US 1904781 A
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April 18, 1933 J. F. CRAWFORD FURNACE Filed Dec. 27, 1932 l IN1/EN TOR. Ja/-m/ FCRA/Mmm:
ATTORNEY lPatentedApr. 18, 1933 UNITED STATES PATENT OFFICE y JOHN F. CRAWFORD, F RACINE, WISCONSIN, ASSIGNOB TO J. I. CASE COMPANY,\OF
RACINE, WISCONSIN, A CORPORATION FURNAGE Applibation'led December 27, 1932. Serial No. '$48,914.
vIn manufacturing operations where castings, forgings and' other metals are finished in machine shops a .large amount of chips are 'produced in the form of4 borings, drillings,
sustain combustion, which causes them to oxidize rapidly, and, such treatments result in excessive metal loss and particularly so when cast iron is melted. I am aware that such chips can be melted in electric furnaces,- and may also be pressed into briquettes, or placed in sheet metal containers, and then melted in a cupola, but for practical purposes such methods are unduly expensive and prohibitive when economy is considered. Itis myA object, therefore, to providean improved furnacefor melting chip or scrap metal ofthe character referred to, which I accomplish in a simple and effectivemanner' and at the same time with such economy'ras to enable me to utilize such material about a manufacturing plant to be melted and reclaimed for commercial purposes.
In the accompanying drawing, forming .part hereof, Figureel is a longitudinal vertical sectional view of 'my improved furnace, and Fig. 2, an enlarged detail of a art thereof showing 'mechanlsm for feeding c ip material to the furnace.
In-said drawing, thefurnace proper com- -prises' a metal casing 5 having an open taperedforward end 6 and a lining .Tof suitable refractory material, constituting a charging chamber, and which chamber is supported 1n inclined. position to rotate about an inclinedv axis, as indicated, for the' pur-A pose to-appear, the supporting means consisting of wheels 8, which may be driven by a chain-and-spr'ocket system 9,v or otherwise, directly' from a motor 10 or other suitable source 'of power. w
A non-rotatable flue body comprising a metal casing 11, lined with refractoryl material 12, and having a discharge outlet 11', is supported on a movable carriage 13 including wheels 14 adapted to engage and travel lpon vnace chamber.
'veyor 27 therein driven by a motor 28 or otherv tracks 15 forming part of a frame 16, the o n end 17 of said body mating with and a utting the forward open end 5 of the fur- Within the flue a fuel duct 18 is installed through which fuel (powdered coal or other material) mixed with air is supplied through a pipe 19 from a conventional source (notshown), and is discharged into the chamber through a burner 20. The path of the gases and fuel in the process of combustion is indicated by the arrows, Fig. '1, and it will be apparent that the duct 18 being in the path of the exhaust gases will throughy its walls convey an appreciable amount of heat to the incoming fuel and air mixture, resulting in a condition to make for fuel .economy and high temperature within th furnace proper.
In Fig. 1 the'furnace is shown in tapping condition, the tap-hole 22 being closed by a clay stopper 23, so that the furnace may be tapped in the ordinary manner, or it may be y rotatedto bring the tap-hole above the level` line of the metal bath-24 and the hole opened and then'rotated to bring the tap-hole to the pouring position, Fig. 1, and after the required metal has been drawn the furnace may b e positioned to prevent pouring.
In beginnin themeltin .operations the carriage 13 is rawn away rom the furnace 5 along tracks 15 on frame 16, to the lposition indicated by dotted lines in Fig. 1, t us sep-- arating the flue 11 from the furnace chamber. Kndling isV then placed` in the chamber through its rear open end together with a supply of chips to be melted, the charge then covered withY slag, and fired, whereupon the flue is moved intocontact with the chamber fournace chamber. -At the lower axis of the furnace lopposite the burner is a flared inlet opening 25 with which a cylindrical casing 26 communicates, said easing having a conpower as desired, a hopper 30 being associat-` ed with the casingv for. delivering chip4 or L scrap metal thereinto from a bin 31 or other suitable source. The furnace now being sufficientlyvcharged with scrap metal and fired, 100
the initial portion of the molten metal bath 24 is produced, and-as the molten slag 24 thereon is of a viscous and expansible consistency the high temperature Within the chamber and the rotation of they latter will cause such slag to flow around the interior of the furnace and form a continuous pliant lining adhering to the furnace wall in the manner substantially as indicated in Fig. 1, and which normally covers the inlet 25. Metal chips, or scrap, of the character described, are relatively cold and, as they pass from hopper 30 into casing 26 and then advanced by the conveyor 27 through the inlet 25 they come into contact with the pliant slag lining or curtain 24', pushing the same inwardly and at the same time chilling it. The slag becomes depressed and stiff in the area contacted by the incoming cold metal, and thus serves as a. curtain between the combustion chamber of the furnace and the incoming chips, whereby they are free to flow into'the molten bath, which contact of the chips with the bath causes them to melt rapidly and become a part thereof, the molten mass occupying approximately the space indicated in Fig. l, itslevel line being beneath thev flared inlet 25. By this process the chips or other metal charge which readily oxidize are separated and protected from all combustion gases by the slag curtain and are instantly converted into molten metal to be drawn from the furnace in quantitiesAll as desired. It will be understood that the rotation of the furnace with the intense heat in its chamber distributes the slag in blanket form to produce the adhering curtain about the interior of the furnace and which curtain remains intact until the furnace becomes chilled, the tapering formation of the end thereof retaining the pliable slag mass in relation to the furnace wall, as indicated in Fig 1. y
claim as my invention: 1. A furnace for melting metal, comprising an inclined rotatable melting chamber having an open tapered fuel receiving end and a closed opposite end including a liared conducting inlet, means for establishing an intense heat in the chamber to reduceslag covered metal inthe chamber to a molten mass, and means for rotating the chamber to spread the slag to form a lining throughout its interior for retaining/the mass in the chamber and separating such massy from the products of combustion lin the chamber and whereby the slag may be depressed and chilled by incoming metal to provide space forythe deposit of such metal into the molten mass.
2. A furnace for melting metal, comprising a member including a chamber rotatable about an inclined axis substantially coincident with the axis of the chamber, the latter having a fuel receiving opening in one end thereof, means for rotating the chamber, a non-rotatable flue normally abutting the fuel receiving end of the chamber, and means for supporting and conveying the. flue into and out of contact with the chamber.
, `3. A furnace for melting metal,.compris ing an inclined chamber having a fuel receiving opening in one end and a flared metal conducting opening in its opposite end said openings being substantially coaxial with the chamber, means for conveyin metal through said flared opening, a porta le iiue having fuel conveying means therein and adapted to kbe disengaged from the chamber for access thereinto and to be engaged with the chamber during the process of melting the charge therein, and means for rotating the chamber whereby the slag may be depressed and chilled by incoming scrap metal to provide space for the deposit of such metal into the molten mass, and means forengaging and disengaging the heat establishing means in `relation to the chamber for the purposes set forth.
5. A furnace for melting metal, comprising a chamber rotatable about an inclined axis substantially coincidentv with the axis of the chamber, said chamber having a fuel receiving inlet in one end and a metal receiving inlet in its opposite end, means for supplying metal to the chamber throu h the latter inlet, means for rotating the (ilxamber, a non-rotatable Hue normally abutting the fuel receiving end of the chamber, means associated with the Hue for conveying fuel into the chamber, and means for engaging and disengaging the flue in relation to the chamber.y
In testimony whereof I aiiix my si ature.
JOHN F. CRAWF wRD.