US1837070A - Apparatus for charging aluminum producing furnaces - Google Patents

Description

Patented. Dec. 15, 1931 UNITED STA ERNST BOTH, OF LAUTAWER-K/LAUSITZ, GERMANY APPARATUS FOB, CHARGING ALUMINUM PRODUCING FURNACES Appna'ao med December 2s, 1929-, serial No.

My invention relates to an improved ap-4 paratus for charging an aluminum produclng furnace with aluminum-oxide for the purpose of reducing manual work and im- 5 proving the operation of the furnace.

The price of aluminum is greatly influenced through the great amount of manual operations connected with` its manufacture, beginning at the moment, when the aluminum-oxide enters the furnace-building and prevailing, until the produced metal leaves the same. Particularly the charging of the furnace is till now performed manually, a number of workmen arevbusy in shoveling the charge into the furnace and distributing the same around and between the electrodes. The charged mass however does not drop into the bath immediately, but is greatly retained by the crust, which is formed on the surface of the bath. Y A

The consequence is that, as the aluminumoxidev in the molten bath continues to be reduced, the latter gets poor in aluminum-oxide; as soon as an electric alarm bell indicates this unsatisfactory condition of the bath, a column of workmen get busy in order to loosen and break the crust by means of -hammerscrowbars, chisels or` similar tools, to submerge the broken crust particles into the bath and to shovelJ fresh charge into the furnace. Occurrences of this kind happen very frequently and often at the same time in several furnaces. f

The object of my invention is to remedy this defect. Vith this object in view I provide means for automatically charging the fur nace and in proportion to the formationof metallic aluminum by reduction.

A preferred embodiment of the invention 40 is shown in the accompanying drawing, which shows by way of examplea sectional view of a furnace, equipped with the present charging device.

In the anode b there is provided a vertical central passage c; mounted on the top of the anode is a funnel al for the reception of the aluminum oxide the arrangement being such, that the orifice at the bottom of the funnel will occupy a position invertical axial alinement with the channel c of the anode. The

.valve t is connected with a current indicating 411,236, and in Germany November 27, 1928.

discharging orifice of the funnel is provided with a suitable controlling device such as an adjustable valve or theflike, adapted `to ensure an absolutely reliable regulation with the result, that always so much aluminum oxide will be allowed to pass into the bath, as is required for saturating the same with the necessary amount.

In order to accomplish this result the slide device e in a manner, that the slide valve will be drawn back so as to increase the free area of the orifice accordingly andallow a'larger proportion of aluminum oxide to drop into the container a, whenl the bath exercises an increased resistance due to its growingscarcity of aluminum-oxide, whereupon the resistance will again decrease to normal condition.

It will be seen that in this way the supply of aluminum oxide to the bath will be automatically and reliably controlled and excessive poorness of aluminum-oxide cannot occur. The bath directly below the anode is always in a perfectly molten or liquid state, especially also at the central point vertically below the passage c and the orifice of the funnel (Z. Consequently the charge dropping from the funnel does not come in Contact with the solidified crust but falls immediately into the moltenmass. As the aluminum oxide is supplied to the bath in proportions corresponding toits reduction to metallic-aluminum, noundecomposed charge .will get access to the cathode-metal.

It may be of advantage to prevent the charge from impinging always on one and the same point of the surface of the bath, which is the centre thereof; in such a case I provide a. distributing member g close below the lower end of the passage or channel c, preferably a flat cone made of suitable sheet metal or any other appropriate material and so disposed that the apex of the cone coincides with the axis of the passage c. The charge dropping from the funnel through the passage drops upon the apex of the cone and is distributed uniformly over the conical surface. Such distribution of the charge 1n the bath will ensure a'quiet and regulated f working of the furnace, which is free of disr turbances.

What I claim is: l An electrical furnace for the production 5 of aluminum comprising an anodeqwith a centrnl charging channel, whose diameter is practically equal to the diameter of the cathode forming the furnace-bottom, an automatic charging device on top of the anode, a current-indicator controlling the :charging device and a distributing device within the central charging channel. w

In testimony whereof I aHix my signature.

ERNST ROTH.

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