US1299664A - Electric furnace and transformer for use therewith. - Google Patents

Description

F. E. BERRY.

ELECTRIC FURNACE AND TRANSFORMER FOR USE THEREWITH.

- APPLICATION FILED JAN/19.1918.

1,299; 6 64. Patented Apr. 8,1919.

L U ED ST E PA E OFF-10E.

le a- To all hom it may concern Be it'k-nown that I, FREDERICK EDMUND BERRY, a subject of the King of Great Britain and Ireland, residing at .Hayes, in the county of Middlesex, England, have invented Improvements in or Relating to Electric Furnaces and, Transformers for Use Therewith, of, which the following is a specification.

- This invention-has reference to improved arrangements of three phase transformers known ways so so istracted as phase transformers may be coupled up for and electric-furnaces, designed to give a better distribu-tionof heat tlrrough the bulk of the metal or charge in the furnace and abet-' ter mixing of the molten metal or charge,

For. this purpose" in a transformer a rthe {invention there is used a three phase 'transformerthe primary windings, of which can delta or star connected, or inter-con-- nected star, or'be a combination of such groupings, but thesecondary windings of which aresoarranged that each phase is brought out to separate terminals so as to give at the transformer itself a separate circuit for each phase. "The secondary windings ,may be connected up in any 1 of the long as a separate circuit is provided for eachphase.

The three phase transformer may be cona single structure, or three single three phase working as well understood.

The three pairs of terminals of the secondary windings are combined with an electric furnace in such manner that three of them form an upper set of terminals or electrodes and the'fothr three are disposed at the lower part of fit-he furnace, to form a lower set of terminals or electrodes that are spaced apart and are in contact, it may be, with the lining of the furnace and in electrical connection with the metallic chargein such furnace.

In order that the invention may be readily understood it will now be further described with the aid of' the drawings filed with ourprovisional specification.

,In these drawings, Flgure 1 shows, d1a grammatically, a three phase transformer and electric furnace according to the invention and Fig. 2 is a plan showing the relative positions of the secondary termlnals or electrodes in the furnace.

For simplicity, Fig. 1 shows a three phase transformer having its primary windings 1 FREDERICK EDMUND BERRY, or HAYES, ENGLAND. j l I v i I Q 7 K 1 l V ELECTRIC FURNACE AND TRANSFORMER FOR USE 'THEREWITH.

Specification of Letters Patent. Patented Apr, 8 1919, Applica'tionfiled January 19, 1918. Serial No. 212,747. I

a, b and 0 delta connected and its secondary w nd ngs arranged to form three separate windings d, e and f. I

The corresponding ends of the secondary or phase windings d, e and f are connected to electrodes 1, 2 and 3 at the top of the furnace and the opposite ends of such windings are connected to terminals 1, 2*, and 3 arranged in the lower part of the side portions of the furnace so as to make contact with the metal charge therein at the periphery thereof, or, .as is more usual, with the lining of the furnace which, at a high temperature, is conducting so that-the circuit through the-metal is completed through such lining.

The relative positions of the electrodes 1, 2 and 3 and terminals 1 2 and 5 in the furnace may be varied.- Thus, the positions of the electrodes 1, 2 and 3 in the upper part of the furnace may be the reverse of those of the terminals 1*, 2 and 3 in the body of the furnace, as shown in Fig. 1,'so that the 'movement of the metal in the upper part of furnace, due to the current and to'the "electromagnetic effect of such current, will be in't'he opposite direction to the movement of the metal in the lower part of the furnace, so as to more effioient-ly mix the metal" and bring all parts thereof under the influence of the heat produced by the passage of the current through the furnace.

- The described arrangement of the transformer and the electrodes and terminalslconnected thereto, constitutes in effect, a six phase cqnnection'tothe furnace. Each of the circuits 1 to l 2 to 2*, 3 to 3, are single phase circuits but the effect of the currents at the electrodes 1, 2 and 3 and also at the terminals 1 2 and 3 is to give a three phase distribution with corresponding movement. and mixing of the metal in the furnace, and, as hereinbefore stated, the disposiition of theelectrodes 1, 2 and 3 and the terminals 1*, 2 and 3 may be such as to create opposite movements in the metal influencedat these positions so as to improve the mixing of the rectal.

The secondary winding (Z, 6, or f of each phase should be so designed as to give the correct voltage necessary to supply the current required against the resistance of the are between the corresponding electrode 1,

lining, in addition to the resistance of the winding itself and the connections external to the transformerand furnace.

If necessary, when starting up the fur vnace, or at'any subsequent period if desired, the terminals 1, 2* and 3 in the furnace lining may be short cirouited by a suitable switch, either actually at the terminals themselves or at the terminal-s of the transformer windings that are connected to these-'ipoin'ts.

In this case the arrangement becomes-that of a simple three phase supply,

Thetransform'er may of course be fitted with primary or secondary tap'pings for varying the voltage to the furnaceas re quire-d. 1 Y

By the arrangement described a better distribution of the heat in .the furnace is effected and a better mixing of the metal or charge -in the furnace obtained, whereby a v more etlicient working ofthe furnace is insured and smaller electrodes can be used for the same heating effect than with other arrangements" of combined transformer-and electric furnace heretofore used,

.lVhat I claim is 1. A three phase electric furnace having upper electrodes arranged above the furnace charge and lower and laterally arranged electrodes in electrical connection with. said charge when the furnace 1s'1n operation each of said lower electrodes "being ofsuch dimensions and so arranged that it is located wholly at a part of the furnace wall that will be between the top and bottom of the furnace charge when the furnace -1s in acti )ll.

2. A three pha*e electric furnace according to claim 1', 4 herein each of the lower electrodes'is embedded. in the side wall-of the furnace and above the bottom of the furnace so that it willbe separated from thefurnace charge by furnace.

i 3. A three phase electric furnace according to the claim 1, whereir the polarities of the electrodes in the upper part of the furnace are the reverse of those in the. lower part thereof.

4. A three phase electric furnace having upper electrodes arranged above the furnace charge and lower and laterally arranged electrodes in electrical connection with the said charge when the furnace is in operation, each of said lower electrodes being of such dimensions and so arranged that it is located whollv at a part of the furnace wall part of the refcartory wall of the that will be between the top and bottom of the furnace charge when the furnace is in operation, and means whereby the lower electrodes can, when desired, be temporarily short circuited'outside the furnace.

'5. A threep hase electric furnace according to claim 1 combined with three secondary winding of atransformer, said windings being separate from each other and each 4 having its two ends connected respectively toanv upper electrode and a lower electrode..

6. An electric furnace and a three phase electrical transformer having a delta con nected primary winding and three separate secondary windings, said furnace having three pairs of upper and lower electrodes, eachpair being connected to the ends of one of saidseparate secondary windings and each of the lower electrodesbeing of such dimensions and so arranged that it is located at a. part of the furnace wall that will be between the top and bottom of the furnace charge when the furnace is in action.

7. An electric furnace and a three phase A electrical transformer having a delta connected primary-winding and three separate secondary windlngs, said furnace having three pairs of upper and lower electrodes,

each pair being connected to the ends of one of said separate secondary windings and each of the lower electrodes being of such dimensions and so arranged that it is located at a part of the furnace wall that will be between the top and bottom of the furnace charge when the furnace is inaction at a part of the furnace wall that will be be'-.

tween the top and bottom of the furnace charge when the furnace .is in action and a short circuiting device adapted to short cir.

cuit the electrical connections between the lower electrodes and the corresponding ends of the separate secondary conductors.

Signed at London, England, this 21st day of December, 1917.

FREDERICK EDMUND BERRY.

Images