It is also to be observed that certain. width, it; might be constituted by a plurality of parallel masses. Similarly, the

furnace may be constituted by a plurality of superposed floors.

Claims:

1. In an electric furnace, a principal resistance constituted by a mass of granulated carbon, and a secondary resistance constituted by blocks less conductive thanthe car- 3. In an electric furnace, a principal resistance constituted by a mass of granulated carlmn, a secondary resistance constituted by blocks less conductive than the carbon, exerting a pressure on the principal resistance and electrodes constituted by large granules of carbon and metal plates.

4. In an electric furnace, a principal resistance constituted by a mass of granulated carbon, a secondary resistance constituted by hollow blocks less conductive than the carbon, exerting a pressure on the principal resistance, retorts arranged in the hollow blocks, and electrodes constituted by large granules of carbon and metal plates.

7 The foregoing specification of our improvements in electric furnaces signed by us this 19th day of December, 1918.

ADOLPHE MINET. HENRI LOUIS LEoNoE LUCAS.

Witnesses:

HANSON C. Coxn, Rem THIRIOT.

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