US1715678A - Melting furnace - Google Patents

Description

June 4, 1929. 5, SCHNEIDER 1,715,678

MELTI NG FURNA CE Filed Sept. 15, 1926 WI ESSES' I I lNVENTOR X sii pfiansr/ifl/bi r ALITORNEY Patented June 4, 1929.

UNITED STATES PATENT OFFICE.

STEPHAN SCHNEIDER, OF MEISSEN, GERMANY, ASSIGNOR T0 WESTINGHOUSE ELEC- TRIC 86 MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

MELTING FURNACE.

Application filed September 13, 1926, Serial No. 135,053, and in Germany December 14, 1925.

My invention relates to melting furnaces and particularly to electrically heated melting furnaces for melting aluminum and similar metals.

An object of my invention is to prevent loss in melting by providing an atmosphere of a non-oxidizing or reducing gas in a melting furnace.

Another object of my invention is to provide means for forcing the molten metal out of such furnaces by increasing the pressure of the reducing gas.

Another object of my invention is to provide a melting furnace having a reducing atmosphere, in which the molten metal will form a seal to prevent escape of the gas.

I of the discharge outlet.

Another object of my invention is to provide an electric melting furnace of the above indicated character that shall be economical to manufacture.

Other objects of my invention will be apparent from the disclosure.

In melting metals, considerable loss occurs by reason of the contact of air with the hot metals and the consequent oxidation of the metals. Such losses may reach as high as 2% in the case of aluminum, and, in addition thereto, a layer of oxide is formed on the molten metal which causes impurities therein and necessitates skimming'of the molten metal, thereby causing further loss.

In the manner of practicing my invention, which is disclosed herein, an electrically heated furnace, having a discharge conduit adapted to be sealed by the molten metal from the outside atmosphere, is employed. Means are provided for introducing into the furnace a non-oxidizing or reducing gas under pressure. After the metal is all melted, the pressure of the gas is increased to force the molten metal out of the furnace by way The single figure of the drawing is a view, in vertical section, of a melting furnace embodying my invention.

Referring to the drawing, which illustrates the present embodiment of my invention, a base member 10 has a crucible or melting pot 11 mounted thereon. Surrounding this melting pot and also resting on the base member 10 is an outside wall of refractory insulating material 12. Imbedded in this insulating material are the coils 13 which receive an electric current from any suitable source for the purpose of heating the furnace.

A suitable cover means is provided which, in the present embodiment of my device, comprises aninterior removable cover 14 resting on the top of the crucible and an outer cover member 15 having a recess 16 which is somewhat larger than the inner cover member 14. The outer cover member rests on the insulating material 12, the inner cover member being received in the recess 16. As a result of the recess 16 being somewhat larger than the inner cover member 14, an air space is provided which, of course, will aid in retaining heat within the furnace. An eye member 17 may be provided on top of the outer cover member 15 to permit ready re moval thereof.

As shown in the present embodiment, two covers are provided but it is obviously within the scope of my invention to employ only a single cover if desired.

Mounted on the inner cover member and extending through a hole therein, preferably situated at the center of the cover member, 18 a discharge conduit or outlet member 18. The upper end 19 of the conduit 18 extends slightly above the inner cover member, while the lower end 20 extends downwardly to a point slightly above the bottom of the melting pot 11. The outer cover member 15 is provided with a discharge passage 21, the outer end'22 of which opens to the atmosphere through a projecting spout portion 23 of the cover member '15. The inner end 24 of said discharge passage receives the end 19 of the discharge conduit, the conduit fitting snugly therein. The end 19 of the discharge conduit may be cemented to the end 24 of the discharge passage by the use of suitable heatresistmg cement.

Extending through the refractory insulating wall and the crucible wall and opening into the interior of the crucible, is a conduit 25, the outer end of which is connected to a suitable source for supplying a non-oxidizing or reducing gas, under pressure. This source of supply is not illustrated.

In one method of operating the furnace, the cover members-are removed, the crucible charged with material to be melted, and the cover members then replaced. The non-oxidizing gas is introduced through the conduit 25.t0 the interior of the crucible, and the crucible is heated by current through the coils 13.

As soon as enough of the metal is melted to reach the lower end 20 of the discharge conduit, a seal of molten material, which will prevent the escape of the non-oxidizing gas to the atmosphere, will be efiected. After the material is all melted, the gas pressure is increased sufiiciently to force the molten i the appended claim.

' I claim as my invention:

A furnace for melting metal comprlsing a melting pot, electrical means for heatlng said melting pot, means for supplying gas under pressure to said neltingpot, a removable cover member for said. melting pot, a discharge conduit having its upper end mounted in said cover member and extending therethrough, the lower end of said conduit extending toa point near the bottom of said pot, a second cover member having a recess adapted to receive said first-mentioned cover member, a discharge passage in said second cover member, the inner end of said discharge passage being adapted to receive the upper end of said discharge conduit.

In testimony whereof, I have hereunto subscribed my name this 12th day of August, 1926.

STEPHAN SCHNEIDER.

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