US1420687A - Electric furnace - Google Patents

Description

S. MCASTLE., ELECTRIC FUfN/fln MPLlcAmu FILED Amma, 1918. l 'n 50d. 1942?@@8 @Q l f j www@ dam! f @it BY w, @ATTORNEY @TENT FFEQL- SAMUEL N. CASTLE, OF NEW ROCHELLE, NEW (YORK.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented June 27, 15922.

Application led August 13, 1918. Serial No. 249,622.`

To 11]/ ich/)m if 12u/.y concern.'

lie it known that l. SAMUEL tAs'rLn. a citizen ot' the United States, residing at New Rochelle, 'estchester tounty, State ot' New York. have invented new and usetul lmprovementsl in lllectric Furnaces. of which the following is a specitication.

llns invention relates to electrlc turnaces ot' the induetion type; that is, .that type wherein a heating current is magnetically induced in the charge.

r1`he main ohject ot' the invention is to improve the metallurgical conditions ot' furnaces ot' the type referred to, particularly those tor making steel. A. large. surface ot hath is desirahle tor refining purposes vand also it is desirable that the greatest heat shall he generated at the surtace. Accordingly hearing in mind that there. is a large leakage tlux adjacent. the windings and outside the core in apparatus ol this character, I make the walls of the crucihle sloping so as to give. an increased surface/ol'` hath and the inducing windings are placed ahove. the hath so that the surface, heing the nearest tothe windings. has the greatest heat developed in it. ahove the hath and sloping the walls also have the praeti al advantages that'. it' in the one case thev metal hrealis through the lining it does not overrun and destroy the winding as it does where the winding is within or helow the hath. and in the other case the slopingwalls may he. patched. With suhstantially vertical walls the patch would not stay in place. 'l`his greatly facilitates repairs. lt the inducing magnetism is unevenly distrihuted across the hath` the unbalanced condition tends to cause electrodynamic. action in the hath and it' the inequality is sulliciently great a violent commotion will take place whereas a gentle circulation res'emhling that of the crucihle l'urnace is desirahle; also it' magnetism is concentrated to any considerahle extent at one side ol the hath the overheating ot the lining at that side is harm l`ul to it and unequal heating of the parts is liahle to cause cracking. To avoid the `disadvantages as indicated, and which are especially liahle to occur where. the. hath is wide., the inducing winding is distrihuted transversely ol' the hath so that the magnetism is so distrihuted as to achieve the desired results. These will he snch'as to prevent any undue violence ot The mounting ol the windingV circulation in the hath and usually a unitorm temperature gradient and heating transversely ot the hath.

ln addition to the ohjects as above indii ated, other and ancillary objects of the invention will appear hereinafter.

In the accompanying drawings. which illustrate the invention, v

Fig. l is a vertical axial section ot a turnace embodying the invention.

Fig. 2 is a top plan view on a reduced scale, and

Fig. 3 is a side elevation, hut with'part in section, on the scale of Fig. 2,. but viewed, from a point ninety degrees removed from the. View ot- Fig. l.

Referringlto the drawings, the apparatus comprises rockers l and 2, each ot which rests on rollers 8 and 4. Supported by the rockers are the transformer core 5 ot` laminated iron and the annular crucihle 6 containing the hath or charge 7. As Will be seen. the crucihle surrounds the. central leg ot' the core .'i and extends between it and the two outer legs, and hetween the upper and lower yokes magnetically uniting the legs.

Secured to the top ot the core are. the rings 8, 9 and l() trom which depend holts or rods 1l which support the hars or plates l2 and which in turn support the primary or inducing windings t8. which are annular in top plan view` may he secured to these hars in any well known or suitahle manner. 'l`he rods ll, or some of them are extended and are secured to the cover 14 of the crucihle. r'his roof may he made in a single piece ot hriclts huilt up in arch form hetween the marginal hars 15 and lt ot circular torni. The top yoke ol' the core;y the. windingsand the cover ol' the crucihle are thus secured together and canihe removed and replaced as a unit. llye pieces i7 and i8 secured to the top of the yoke provideI a means wherehy crane hoolts can he engaged with the unit to lift it.

The crucihle may he ot materials commonly used in tlle art for this purpose, the refractm'y lining heing frequently magnesite or dolomite. Also the construction ol' the crucihle may contorni to the knowledge of the art except that the side walls lt) and 2l) are inclinedl so that increased surface oll the hath and ca'pahility ot patching .the linuw. as helore. referred to, are secured. .\s siown these rl`he windings lt will he observed that the entire winding ol` the apparatus is'at a higher level than the hath so thatl itl the latter breaks through the lining` ity will not destro;v the winding. Also the loeation of the winding above the li:iti",1.(tl1e annular roils being direetlvv ahove the annnlar erueihle) produces greatest heat at the hath snrt'aee as helore stated; The winding is so distriluited transversel)v ot' the hath that the inagfnetie distribution across it is substantially uniform and a uniform temperature ,gradient aeross the hath is se eured. This is serured in the struct-ure illustrated hy unilorlnljv distributing:w the winding ahove the entire snrt'aee ol" the hath and even eansing' it to extend lievond the hath to some extent at the sides in order lo insure that the desired distrilnition ol' magnetism shall extend completely to the sides o'lg the hath` The advantages of this have heen already referred to.

-While the invention has heen illustrated hy a lnrnaee intended to he operated h v .sing-le phase,current` it ma)v he as readily made nse ol' in polvphase apparatus asin single phase. onl)v sueh difl'erenees in the struetures hein;- neeessar)1 as are well nnderstood h v those skilled in the art. Also the invention may have other exnluuliinents without departing'from its ,spirit`r and is not therefore` limited to the strueture shown in.'

the drawings.

ll'hat I elailn 1. An eleetrie furnaee oll the induction type havin; lv a eore, a erueihle having sloping` walls making angles ot not less than l5@ with the vertieal '.t'or eontainintr the hath intel-linked wit-h said eore. windiiws interlinked with said coro, and means 'for supporting all of the windings at a higher level than said bath.

2. n eleetrie furnace vor' the, induction' type. havingga eorev` a Crucible having 'voke whereh)Y said `voke and windingi` are removahle together as a unit.

l4. n eleetrie tnrnaee ot the indnetion type having a eore comprising a removable voke. a erurihle Jfor containing the hath interlinked with said eore., said erneihle having a eover and. a winding interlinked with said core. said yoke, winding' and rover beingseenred together wher/abiv they are relnovahle as a unit.

5. n eleetirie furnace ot the induction t \'pe ha vin;v aeore. a erueilile ha ving sloping' walls makin;r angles of not less than l5O with the vertical for eontaining' the hath interlinked with said eore, wii'iding's interlinked with said eore. and portingl all ol the windings direct-ly above said hath` said windings heine' uniformly distrilnited transversely o'lf' the hath.

(i. An electric. 'l'urnaee ol" the induction type having' a eore` a erueilile havingY sloping' walls` making` angles ol not less than l5@ with the vertieal hath interliuked with said eore.

winding-s mternnked with said rore and supporting' all of the windings AdireetljY ahove said hath. i-

ln testimoniY whereoi" have Signed this speeilieation this 24th dav ol .fl-April. lill?? meansv l'or sup lfor containing 'they

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