US938752A - Method of working metals, ores, and the like. - Google Patents

Description

Patented Nov. 2, 1909.

0. FR METHOD 0? WORKING METALS, 0113s, AND THE LIKE.

APPLIOATIOH FILED AUG. 31, 1905.

To all whom it may concern:

Be it known that I, Or'ro FRICK, a subject of the King of Sweden, and a resident of Saltsjiibaden, in the Kingdom of Sweden,

have invented new and useful Improvements in Methods of WVorking Metals, Ores, and the Like, of which the following is a specification, reference being had to the drawing accompanying and forming a part hereof.

This invention relates to an improved method of working, whereby the power factor may be increased in the melting of metals, ores, and the like, and in reducing ores by means of electric transformer furnaces.

In melting metals and the like the melting of the principal parts of the charge as well as the following treatment, 2. 6., the refining and the addition of special materials or chemical combinations for imparting special qualities to the product, and so forth, were hitherto usually accomplished in one and the same'furnace, the material to be melted and I the melted mass forming a single conductor of approximately constant cross-section.

'The said method has, however, a great disadvantage, inasmuch as it is difficult to treat large charges by it, the self-induction being very considerable and, consequently, the power factor becoming very small. The power factor decreases nearly in proportion to the increase in the cross-section and in the weight of the charge.

, 'The British patent No. 28,805 of Charles .Prosper Eugene Schneider, dated December 31st, 1903, discloses an electric transformering too large lag, a furnace being used wherein the larger part of the melting-room has a considerably reduced cross-section.

The object of the present invention islto make it-possible to treat charges of any size by means of transformer-furnaces.

The invention consists in carrying out the treatment in two separate transformer-furnaces the first of whichis constructed for a comparatively small charge and. great consumption of energy, essentially for melting the principal parts of the material to be produced, while the second-furnace, whichis constructed for a large. charge and is capable of storing the melted materials as they are continuously or intermittently poured into it from the first. furnace, is adapted for a comparatively small consumption of energy andis mainly used to-keep the melted ma- Specification of Letters Patent.

furnace, the object of which is to render it u, possible to treat large charges, while obviat- Unirn' earns PATENT orrron.

OTTO ERICK, OF SALTSJ6BADEN, SWEDEN.

METI-IGID OF WORKING METALS, ORES, AND THE LIKE.

terials at constant heat until the whole charge is ready. The favorable influence of this method on the power-factor in the pnmary circuit will be easily understood by an example. Supposing the angle of lag to be y the same can be estimated by the following equation:

an.q)-c. WP+Ws if the current necessary for the magnetization. of the transformer core is small, so that the ampere-turns of the primary winding may be supposed to be equal tot/hose of the bath, which is practically tllx, case inevery well-designed transformer.

In the above equation a constant,- frequency per second, r resistance of the melting-bath in ohms, magnetic resist ance of the primary flux of leakage. W magnetic resistance of the secondary flux of leakage. From this formula it is seen that tan. go is universally proportional to the resistance of the melting bath. The resistance of the bath evidently decreases with increasing crosssection and weight of charge. The power-factor, or cosine mp deincreases as tan. p increases. Consequently, the power-factor decreases with increasing cross-section and weight .of bath. If, for instance, one transformer-furnace were to be used for melting a charge of tons of steel,

the cross-section of the melting-bath being constant, the lag between current and voltage, for instance at periods a second, would correspond to a power factor cos. =0.20,

that is to say the'current would be ='5 times larger than if.the power factor, or the real power apparent power the copper windings of the dynamo arelto be dimensioned to suit the current, it is evident that they must be calculated for 5 times the real power. I

If the furnace-plant be constructed acwere= 1. As the leads and Patented Nov. 2, 1am. Application filed August 31, 1905. Serial No. 276,519. i

cording to my present invention, and the larger furnace be adapted for a charge of 15 tons, then, under the same conditions, the power factor of this furnace is also 'cos. 91:020. As, however, the principal function of this furnace is to maintain the molten steel at a constant temperature, the energy consumed has, practically, only to cover losses due to heat radiation, and may for instance amount to only 10 per cent. "of the total energy'required for the whole melting effected in the large furna The other 90 per cent. of the total process.

is consui'ned in the smaller energy furnace g in which the materials are melted and which, 1

the same can be increased without difiiculty to cos. 9 0.6.. The leads and the generator factor of thus in this case need only be calculated for 1 an apparent power of twice the real power,

This useful result 1S losing any advantage of r usual transformer-furnace. Gn the coronary, further advantages are gained over the welllsnown single transforiner-furnaces, which are not suited for continuous working if different products, such as alloys of steel and chro mium, tungsten, nickel, and so forth, are to produced, one after another It is a wellknown fact that a tronsformer-furnace must always have a molten continuous bath, for which reason it is necessary to leave part of the bath in the furnace from one charge to the next. In making ordinary carbon steels this is not very inconvenient, but in making steel-alloys it may not be desirable to leave a part of a charge of niche -steel to a followin charge of chrome-steel.

hen using two furnaces, according to this invention, this inconvenience does not occur as the addition ofspecial materials, such as nickel, chromium, and so forth, is e which may be totally emptied after each charge, it being refilled from the smaller furnace.

By using two furnaces continuous working and the full continuous utilization of the available machinery "will also be improved in cases where the melted material requires certain time for refining, as a new charge may be started in the small furnace during; the time the preceding charge is being re need in the larger one.

The two furnaces may be supplied with current by means of a eaunmon, generator or by separate generators.

lin order to gain the above mentioned result it is necessary to dimension the core and the primary winding of the smaller furnace in such a manner that a higher effective voltage will beugenerated in itsbath and that the greatercpart of the power will he consumed by the said furnace in spite of the higher resistance of the bath, The iron core and the primary winding of the larger furnace must,'on the other hand, he so diiued without meusioned that the bath. of the same consumes a coi'nparatively uuull amount of energy. T his is carried out in such a manner that the smaller furnace has a? magnet-core of a larg r cross-section an l is generally worked h a smaller number of turns in the primary coil than the larger furnace.

in the drawing, Figures 1 and 2 show, in vi tical section and plan-view, respectively,

.urnace-plaut adapted to be used in carrying out the process above described.

Referring to the drawing, 1 is the smaller furnace in which the main melting-process is accomplished and from which the melted material is conveyed, either continuously or intermittently into the larger furnace 2, which serves as a refining furnace and as a storage receptacle, until the whole charge is ready. and i are masonry of lire-proof or other suitable material. and 6 are the ring-shaped crucibles inclosed in the masonry. 7 and 8 are the primary windings supplied with alternating electric current from the same source of current, or from two separate sources of current 9 and 10 are the magnet cores.

Having now described my invention, what I claim as new and desire to secure. by Letters Patent is:

1. The method of increasing the power factor in treating ores and metals by means of electric transformer furnaces, which conin melting the principal part of the charge in one transformer furnace, c0nvey--' ing the melted material from the said furnace into another transformer furnace adapted to hold an essentially larger charge than the former one, and refining and storing the said material in the said larger transformer furnace, substantially as and for the purpose set forth.

2. The method of increasing the power factor in treating ores and metals by means of electric transformer furnaces, which conin melting the principal part ofthe charge in one transformer furnace, conveying the melted material from the said furinto another transformer furnace adapted to hold an essentially larger charge than the former one, and storing the said material in the said larger transformer fornace, substantially as and for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

J OTTO ERICK.

Enwnno L. ADAMs,

lam. Frances.

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