US2464714A

US2464714A - Intermittent discharge induction melting furnace

Info

Publication number: US2464714A
Application number: US637515A
Authority: US
Inventors: Paul E Petersen
Original assignee: Chase Brass and Copper Co Inc
Current assignee: Chase Brass and Copper Co Inc
Priority date: 1945-12-28
Filing date: 1945-12-28
Publication date: 1949-03-15
Anticipated expiration: 1966-03-15

Description

March 15, 1949. P. E. PETERSEN 2,464,714

INTERMITTENT DISCHARGE INDUCTION MELTING FURNACE Filed Dec. 28, 1945 2 Sheets-Sheet l F'ol.

/A/VE/VTOIE' PA u E. PETERSEN TTOBNE Vs M r 15, 1949. P. E. PETERSEN INTERMITTENT DISCHARGE INDUCTION MELTING FURNACE 2 Sheets-Sheet 2 Filed Dec. 28, 1945 /NVENTOR PAUL E. PE TERSEN %www ATTORNEYS Patented Mar. 15, 1949 &464.714

INTERMITTEN T DISCHARGE INDUCTION MELTING FURNACE Paul E. Petersen, Waterbury, Conn., assignor to Chase Brass & Copper Co. Incorporated, Waterbury, Conn., a corporation Application December 28, 1945, Serial No. 637,515

3 Claims.

The present invention relates to improvements in melting-furnaces and relates more particularly to melting-furnaces of the intermittent discharge type, i. e., melting-furnaces designed to discharge a portion of their contents of molten metal or the like at relatively-short intervals, rather than discharging their contents substantially completely at one time.

One of the main objects of the present invention is to provide a superior intermittent discharge melting-furnace characterized by simplicity and reliability of operation.

Another object of the present invention is to provide a superior induction-heated meltingiurnace which may be discharged without requiring the shutting-ofi of the current-supply thereto and therefore without requiring the cessation of melting during such discharge.

A further object of the present invention is to provide a superior melting-furnace of the character referred to, which may be either intermittently or continuously supplied with unmelted metal or the like which, after being melted, may be effectively intermittently discharged.

Still another object of the present invention is to provide a superior intermittent discharge melting-furnace especially well suited for the melting of relatively-small particles of material such, for nstance, as brass chips, small-arms Cartridge-cases, etc.

A still further object of the present invention is to provide a superior melting-furnace of the character referred to, which is capable of melting material in the presence of an inert or reducing atmosphere.

With the above and other objects in view, as will appear to those skilled in the art from the present dlsclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Flg. 1 is a top or plan view of an intermittent dlscharge melting-fumace embodying the present invention:

Fig. 2 is a transverse sectional View taken on the line 2-2 of Fig. 3 but with the pool of molten metal omitted:

Fig. 3 is a vertical central section taken on the line 3-3 of Fig. 1. and

Fig. 4 is a transverse sectlonal view taken on the line 4-4 of-F'ig. 3 but on a larger scale.

The particular intermittent discharge meltingfurnace illustrated in the accompanying drawings for purposes of making clear one form of the present invention, is of the induction-type and includes a casing generally designated by the reference character o and comprising a multi-part shell l'l and a multi-part lining !2.

The shell ll above referred to may conveniently be formed of cast iron or the like, while the relatively-thick lining |2 is preferably formed of ceramic material resistant to the eroding and other harmful efi'ects of a pool of molten metal or the like !3 adapted to be contained within the casing lo.

The casing o is so shaped as to provide within its interior what might be aptly termed a "melting-compartment" or portion !4 located to the right as viewed in the drawings, and a "storage-compartment" or portion !5 located to the left, all as is especially well shown in Figs. 2 and 3.

Leading downwardly from the lower portion of the melting-compartment l4 proper, is a substantially U-shaped passage [6 into which the molten metal extends, to provide what is commonly known in the art of induction furnaces as a "loop" which acts as a secondary" for a primary winding I'I extending through the aforesaid loop. In the instance shown, the primary winding I'l encircles the upper reach of the usual magnetic core designated by the reference character I8.

Communicating with the lower portion of the storage-compartment IS proper, is a U-shaped passage l'9 similar to the U-shaped passage !6 before referred to, and serving to accommodate molten metal in the form of a so-called "loop" or "secondary" for a primary winding 20. The primary winding 20 encircles the upper reach of a magnetic core 2| similar to the magnetic core !8 before referred to.

connected to the top wall of the casing lil at a point preferably centrally with respect to the melting-compartment I4j"is a charging-tube 22 communicating at its lower end with an outwardly-and-downwardly-flared charging opening 23 formed in the upper portion of the Iining [2 of the casing I 0, as is especially well shown in Fig. 3.

Extending through the side wall of the lining |2 and the shell I I, is a gas-inlet passage 24 located above the level of the pool of molten metal !3, The inner-end of the passage 24 communicates with the upper portion of the meltingcompartment l4, though when desired it may communicate directly with the storage-compartment 15. At its outer end the passage 24 communicates with a supply-pipe 25 leading from am suitable source of an inert or reducinggas, all 'for purposes as will more fully hereinafter appear.

Preferably and as shown, there is interposed between the melting-compartment M and the storage-compartment l'5 what might be aptly termed a "bame-wall" designated by the reference character 26. The said bame-wall may be formed integrally with the remainder of the lining I2 if desired and. as shown. terminates short of the top of the lining to provide a gas-passage 21 through which a reducing-gas or an inert gas may flow into the storage-compartment l5.

The bame-wall 26 above referred to also terminates short of the bottom of the main portion of both the melting-compartment |4 and the storage-compartment to provide a flow-passage 28 through which molten metal may flow between the two said compartments.

The side wall of the casing o, at a point opposlte the melting-compartment I 4, is provided with an inverted U-shaped discharge-passage 29 communicating at its inner-end with the lower portion of the pool of molten metal !3 below the upper surface thereof and having an outer leg or reach located exteriorly of the main portion of the casing !0, so as to discharge molten metal into any suitable receptacle such as a mold.

The material of the lining !2 is so shaped adjacent the cross-reach of the inverted U-shaped discharge-passage 25 as to provide what may be aptly termed an overflow-lip 30 located above the normal level of the pool of molten metal !3 within the casing !0, and over which molten metal from the storage-compartment !5 is adapted to be flowed on occasion, all in a manner as will more fully hereinafter appear.

For the purpose of causing the pool of molten metal [3 to flow over the overflow-lip 30 without requirng the tilting of the furnace, a relativelythck disk-like metal-displacing member 3I is employed. The said metal-displacin member may be formed of any suitable material resistant to the effects of molten brass and the like, such, for instance, as carbon or ceramic material.

The metal-displacing member is located within the storage-compartment |5 and is normally retired upwardly substantially out of the pool of molten metal !3 as is shown by full lines in Fig. 3, though movable downwardly in the said pool, as is indicated by the broken lines in Fig. 3.

The metal-displacing member 3! above referred to is coupled to the respective lower ends of three 5 (more or less) parallel synchronized plungers 32 which are adapted to reciprpcate through the top wall of the casing ID and which project above the said top wall to a considerable extent for purposes as will hereinafter appear.

Each of the three plungers 32 corresponds to the other and has its upper portion threaded as at 33, as is indicated in Fig 3, and extended upwardly through a housing 34.

The housing above referred to is held in spaced relationship above the top surface of the casing !0 by means of a standard 35 and accommodates three plunger-actuating gears 36, as is indicated in Figs. 3 and 4. The gears 36 are arranged equidistantly around and in mesh with a drive-gear 31 mounted for rotation centrally within the housing 34 and operatively connected to a drivemotor 38 mounted upon the top of the housing 34 and preferably of the reversible type.

M is indicated in the upper portion of Fig. 3,

4 the threaded upper portion 33 of each of the given plungers 32 is in threaded engagement with the threaded bore of its complemental one of the plunger-actuating gears 36, so that as the latter is turned in one direction or the other, it will either lower or raise the given plunger 32 in synchronism with the similar movement of the other plungers.

operation Let it be assumed that both of the primary windings H and 20, having terminals |`|0 and 200 respectively, are energized and pieces of metal are being continuously introduced into the melting-compartment !4 through the charging-tube 22 and the charging-opening 23, so as to become immersed in the pool of molten metal 13 for being rapidly melted therein.

It may further be assumed that an inert or reducing-gas is being continuosly introduced under pressure into the interior of the casing |0 through the supply-pipe 25 and gas-inlet passage 24. It may here be noted that when a reducing-gas is employed, provision will be made to prevent the unhindered escape thereof through the upper end of the charging-tube 22 Now when it is desired to discharge a portion of the pool of molten metal l3, the electric drivemotor 38 will be energized to cause the three plungers 32 to descend in synchronized relationship, to thereby force the metal-displacing member 3l downwardly into the pool !3, as is indicated by the broken lines in Fig. 3.

The descent of the metal-displacing member 3l will cause the level of the pool |3 to rise sufliciently to cause molten metal to flow over the overflow-lip 30 and into a mold or any suitable receptacle located beneath the outer end of the discharge-passage 29. The rapidity of the downward movement of the metal-displacing member 3l will, of course, determne the rapidity of the outflow of molten metal through the dischargepassage 29 and may be precisely controlled.

As soon as suflicient metal has fiowed over the overflow-lip 30 to fill the desired receptacle, the metal-displacing member 3l may be raised by suitably energizing the drive-motor 38, to thereby lower the level of the pool of molten metal 13 and efl'ectively shut off the further flow of the metal until such time as such flow is again desired. i

Instead of continuously supplying unmelted metal into the furnace, such metal may be intermittently introduced thereinto, either in the form of so-called "chips," in the form of massive pieces of metal, or mixtures thereof.

From the foregoing it will be seen that by means of the present invention, the intermittent discharge may be efiected without tiltin the furnace and without losing the desired inert or reducing atmosphere within the furnace. such controlled amount of inert or reducing atmosphere as may be desired can be permitted to move upwardly through the charging-tube 22 without reducing the required gas-pressure within the furnace.

Furthermore and by means of the present invention, an induction melting-furnace may be discharged without requiring the cutting-off of the current thereto during the discharge period with the consequent loss of melting-time In this connection it may be explained that when ordinary induction furnaces are tilted to effect the discharge of the major portion of their contents, it is necessary to shut ofi the supply of current, inasmuch as to leave the current on when the head" of metal above the loop is materially lssened would cause the remaining metal to be violently agitated as to be squirted indiscriminately over the interior of the furnace.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore. to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. An intermittent discharge melting-urnace comprising a furnace-casing having a meltingportion and a storage-portion arranged side by side therein; individual induction heating-means mounted within said melting-portion and said storage-portion respectively; a partition separating said melting-portion and said storage-portion, said partition having a liquid-transfer passage in the bottom thereof and a gas-pressure equalizing-passage in the top thereof, each passage communicating with said melting-portion and said storage-portion; a charging-opening in the top of said meltirg-portion; a dischargepassage in the wall of said storage-portion comprising an overflow-lip located above the normal level of a pool of molten metal in the said storageportion; a metal-displacing member supported entirely within said storage-portion and movable toward and away from the pool of molten metal therein; and Operating-means comprising a power-driven plunger connected to said metaldisplacing member arranged positively to move said metal-displacing member into the pool of molten metal in the said storage-portion to raise the level of the said pool above the overflow-lip in the discharge-passage of said storage-portion.

2. An intermittent discharge melting-furnace comprising a urnace-casing having a meltingportion and a storage-portion arranged side by side therein; a recess in the bottom of each of said meltingand storage-portions; induction heating-means in the respective recesses of said meltingand storage-portions; a partition separating said melting-portion and said storageportion, said partition having a liquid-transfe' passage in the bottom thereof and a g-as-pressure equalizing-passage in the top thereo, each passage communicating with said melting-portion and said storage-portion; a charging-opening in the top of said melting-portion; a dischargepassage in the wall of said storage-portion comprising an overow-lip located above the normal level of a pool of molten metal in the said storageportion; a metal-dispacing member supported entirely within said storage-portion and movable toward and away from the poo] of molten metal therein; and metal-displacing member Operatingmeans comprising a plurality of power-driven plungers connected to said metal-displacing member positively to move the same into the pool of molten metal in the said storage-portion to raise the level of the said pool above the overflow-lip in the discharge-passage of said storageportion.

3. An intermittent discharge melting-furnace including in combination: a furnace-casing having a melting-portion and a storage-portion arranged side by side therein; individual induction heating-means mounted within the said meltingportion and the said storage-portion respectively; a partition separating the said melting-portion and the said storage-portion and extending both above and below the normal level of molten metal in the melting-portion and the storageportion, the said partition being constructed and arranged to prevent unmelted metal and dross in the said melting-portion from moving laterally across the surface of the molten metal into the said storage-portion; the said fumace-casing being provided with a liquid-transfer passage located below the normal level of molten metal in the two said portions and providing communication therebetween, the said furnace-casing also being provided above the normal level of molten metal in the said melting-portion and storageportion with a gas-pressure equalizing-passage interconnecting the two said portions; a charging-opening leading into the said melting-portion; a discharge-passage in the wall of the said storage-portion comprising an overflow-lip located above the normal level of molten metal in the said storage-portion; a metal-displacing member located within the said storage-portion and movable toward and away from the pool of molten metal therein; and power-driven operating-means connected to the said metal-displacing member and arranged to positively move said metal-displacing member into the pool of molten metal in the said storage-portion to raise the level of the said pool above the overow-lip in the discharge-passage of the said storage-portion.

PAUL E. PETERSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 39291311 Severin Eti June 30, 1903