US3043895A - Multichamber smelting furnace - Google Patents

Description

July 10, 1962 J. P. ROHN 3,043,895

MULTICHAMBER SMELTING FURNACE Filed April 2'7, 1959 H44 P&nr BY will be drawn back into the respective chambers.

Patented July 10, 1962 7 3,043,895 MULTICHAMBER SMELTlNG FURNACE Johann Peter Rohn, Hochkirchen, near Koln, Germany,

assignor to Russ-Elektroofen K.G., Koln-Bayenthal,

Germany, a German firm Filed Apr. 27, 1959, Ser. No. 809,132 Claims priority, application Germany Apr. 28, 1958 10 Claims. (Cl. 13-27) The present invention relates to a multichamber furnace for melting metals.

In the design and operation of melting furnaces for metals, especially nonferrous and light metals, but also for iron, many efforts have been made to maintain the molten metal at the place of its discharge from the furnace as pure and as quiet and undisturbed as possible.

For this purpose, there have been prior disclosures of furnace designs which consisted of two adjacent parallel chambers which were connected with each otherat the bottom by channels, and wherein the space between the two chambers was filled out by the electric heating coil which surrounded the connecting channels between the chambers and was used primarily for melting the metal within these channels.

Although a furnace design of this type has the advantage of having a low height and of also achieving a relatively quiet metal bath, it also has a series of disadvantages which have prevented it from being used extensively. The foremost deficiency of this furnace design is the fact that the metal is melted in both chambers. Consequently, the material is also agitated in both chambers, with the result that the metals will not properly alloy with each other. Furthermore, this furnace design is always subject to the danger that the channels will become overheated and to the further danger that, because of the prevailing flow conditions, such overheated metal It has also been found that the large surface of the metal bath and the large sump of metal which is necessary for starting the operation of the furnace constitute a deficiency of this furnace design.

In order to overcome the above-mentioned disadvantages and to attain the least possible movement of the metal bath and the greatest possible purity of the calmed molten metal at the point of its removal from the bath, there have been other furnace designs in which one chamber served solely as a melting and alloying chamber, while the other chamber was designed for maintaining the metal at the proper temperature and for permitting its removal for subsequent use. This heat-maintaining and output chamber was made smaller than the melting chamber and was connected with the latter by a channel 'at the bottom, and the melting chamber, in turn, was

extended downwardly to form a melting trough which alone was acted upon by the electric heating coil. The metal was charged into the melting chamber and the actual melting occurred in the downwardly extending trough so that the molten metal could become quiet within this trough and the lighter impurities could rise toward the surface. Consequently, only purified and quiet metalcould enter into .the heat-maintaining and output chamber. An excessive heating of the channels was thus avoided and only a relatively small sump was required for starting the operation.

However, such a furnace also has the disadvantage of a relatively large bath surface and thus of a considerable oxidation of such surface. Furthermore, the metal is heated more intensively in the melting chamber than in the adjacent heat-maintaining and removal chamber which is not alfected by the heating coil. In both types of furnaces as above described it was also found to be a very great disadvantage that the lining thereof with a refractory material was extremely diflicult. T-he tamping of such material around the two parallel chambers, the connecting channels between them, the troughlike downward extension of the melting chamber and other furnace parts was a very complicated and expensive procedure.

it is an object of the present invention to overcome the above-mentioned disadvantages of the known furnace designs by proceeding along entirely new directions different from all the attempts which have previously been made to avoid these disadvantages.

A further object of the invention is to provide a furnace which permits the molten metal to be removed therefrom in a refined condition without any disturbing movement of the bath in the removal chamber.

Another important feature of the new furnace design is the fact that there are no connecting channels between the chambers, and that the furnace is of a very low height. It also permits an easy preparation and thus an easy possibility of alloying, and a preferred embodiment of the invention also permits thefurnace to be started with a solid charge.

More particularly, the invention therefore relates to an electric multichamber furnace for smelting various metals including iron and steel, which comprises a melting chamber and one or more heat-maintaining and removal chambers. The most distinguishing feature of the new furnace is the fact that the heat-maintaining and removal chamber or chambers are provided in the form of one or more inserts which are mounted within the melting chamber near the side wall thereof, and that one or more apertures are provided in the bottom or side wall of such insert chamber for the fiow of molten metal into the same after it has been refined in the melting chamber.

The melting chamber of the furnace may be easily lined with brick or by tamping the refractory material in place. However, such lining is not absolutely necessary. If the kind of alloy to be produced is to be changed frequently, a crucible may be removably inserted into the furnace coil. Such a crucible may consist of refractory material alone which has been molded or tamped into shape and then been calcined. Such a crucible may, however, also consist of graphite or a suitable alloy of steel or iron.

Further objects, features, and advantages of the present invention will appear from the following detailed description thereof, particularly when read with reference to the accompanying drawings, in which FIGURE 1 shows a central vertical section of the furnace according to the invention on a reduced scale;

FIGURE 2 shows at the upper part a plan view of onehalf of the furnace according to FIGURE 1 without the heating coil and without the outer frame and cover, and at the lower part a horizontal cross section of the other half of the furnace, also without the supporting frame; while FIGURES 3 and 4 show diagrammatically two modifications of the invention.

FIGURE 1 of the drawings illustrates a preferred embodiment of the invention, namely, a crucible furnace which permits the operation of the furnace to be started with a solid charge. The melting chamber 1 has an upper opening A through which the solid metal is inserted so as to be melted within chamber -1 by an electric heating chambers side-by-side, for example, a melting chamber and a heat-maintaining and removal or output chamber which are connected by channels, but that one chamber, namely, the removal chamber, is disposed within the other melting chamber. This new furnace design has the advantage that the entire furnace not only requires considerably less space, but that the danger is completely avoided that the connecting channels between the two chambers will be excessively heated. Furthermore, the new furnace may be built in the form of a crucible furnace.

The output or removal chamber 8 is made in the form of an insert '9 of any suitable material which is removably suspended in the melting chamber 1 and may, for example, be secured to the furnace cover It In the embodiment according to FIGURE 1, the insert 9 is made of a conical shape and inserted into a ring 11, the inner surface 12 of which is likewise conical in accordance with the angle of the conical outer surface of insert 9. The upper end of chamber 8 may be closed by a cover 10.

Insert 9 has one or more apertures 14 in its bottom through which the molten metal M may flow from the melting chamber 1 into the removal chamber 8, as indicated in FIGURE 1 by the arrows. If desired, the side wall of the insert 9 may also be provided with such apertures. Since the interfering movements of the bath of molten metal in the melting chamber 1 occur primarily near the surface thereof and the impurities generally likewise collect near the surface, the molten metal rising into the removal chamber 8 through the aperture 14 at a point far below the surface of the metal in chamber 1 will be entirely free of impurities as well as entirely quiet, that is, without any agitation. This refined metal may then be easily ladled out of the removal chamber 8 after the cover 13- has been removed.

The upper part of FIGURE 2 shows a plan view of onehalf of the furnace according to FIGURE 1 after the cover 13 has been removed, and also without the heating coil 2 and the supporting frame 7, while the lower part of FIGURE 2 shows a horizontal cross section of the furnace taken underneath the crucible insert 9 in FIG- URE 1 and also without the supporting frame 7. Both FIGURES 1 and 2 show the eccentric arrangement of the insert 9 in which the molten metal is maintained at the proper temperature by the surrounding body of metal in the melting chamber 1. This eccentric position of insert 9 relative to melting chamber 1 has the advantage that the insert is more easily accessible from one side of the furnace and that sufficient space will be left for easily charging the furnace through the top opening A. Naturally, if for any reason it should be desired, the insert 9 may also be mounted centrally of chamber 1.

In the modification of the invention as illustrated in FIGURE 3 the furnace chamber 15 is not made round but oval so that, when the insert 16 is mounted eccentrically therein, the area B for charging the furnace will be even larger than the corresponding area of the round furnace according to FIGURES 1 and 2.

It is also possible according to the invention to provide two or more removal chambers within one melting chamber. One preferred embodiment with two removal chambers in an oval furnace 17 is illustrated in FIGURE 4. These two chambers are again provided in the form of inserts 18 and 18a which are disposed near the opposite highly curved wall portions of the oval melting chamber 17 and are shaped so that the sides 19- thereof facing towardthe center of chamber 17 are flattened, while the other parts of the inserts substantially correspond to the curvature of chamber 17. Through this flattened shape of the inserts a large space Cwill be left free between them through which the furnace may be easily charged.

The furnace insert forming the removal chamber may be made of any suitable material, for example, graphite, fireproof clay, calcined magnesite, silimanite, or a special metal alloy. If during the operation of the furnace, the insert should be broken or damaged, it may be easily removed and replaced by a new insert without requiring any long interruption of the operation since the broken parts will not alfect the molten metal, but will pass to the surface of the molten metal in the melting chamber from which they may then be removed.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

1. An electric melting furnace for smelting metals comprising, in combination, a single, upright, stationary melting chamber made from electrically non-conductive material and having an upper charge opening for charging the melting chamber with metal to be molten therein; at least one electric coil surrounding said melting chamber; and at least one insert chamber arranged within said melting chamber eccentrically with respect thereto and with respect to said coil surrounding said melting chamber and extending from the top of said melting chamber toward the bottom thereof so as to be adapted to dip deeply below the surface of the molten metal in said melting chamber, said insert chamber having a bottom portion formed with at least one aperture therethrough from which the refined and molten metal may enter from said melting chamber into said insert chamber to be maintained in the latter in quiet state and proper temperature and for being removed therefrom, the inner volume of said insert chamber being considerably smaller than the inner volume of said melting chamber.

2. A furnace as defined in claim 1 in which said aperture is arranged substantially centrally through the bottom wall of said insert chamber.

3. A furnace as defined in claim 1, wherein said melting chamber has a substantially circular cross section and said insert chamber is disposed eccentrically within said melting chamber near one side thereof.

4. A furnace as defined in claim 1, wherein said melting chamber has an oblong cross section and said insert chamber is disposed within said melting chamber near one end thereof.

5. A furnace as defined in claim 1, wherein at least two of said insert chambers are disposed within said melting chamber in a spaced relation to each other to accommodate said charge opening.

6. A furnace as defined in claim 1, wherein said insert chamber has a flattened side in the direction facing toward said charge opening.

7. A furnace as defined in claim 1, further comprising a cover on said melting chamber having a conical opening therein, said insert chamber having a conical shape adapted to be suspended within said conical opening in said cover.

8. A furnace as defined in claim 1, further comprising a lining of refractory material on the inner wall of said melting chamber.

9. A furnace as defined in claim 8, wherein said lining forms an integral unit adapted to be inserted into and removed from said inner wall.

10. A furnace as defined in claim 1, wherein said melting chamber comprises a removable unit of refractory material.

References Cited in the file of this patent UNITED STATES PATENTS 5 UNITED STATES PATENTS Wilke Nov. 4, 1924 Goldberg May 11., 1937 McParlin Jan. 2, 1949 5 Cornell June 7, 1949 6 Lillienberg Aug. 11, 1953 Hogel et a1. Aug. 25, 1953 Rusler June 30, 1959 FOREIGN PATENTS Great Britain June 4, 1948

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