US1517938A - Electric furnace - Google Patents

Description

T. B. BECHTEL ELECTRIC FURNACE 4 Sheets-Sheet 1 Filed Dec. 12, 1922 T. B. BECHTEL ELECTRIC FURNACE Filed Dec. 12, 1922 4 Sheets-Sheet 2 Dec. 1924- 1,517,938

1'. a. BECHTEL ELECTRIC FURNACE Filed Dec. 12, 1922 4 smu -5mm a 1922 4 Sheets-Sheet 4 iled'Dc iii in Philadelphia,

Patented Dec. 2, 1924.

UNIT-so sures PATENT OFFICE. I

THEODORE n. macn'rnn,

or'rmnannnrnm, "rnimsrLvAinn, assume]; we r. .1.

RYAN a comm, or PHILADELPHIA, rnnnsvnvnma, a fconrona'rron or zonnawnnn ELECTRIC rumvacn Application filed December 12, 1922. Serial N0.-806,3B5.1

3T0 all whom it may, concern:

Be it known that I, THEODORE B. Bronrn a citizen of the United States, residing Pennsylvania, have invented an Electric Furnace, of which the following isa specification.

This invention relates to electric furnaces of'the resistor type and one of its ob ects 1S to provide such a furnace with novel means rangement and the resistors due to expansion or contraction,

particularly with a view to preventing sagging of said resistors.

It is also desired to provide anovel built structure for supporting the's'everal sets electric conductors constituting the resistors of an electric furnace, which structure shall be formed of a minimum number of different parts designed toc'arry the resistor conductors independently of the adjacent walls of the furnace.

Another object of my invention is to lessen the losses of h'eatby conduction by supporting. the resistors away" from andindependently of the furnace walls and to provide a construction which permits rearrangement of the resistor and its spacing after the furnace structure has been completed, in order to obtain. any desired relation of the resistors and the objects to be heated.

I also desire to provide an electric furnace in which any of the resistors may beremoved or replaced when desired without affecting the furnace structure. 1

These objects and other advantageous ends I attain as once being had to the accompanyingdrawings, in which, g

ig. 1 is aplan ofa furnace constructed in accordance with my invention; i

Fig. 2 is a vertical section on the line 2-2,

Fig.1; a

ig. is a. horizontal section on the line 33,F1g.2; v I

i number of hereinafter set forth, refer- "or sections of an and 5 are respectively a side and an end elevation of one of theresistor elements with-its associated supporting structure; 1 v 6 is aoentral vertical section illustrating a modified form; of'my invention;

and

Fig. 7 is a fragmentary vertical section on the line 7--7, Fig. 6.

In the above drawings, 1 represents a shell or casing-enclosing the bottom 2 and side walls 3 of a vertical type of furnace. Mountedon the] top or otherwiseopen end of this structure is .a cover or closure 4 and the walls and botliem of the, furnace have their inner facescovered with a refractory lining 50f any suitable material. Mounted on and carried wholly by the bottom or floor of the furnace is a supporting frame consisting in the present instance of a number of vertically extending series of posts or columns 6 of highly refractory material such as porcelain, lava or the like, although it is to be noted that without departing from my invention these columns maybe of metal of a sufficiently refractory nature when the furnace is designed to operate at relatively low temperatures. i I a The lower ones of these columns rest directly on the floor and each has interposed between it. and thecolumn next above it a cross fitting. 7 having upwardly opening or recessed arms for the reception .of the end portions of horizontally extending support ing bars 8. The .columns ,6, as shown in Figs. 2, 3 and 5 may consist of any desired sections 6 and .6 and they are preferably made tubular for the greater part of their length, being each provlded at one 'endwith a projection or dowel-like portion '9 designed to. fit into the lower end of the tubularcavity of the-next higher section or cross fitting.

Thebars 8, shown diagrammatically in Figs. 1 and 3 as elongated cylindrical rolls of insulating material, are preferably each formed with or consist of a series of grooved collars,or annular ribs .10 designed to define grooves for the reception of the convolutions electrical conductor 11. Said conductoris thus suspended from the bars 8 and is arranged in the form of a series of flat similar loops or convolutions whose lower ends areengagedand spaced by a secadjacent the vertical face of the refractory lining 5, being arranged, in the case illustrated, to outline a hexagonal prismatic chamber having three of the resistor coils 11 arranged vertically over each other adjacent each of its vertical sides or faces. The distance between the top and bottom bars 8 and 12 of vertically adjacent resistors is such that the adjacent resistors are maintained at the proper distance apart.

Refractory insulating tubes 13-13 are mounted to extend through the furnace ca'sing, wall and lining to lead the necessary supply conductors to the ends of the several resistor coils or conductors and under conditions of operation an object to be heated is placed within the chamber defined by the various resistors, the cover 4 being temporarily removed for this purpose. After said cover has been replaced, current delivered to theresistor coils heats these so as to raise to, and maintain the furnace and the articles therein at the desired temperature.

It is noted that with the above described arrangement of carrying frame, the resistors are supported so as to be altogether independent of the side walls and lining of the furnace, sin e said frame rests upon and is carried solely by the bottom or floor of the furnace. In that form of my invention shown in Figs. 6 and 7 I-have shown the casing structure or setting 1 as carried by a series of supports .14 mounted upon the foundation members 15, the furnace proper 3 having in the present instance an arched top 3". Mounted within said casing and in this instance in addition to vertically extending resistor elements 11, are flat coil elements 11 mounted to lie in a plane substantially parallel with and immediately adjacent the floor. I also provide top ,resistor elements 11 in the form of flat coils mounted immediately adjacent the top of the furnace.

As in the former case, the vertically extending resistor elements 11 are carried by vertically extending posts or columns 6 having projection-and-recess connections and carrying at their upper ends cross or other fittings 7 and '7", designed to support horizontally extending bars 8 of insulating material. The conductors constituting the resistors as before are arranged in flat coils hung from these bars and carrying in their lower portions other bars12. In this case fittings 7' are mounted under each vertical series of columns 6" and are formed with recessed arms for the reception of cross bars 20 designed to cooperate with other suitably supported cross bars 21 to carry the horizontal or bottom resistor coils 11". The fittings 7" are designed to carry sets of columns 22, 22 and 23, arranged in arch form across the top of the casing and serving to support horizontally extending bars 24 and 25, on which are carried the top resistor elements 11.

As before the. insulatin tubes 13 are provided at suitable points 0 the furnace structure for the reception of the conductors through which current is supplied to the various resistors, sothat under conditions of operation I an. object properly supported within the heating chamber of the furnace is surrounded by the electrically heated resistor elements. In this case as in that previously described, these elements are carried upon insulating or metallic frame structuresv of simple form, easy to build up or assemble and altogether independent of the side or top walls of the furnace structure to which they are adjacent. In the event of the breakage of any of the frame members or of injury to any of the resistors. it may be easily and uickly replaced without dismantling the rnace and with but little disturbance to the remainder of the frame or resistors.

While I have shown the resistors as made up of metallic bars, rods or wires. it is to be understood that without de arting from my invention any other suitable electrical conductors may be used in whatever form may be required. For example, properl formed resistors containing or made of carbon may be substituted for the metallic coils shown.

I claim:

1. The combination in an electric furnace of a supporting frame including horizontally extending bars; resistor conductors respectively hung in coils from said bars; with auxiliary bars hung in said coils and free to move as the coils expand or contract. said auxiliary bars being mounted independently of said supporting frame.

2. The combination in an electric furnace of a casing; a supporting frame of insulating material mounted adjacent "but structurally independent of the side walls of said casing and including horizontally extending bars; resistors hung in coils from said bars respectively; and auxiliary bars mounted in the lower parts of said coils respectively. said auxiliary bars being mounted independently of said supporting frame.

3..The combination in an electric furnace of a casing; a frame within the casing carried solely by the floor thereof independently of the side walls; and resistor elements so m unted on said irame ja nt said side walls as to form dependin coils.

4. The combination in an electric urnace of a casing; a supporting frame within the casing comprising sets of columns and interconnecting su'pportin elements; and re sistor elements mounte on said interconnectin elements.

5. 'Ifiie combination in an electric furnace of a casing; sets of columns of insulating material mounted on the floor of said casing; horizontal bars extending between adjacent columns; and resistor elements hung from said bars.

6. The combination in an electric furnace of a casing; sets of columns mounted on the floor of said casing; cross fittings associated with the columns; bars extending between adjacent cross fittings; and resistor elements carried by said bars.

7. The combination in an electric furnace of a casing; sets of columns mounted on the floor of said casing; fittings carried by the columns and having upwardly openin recesses; bars mounted in the recesses 0 adjacent fittings; and resistor elements carried by said bars.

8. The combination in an electric furnace of a casing; sets of insulating columns mounted on the floor of said casing; fittings carried by the columns and having upwardly opening recesses; bars mounted in the recesses of adjacent fittings; and resistor elements carried by said bars in the form of flat depending coils; with auxiliary bars respectively mounted loosely in the bottoms of said coils.

9. The combination in an electric furnace of a casing; series of column sections doweled together; horizontal cross bars carried by adjacent columns; and resistor elements hung from said cross bars.

10. The combination in an electric furnace of a casing; columns mounted therein and each consisting of a series of sections connected by dowels; fittings interposed between the sections of the columns; horizontal bars carried by the fittings; and resistors hung respectively from said bars.

11. The combination in an electric furnace of a casing; vertically extending columns mounted adjacent the sides of the casing; horizontal bars supported by said columns; vertically set resistor coils carried by said bars and resistor elements extending substantially parallel with and immediately adjacent the floor of the casing.

12. The combination in an electric furnace of a casing; vertically extending columns adjacent the side walls thereof; supporting members carried by said columns and extending adjacent the top of the casing; horizontal bars carried 'by said members; other horizontal bars carried by the columns; vertically extending resistor coils carried on said latter bars adjacent the sides of the casing; and other resistor elements supported on the bars carried by the top members.

13. The combination in an electric furnace of a casing; a series of columns supported solely by the floor of said casing. and each consisting of a series of separably connected sections; cross fittings interposed between the sections of said columns and each having at least one upwardly opening recess; horizontal bars removably carried in the recesses of adjacent fittings; coils hung from said bars respectively; and means for spac-- ing the lower parts of said coils.

14. The combination in an electric furnace of a casing; a series of columns supported solely by the floor of said casing and each consisting of a series of separably connected sections; cross fittings interposed between the sections of said columns and each having at least one upwardly opening recess; horizontal bars removably carried in the recesses of adjacent fittings; coils hung from said bars respectively; and means for spacing the lower parts of said coils consisting of auxiliary bars loosely hung therein. v

15. The combination in an electric furnace of a'casing; a frame within the casing carried solely by the floor thereof independently of the side walls, said frame comprising a plurality of sets of built-up columns and removably positioned connecting bars individual to each set; and resistor elements mounted on said removably positioned connecting bars.

THEODORE B. BE CHTEL.

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