US1685914A - Electric furnace - Google Patents

Description

c. B'. FOLEY ELECTRIC FURNAGE` original Filed March 13 1920` 2 `sheets-sheet 2 Patented Oct. 2, 1928.

1,685,914 PATENT OFFICE.

UNITED STATES CHARLES B. FOLEY, F FORT WAYNE, INDIANA, ASSIGNOR T0 CHARLES .'B. FOLEY,

INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

ELECTRIC FURNACE.

Application kled March 13, 1920, Serial No. 365,632. Renewed February 23, .1928.

My invention relates to elect-ric furnaces and process for making the same.

It relates particularly to induction fur naces, but is applicable to other kinds of electric furnaces.

The greatest difficulty experienced in elec-V tric furnaces is in finding a refractory lining that will stand the effects of expansion and contraction, and the wash effects due to slags I0 and circulationof the molten material. The

refractories used as lining for electric fur.- naces are, asa rule, very expensive and' their useful iife is very limited. The need of constant renewal after a few heats causes muc-h '5 interruption of working conditions, makes necessary the provision of auxiliary furnaces to take the place of those undergoing repairs, and the expense for refractory material and la'bor adds greatly to the cost of the finished product. Joints in the refractory are a constant source of trouble, and it is desirable to avoid them so far as possible. A solid onepiece lining forming the furnace itself would be the ideal construction.

The main object of the invention is the construction of a furnace or furnace lining of uniform density that shall be as far as possible a one-piece structure and shall have the minimum amount of joints in the parts exposed to the action of the molten materialv of the charge.

In the drawings accompanying and forming a part of the present application, there are illustrated various steps in the process and various forms of structure.

Referring to the drawings Fig. I illustrates a common and defective method of making a crucible furnace (partly broken away) Fig. 2 is a view of the structure shown in Fig. 1, also partly broken away, on a. section atright angle to that of Fig. l;

Fig. 3 is a plan view ofthe mold used in the process of carrying out my invention;

Fig. 4 is a side elevation, partly broken away, ofl Fig. 3, looking in the direction of the arrows in Fig. 3; c

Fig. 5 is a top View of the furnace set up, without the cover; I

Fig. 6 is a view showing half of my furnace with the top removed; and

Fig. 7 is a similar view' showing the top integral with the sides and bottom.

In the drawings z-l is the refractory .ma-h terial which may itself form the furnace,.or

may under certain conditions serve as a lining; 2 is a. refractory tube located near the bottom of the inside of 1, having a constricted passage 3, opening upwardly and outwardly around the tube 2; 4. is a passage through. the tube 2 adapted to receive the current-inducing means, and' 5 is a wooden core about which the refractory is formed. 6 is the mold in which my furnace is formed, held together by bolts 7 and reinforced by strips 8; 9 is the furnace frame provided with pressure set-screws 10, abutting on plates l1, located around the furnace proper and taking up strain and holding t-he furnace together and in place.

Taking first the method shown in Figs. l and' 2 and which my invention is designed to replace, the crucible which may serve, as desired, either as the furnace proper or as a refractory lining, is shown as rammed up from platic material around a wooden mold 5. When the Crucible thus formed dries, the core is burnt out in any well-known manner. Now, although it is comparatively easy to secure a reasonably uniformly dense packing on the sides, yet it is practically impossible to secure the same result in the constricted passage 3, the part most exposed to heat and convection action. The result is unevenness of refractory structure, seen in Fig. l, leading to rapid deterioration owing to its spongy nature, washing action of the circulatory metai, and tendency of the metal to penetrate and work out into the spongy mass. I have thoroughly tested this method of construction and have discarded it for the construct-ion disclosed in this application.

In contradistinction to this method, I prepare a mold, one example of which is shown in Fig. 3, and fill the same with finely divided 95 material, which is to form the refractory lining of the Crucible. The nature of this lining may vary, acid lining for so-me materials, basic lining for others. This finely divided material is forced into the mold under high 10o pressure, pneumatic, hydraulic, or anywellknown means. This forms the material into an exceedingly dense, uniformly compressed soiid block (seen in the cut away part of Fig. 4), and out of this block I cut away, in 105 any` welldinown manner, the operative portions of the furnace. Such a block is shown in Fig. 6, which is a half portion of the furnace shown complete in Fig. 5 (without cover), in which the line 12 marks the di- 11e` vision between the two furnace halves. The refractory can be carved, or drilled out, as in Fig. 7, which shows the body 1, refractory tube 2, constricted passage 3 and cover 13, all in one piece. This is an excellent form for many purposes, especially for treating easily volatile materials.

The refractory .material having been thus shaped into the desired form, say as shown in Figs. 5 and 6, two of the like parts are provided on their abutting surfaces with a suitable cementing material and clamped together in a suitable frame, such, for instance, as is illustrated in Fig. 5, when the furnace proper is held rigidly together and in place by adjustment of the screws 10 acting through plates 11 on the various sides of the furnace.

The furnace constructed as above described needs only to be provided with proper current-inducin means to be ready to receive current, fee ing and tapping devices being added, and from various experiments extending over months, l know that a furnace constructed as above described will ontlast many times one of the usual construction.

Having thus fully illustrated and described my invention, what I claim is l. The process of makin electric induction furnaces of the cruci le type, which' comprises reducing a refractory material to a finely divided state, fashionin the said material into a uniformly dense, highly compressed block, carving out the block to formv yhalf of a Crucible, fashioning as' van integral ,portion of the solid block near the bottom of lthe Crucible portion, a tube having a conlstricted passage between the tube and the bottom and sides of the crucible, anduniting two blocks thus produced to form a complete furnace.

2. The process of making electric furnaces, which comprises reducing a refractory ,material to a finely divided state, shaping under great pressure said refractory into a solid block, carving out the blo'ck to form half of a Crucible having its top integral with the sides and bottom,` and uniting two such halves to form a complete crucible,

3. An electric furnace of the crucible type composed of two halves carved from a solid block of dense refractory material, each half having its top integral with the sides and bottom.

4:. A furnace of the class described having, in combination, a container for molten metal, a two-part channel box secured to the container, a lining for said box comprising a plurality of sections of refractory material aving in their adjacent inner faces registering surfaces forming a channel whose ends open into said container, said sections lying between the two parts of said channel box, and means for holding said two parts together so as to clamp the said sections between them.

5. A furnace of the class described having, in combination, a container for molten metal, a two-part channel box secured to the container, alining for said box comprising a plurality of sections of refractory material having in their adjacent inner faces registering surfaces formin a channel whose ends open into said container, said sections lying between the two parts of said channel box,

means for holding said two parts together' so as to clamp the said sections between them, and a filling between the adjacent faces of said sections.

6. A furnace of the class described, having in combination a container and a channel block depending therefrom and having a channel whose ends extend upwardly and open into the lower-portion of said container, said block being composed of a plurality of sections having their opposing faces vertical and having'registering grooves located in said opposing faces and forming said channel, and means engaging the outer faces of said sections for clamping said sections to ether.

. 7. A 'urnace of the class described having means'for containing molten metal, which said means comprises two blocks of refractory material each of integral construction and each havinga portion of a channel for said metal-formed therein and which said channel portions are adapted, when said blocks are placed together face to face, to register one with another and form a channel capable of retaining said metal, combined with apparatus for so holding said blocks together.

8. A furnace of the class described having means for containing molten metal, which said means comprises two blocks of refractory material eachof integral construction and each having a portion of a channel for said metal formed therein and which said vchannel portions are adapted, when said blocks are placed together face to face, to register one with another and form a channel capable of retaining said metal, combined with apparatus for so holding said blocks together and a layer of cementitious filling between said blocks.

CHARLES B. FOLEY.

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