US1751334A - Electric furnace - Google Patents

Description

- March 18, 1930. w. KEENAN 1,751,334

ELECTRIC FURNACE Filed Dec. 27, 1924 William Keenan,

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Patented Mar. 18, 1930 UNITED STATES PATENT OFFICE WILLIAM KEENAN, OF SCHENECTADY, NEW YORK, ASSIGNOR '10 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC If.-UIlEtIl l'AQIEl Application filed December 27, 1924. Serial No. 758,473.

resistor in such manner that heat is radiated directly therefrom into the heating chamber.

My invention relates more specifically to means for supporting resistance heating units or resistors of the type comprising a plurality of horizontally extending self-supporting convolutions, such as described and claimed in U. S. Patent No. 1,432,442 to C01- lins dated October 17, 1922. Such heating units are self-supporting and may therefore be upheld by suitable means cooperating with the extremities only of the convolutions. In the Collins patent a single resistor is shown, this resistor extending across the furnace chamber and being supported at the side walls. My inventionhas particular applica- :tion to furnaces in which it is impracticable for various reasons, such as relatively great width of the heating chamber, to use a single resistor extending from side to side of the heating chamber. F or example; in a relatively wide furnace it may be necessary to use a plurality of comparatively narrow resistors in order that the resistors may have sufficient rigidity to be self-supporting.

In carrying out my invention 1 provide supporting means for the resistor comprising a plurality of pins which are removably secured in specially constructed bricks built in the roof of the furnace. With this construction, the resistor may be easily and quickly put in place, and it is free to expand and contract by reason of the freedom of the pins.

' Moreover, radiation of heat from the resistor end elevation view partly in section of an electric furnace embodying my invention; Fig. 2 is an enlarged fragmentary plan view of Fig. 1. Fig. 8 is an enlarged detail view by spacing bricks.

of the supporting means; while Fig. 4 is a plan view of the resistor.

Referring to the drawing,.l[ have shown my invention in one form as used for supporting a heating resistor from the roof of the furnace, although it obviously may have other applications. The side walls and bottom of the furnace heatin chamber 10 are formed by heat refractory bricks 11 and the roof, which may be slightly arched, is constructed from wedge-shaped heat refractory bricks 12. Enclosing the whole is a layerof heat insulating bricks 13.

Rows 14 of specially constructed heat refractory bricks 15 are built in the roof of the furnace. These bricks 15 may be placed side by side in engagement with each other in the rows 14 as shown, or they, may be separated They support metallic pins 16 which project downward into the heating chamber and in turn form hangers for resistance heating units or resistors 17, 1 8 and 19. The rows of specially constructed bricks are spaced apart in pairs and each pair of rows carries the pins on which a resistor is mounted. Each resistor extends back and forth in zig-zag formation between the rows of bricks from which it is supported and therefore takes the form of a plurality of integral, end connected, substantially parallel extending straight convolutions which are relatively heavy so as to be self supporting between the pin sup orts. The resistors are made from a suita le electrical resistance heating material, such as a nickel-chromium alloy, and the pins 16 may be made from the same material.

As shown, three pairs of rows of specially constructed bricks are built in the roof whereby the three heating resistors 17, 18 and 19 are supported. These resistors may extend substantially the full length of the heating chamber.

The construction of the bricks 15 is shown in detail in Fig. 3. A recess 20 is provided on one side. of each brick at its lower end. As viewed from the side of the brick this recess is rectangular in shape and somewhat deeper than the diameter of pins 16. At the upper end of this recess is a transversely extending inner recess 21 which is L shaped to provide a depression or notch 22. It will be understood that the side opening of recess 20 is closed by the adjacent brick 15 so that the recess 20'is open only at the bottom. This bottom opening23 has its greater dimension extending crosswise of the row 14 whereby the pins 16 are free to move in recesses 20 to provide for expansion and contraction of the resistor. v

A short portion 24 on -the' upper end of each pin 16 is bent over at right angles. After the bricks 15 have been built into the furnace wall, the pins are inserted through the openings 23-. After insertion, each pin is turned through a quarter revolution until the end portion 24 lies in the inner recess 21, and the pin is then adjusted sideways until this end portion falls into the notch '22, whereby the pin is secured in place in interlocking relation with the furnace wall. It will be observed, however, that by raising the ins out of notches 22 and turning them in t e reverse direction through a quarter revolution, they may be removed.

Suitable hooks 25v are provided on the lower ends of the pins in which the bends of the zigzag resistor are placed whereby it will be observed each length or convolution of the resistoris supported by two hooks, one

. at each end. Preferably the shank of the ,pin extendsthrough the loop of the resistor,

' the end of the hook'being on the outside.

As shown the resistor is made from a ribbon which is preformed or bent before installation in such manner that it is supported edgewise, i. e. with the greater sectional dimension of the ribbon extending vertically, This gives the resistor suflicient rigidity to prevent sagging when hot. The resistor may, however, be cast with the desired configuration. As shown in Fig. 4 the resistors 17, 18 and 19 may have a common connection 26 so that they may be operated on a threephase source of supply. The terminals 27, 28, and 29 of the resistors may be brought out through suitable bushings in the furnace roof for connection with the source of embodied in concrete form and as operating in a specific manner in accordance with the provisions of thespatent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in'the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electricvfurnace comprising a heating chamber enclosed by walls formed of heat refractory material, a plurality of metallic pins removably interlocked with one of said walls so as to project endwise into said heating chamber, and a sinuous heating resistor in said chamber mounted .on said pins in spaced relation to said heat refractory material.

2. An electric furnace comprising a heatingv .chamber provided with a roof con structed of heat refractory material, a plurality of metallic pins removably secured in spaced relation to said roof so as to project endwise downward into said heating chamber, and a sinuous heating resistor in said chamber having its convolutions mounted in acubstantially horizontal position on said ins.

3. An electric furnace comprising a heating chamber having a roof constructed of heat refractory material provided with recesses, a plurality of metallic pins in said recesses removably interlocked with the walls of said recesses so as to project endwise downward into said heating chamber, hooks on the lower ends of said pins, and a sinuous, preformed, self-supporting heating resistor in said chamber having its convolutions resting in a substantially horizontal position on said hooks.

4. An electric furnace comprising a heating chamber provided with a roof formed of heat refractory material, heat refractory bricks'provided'with recesses built into said roof, metallic pins removably secured in said recesses so as to project endwise into said heating chamber, and a preformed self-supporting heating resistor provided with a plurality of horizontally extending convolutions mounted directly on said pins in spaced relation to said roof.

5. Means for supporting a heating resistor in a furnace chamber, comprising heat refractory bricks provided with recesses built in the roof of the furnace chamber, and pins forming hangers for the resistor inserted endwise into said recesses so as to hang downward into said chamber in substantially vertical positions, said pins being provided with locking means engaging the Walls of said recesses so as to detachably secure the pins therein.

6. Means for supporting a heating resistor in. a furnace chamber comprising heat refractory' bricks built-in the roof of the furnace chamber, said bricks being each provided with an outer recess and an inner trans versely extending recess, and metallic pins greases having projections inserted in said outer recesses and secured by turning said pro ections into sa d inner recesses, said pins forming hangers for the resistor.

bricks built in said roof, said bricks being each provided with an outer recess and an inner transversely extending recess, metallic pins having projections inserted in said outer recesses and secured by turning said projections into said inner recesses, and a sinuous heating resistor supported by said pins.

9. An electric furnace comprising walls forming a heating chamber provided with a roof formed of heat refractory material, heat refractory bricks laid in said roof, said bricks being eac provided with an outer recess having an elongated, transverse section, and an inner transversely extending recess, metallic pins inserted in said outer recesses having end portions bent at right angles, said pins being locked by turning said right angle portions into said inner recesses, and a sinuous heating resistor supported by said pins.

10. An electric furnace comprising a heating chamber provided with a roof formed of heat refractory material, heat refractory bricks built in said roof, said bricks being each provided with an outer recess and an inner transversely extending recess of irregu lar shape to provide a notch, and metallic 'fso pins inserted in said recesses havingend portions bent at right angles, said pins being detachably locked by turning said end portions into said inner recesses and seating said end portions in said notches, and a sinuous heating resistor supported by said pins.

11. An electric furnace comprising a heating chamber provided with a roof formed of heat refractor material, two rows of heat refractory brie s provided with recesses built in said roof, pins inserted in said recesses provided withlocking means engaging the walls of said recesses so as to secure the pins therein, and a heating resistor extending back and forth between said rows of bricks and sup ported at its bends by said pins inspaced relation with said roof;

- 12. An electric furnace comprising a heating chamber provided with a roof formed of heat refractory material, two rows of heat refractory briclc's, having recesses built in said roof, pins inserted in said recesses provided with locking means engagin the walls of said recesses so as to detaeha ly securethe pins therein, and a ribbon-shaped heating resistor bent insZig-Ztig' conformation between said rows of bricks into a plurality of edge- Wise convolutions and supported at its bends on said pins.

13. Means for supporting a heating resistor in a furnace chamber comprising a plurality of pins forming hangers for the resistor pivotally secured to the roof of the furnace chamber so as to move freely with the resistor upon expansion and contraction thereof.

14. Means for supporting a heating resistor in a furnace chamber com-prising heat refractory bricks provided with recesses built in the roof of the furnace chamber, and pins forming hangers for the resistor secured in said recesses so as to move freely with the resistor upon expansion and contraction thereof.

15. An electric furnace comprising a heating chamber, a plurality of pins pivotally secured to the roof of said heating chamber, and a sinuous heating resistor mounted on said pins provided with a plurality of lengths extending substantially in the directions of the swinging of said pins whereby said resistor is free to expand and contract independently of said roof.

16. An electric furnace comprising a heating chamber having a roof constructed of heat refractory material provided with elongated recesses, a plurality of pins pivotally secured in said recesses so as to be free to swing there in, and a heating resistor mounted on said pins'provided with a plurality of lengths extending substantially in the directions of saidrec'esses whereby said lengths are free to expand and contract independently of said room.

17. An electric furnace comprising a heating chamber provided with a roof formed of heat refractory material, heat refractory bricks provided with elongated recesses built into said roof, a plurality of pins having end portions bent at right angles secured in said recesses so as to be free to swing on said end portions, and a heating resistor mounted on said pins provided with a plurality -of lengths extending substantially in the direction of said recesses whereby said resistor is free to expand and contract independently of said roof by the swinging of said pins in said recesses.

18. An electric furnace comprising a heating chamber provided with a roof formed of heat refractory material, heat refractory bricks built in said roof, said bricks being each provided with an outer elongated recess and an inner transversely extending recess, metallic pins inserted in said recesses having end portions bent at right angles, said pins being detachably locked by turning said end portions into said inner recesses whereby said pins are free to swing on said-end portions in said elongated recesses, and a heating resistor mounted on said pins provided with a plurality of spaced convolutions extending substantially in the directions in which said pins are free to swing, whereby said resistor is free to expand and contract independently of said roof.

19. In an electric furnace, in combination, a preformed, relatively heavy resistor member comprising a plurality'of end-connected substantially parallel-extending straight convolutions, and a plurality of spaced hook members removably mounted in and interlocked with a wall of said furnace for supporting said resistor member.

20. In an electric furnace, in combination, a plurality of refractory walls enclosing a furnace chamber, a plurality of spaced sets of hooks supported in spaced relation relatively to each other in one of said walls, said hooks being removably mounted in and interlocked with one of said walls, and a relatively heavy resistor member preformed to comprise a plurality of substantially parallelextending straight convolutions, each of said convolutions being supported by at least two of said hooks. I

21. In an electric furnace, in combination, a plurality of refractory walls enclosing a furnace chamber, a relatively heavy resistor member preformed to comprise a plurality of integral, end-connected-substantially parallel-extending, straight convolutions, and a plurality of spaced hooks for releasably supporting said resistor member, said hooks being so mounted in one of said Walls as to be removable therefrom by a turning movement relatively thereto.

22. In an electric furnace, in combination, a plurality of refractory walls enclosing a' furnace chamber, a relatively heavy resistor member preformed to comprise a plurality of end-connected, integral, substantially parallel-extending, straight, convolutions and a plurality of hook members, removably supported by one of said walls and interlocked therewith, for operatively engaging said convolutions at spaced points to support said resistor in its operative position in said furnace chamber.

23. An electric furnace comprising walls forming a heating chamber, one of said walls being provided with recesses each including an inner transversely extending recess, pins in said recesses, said pins being provided with projections extending into said transversely extending recesses so as to removably interlock said pins with said'wall, and a sinuous heating resistor supported by said pins.

24:. An electric furnace comprising heat vided with locking means engaging the-walls of said recesses so as to removably secure the pins therein, and a heating resistor extending back and forth between said pins and supported by said pins in spaced relation with said wall.

In witness whereof, I have hereunto set my hand this 26th da of December, 1924. WI LIAM KEENAN.

refractory walls forming a heating chamber,

one of said walls being provided with two rows of recesses, pins 1I1 S&1d recesses pro-

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