US1728752A - Electric heating unit - Google Patents

Description

Patented Sept. 17, 1929 'UNITED STATES PATENT OFFICE HARRY A. FRIETCHEN, OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELEG- TRIC & MANUFACTURING COMPANY, A CORPOEATION OF PENNSYLVANIA ELECTEIC I-IEATING- UNIT Application filed November 6, 1328.

My invention relates to furnaces and more particularly to removable heating units for electric furnaces.

An object of my invention is to provide a relatively simple, light-weight and highly -efiicient heating unit for an electric-resistor furnace.

Another object of my invention is to provide a heating unit that shall embody a skele- *ton frame so constituted that it will tend to enzage a supporting side wall of the furnace.

In practicing my invention, I provide a substantially plane skeleton metal frame having a plurality of in-turned side-wall Channels in one face thereof and having a bottom portion extending laterally from the plane of the frame. Refract-ory resistor-supporting members, of substantially T-shape in lateral section, fit into the channels to support and space the relatively heavy preformed resistor conductor.

In the single sheet of drawings:

Figure l is a view, in front elevation, of a heating unit embodying my invention;

Fig. 2 is a view of the heating unit, in vertical lateral section taken on the line II-II of Fig. 1;

Fig. 3 is a view, in vertical lateral section of a furnace in which is located a heating unit embodying my invention;

Fig. 4 is a top plan view of a refractory resistor-supporting member;

' Fig.`5 is a View, in lateral section taken on 'the line V-V of Fig. l;

Fig. 6 is a top plan View of a resistorspacing member; and

Fig. 7 is a view, in lateral section taken on 'the line VIT-VII of Fig. 6.

Referring more particularly to Fig. 1 of the drawings, a heating unit, designated generally by the numeral 11, embodies a skeleton 'metal frame 12 which may be made of a suit'- 'able material to withstand the temperatures 'to which it will be subjected when located in a furnace chamber. The front surface of the 'frame 12, which may be provided with a plurality of openings 13 to lighten the weight 'and reduce the heat-storage Capacity thereof, is provided with a plurality of substantially 'horizontal ribs l& for stifening purposes.

Serial No. &17,637.

The rear face of the frame 12 is provided with a plurality of channels 15 formed by pairs of ribs or side walls 16 and 17 the outer ends of which are inturned toward each other, substantially as shown in Figs. 2 and 3 of the drawings.

The bottom portion of the frame 12 has a base 18 which extends laterally away from the plane of the frame and towards that side thereof having the ribs 14. The bottom of the base 18 is provided with a slight upward bevel, for a purpose to be hereinafter described in detail.

As shown in Figs. 2 and `3 of the drawings, I may provide three Channels 15, each of which receves refractory members. The upper channel 15 receives a plurality of refl-actory resistor-supporting members 19, shown in Figs. 4: and 5 of the drawings.

As there shown, the member 19 is of substantially T-shape in lateral section, the head or enlarged portion thereof fitting into the channel. The forward portion is provided with a plurality of laterally-extending recesses 21 suitably spaced apart and with a l ongitudinally-extending groove 22 in one Iace.

The two lower Channels 15 receive resistor-spacing members 23, shown more particularly in Figs. 6 and 7 of the drawings. The shape of the members 23 is substantially the same as that of members 19 with the exception that they are provided with reccsses 24 which are somewliatdeeper than the recesses 21. lVhile I have shown three Channels, l do not desire to be limited to this number.

A resistor or heating element 25 comprises a plurality of loops having substantially straight portions connected by suitable return-bent portions at the top and bottom thereof. The general shape of the performed heating element is shown in Fig. 1 of the drawings and, while I have there shown a resistor wire or rod, I may use a strip instead. The upper loops are supported by the members 19, the depending portions fitting into the recesses 21. The lower part of the substantially-vertically extending straight portions are located in the recesses 24 and,

as stated above, I prefer to use a plurality tations shall be placed thereon as are imot such spacers, particularly so if the length of the depending straight portions is relatively great and the resistance conductor is relatively heavy.

A furnace structure 26 is illustrated generally in Fig. 3 of the drawings and comprises a plurality of walls of refractory material so arranged as to enclose a furnace chamber 27. As the furnace structure itself constitutes no part of my invention, I do not deem it necessary to illustrate or describe the same in further detail.

The heating unit ll embodying my invention is more particularly adapted to be lo` cated closely adjacent to a vertically extending wall of the furnace, the base portion 18 resting upon the bottom wall, the Construction of the base portion being, as hereinbe` fore described such as to cause the heating unit ll to lean against the cooperating wall, the outer faces of the members 19 and 23 operatively engaging the inner surface of the adjaeent wall. In order to insure that the heating unit 11 shall remain in its normal operative position, I provide one or more hook members 28 of substantially L- shape and cooperating washers and nuts 29, the hook members extending through the wall and operatively engaging the frame 12.

A support for material to be heat-treated, while located in the furnace chamber 27, may be a pedestal 31 which may be of any suitable or desired highly refractory material usually employed for such purposes.

lVhile I have shown only one heating unitlocated adjacent to one of the side walls of the furnace, I do not desire to be limited thus, as I may use heating units of this kind on or against any or all of the substantially vertically-extending walls of an electric furnace.

If it becomes necessary to remove one of the heating units 11, this can be done very easily by loosening the nut or nuts 29 on the hook bolts 28 and then pulling out the heating unit, it being understood, of course, that suitable terninal members (not shown) are provided and 'that these have been disengaged preparatory to removal of the heating unit.

The skeleton-frame Construction hereinbefore described provides a minimum heatstorage Capacity of the frame consistent with the necessary strength and the resistor, which consists of a preformed relatively heavy conductor, is supported and spaced thereby, and both lateral and longitudinal movements of the individual loops or convolutions isprevented by the refractory members.

Various modifications may be made in the device embodying my invention without departing from the spirit and scope thereof and I desire, therefore, that only such limiposed by the prior art or are set forth in the appended claims.

I claim as my invention:

1. In an electric furnace, a heating unit, comprising a skeleton metal frame having a plurality of Channels therein, the side walls of which have inturned ends, a refractory resistor-supporting member in the uppernost channel, a refractory resistor-spacing member in the lowermost channel and a relatively heavy preformed resistor supported by the uppermost refractory member and extending through the refractory spacing member,

2. In an electric furnace having a plurality of walls enclosing a furnace chamber, a heating unit extending along one of the walls and comprising a skeleton metal frame having a plurality of horizontally-extending channels in one face, the side walls of each having inturned ends, refractory electricinsulating members in each channel, the outer edges thereof operatively engaging the side wall, and a preformed resistor member of a relatively heavy conductor supported by the upper refractory member and spaced apart by the lower refractory member.

3. In an electric furnace having a pluralit-y of walls enclosing a furnace chamber, a heating unit extending along one of the side walls and comprising a skeleton metal frame having a plurality of horizontally extending Channels in one face, refractory members having a portion located in a channel and another portion extending away from the frame and operatively engaging the face of the wall, and a resistor member supported by one of said refraetory members and having portions thereof spaced apart by other of said refractory members.

4. In an electric furnace having a plurality of walls enclosing a furnace chamber, a heating unit extending along one of the walls and comprising a resistor conductor having a plurality of Suspended loops, a refractory support therefor, a refractory spacing member for the lower part of the resistor loops and a combined resistor-supporting and protecting skeleton frame having interfitting engagement with the refractory members to support them and having also a base portion extending laterally away from the plane of the frame to cause it to lean toward the adjacent wall.

5. In an electric furnace having a plurality of walls enclosing a furnace chamber, a heating unit extending along one of the vertical walls and comprising a resistor, refractory resistor-supporting-and-spacing members, and a combined resistor-supporting and protecting frame having a base portion extending laterally from the plane of the frame to cause it to lean toward the adjacent vertical wall.

6. In an electric furnace having a plurality of walls enclosing a furnace chamber, a. heating unit extending along one of the Vertical Walls and comprsing a resistor, refractory resistor-supporting-and-spaeing members, and a combined resistor-supportingand-proteeting frame having a base portion eXtending laterally from the plane of the frame to cause it to lean toward the adjacent Vertical Wall, and means extending through the adjaeent vertical Wall and engagng the upper edge of the rame for holding` t in proper operative position relatively thereto.

In testmony Whereof, I have hereunto subscrbed my name this 29 day of Oct. 1928.

HARRY A. FRIETCHEN.

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