US1373787A - Melting-furnace - Google Patents

Description

T. F. BAILY AND F. T. COPE.

MELTING FURNACE.

APPLICATION FILED FEB. 16, 1920.

1,373,787. Patented Apr. '5, 1921.

zrnannnrrs r. BAILY AND FRANK r. corn, or ALLIANCE, onro, Assralqons To THE minerals FURNACE oomrm, or ALLIANCE, care, A eonroaarron (mm MELTING-EUBNACE.

wearer.

Specification of Letters Patent.

Patented Apr. a, 1921.

Application filed February 16, 1920. Serial No. 359,090.

\ of which the following is a specification.

Our invention relates to melting furnaces and more particularly to a furnace especially adapted for melting brass and provided with meansfor preventing the usual loss of a considerable percentage of the zinc from the brass during the melting process.

It is well known to those versed in the metallurgy of non-ferrous metals that inmelting brass in the usual form of melting furnace a considerable amount of the zinc from the brass is lost in the form of zinc vaporwhich may be deposited around the furnace in the form of a' fine powder. I

This loss of zinc from the brass is probably .due to the great difference between the melting points of zinc and brass.v As is well known to those skilledin the art, brass is an alloy of copper and zinc in which the proportions of. the two metals vary for different uses. The majority of these alloys contain a very large percentage of copper,

the melting point of which is 1929. As the melting point of zinc is only 779 while the melting point of brass is 1692, a considerable amount of zinc in the alloy is vaporized during the melting of the brass.

In the ordinary melting furnace such as is in general use for melting brass a considerable per cent. of this zinc vapor is lost escaping from the furnace and being deposited around the furnace in the form of a fine powder. This loss of zinc from the brass represents not only a loss of a certain per cent. of the metal but also changes the ,proportions'of the alloy since owin to the high temperature of vaporization 0 copper there is no loss of copper fromthe alloy during the melting process The objects of the invention are to provide a furnace especially adapted for melting brass in which means are provided for preventing the loss of zinc from the brass in the form of zinc vapor, during the process of melting; and to generally improve and simplify melting furnaces of this character. I

These objects are attained by providing one or more condensers in communication wlth the heating chamber of the usual melting furnace, the zlnc vapor from the heating chamber passing into these condensers where it is condensed into metallic zinc. When a condenser has become partly filled with metallic zinc it is removed from the furnace and the zinc emptied therefrom, the zmc which is thus received into the condensers representing the usual loss of zinc from the brass which in practice varies from four to 1n some cases as high as twenty per cent. of zinc in the alloy.

pended claims, it being understood that va- I rious changes in the form, proportions, size and minor details ofconstruction may be made wlthin the scope of the appended clalms, without departing from the spirit or sacrificing any of the advantages of the invention.

The invention thus set forth in general terms is illustrated in the accompanying drawings forming part hereof, in which- Figure l is a vertical sectional view through a brass melting furnace showing a condenser in place upon the furnace.

Fig. 2 is an enlarged sectional. view through a tyne of condenser which is well adapted for use with the furnace.

Fig. 3 is a fragmentary-sectional view through a portion of a furnace showing a modified form of condenser.

Similar numerals of reference indicate corresponding parts throughout the several figures of the drawings.

Although our invention may be applied to, any form of melting furnace we have illustrated it in the accompanying drawings in connection with" an electrically heated brass melting furnace of the type upon which we obtained United States Letters Patent No. 1,272,286, July 8, 1918.

In this form of furnace the numeral 1' indicates a metal plate upon which the .base 2 of the furnace is supported, this base being composed of suitable insulating material such as bricks formed of kieselguhr, a metal plate 3 being preferably located upon work 4 preferably formed of fire brick and provided with the concave hearth 5 which is lined with suitable brick, heat resisting material and provided at one side with a reduced neck 6 having a pouring spout 7. A circular wall 8 formed of fire brick or other suitable material is supported upon the brick work 4 and a roof 9 preferably tend through concaved as shown is provided over said circular wall, thus forming a heating chamber between the roof, hearth and circular walls.

Mounted within the heating chamber intermediate the hearth and roof thereof and spaced from the circular side-wall is a resistance trough 10 preferably circular as shown. This trough is provided with a resistance body consisting of a carbonaceous material in granular form, such as crushed coke, graphite, carbon or the like, said resistance material being designated by the numeral 11. The trough is preferably formed of refractory material or the like and comprises the bottom wall 12 and the circular upright Walls 13, and is supported upon the radial supporting walls 14, composed of fire brick or other heat resisting material.

Embedded in the resistance material pref erably at diametrically opposite sides of the trough are suitable electrodes 28 which exthe furnace walls in the usual manner. these electrodes are arranged in an electric circuit, such construction being well known in this art. When current is supplied to the electrodes it will be conducted from one electrode to the other through the resistance material, thus raising the resistance material to an intense heat.

A metal casing 16 is preferably provided around the furnace and it will of course be understood that furnaces of this type can be mounted so that they may be tilted to pour the melted metal therefrom and for this purpose any usual construction may be provided for rocking or tilting the furnace to pour the melted brass therefrom through the pouring spout 7 but this feature of the furnace construction forms no part of the present construction and is therefore not illustrated, since it is well known and in general use.

The heat rays which radiate downward from the resistance trough will strike directly upon the hearth containing the metal to be melted while those rays which radiate upward from the trough will strike the arched roof, the greater majority of said rays being. reflected through the central opening in the trough upon the metal on the hearth- In melting brass in any melting furnace such as in general use, the low melting point of zinc causes a certain amount of the zinc t is, of course, understood that clined neck 25 back in the brass to vaporize during themelting of the brass, this zinc vapor escaping from the furnace.

In order to overcome this loss we provide one or more suitable apertures 17 in the upper portion of the heating chamber, a condenser 18, provided with the reduced neck 19 being-fitted into each aperture. Each of these condensers is provided with the downwardly inclined condensing chamber 20, a small aperture 21 being formed in the outer end of the condenser to cause a slight draft from the heating chamber through the condenser drawing the zinc vapor which is given ofi by the melting brass into] the condenser, the vapor contacting with the cooler walls of the condensing chamber and condensing, being deposited in the bottom of the condensing chamber in the form of metallic zinc.

Any suitable support for the condenser, such as the bracket 22 may be provided upon the furnace wall in order that the condensersmay be held in placeupon the furnace and easily removed therefrom when it is desired to remove the condensed zinctherefrom. By the use of this condenser, the zinc which would ordinarily escape from the ordinary form of melting furnace in the form of zinc vapor is thus collected and condensed within the condenser, thus producing a considerable saving of zinc.

In the modification shown in Fig. 3 the condenser 18 is provided with a reduced neck 19 at its upper end which fits into a suitable aperture in the upper portion of the heating chamber, a downwardly and inwardly inclined neck 25 being provided at the lower end of the condenser, this neck passing through a suitable aperture 26 in the heating chamber just above the hearth 5 of the furnace. With this construction the zinc as it is condensed within the condenser 18* will be carried through the in-= to the hearth of the furnace.

We claim:

1. A melting furnace and a condenser communicating with the heating chamber thereof.

2. A melting furnace provided with an aperture in the heating chamber thereof and a condenser located in said aperture and communicating with the heatin chamber.

3. A melting furnace and a condenser communicating with the heating chamber thereof and extending beyond the exterior of the furnace.

4. A melting furnace and a condenser communicating with the heating'chambcr thereof, the condenser provided w1th a large condensing chamber having a reduced aperture at its outer extremity.

6. A brass melting furnace having a zinc vapor condenser communicating with the heating chamber of the furnace.

7. A brass melting furnace provided with an aperture communicating with the heating chamber thereof and a zinc vapor condenser having a reduced neck located in said aperture and communicating with the heating chamber.

8. A brass melting furnace and a zinc vapor condenser communicating with the heating chamber of the furnace and extending beyond the exterior of the furnace.

9. A brass melting furnace and a zinc vapor condenser provided with a reduced neck communicating with the heating chamber of the furnace and having an enlarged condensing chamber located beyond the exterior of the furnace.

10. A brass melting vapor condenser having a reduced neck comfurnace and a zinc municating with the heating chamber of the furnace and having an enlarged downwardly inclined condensing chamber located beyond the exterior of the furnace.

11. A brass melting furnace having an aperture communicating with the heating chamber thereof and a zinc vapor condenser provided with a reduced neck located in said aperture and with an enlarged condensing chamber extending beyond the exterior of the furnace and provided with a reduced aperture at its outer extremity.

12. A brass melting furnace and a condenser communicating with the upper portion of the heating chamber thereof, the condenser provided with an inclined neck communicating with the heating chamber near'the hearth of the furnace.

In testimony that we claim the above, we have hereunto subscribed our names.

THADDEUS F. BAILY. FRANK T. COPE.

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