US1363188A - Method of and furnace for melting metallic masses - Google Patents

Description

T. W. MUCKLE. METHOD oF AND EURNACE FOR MELTING METALLIC MAssEs.

APPLICATION FILED APR. 22, 1919.

Patented Deo. 21, 1920.

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\mm \m aww/nto@ `T. W. MUCKLE. METHOD oF AND FuRNAcE Fon MELHNG METALLlc MAssEs.

APPLCAHON FILED APH. 221 |919.

Patented Deo. 2L 19.20

2 SHEETS-SHEET 2.

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UlNlTD STATES THEOIDORE W. MUCKLE, OF DENVER, COLORADO.

METHOD 0F AND FURNACE FOR MELTING METALLIC MASSES.

Specification of Letters Patent.

Patented Dec. .21, 1920.

Application led 'April 22, ,1919. Serial No. 291,934.

To all zii/"wmy t may concern:

Be it known that l, THEODORE lV. MUGKLE, a citizen of the United States, residing at the city and county of Denver and State of Colorado, have inventeda certain new and useful Method of and Furnace for Melting Metallic Masses; and l do hereby declare the following to be a full, clear, and exact description of the invention, such as willv enable othersr skilled in the art to which it appertains to make and use the same.

This invention relates to the art of melt'- ing metallic masses, and embodies both a novel method of reduction as well as an improved type of furnace construction for more expediently and expeditiously carryinO 4forward the steps thereof.

he objects and advantages of the same will be so clearly apparent, as incidental to the following complete disclosure, that it would only be undesirable surplusage to initially refer to them, and as it is believed that a better conception thereof, and of the.

distinguishing features over the prior art as understood, may be had after a more thor ough understandingof the improved furnace itself, it is deemed more expedient to first generally describe the latter.

Before doing so, however, it may not be amiss to state that while the actual method involved may doubtless be performed with other types of furnaces, which are suitably equipped and adapted for the purpose, and that 'the furnace may likewise be employed in relations other than with the particular method for which it has primarily been designed, still the tivo are so inseparably allied, in broader aspects, as to be fairly considered of substantially one and the saine identity.

ll'ith these prefacing remarks, therefore, reference shall immediately be had to the accompanying drawings, forming a part of this specification, in which drawings- Figure l is a vertical cross-sectional view of the improved furnace, taken along the line l-l of Fig. 5%; liig. 2 is a local sectional view `tlirough the arched top wall of the furnace body and one of the removable .biin0s.` associated therewith for charoin0A b h i purposes, as shown in side elevation in Fig. l, the section being taken between abutting faces ol a pair of the bricks of said removable bun;a disposed adjacent to thevcentralv truss-bearing'and lifting support therefor; and lfig. 3 is a` front elevational view of a l furnace employing a series of four heating units.

thereof, are provided with slag openings 1l, Y

disposed adjacent the approximate metal line, and these ,openings are preferably formed, as shown, with the inclined bottom face 12 and the horizontal Ashelf-like face 13, which permits the operative to more facilely skim off or drag out any dross matter accumulating on the li uid surface of the fusing metallic mass. hese openin s are controlled by any suitable doors or c osures, conventionally illustrated by a refractory plug i4.

Also, any suitable tapping outlets may be provided in either one or more of the Walls, but this has simply been illustrated by a single tap-bore l5, leading from near the bottom of the melting chamber, through the front Wall 8, and discharging into a trough or delivery spout 16. Obviously this tapbore 15- is controlled by the usual plugging means. A

17 designates a flame inlet opening or passageway through the front wall 8, t0- ward the upper end thereof, the side faces of which are preferably flared inwardly, as indicated at 18, to provide a laterally divergent delivery opening for spreading out the entering fuel mixture, or flame upon ignition, which is introduced into the melting chamber in the nature of a substantial blast.

As many of these inlets may be yemployed as the length of the furnace and the practically iinlimited scale of operations may require, but for each one thereof the melting chamber is furnished with dually arranged exits for conducting off the gaseous formations and products of combustion from the spent blasts. These exits may be located at any suitable positions relatively to the front wall of the melting chamber, provided that one at least is disposed in a plane at each 8 designates the front Wall of the furnace side of each inlet opening. Thus the exits coperate in pairs to exhaust the said prod' more fully hereinafter appear.

A satisfactory expedient toward this important end has been found in the provision of the pairs of fines 19 and 20, extending through the front wall 8, one on each side of the vertical plane .of its own particular inlet opening 17. although further experimentation niay demonstrate that a single flue intermediate of the flame openings might suflice., providing they cooperate in pairs relative to any particular inlet opening. Also, the flues 19 and 20 may pass on up through the front wall as shown, exhaustingl at the top thereof, although obviously this arrangement may be otherwise,

,and'fin any event expensive chimney constructions are wholly avoided. rThe lower ends of the fines may open into the melting chamber near its bottom, as at 21, and the. bottom walls thereof are preferably disposed at an incline, as at 22, so that as the molten mass is tapped off, none of it will remain lodged in the bottom of the flues.

The top wall of the melting chamber is in the form of a substantial arch 23. built up of refractory material such as fire clay sections or bricks. The major portion of the top wall is preferably of a fixed `structure. extending from the front wall 8, immediately above the inlet openings 17, to the top of the rear wall 9; but its length provides for a suitable number of transversely disposed charging openings, in each of which a removable bung is adapted to be snugly seated.

` These lremovable brings are .of the same curvature as the ,top arched wall 22%iand may be formed ofany appropriate refractory sections. although preferably built up into a firmly keyed structure of fire clay bricks 24, recessed to provide rabbeted corners and the depending tongue portions and the whole unit serving as a substantial elongated form of plug closure for the transversely disposed charging openings. the tongue portions 25 being of a Vlength to neatly lit said charging openings. while the rabbeted cornei's provide seating shoulders for resting upon the spaced top surfacesof the fixed arch 23. As this removable bung unit is quite heavy, the-tongue portions of the bricks are of :onsiderable less depth than the overhanging upper ledge portions thereof, which have to sustain the load. Also.

as the assembled bricks have to be held compactlyragainst separation from strains and internal pressures, it is desirable that a light metallic support be employed, which will serve both as a keying truss and a handling means therefor, and which will now be described, particular reference being had to Fig. 2 viewed in connection with Fig. 1.

26 designates a centrally disposed base member, having an upwardly projecting apertured lug 27 anda pair of top grooved seats 28, while 29 designates a pair of arched metallic side plates secured centrally to the base member as by bolts 30. The side platesterminate in vertical ears 31, between which a pair of end plates 35 are niovably supported. as by being hinged thereto, and these end plates are suitably engaged by the threaded ends and nuts 3T of a pair of divergently bent tie rods 3G. the central bent portions of which seat in the grooves 28 of the base member 26.

rlhe upper longitudinal edge faces of the bricks are set against the concave edge faces of the side plates 29. and upon tightening up the nuts 3T the end plates 35 are 'ob viously drawn up against the ends of the row of bricks, binding the same together as a keyed unit by the ti'ussing action of the tierods. while the apertured lug of the central base member 26 serves as a ready means for handling the removable biings by a traveling crane operating longitudinally above the furnace.

F or the purpose of convenient reference later` 31 simply designates the inside surfaces of the end walls of the melting chainber, and 32 the inside surface of the front wall. but more particularly the surfaces between tlie pairs of .fines 19 and 20. while 82E indicates the deflecting surface of the top wall arch 23. ln the end wall of Fig. 1. the slag opening 11 is omitted to permitof a clearer illustration of the path of the hot gases in the melting chamber. but it is understood thatsuch slag openings may be supi plied for the end walls, if desired. and as indicated in Fig. 3.

From a broader aspect. it may be found sufficient to introduce blast flames through the inlet openings 17 (or blasts of combustible mixtures immediately convertible into flames, from any suitable sources` such as hydrocarbon burners generally. whether of the gas or oil type, or even from powdered coal burnersl or the like: but in actual prac tice it has been determined most expedient to employ an oil burner of the low pres-sure type. both in point of successful and economical operation.

As will be understood from Fig. Il. these burners are arranged in series. thenumber employed being only limited by the dimensions of the furnace. and referring to the same conventionally. 40 simply designates a burner casing, 41 its nozzle tip, 42 its needle valve controlling stem, 43 the oil serving conduits therefor, and 44 air supplying branches from the main pressure air conduit 45. Obviously the pipe line 43 is fed from any suitable oil supply, while the main air conduit 45 is likewise supplied, with air under a fairly loiv pressure, from any suit'- able source, as by means of a rotary blower (not shown) coupled up therewith. Also, each burner may be provided with damperiiig means, for locally controlling; the pressure air delivered to the burner casing, as well as adjustable means for independently regulating the admixture of said pressure air with the fuel oil; but these are rather details of the burner construction, requiring no specific description herein.

, The general operationef the improved furnace construction will be fairly apparent from an inspection of Fig. l1, in view of the foregoing description, but as it willn probably be made even more comprehensive, from an amplified statement of the method involved heiein, l will now proceed indetail with reference to the latter.

In my former Patent #1,286,719 of December 3, 1918, I originally disclosed a particular novel type of furnace for melting metals generally with. certain superior results, and a broad feature common to both inventions is my generic idea of so initially introducing a blast flame, into the melting chamber of the furnace, as to first provide for the burning out of all of the oxygen of the flame by its complete combustion, after which the resultant hot gases and products of combustion (in the form of a continuing deoxidized heat blast only vand not as a true flame at all, its oxygen being wholly exhausted) are caused to traverse the melting mass in sulfused intimate Contact therethereof is rapidlyand economically accom plished wit ioiit any undue oxidizing'effect In the i stant case I' have made stil further advances in respect of certain d cidedly important particulars, the disti guishing characteristics of which may be..

more sharply' defined by Way of comparisons, and` which provide not only for improved furnaces of practically unlimited' capacities but more important'still. the` improved method enables nie to practically revolutionize, as it were` the highly expensive and time con'siiming operations here` tofore practised in the special industryof producing malleable ironA castingsmost-,ess' sciitial present day factors in the manu-j facture of agricultural implements, automobile and railway equipment, and various other classes of work subjected to corrosion and shock.

its is well understood, these castings are poured from a special quality of cast iron,

final product of tough pliancy.

.Therefore, in reducing iron masses for such uses, the poured product must obviously retain approximately all of its carbon in combined form, for if the chemically combined form thereof is destroyed by oxidation, or otherwise burned out of the mass entirely, in the melting operations, then the poured product could not successfully undergo the annealing process, essential to the final production of malleable iron castings.

The advantageous employment of oil' burners has long been recognized in met-al heating operations generally and even in reductions for malleable iron castings they, have actually been tried out, but unsuccessfully so because, by the manner of use then attempted, the carbon in the fusing mass chemically united with the unconsumed i oxygen of the, contacting llames, While the contained silicon and other values were likewise eliminated, resulting in a pouring product in the nature of gray iron, wholly unsuitable for subsequent annealing. To the best of my knowledge, therefore, theold method of melting withA an indirect or reverberated heat, up to the time of my present invention, has been continuously practised in this particular field, although necessitatingl the costly slow melting operations with, whereby a direct intensive heating by the use of coal fires and expensive furnace and chimney construction equipments. In my own attempts to apply the broader 'rinciples of my discoveries, to the redlicon of metalfor the specific industry of alleable iron castings, on a large scale by the equipment of furnaces of great lengths and-comparatively unlimited capacities andwith a series of burners discharging into a common melting chamber` I myself encoiiiitered vfurther serious obstacles.-

The carbon dioxid, forming as the blast flames became consumed. not only would ten l t `bottom of the furnace chamber` and At'liereover more or less as a stagiiated heat dampering or blanketing'layer. which was largely overcome, however, by the swirl- 'iiig motion of the hot gases, but lmore serious i heavily sink toward the melting mass,

still, Where the exhaust was provided toivafrd l the end of the melting chamber asheretofore,

the rapid accumulation of these dense incombustible C02 gases would'very quickly ing flames, extinguishing the burners completely. rl`his would be all the more so true where the actual flames positively impinged upon the melting mass (in furnaces where oxidation was not intended to be avoided) for greater volumes of C02 gas would then be formed by the action of the flame on the metallic mass.

Finally l devised the method of establishing a practically separate heating zone, for cach burner, by conducting off' the spent hot products of combustion and all other gaseous formations from that individual burner independently of the others vlofthe series, and this appears to have met all further difliculties.

It now remains to set forth the steps of the method in sequential order of operation, it being assumed that suitable charges have been introduced, into the improved furnace shown, by way of the removable-bung closed openings, and that lindicates the formation of ,a silica slag layer.; while 47 designates the liquid surface line of the fusing mass.

rllhe streams of combustible mixture from the low pressure oil burners t0, being projected through the inlet openings 17, are

initially spread out laterally and as ignited masses or blast flames are guided around the surface 33 of the arched top wall, as indicated by the black arrows a.

Being thus initially directed across the upper space of the: melting chamber and downwardly toward the rear wall thereof, substantial complete Lcombustion will have been effected as the resultant hot gases and products of combustion (now converted into' a deoxidized heat indicated by the doubletail arrows are diverted towafd the fus.

ing mass below, from whence they are turned and caused (as a continuing 'blast of deoilxidized heat indicated by the single-tail arrows c) to traverse the fusing metal, as a bottom confining wall, across toward the front wall of the melting chamber.

t this latter position, the main body strikes against the` inner surface 32 of the front wall, between the flues 19 and 20, and are caused to swirl upwardly and baclragain toward the rear of the melting chamber las vindicated by the dotted arrows Zr) in recentral zone of the melting chamber is as a vacuous space e, and an expansive force 1s established which causes the deoxygenized .blasts to be suffusedly pressed down powerfully upon the liquid surface of the fusing metal, which liquid surface is to a large de gree agitated or riflled by the swirling motion of the heat, whereby the heat units are positively impressed right into the surface .of the mass, and thus ancre intimately absorbed bythe molecular'particles thereof.

From the foregoing complete disclosure, it maybe summed up that, outside of the direct application of heat, resultant from a series of blast flames, without anyundue oxidation occurring, as contradistinguished from an indirect or reverberated heating, satisfactory provision is made for conducting off substantially allof the spent products of combustion and gaseous formations from each separate burner at the extremities of its particular heating zone, insuring proper functioning of'the low pressure oil burners employed, and thus especially adapting my novel method, as an economically successful radical departure, to the important industry s of producing malleable iron castings of superior qualitylvliat l claim, as new and patentable, is

1. The method of reducing metals en masse in a suitable melting chamber, which includes the steps of soprojecting a series of blast flames into said chamber as -to perireit of their'complete combustion initially, after which the continuing blasts of resultant hot gases and products of combustion, as now converted into deoxidized' heat, are caused to forwardly traverse the melting max-1s, in suffused intimate contact therewith, and are thence conducted upwardly into entrained regenerative association with their complementary incoming flame blast, and finally exhausting the spent products of combustion and gaseous formations.

2. The method of reducing metals en masse in a suitable melting chamber, which includes `the steps of so projecting a series Aof blast flames initially across the top and downwardly of the combustion space thereof as to allow for substantially complete combustion before contact with the metallic mass below, after which the continuing blasts of resultant hot gases and products ofcombustion, as now converted int-o deoxidized heat, are'caused toforwardly traverse the melting mass with a swirling motion bringing them back rinto entrained regenerative association with their complementary incoming flame blast, and finally exhausting substantiallyall of thespent gases and products of combustion of each separate flame at the extremities of its particular heating zone. fy l A reductionl furnace embodying an elongated chamber providing a lower melting space and an upper combustion space, with a series of inlet openings for the latter proximate its forward top wall; in combination with means associated with said inlet openings for projecting a series of blast flames across said upper space toward its rear wall, Vto allow for the substantially complete combustion of said ames before striking the fusin'g massin the lower space, the top and rear walls of said combustion space serving to divert anddirect the con tinuing resultant. blasts'of deoxidized heat forwardly across the melting mass in 'suffused intimate Contact therewith; and a series of outlets'leadingv through said front wall from the lower portionof said chamber, which outlets are positioned at each side of the vertical planes of said inlet open- -ings and coperate in pairs toexhaust the residue products of ,combustion from each separate blast flame at the extremities of their individual heating zones, substantially as described. l

4. A reduction furnace, embodying an elongated chamber providing a lower melting space and an upper combustion space,`

with a series of inlet openings for the latter proximate' its forward top wall; in combination with means associated withv said inlet openings for projecting a series of blast flames across'said upper space toward its rear wall, to allow for the complete combustion of said flames before striking the fusing mass in the lower space, the top and ing to divert and direct the continuing resultant blasts of deoxidized heat forwardly l across the melting mass in suused intimate contact therewith; and exhausting lues leading from. the lower portion of said chamber, through said front wall, and cooperating in pairs at positions lying in vertical planes on the opppsite sides of practically all of said inlet openings, substantially as described.

5. A reduction furnace, embodying an elongated chamber providing a lower melting space and an upper combustion space, and including a rear wall, a substantiall higher front wall and an archedtop wal curving downwardly from' said front wall to said rear wall, a series of inlet openings being provided, through said vfront wall, proximate said arched top wall; in combi- .nation with means associated with said in let openings for projecting a series of blast flames across the deflecting surface of said arched top wall; and exhausting flues leading from the lower portion of said chamber, through said front wall, and coperating in pairs at positions lying in vertical planes on the oppositev sides of practically allof said `inlet openings, substantially as described.

In testimony whereof, I aliix my signature.

T HEoDoRE wgMUcKLE.

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