US2063274A - Electric furnace - Google Patents

Description

Dec. 8, 1936. H. E. STAUSS ET AL ELECTRIC FURNACE Filed June 29, 1935 2 Sheets-Sheet 1 INVENTORi a? m W AT I ORfiEYS.

1935- H. E. STAUSS ET AL 2,063,274

ELECTRIC FURNACE Filed June 29, 1935 2 Sheets-Sheet 2 ATTO 1'EY5.

INVENTORJ.

Passed Dec. a, 1936 i 2,063,274

UNITED STATES PATENT OFFICE ELECTRIC FURNACE Henry E. Stauss, East Orange, and Joseph Ogden, Kearny, N. 1., assignors to Baker dz 00., Inc., Newark, N. 1., a corporation of New Jersey 1 Application June 29, 1935, Serial No. 29,110

1 Claim. (01. 13-1) This invention relates to a novel and improved elements and surrounded by insulation, but such form of electric furnace, the novel features of arrangements as have been suggested have prewhich will be best understood from the following sented certain difllculties in the pouring of molten description and the annexed drawings, in which material from the crucible. One attempt 'to we have shown selected embodiments of the inovercome such dimculties, as shown in the patent 5 vention and in which: to Northrup 1,551,766, proposed to provide a Fig. 1 is a top plan view of one form which pouring spoutlextending from the crucible to the invention may take; the outer wall of the container. However, the

Fig. 2 is a vertical elevation of the device shown molten material passing over the extended surin Fig. 1, parts being broken away and shown in face of the pouring spout tends to coagulate be- 10 section; cause of the chilling eflect of the extended sur- Fig. 3 is a vertical sectional view approximateface. ly on the line 3-3 of Fig. 1; We have overcome the difllculties in pouring 9.

Figs. 4 and 5 are views similar to Fig. 3 but molten material fromacrucible wound with elecshowing different forms of the invention. tric heating elements and fully supported by the 15.

Referring first to Figs. 1, 2, and 3, the inveninsulation by providing a pouring lip directly at tion is shown as comprising a crucible i of any one edge of the container, such a lip being exemsuitable heat-conducting material and which is plifled by the lip I which, it will be seen, is dishown as having an open top. In operation, a rectly adjacent the upper edgeof the container lid of any suitable form may be used to cover the wall 6. The small portion of the lip which excrucible, but since the lid itself does not affect the tends above the upper edge of the wall 6 may be 20 invention claimed herein, it has been omitted. supported by --'cement 1, which in fact is shown The crucible is shown as being disposed within as extending completely around the top edge of a container 2 containing insulating material 3 the crucible.

closelyv and compactly surrounding the crucible From the lip 5 extends downwardly and inwardand covering the walls thereof. Between the inly towards the center of the container one wall I sulating material and the walls of the crucible is of the crucible.

placed an electric heating element 4 which is Looked atin another way, the crucibleis placed wound around the crucible and may be embedded in the container with its normally vertical axis in a thin coat of cement 4', asalundum or the like, tilted to the vertical sufficiently to bring one wall which serves the dual purpose of distributing the at the top edge substantially to the top edge of heat from the heating element uniformly along the container wall. Then the top edge of the the crucible between the turns of the winding, and crucible may be cut off so as to make it horizontal, of protecting the winding from contamination by or a crucible ofproper shape maybe used, as

the insulating material. The element 4 may be indicated in Figs. 2 and 3, and a suitable lid may 35 made of any suitable material adapted to form an be used to cover the crucible, if desired, although electric resistor, although we have found that oftentimes with electric heating a lid is found a wire of platinum or platinum-rhodium is prefunnecessary. erable for the purpose. It will be seen that the insulating material sup- 40 We are aware that crucibles of suitable-material ports the wall 8 as well as all the rest of the] have been wound with electric heating elements crucible, so that when pouring, no additional or have been heated by other means. Usually strains are placed on the material of the crucible. such crucibles have had to be lifted while fully At the same time, the molten material in the. loaded and while hot, and have had to be tilted for crucible may be poured directly from the crucible pouring. It is our belief that the shearing without having to pass over an extended surface 45 stresses set up in the material of the crucibles which will cause it to be chilled. The small pourby the handling have been responsible for'the failing lip, being formed of the same material as the ure by breakage of thecrucibles. wall 8, and in fact being a part of that wall,

The above difliculty we have overcome by placwill be maintained hot by the heating element,

ing the crucible in a container and supporting it and it does not extend away from the crucible 5o thoroughly with the insulating material, thus refar enough to be chilled and thus chill the conlieving the crucible from the shearing stresses tents of the crucible during its pouring. Thus which the ordinary crucible has to stand. the molten material will be kept molten until 65 We are also aware that it has been hitherto propoured.

posed to construct crucibles heated by electric For convenience of handling, particularly where the device is small and used for melting small quantities of metal, we provide a handle 9 of wood or other suitable insulating material, which may be secured to the container by means of fasteners l0, and which may be further insulated from the container by a sheet II o! mica and a sheet I! of asbestos. The container 2 may conveniently be made of sheet metal. The handle may be used as a conduit for a cable it containing two conductors l4 attached to binding posts 15 on the mica sheet, and to these binding posts may be attached the electric element 4 used for winding the crucible.

In Fig. 4 is shown a form or crucible l6 which is cylindrical in form but which, like the other forms of Figs. 1, 2, and 3, is provided with a pouring lip I! over the top edge of the wall 8 o! the container. From this lip ll extends downwardly and inwardly towards the center of the receptacle a wall l8 oi! the crucible, and here again it will be seen that the inner surface of this wall is substantially continuous to the pouring lip, thus obtaining the advantages outlined above. Otherwise, the construction of the form shown in Fig. 4 follows closely that shown in Figs. 1, 2, and 3.

Referring now to Fig. 5, we have shown therein how the invention may be employed with re- 7 bodied in certain specific forms, those forms have been selected purely as illustrative, and we do not intend to limit ourselves except by the appended claim.

'We claim:

In an electric furnace, a container having a vertically extending wall, a crucible oi heat-conducting material disposed within said container and having one wall thereof inclined to the vertical, with its upper edge substantially at the upper edge of the container wall and its lower portion spaced from said container wall, said crucible wall extending continuously upwardly to its.said upper edge, whereby said upper edge of the crucible wall forms a spoutless pouring lip, insulating material disposed in said container and supporting said inclined crucible wall, and an electric heating element arranged to heat the crucible wall, whereby said crucible wall is thoroughly supported and heat may be imparted to and retained by said lip.

HENRY E. S'I'AUSS. JOSEPH OGDEN.

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