US1930323A - Crucible furnace - Google Patents

Description

Oct. 10, 1933- F. souTH, JR., Er AL GRUC IBLE FURNACE Filed Sept. 16, 1930 my, n? w NUMn N EH R Va m mmf T 4N A 3. @Zw M 5 o V.. B

Patented Oct. 10, 1933 y 1,930,323 onUolBLE FURNACE Furman South, Jr., Pittsburgh, and Oscar E. Neuhausen, Zelienople, Pa., assigncrs to Lava Crucible Company, Pittsburgh, Pa., av corporation of Pennsylvania Application September 161930 Serial No. 482,254 e 3 Claims. (Cl. 263-14) Our invention relates to improvements in crucible furnaces,`or furnaces of the type wherein metals are melted or otherwise treated in crucibles disposed within the furnace, the crucibles being 5 heated and the heat transmitted to the contained metal by conduction, convection and/or radiation through the walls of the crucibles.

Furnaces of the character designated, as heretofore constructed and operated, require almost constant attention and frequent charging; the

repeated charging and attention is highly objectionable and the cost of production is considerably more than it should be. Also, the operator is subjected to intense heat, being required to work in close proximity to the/flames emitting from the top of said furnace.

The present invention contemplates a construction particularly designed. to overcome the objectionable features above stated and to provide for rapid heating, economical fuel consumption, low metal loss, and high metal purity.

Our invention includes, in a crucible furnace, a melting or reduction chamber in which the crucible is positioned and a removable furnace extension or supplemental member or structure associated with the body of the furnace, said supplemental structure being provided with a charging chamber, or hopper therein of such dimensions and configuration as to form a continuation of the crucible within the melting chamber, and permitting the entire charge to be placed in the furnace before starting the latter, whereby the entire charge may be initially introduced and preheated before actual reduction in the crucible.

A further object is to produce said furnace extension structure with passages therethrough adjacent the charge receiving chamber or hopper for the passage of the heated gases and products of combustion.

4D A still further object of our invention is to provide an elongated combustion chamber in tangen tial communication with the lowermost portion of the reduction or melting chamber, for the purpose of complete combustion therein, whereby the heated gases are passed to the melting chamber at their maximum temperatures.

Additional objects and advantages will become apparent from the following specification taken in connection with the accompanying drawing,

wherein:

Fig. 1 is a vertical sectional view taken through a crucible furnace embodying our invention, said furnace being of the tilting or pouring type and;

Fig. 2, a top plan view thereof.

Referring to the drawing, the crucible furnace A is of the upright cylindrical type and comprises a body proper 2, formed of suitable refractory material surrounded by an insulating lining 3 and a metal casing 4. The inner wall of the cylindrical refractoryl body 2 forms a melting or reduc- 60 tion chamber 5 for receiving a crucible 6, of the usual and well known type. Said crucible is preferably mounted upon a pedestal 7 on the floor 8 ofthe furnace in such a manner that the upper edge 9 of the crucible lies in substantially the same 65 plane asgthe upper surface l0 of the body 2.

Positioned adjacent the lower portion of the body 2 and preferably constructed integrally therewith, weprovide an elongated combustion chamber 11 disposed tangentially with respect to 70. the cylindrical melting chamber 5 and in open communication therewith, the'lowermost portion ofthe chamber 11 being co-extensive with the floor8 of the furnace. Said chamber 11 is also preferably tapered and is provided with any suitf5 able oil or gas burner, diagrammatically shown at 12, at its outer open end.

Due to the foregoing construction, the combustion of the fuel supplied to the'burner 12ftakes place entirely within the chamber v11, thereby passing the heated gases to the reduction or melting chamber 5 at their maximumtemperatures. The tangential relation ofthe combustion chamber to the melting chamber imparts a circular motion to the heated gases to surround the crucible 6 for effective heating. Thus, it will be seen that, due to the entrance of the gases at their maximum temperatures and completely around the crucible, the same will be heated uniformly. The chamber 5, therefore, is truly a melting chamber rather than a combustion chamber, as in prior constructions.

An important and characteristic feature of our invention consists of a furnace extension structure, generally designated B, and comprising a hollow cylindrical body 13 formed of refractory material, designed to be placed upon the body 2 of the furnace. The bottom surface of the structure B is preferably recessed, as at 14, to receive and contact with the upper surface 10 v.100 of the furnace body 2, and is encased in a metal casing 15.

For the purpose of receiving a portion of the charge and subsequently introducing the charge into the crucible 6, the extension member B is .105 provided with a hopper or charging chamber.

As illustrated and as preferred, the hopper 16 is formed as a part of or integral with the body extension B and is `defined by the inner surface of the wall of a centrally disposed slightly taper- .110

the wall of the bore 18, thus forming passages for l the heated gases sufficiently near the hoppery 16 to pre-heat the charge therein. A

It will be understood that the construction described provides a furnace wherebyA the entire charge of metal, from ingots to'borings, may be introduced by a single charging operation, and the furnace will require no further attention until the molten metal is in condition to be re-y moved or poured.

A lid or cover 23 is removably positioned over the hopepr opening and is adapted to be elevated and swung aside'by any suitable means, as for example,a pivoted swinging arm 24. By placing the cover over the hopper,.the entire charge in y thehopper and furnace is'enclosed. Upon ignition of `the burner 12, the charge is'melted-by means ofthe transfer of heat in the chamber 5 by conduction, convection and/or radiation.

As stated, the extensionmember B is removable,'and may be displaced to enable removal of the cruciblef6 as for pouring or repairs. :Suitable meansmay be Aemployed for handling the said member, but as the same do not form a part of the present invention,f=and are tobe made the 'subject of avv separate application, fthey are not fully described herein.

The furnace A illustrated -is of the tilting or pouring type, as contrasted with the pit or stationary type. Suitable trunnionsf25 are provided on the furnace A for rotation thereof, and the furnace, it'will be understood that said extension` is interchangeable and maybe applied to any` type of crucible furnace.

VIt will be readily'seen from the-foregoing that vwith the adjacent portions of both a great saving in time and labor is accomplished by providingfor a single charging of the furnace, as well as a more ecient construction, due to the combustion chamber and the enclosed melting or reduction chamber. Also, by reason of the extended height of the furnace, the operator is not subjected to the direct heat encountered in the operation of the low form of crucible furnace.

We claim:

1. A crucible furnace comprising a body proper having a melting chamber, a crucible in said melting chamber, a refractory body extension on said body proper, said body extension having a hopper opening therethrough in communication with the crucible, said extension having a plurality of passages for heated gases about said opening defining a Wall surrounding said opening, said passages being provided in an integral part of the extension, the portions of the extension between adjacent passages being integral the extension proper and the said wall.

2. A crucible furnace comprising a body proper having a melting chamber, acrucible in said melting chamber, a refractory body extension on said body proper, said body extension having a hopper opening `therethrough in communication with the crucible, said extension having a plurality of passages for heated gases about said opening defining a ywall surrounding said opening, said passages being provided in an integral part of the extensionythe portions of the extension between adjacent passages being integral with the adjacent portions of both the extension proper andthe said wal1,.the lower edge of said wall resting on the upper edge lof said crucible.

3. In an extensionbody for the melting chamber of a furnacev having a crucible therein, an integral part of vrefractory material having passages'y for the outlet of heated gases from the furnace,.said integral part outwardly of said pas? FURMAN SOUTH, yJR. vOSCAR E. NEUHAUSEN.

Paen N0. 1,930,323. Qcobe l0, 1933.

FURMAN SUTH, 5R., in AL,

Ii is hereby ceried tha the name h?, assigaee n i'he above mimbeed pateni was erroneusy described an@ specie "Lawa Crucible @amp i whereas said nauw smu have Eem descrbe all seefied as Lava Cra Company of Pitsburgh, as shwu by the rsmfds si assgnmenis in his of and thai the said Letters Pasent shoud be a with hs ofrection hee ha the same may conorm io he resord 0 he can@ in the Fatemi -iice.

Signed and sealed this 5th day of Deeember, A. E. i933.

F. M, Hopkins (Seal) Asng Commissioner of iatents.

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