US761920A - Electric furnace. - Google Patents

Description

No. 761,920. I 4 PATENTED JUNE 7, 1904. G. P. E. SCHNEIDER.

ELECTRIC FURNACE.

APPLICATION mum own, 1903.

. no menu. s snnms snnm 1. K

PATENTED JUNE 7, 1904.

C. P. E. SCHNEIDER. ELECTRIC FURNACE.

APPLICATION FILED 001212, 1903.

3 SHEETS-SHEET 2.

no MODEL.

PATBNTED JUNE 7, 1904.

0. P. E. SCHNEIDER. ELECTRIC FURNACE.

-.APPLIOATION FILED, 00T.12, 1903 s sums-sum. a.

no MODEL.

UNITED STATES Patented June '7, 1904.

PATENT OFFICE.

ELECTRIC FURNACE.

' SPECIFICATION forming part of Letters Patent No. 761,920, dated June 7, 1904.

Application filed October 12, 1903. Serial No. 176,719. (No model.)

To all 1071/0777, it may concern.-

Be it known that 1, CHARLES PROSPER EU- GENE SCHNEIDER, of Le Creusot, Sa6ne-et- Loire, France, have invented certain new and useful Improvements in Electric Furnaces; and I 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 ap pertains to make and use the same.

My invention relates to electric furnaces, and more particularly to that class of furnaces known as "induction-furnaces, in which heat is produced by the influence of an external alternating magnetic field.

Heretofore it has been usual to employ in these furnaces annular crucibles of approximately uniform section in which the molten metal naturally assumes its level, leaving a considerable space between the cover of the crucible and its surface. The result of this approximately uniform section of the ring of molten metal is great conductivity, and consequently the production of an extremely intense secondary induced current forming around the magnetic core a number of ampere-turns out of proportion with that necessary in order to insure eflicient electrical operation of the whole. The reaction of this current upon the primary coil produces an unfavorable phase displacement of the primary current.

The improvement which forms the subject of the invention permits of obviating these defects and, further, of obtaining the advantages hereinafter set forth.

The invention is based upon the idea of imparting great resistance to the molten metallic circuit by constituting it by a tube of small section communicating at its two extremities with a melting-pot or crucible of large dimensions containing the greater part of the molten metal. Then, as with this arrangement it might happen that only the metal in the tube became heated, sufiicient inclination is given to the tube as a whole to insure the production between the tube and the meltingpot of an active circulation of the metal under the influence of the difference of density which invariably exists between the hotter and the cooler particles of the molten metal. The tube is thus quitefull of metal under slight pressure, and the surface of the metal is free only in the basin or crucible communicating with the tube, and the metal of the melting-pot constantly enters the tube by one of its orifices and leaves it heated through the other, the two orifices beng always immersed in the metal of the melting-pot. Several tubes may be employed with one or more melting-pots.

Certain mechanical expressions of the inventive idea involved are shown in the accompanying drawings, which are designed merely as illustrations to assist in the description of the invention and not as defining the limits thereof.

Figure 1 shows a form of furnace consisting of a melting-pot in communication with two heating-tubes. Fig. 2showsa modification in which-two 111elting-pots aroused. Figs. 3, L, and 5 show other modifications of the furnace. Fig. 6 is a vertical section showing the application of the invention to a blast-furnace.

Fig. 7 is a section on line A B of Fig. 6. Fig

8 is a detail View of a portion of the apparatus shown in Fig. 2. Fig. 9 is a sectional plan of a multiple-chamber regenerative furnace of the Siemenss type, taken on the line S T of Fig. 10. Fig. 10 is a vertical section of the same on the line C D E F of Fig. 9. Fig. 11 is a vertical section of part of the apparatus shown in Fig. 9 on theline G H IJ but reversed. Fig 12 is a longitudinal section on the line H L of Fig. 13, showing a practical constructional form of a furnace employed exclusively as an electrical furnace. Fig. 13 is a sectional plan of the same on the line M N O P of Fig. 12; and Fig. 14L is a transverse section of the furnace shown in Fig. 12, taken on the line QR. Referring to the drawings, Figure 1 shows diagrammatically a circular melting-pot in communication with two U form heatingtubes 1 and 2, slightly inclined in such a manner that their communications 0 and f with the melting-pot are at different levels. Through each loop formed by the tubes 1 2 passes a magnetic frame or iron core 6, carrying a primary winding 0, traversed by the alternating current coming from dynamo 11, whereby magnetic lines of force are produced in the iron core 6.

In the construction shown in Fig. 2 two melting-pots c are connected by the circulation and heating tubes 3 and at. In addition a U-shaped tube 1 2 heats one of the meltingpots. The induced currents are produced by the magnetic frames or cores 6 7), provided with wimlings a, the frame and winding being shown in detail in Fig. 8.

In Figs. 3, 4, and 5 the melting-pot is shown as taking an irregular form in cross-section. Theheating tubes or conduits 1 2 are formed by the walls a of the melting-pot itself and those of an annular false" partition 7'. Branches of these conduits are surrounded by the magnetic cores 0 7/, provided with windings c. A duplicate form of melting-pot shown in Fig. 5, where the two pots (4 a are connected by a narrowed conduit, in which is located an annular partition f, the walls of which, with those of the conduit, form additional heating-tubes 3 4;. These tubes are also surrounded by suitable cores and coils, as shown in the other forms. The circulation of the molten material is effected in a similar manner to that in Figs. 1 and 2, where circulation takes place under the influence of the difference of density between the hotter and the cooler parts of the molten bath.

in Figs. (3 and '7 is illustrated a blast-furnace, the crucible (L of which is provided with the heating- tubes 1 and 2, the tubes of which are formed, as in Figs. 3, 4, and 5, partly by the walls of the crucible and those of the inner circular partition. The crucible (L thus receives a supplementary amount of heat arising from the heat developed by induction in the tubes 1 and 2. it is therefore possible to supply additional heat to the furnace through the agency of an electric current primarily derived from such source of power as a waterfall or even a motor actuated by the blast-furnace gases.

As an additional illustration of the application of my invention 1 have shown it in Figs. 9, 10, and 11 in combination with amultiplechamber regenerative furnace of the Siemenss type adapted to serve, for example, for the economical manufacture of pig steel. In Figs. 9, 10, and 11, a and 5/ are the two chambers of the furnace, into which open at e and f, respectively, the branches 1 and 2 of the V-shaped heating-tube, which is provided with the magnetic heating-cores b 7).

In one of the chambers a coke or coal of any suitable kind is placed upon an initial bath of cast-metal filling the two chambers a and z and the tubesl and 2 of the furnace. The coke may be accumulated in a trough or hopper surmounting the chamber. The carbon of this coke or coal dissolves in the molten metal and spreads to the chamber r owing to the extremely active circulation of the metal throughout the entire furnace due to the auxiliary heating furnished by the tubular portion 1 2.

Into the chamber (j, which is covered by an arch, ore and the necessary liuxes are introduced by a suitable distributer supplying them in a uniform manner. This ore fuses in contact with the bath and is reduced by the carbon, which it contains in solution in order to give iron, which dissolves in the initial molten-metal bath and gas charged with carbonic oxid, which becomes liberated from the bath. The scoria resulting from the fusion of the gangue and mixed with a certain quantity of fused ore is continuously or periodically conducted into the compartment 1/ through the passage a, which connects the two compartments (1' and and which consequently contains an upper layer of scoria. This passage may be sufficiently high in vertical section to permit the gases which are produced in small quantities above the metal and in contact with the pieces of coke of the chamber a to be liberated freely in the chamber g. The scoria is in contact with the coke, the cindcrs of which it dissolves and which removes its last traces of iron. \Vhen it has been impoverished, this scoria is run through a pouringhole a of the chamber a.

The carbonic oxid liberated may be utilized for heating the chamber It is burned at its formation above the bath by highly-heated air in recuperation-chambers v', comprising stacks of bricks communicating with the chamber by the conduits /I.. Each chamber coinmunicates with a conduit Z, connected to a chimney 0. The two conduits Z' Z' are caused to terminate at a door or damper which directs the smoke of one chamber to the chimney, while it permits of the admission to the other of the cold air enteringthrough the ori- [ice in. By periodically reversing the circuit of the gases by means of the door cold air may be caused to enter the lower part of a chamber, where it burns the carbonic oxid, which is liberated by the bath, to which may be added by way of the conduits x the small amount of gas which is produced in the column of coke. The products of combustion pass into the second chamber g, which it heats, and then passes to the chimney. \Vhen the chambers have operated in this manner for a certain time, the gaseous current is diverted by actuating the door-damper. In this manner a high temperature is produced beneath the arch of the chamber which facilitates the fusion of the ore and its partial attack by the carbonic oxid, which traverses it in rising from the bath through the mass. The combination of the method of the attack of the ore by the car bon dissolved in the metal without any mixture of solid carbon with the ore with the electric furnace comprising tubes and several chambers and the heating of a single chamber by the combustion of the carbonic oxid by means of IIO air-heated by recuperation-chambers of the Siemens type is absolutely novel. The electric energy employed is utilized principally in order to compensate the losses of heat and may be greatly reduced by careful construction of the envelops of the furnaces in such a manner as to retain the heat as much as possible.

I prefer that the orifice c be situated slightly above the orifice f, so as to cause the carbureted metal to circulate from the chamber a toward the chamber g through the passage 8.

Figs. 12, 13, and M illustrate myim provement applied in an exclusively electric'furnace. The heating-tubes 1 2 are shown at one side of the furnace-chamber a and communieating therewith at e and f. The tubes are provided with suitable heating-cores and coils 0 Z). The furnace, with its heating-tubes, is supported upon a table or platform provided with adjustable supports 5, 6, and 7 Two of said supports may be made in the form of screw-jacks, thus permitting of inclining the table or platform, and consequently the furnace. This construction permits the usual furnace operations to be carried on while the heating- tubes 1 and 2 are constantly full of metal and consequently under pressure.

In Fig. 12 is shown a suitable tapping means 5 6, with a receptacle 7, mounted on a truck 8. Apipe 9 supplies air to the distributing chamber 10, from whence it passes through twycrs 11 into chamber a. The furnace is also provided with tap-hole 12 and lip 13, through which the contents may be poured by manipulating the adjustable support 7 WV hat I claim is 1. In combination, a chamber for holding molten metal, one or more pipes communicating with said chamber so constructed as to permit circulation of molten metal, an iron core encircling said pipe or pipes, and means for producing lines of force in said core.

2. In combination, a chamber for holding molten metal, one or more pipes communicating with said chamber so constructed as to permit circulation of the molten metal, an iron core encircling said pipe or pipes and provided with a primary coil, and means for passing an alternating current through said coil.

3. In combination,a heating-chamber,a conduit leading from and returning to said chamber, the ends of said conduit being located at different levels, an iron core engaging said conduit, and means for producing magnetic lines of force in said core.

4:. In combination, a plurality of chambers for containing molten metal, one or more pipes connecting said chambers, an iron core encircling one or more of said pipe or pipes, and means for producing magnetic lines of force in said core.

5. In combination, a chamber for holding molten metal, a pipe leading from and returning to said chamber adapted for conducting molten metal and adjustable means for tilting the furnace-chamber whereby the line joining the outlet and inletof said pipe may be thrown out of the horizontal plane.

In Witness whereof I have hereunto set my hand in presence of two witnesses.

CHARLES PROSIER EUGENE SCHNEIDER.

Witnesses:

JEAN GAMET, Gnonens BOURETTE.

Images