US1296752A - Electric induction-furnace. - Google Patents

Description

0. BROPHY.

ELECTRIC INDUCTION FURNACE.

APPLICATION FILED JUNE 12. I918.

Patented Mar. 11, 1919.

NITED STATES P TENT OFFICE.

oscnn nnornv, or PHILADELPHIA, PENNSYLVANIA.

ELECTRIC INDUCTION-FURNACE.

To all whom it may concern I Be it known that I, OSCAR BROPHY, a citizen of the United States, residing in Phil adelphia, Pennsylvania, have invented Electric Induction-Furnaces, of which the following is a specification.

One object ofmy invention is to provide a relatively simple, eflicient and substantial form of electric furnace which shall be characterized by the novel form of its molten metal secondary as well as by the position and form of its primary relatively to said secondary ;the invention especially contemplating the mounting'of the. primary and secondary elements of the furnace in such relation as will insure brisk circulation of the molten metal. 1

I further desire to provide an induction furnace in which the primary and secondary elements are soconstituted and assembled that the molten metal is caused to circulate by reason of the repulsion exerted by the primary winding upon the secondary as .well as by reason of the cutting of the molten metal at definite points by relativelylarge numbers of lines of force.

These objects and other advantageous ends I attaln as hereinafter set forth, reference bein had to the accompanying drawings inwhic Figureslfand 2 are respectively front and side elevations, to some extent diagram-' matic, illustrating the preferred construc-.

tion of an induction furnace made in accordance with my invention;

Fig. 3 is a plan of the furnace shown in Figs. 1 and 2. Fig. 4 is a diagrammatic side elevation of a modified form of my invention, and

Fig. 5 is an elevation, partly in vertical sBection, further showing the structure of In the above drawings, the core l-of the a transformer is in the form of an open rectangular frame having between the middle parts of its top and bottom a branch 2 on which is mounted the primary winding-.3.

The refractory structure 15 for the reception of metal to be operated on inTmy furnace, has a main cavity or basin 4 shown for convenience as having the form af a vertical cylinder, from the flat bottomof which a tube-shaped cavity extends downwardly.

Thecore-l which isshown as of the shell type, is so mounted with re rd to the body of metal 5 in this cavity t at its branch 2 Specification of Letters Patent.

extends coaxially thereof andin order to permit of the passage of the top horizontal member of the core, there are formed in the tubular body of metal constituting the secondary of the furnace, two transverse upwardly flaring openings 6 at opposite points thereof. The relative positions of the metal shell or tube 5 and the primary winding are such that about one-third of the lengthof the primary windin extends below t e plane of the bottom 0 the molten metal secondary which has the form of a ring surrounding the winding 3 and connected to the basin or main body of metal through the depending legs or branches.

Patented Mar. 11, 1919. Application filed June 12. 1918. Seria1No.239,538.

tion, when alternating current from a suitable source is supplied to the terminals of the winding 3, there is inducedin the secondary provided'by the tubular body of molten metal 5 a current of large volume and small pressure which shortly 'melts said metal and maintains it in ahighly heated molten condition.

Owing to the extension of the axial branch 2 of the bore and its winding below the plane of the bottom of the molten secondary there is exerted upon the latter an upwar repulsive force which is a maximum adjacent the points 8 by reason ofthese lyin in the plane of the core, with the result t at the metal is caused to briskly circulate both by reason of the cutting of the magnetic field through these points and also because ofthe above noted repulsive action.

The molten metal .5 also tends to' circulate since the heat generated by reason of 'its resistance to the current flow induced in it, maintains its temperature above that of the metalin the main body or basin 4, and the hotter metal tends to rise through portions of the branches and be replaced by relatively colder overlying metal.

From the above description itflwill be understood that not only breason of the peculiar form of the seoon ary constituted by .the molten metal, but also because of the downward extension of the winding 3 below the bottom of this secondary, there IS insured a strong circulation of the molten metal which is. most active at the points 8* where the crossv section of the metal is least and where the possibility pf choking otherwise the greatest;

In that form of my invention shown in FigsA and5,I have made the body of molten metal constituting the secondary project below-the main metal body in a V-shaped mass 10 whose branches or arms connect with opposite sides of the bottom of said main body of metal. .Said secondary which preferably has a flat laterally elongated section, extends through the central opening of the trans. former core 11 which in this case is of the shell type and so mounted that its lower member extends immediately adjacent the lowest part of the metal 10. The core 11 has its winding divided into two parts 12 thereto in order that it shall exert a repul-.

and 13 of which the first is placed on the upper cross member of the core while the latter is on the lower core member and is wound with a less number of turns and oppositely sive force on the adjacent portion of the metal 10 so as to cause circulation thereof I claim:

1. An induction furnace consisting of acore having a branch; a primary winding for said core; and a secondary in the form of a tubular body of molten metal substantially coaxial with said core branch and having opposite portions cut away to permit passage of portions of said core.

2. The combination in an induction furnace of a substantially rectangular core sup.-

ported in a vertical plane and having a vertically extending branch; a primary winding for said core; a tubular body of moltenmetal constituting the secondary of the core and mounted substantially coaxial with, the

central branch thereof, opposite portions. of

I the secondary being removed-to permit of passage of the top portion of the core; with a 'main body of molten metal connected to that of said'tubular body of metal.

3. The combination, in an induction furnace of a substantially rectangular core; a primary'winding for said core; a tubular body of molten metal constituting the secondary of the core and mounted substantially coaxial with the central branch thereof, opposite portions of the secondary being removed to permit of passage of the top portion of the core; with a main body of molten metal connected to that'of said tubular body of metal. 4. The combination of a main body of metal; a tubular body of metal extending ownwardly from the bottom of said main y'met al bddy and having oppositely placed openings therein; with a transformer core havlng a portion extending through the openings of said'tubular body of metal and 1 including a member extending-substantially coaxial'th'erewith; with a primary winding on'the core.-

tangu'larcore having. a central member; a tubular body o f metal constituting a secondary for said core and mounted coaxial with the central member thereof, said body ondary.

'of said secondary.

5. The combination of a substantiallyi'eci of metal being cutaway at opposite pointsto permit of passage of a horizontally extending portion of the core; with a" primary winding for the core mounted on the central branch partially within the tubular sec- 6. The combination of a substantially rectangular core having a central member; a tubular body of metal constituting a secondary for the core and mounted coaxial with said central member, said body of metal being cut away at opposite points to permit of passage of a portion of the core; with a primary winding for the core mounted on the central branch within the tubular secondary and extending below a plane of the bottom 7. The combination in an induction fur- .nace of a tubular body of metal constituting a secondary, having openings in opposite portions thereof; a transformer core; and a primary winding mounted on said corein position to exert an upward repulsive force on the metal constituting the secondary.

8. The combination in an induction furnace of a tubular body of metal, having oppositly placed openings; a primary winding; a transformer core for said winding 7 mounted in a plane including the longitudinal axis of said tubular body of metal and extending through the openings thereof in position to cause a relatively large number.

of lines of force .to intersect said body of metal at definite points. i

9. The combination in an induction fur-" and including also anauxiliary cavity for said metal connecting with the main cavity at notless than two points; a transformer having it core mounted to extend between a part of the auxiliary cavity and the main the core positioned to cause circulation of .the metal in the auxiliary cavity.

' 1'1. The combinationin an induction fur nace of a structure having a cavity adaptedto contain a main body of metal to be'treated and including also an auxiliary cavity for said metal connecting with themain cavity at not less than two points; a transformer having its core mounted to extend between apart of the auxiliary cavity and the main cavity ofthe structure; and a* winding on cavity of the structure; and a winding on the core positioned to exert a repulsive action on certain of the metal in said auxiliary cavity to cause circulation thereof.

12. The combination in an induction fur- 5 nace of a containing structure having main and auxiliary cavities for molten metal; a

core; and a winding for the core mounted to eXert a repulsive action on the metal in the auxiliary cavity such as will force it out of the same into the main cavity, the core being positioned relatively to the metal in the auxiliary cavity to cause magnetic lines of force to cut through the same at definite points and thereby cause relatively intense circulation at said points.

In witness whereof I afiix my signature.

OSCAR BROPHY.

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