US1339393A - Electric furnace - Google Patents

Description

J. HUGHES, DECD.

E. W. HUGHES, ADMINISTRATRIX.

ELECTRlC FURNACE.

APPLICATION FILED OCT. .11, 1919.

Patented May 11, 1920.

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J. HUGHES, DECD.

E. w. HUGHES, ADMINISTRATRIX. ELECTRIC FURNACE.

APPLICATION FILED OCT. H, 1919- Patented May 11, 1920,

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ELECTRIC FURNACE.

APPLICATION FILED OCT. 11, 1919.

J. HUGHES, DECD.

E. w. HUGHES, ADMINISTRATRIX.

ELECTRIC FURNACE.

APPLICATION FILED OCT. 11. 1919.

Patented May 11, 1920.

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JOHNSON HUGHES, DECEASED, BY EMILY W. HUGHES, ADMINISTRATRIX, OF

- PHILADELPHIA, PENNSYLVANIA.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented May 11, 1920.

Application filed October 11, 1919. Serial No. 330,105.

T 0 all whom it may concern:

Be it known that JoHNsoN HUGHES, deceased, has invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

This invention relates to electric furnaces for metallurgical and other purposes, in which the furnace or crucible, together with electrodes and their controlling devices, can be tilted for the purpose .of pouring the molten metal into ladles or molds. One of the objects of the inventionis to provide a furnace having novel means whereby burning out of the furnace lining is prevented at places where heat from the furnace cannot radiate freely or readily. Another object is to provide mechanism for tilting and controlling the movements of the furnace. Other objects will be apparent from the following description and the appended claims.

These objects are attained by arranging the furnace as shown in the accompanying drawings forming part of the specification and in which- Figure 1 is a vertical longitudinal section through the furnace on the line 11 of Fig. 3;

Fig. 2 is a top plan View;

Fig. 3 is an elevation of the furnace viewed from the left of Fig. 1;

Fig. 4: is a plan view of a portion of the top of the furnace shell;

Fig. 5 is a section on the line 5-5 of Fig. 4;

Fig. 6 is a sectional view on the line 6-6 of Fig. 5 showing a portion of the furnace shell with the cooling device.

Referring to'the drawings for a further description of the invention, 10 isthe furnace proper, comprising an outer shell 11 fastened to a bottom plate 12 which is secured to the channels 13 and 14 which form the bottom frame of the furnace and at the same time serve for connections of the tilting and counter-balancing mechanism, to be more fully described.

The inside of the shell 11 is lined with refractory brick or other heat and fire resisting material to form walls 15 and the hearth 16 of the furnace, which is covered by an arched roof or cover 17. For observation and other purposes, the furnace is provided with openings 18, which normally are closed by counter-balanced sliding doors 19 lined and operated in the usual manner. At the side of the furnace and fastened to the shell 11 and the supporting channels 13 and 14, are arranged vertical uprights 20 forming the supports for the sliding carriage 21 in which the electrodes 22 are held. That portion of the shell 11 to which the channel posts 20 are attached, is in such close proximity with the posts 20 that the heat from the furnace cannot radiate therefrom as readily as it can from the remainder of the shell, and for this reason the refractory lining in this zone tends to burn out more quickly than the balance of the lining. To prevent thisan air space 23 is provided between the iron shell 11 and the lining 15, as clearly shown in Figs. 1, 4 and 6. The top angle 24: is offset at 25, Fig. 4, and fillers 26 are provided to continue the air space 23 to the top of the furnace. Holes 27 are punched in the shell 11 through which the outside air is conducted into the space 23 and the heat emanating from the furnace will produce a natural draft of air from the outside through the holes 27 upward through the air space 23 and the opening between the fillers 26 and angle 24: to the top of the furnace, and thereby counteract the intense heat from the furnace.

In order to prevent the brick lining 15 from being forced against the shell 11 by expansion due to the heat, a heavy woven wire netting 28 of approximately one inch mesh of three-eighths inch wire is placed between the shell 11 and lining 15, which allows suflicient space to form an air gap for the air ventilation. If for any reason however the ventilation is to be intensified, air may be forced into the gap 23 by pipes 29 and 30 located near the ends of the protected area; in such case, a blower, not shown, is connected to the free end of each of the pipes 29 and 30, and a bafiie plate 31 is provided in proximity to the brick lining to distribute the forced air in the air gap, and prevent the same from entering the interior of the furnace, or crucible, by way of the joints between the brick of the lining.

The entire furnace with the electrodes, supports and operating mechanism attached to the vertical channel posts 20 is arranged for tilting to empty the entire contents of the furnace 10 through the spout 32. To maintain the height of the spout from the floor at about the same distance when the furnace is tilted, the fulcrum of the furnace has been placed directly under the spout.

In order to effect the tilting of the furnace about a fulcrum located under the spout without the expenditure of an excessive amount of power and without the use of extremely heavy mechanism, the weight of the furnace is counter-balanced and tilted by the devices to be described.

The fulcrum for the furnace is formed by a shaft 33 journaled in the standards 34. The channels 13 and 14 forming the supporting frame of the furnace 10 are provided with hinge .plates 34"which are also secured to the shell 11 and the upper ends of which are bored to receive the shaft 33. Near the other end of the channels 13 and 14 are pins 35 serving to connect these channels with two sets of connecting rods 36 and 37. The set of rods 36 connect at their lower ends with two double armed levers 38 supported on a shaft 39 which is journaled in the bearings 40. The free end of each lever 38 is provided with a shaft or rod 41 on which the counterweight 42 of the furnace is suspended. The other rods 37 are connected at their lower ends to wrist pins 43 on the large gear wheels 44. These gears 44 are keyed to a shaft 45 journaled in bearings 46.

Power for rocking the furnace is supplied by a motor 47 having a driving gear 48 keyed to its armature shaft which meshes witha gear 49 secured to one end of a shaft 50 journaled in the housing 51. The shaft 50 carries a worm 52 which drives a worm gear 53 on the shaft 54 to which is secured the gears 55 which mesh with the large gears 44 above described.

Below the rear end of the furnace and spanning the pit 56 is located a beam 57 as a safe guard for the furnace which also serves as a support for the rear end of the furnace in case of, repairs of the lifting mechanism or for any other purpose.

From the above description it is clear that when the motor 47 is started the shaft 45 will be turned by the intermediate gearing, and the connecting rods 37 will move upwardly thereby causing the furnace to tilt about its fulcrum shaft 33. At the same time the counter-weight 42 will rock about the shaft 40 and through levers 38 and connecting rods 36 will assist in establishing an approximate equilibrium of the several forces acting on the assembled structure.

\Vhile this disclosure sets forth with great particularity the specific embodiment of the invention herein shown, it is not to be construed therefrom that the patent is limited thereto as it is clear that changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Vhat is claimed:

1. An electric furnace including a metal shell and an inner refractory lining therefor, the outer surface of said lining having an offset therein forming a gap between the inner face of the shell and outer face of said refractory lining for the circulation of a cooling medium to carry off the heat radiating from said lining.

2. An electric furnace including a metal shell, an inner refractory lining therefor, the outer surface of said lining having an offset therein forming a gap between the inner surface of the shell and the outer face of said refractory lining, and means between said shell and said refractory lining forming a foraminous filler ada ted to prevent warping and distortion of the lining and shell and closing of the gap between the shell and lining without preventing circulation of a cooling medium in said gap.

3. An electric furnace including an outer shell, having a portion of its surface perforated and a refractory inner lining for said shell having the portion of its surface opposite the perforated portion of the shell spaced away from the shell, and a woven wire netting interposed between the shell and lining in juxtaposition to the perforated portion of the shell to prevent the heat of the furnace from distorting either the shell or the lining sufiiciently to close up the space between the two and yet permit the circulation of air in said space.

4. An electric furnace including an outer shell having uprights secured thereto to guide the electrode supporting carriage, an inner refractory lining for said shell having the portion thereof in proximity of said uprights, spaced away from the shell to form a gap between the inner surface of the shelland the outer surface of the lining for the circulation of air to prevent the lining in this zone from burning out sooner than the remaining portions of the lining.

5. An electric furnace including an outer shell, having a portion of its surface perforated and a refractory inner lining for said shell having the portion of its surface opposite the perforated portion of the shell spaced away from' the shell, and a woven wire netting interposed between the shell and lining in juxtaposition to the perforated portion of the shell to prevent the heat of the furnace from distorting either the shell or the lining sufficiently to close up the gap between the two and yet permit the circulation of air in said space, pipes secured to the outer shell for conveying air to the chamber between the shell and the lining and a baffle plate adjacent to the lining for distributing the air forced through said pipes and preventing the air from entering the interior of the furnace by the way of the joints in the lining.

6. An electric furnace having an outer shell, a refractory lining therein, a pouring spout, a pivotal support for the furnace located in close proximity to said spout, mechanism for tilting the furnace comprising a set of connecting rods connected at one of connecting rods joined at one end to the.

bottom of the furnace, and a counterbalance connected to the furnace by said second set of levers.

7. An electric furnace having an outer shell, a refractory lining therein, a pouring spout, a pivotal support for the furnace located in close proximity to said spout, hinge members secured to the furnace and associated with said pivotal support in combination with mechanism for tilting the furnace comprising a set of connecting rods connected at one end to the furnace, a set of gears having crank pins to which the opposite ends of said connecting rods are connected, means for driving said gears and a second set of connecting rods joined at one end to the bottom of the furnace, a set of levers pivotally supported below the furnace to which the lower ends of the last mentioned connecting rods are joined and a counter-weight attached to the free ends of said pivotally supported levers substantially as and for the purposes set forth.

8. An electric furnace including a metal shell, an inner refractory lining therefor, the outer surface of said lining being offset to form a gap between the contiguous faces of the shell and refractory lining for the circulation of a cooling medium therein, means forming a foraminous filler between said shell and said lining 'to prevent Warping and distortion of said lining sufficiently to close said gap, and means for circulating a cooling medium around and through the filler in said gap.

In witness whereof I have hereunto signed my name.

EMILY W. HUGHES,

Administratm'w of the estate of said Johnson Hughes, deceased.

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