US1345976A - Electrical furnace - Google Patents

Description

R. S. WlLE.

ELECTRICAL FURNACE.

APPLICATION FILED FEB. 26. 1920.

1,345,976. at t d July 6, 1920.

2 SHEETS-SHEET I.

5y /7/8 flfforney UNITED STATES RAYMOND SAMUEL WILE, or NEW YORK, 1v. Y.

ELECTRICAL FURNACE.

Specification of Letters Patent.

Patented July 6, 1920.

Application filed February 26, 1920. Serial no. 361,379.

To allwhom it may concern:

Be it known that I, RAYMOND SAMUEL VILE, a citizen of the United States of America, residing at 884 Riverside Drive, New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Electrical Furnaces, of which the following is a specification.

This invention relates to improvements in electrical furnaces and more particularly to the type of electrical furnace which is designed for melting gold, silver and the like in. crucibles as well as for heat treating steel tools and other like heating purposes. I

More especially the invention relates to a novel resister arrangement in a furnace of this character.

One of the important objects of this invention is to provide a novel arrangement of the resisters to effect a concentration of the heat near the center of the furnace.

Another of the important objects of the invention is to provide an improved form of resister element adapted to form, with other like elements and the terminals of the furnace, a hollow cylinder.

A third important object of the inventio is to so form resister elements that, when the elements are combined, the current flow producing heating of said elements will be greater nearer the center of the furnace than toward the exterior of said furnace.

A fourthimportant object of this invention is to provide, in combination with an electric furnace, a transformer arranged to afford a range of voltages for the furnace so that the current of the furnace may be controlled within wide limits and thereby an extreme flexibility attained in the temperature control.

With the above and other objects in view, as will be hereinafter apparent, the invention consists in general of certain novel features of construction, combinations of parts and arrangements of elements hereinafter fully described, illustrated in the accompanying drawings and specifically claimed.

In the accompanying drawings like characters of reference indicate. like parts in the several views, and

Figure 1 is a transverse section through a furnace constructed in accordance with this invention, the section being taken on the line 1-1 of Fig. 2.

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is an end view of one of the resister elements.

Fig. 1 is a side view of a portion of one of said elements. Fig. 5 is a side view of the furnace showing one of the supports on which it is mounted, the other support being removed.

In the embodiment of the invention herein illustrated, and which is to be taken as merely typical of various embodiments of which the invention is capable, a circular furnace is disclosed having a base plate 10 whereon is mounted a circular series of segmental blocks 11 supporting a cover plate 12 having a centrally disposed opening concentric with the furnace and normally closed by a cover 13. j 7

These parts are all formed of some suitable material sufiiciently refractory to stand the maximum heat to be used and the parts are cemented, luted or otherwise suitably secured together so that the furnace as a whole may be manipulated by means of a handle 13. Moreover, it is preferred to support the furnace rotatably on a pair of standards, one of which may be seen at 14 face of the wall of which is circular in section. Positioned against this inner wall surface are the resister elements 16, which are usually, though not necessarily, formed of carbon. Each of these elements consists of a corrugated and tapered wedge, the construction being equivalent to a series of circular rods decreasingly graduated in diameter from the outermost inward and united by short necks or webs. The sizes of these rod portions are so graduated that, when the parts are-assembled as shown in Fig. 1, the different sizes form arcuate series, the rod portions of each series being in close contact so that current can flow through the several series. In order to provide current to the resister terminal, blocks 17 are employed which may be moved by hand screws 18 to effect desired compression of the series of resister elements and thus enable the current amperage flowing through the resister to be regulated. From this peculiar arrangement and the shape of the resister elements it will be seen that, in effect, a series of paths is provided through the resister for the current flow and that the inner path is the shortest, so that, under the usual laws of multiple circuits, a greater current will flow through the inner ends of the resister elements than through the rest of said elements, the resistance increasing and the current consequently decreasing outwardly. Thus the heating effect is concentrated about the center of the furnace by this novel arrangement.

From the terminals 17 extend wires 19 to a transformer (not shown), either air, oil or otherwise cooled and which forms an integral part of the furnace, although it is preferably not attached thereto. This transformer may be of any suitable type such as is now on the market, and on this account is not here illustrated. A suitable form could be an air cooled transformer having a primary voltage of say 110 volts and secondary voltages of say 15, 20 and 25 volts. An adjustable switch can be used to connect any one of the secondary voltages to the furnace so that with the regulators 18 the temperature can be controlled within the widest limits as set forth in the stated objects of the invention aforesaid.

There has thus been provided a novel and efiicient furnace fully accomplishing the objects set forth.

Having thus described the invention, what is claimed as new is:

1. A furnace of the class described having a resister provided with current paths in parallel decreasing in length from the outside inwardly.

2. A furnace of the class described having a. resister consisting of a series of arcuately' arranged wedge shaped elements, said elements contacting each to each at intervals of their confronting faces. V

3. A resister element in the form of a blunt wedge corrugated on its sides parallel to its base.

at. A resister element formed of a series of integrally united circular rods graduated regularly in size to form a generally wedgeshaped structure.

5. A resister consisting of a series of resister elements in arcuate arrangement and contacting at spaced intervals transverse the arc to form a plurality of arcuate current paths.

6. The combination with an electric furnace having a series of contacting resister elements therein, and means to adjustably press said elements together, of a transformer having a plurality of graduated secondaries, and selective means for connecting said secondaries and the resister.

In testimony whereof I aflix my signature.

RAYMOND SAMUEL WILE.

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