US1853382A - Supporting means for electrical heating elements - Google Patents

Description

pri 12, w32.. E. i.. SMALLEY 1,853,382

SUPPR'TTNG MEANS FOR ELECTRICAL HEATING ELEMENTS Filed Feb. la, 195o 4 sheets-sheet 1 ,1 @fw /fi My ATTORNEY prl 12, 1932?.l E. 1 SMALLEY 1,853,332

SUPPORTNG MEANS FOR ELECTRICAL HEATING ELEMENTS Filed Feb. 18, 1930 4 Sheets-Sheet 2 :PIE- E .Fl an... 5

IN VEN TOR.

BY dvi ATTO NEY April l2, 1932. E. L., SMALLEY 18532382 SUPPORTING MEANS FOR ELECTRICAL HEATING ELEMENTS Filed Feb. 18, 1930 4 Sheets-Sheet 5 s- El xf ma.; a

1N VEN TOR.

Y BY EIR-..12 :Win15 Mg i ATTORNEY E. L. SMALLEY 1,853,382

SUPPORTIG MEANS FOR ELECTRICAL HEATING ELEMENTS April 12:x 1932.

Filed Feb. 18, 1930 4 Sheets-Sheet 1N VEN TOR. w/vv y ATTOR EY Patented Apr. 12, 1932 UNTED STATES PATE? OFFICE EDWIN L. SMALLEY, 0F WHITEFISH BAY, WISCONSIN, ASSIGNOT TO I-IEVI DUTY ELECTRIC COMEAEY, OF MILW'AUKEE, W'ISCONSEIT, A CREORATION OF WISCONSIN SUPPORTING MEANS ELECTRICAL HEATING ELEMENTS Application led February 18, 1930.

My invention relates broadly to electric fm'naces .and more particularly to a construction of refractory support for the heat-ing elements in an electric furnace.

- @ne .of the 'objects-of my invention is to provide .a system for mounting resistor elements Within an electric furnace, with means for re- ,sisting Athe conductivity lof heat through the furnace Awall from .the resistor mounting.

Another object of my invention is to provide a construction of refractory support for :resistance elements within .an electric furnace, wherein the resistor support is substantially .separated'from the furnace wall by a confined .air space for reducing theconduction of heat from the resistor support through the furnace wall.

Still another 'object of my invention is to prov-ide a construction of ceramic, or metallic refractory support engageable in a groove in the wall of a furnace in selected .spacia'l relation in such manner that conduction of heat from the resistor through the re- -sistorlsup'port and .through the furnace wall is .substantially reduced.

A. Vfurther object of my invention is to provide a construction of support for the heating `elements within an electric furnace, wherein the supports 'for the heating elements may be manually inserted into grooves in the wall of the furnace and maintained in position there in in a manner substantially preventing the .direct conductivity of heat from the resistor elements through the furnace Wall.

A still further object of my invention is to provide a construction of ceramic refractory support for .the heating elements in an electric furnace which differs substantially from the material of :the furnace wall and has a high dielectric strength, but comparatively low thermal resistivity, the major area of the support being substantially spaced from the furnace wal-l 'for reducing the conduction of heat from the heating elements rthrough the furnace wall.

Still .another object of my invention is to provide a construction of ceramic, or metallic refractory hook Afor the vheating ele-ments within an electric furnace, the hook having means for engaging the upper inside and Serial No. 429,400.

lower edge portions of va longitudinally extending groove in the furnace wall, while the major area thereof is substantially spaced from the furnace wall for preventing the direct conduction of heat from the resistance elements through the furnace wall.

Another object of my invention is to so a1'- range the assembly of refractory supports, spacers and insulators, as to effectively close the opening to the supporting groove for such refractory members and thereby substantially intercept convection of heat to the interior surface of the groove in a furnace wall.

Another object of my invention is to so form the surface of a refractory Vsupport for a ribbon element that the surface vof the ribbon in contact with the support has freedom for release of heat from such surface of the ribbon element.

Other and further objects 4of my inven- .tion reside in the construction lof-ceramic refractory supportand inserta'ble spacer members therefor in an electric furnace, as set forth more particularly in the specification hereinafter following by reference to the accompanying drawings, in which Figures l, la and l?) show elevational views of progressive portions of the interior of a furnace wall illustrating the resistor supports and the resistor elements mounted in accordance with my invention; Fig. 2 is a vertical sectional view on an enlarged scale showing the method -of suspending the resistor elements; Fig. 8 is an enlarged elevational view showing the resistor elements mounted in position; Fig. i is al horizontal sectional view on li-ne lr-l of vFig. 2 through the supporting refractories employed in the construction of the support embodying my invention; Fig. 5 is a sectional view on line 5--5 of Fig. 2 through the spacer refractory inserts which serve as spacer members in the resistor mounting construction of my invention; Fig. 6 is a side elevation of one of the refractory insertable hooks embodying my invention; Fig. 7 is an end view of the refractory insert shown in Fig. 6; Fig. 8 is a top plan view of the refractory insert illustrated in Figs. 6 and 7 Fig. 9 is a cross-sectional view of the'insert on line l9---9 of Fig. 6; Fig.

10 is a cross-sectional view through the hook portion of the insert on line 10-10 of Fig. 6; Fig. 11 is a fragmentary cross-sectional view through the insert on line 11-11 of Fig. 7; Figs. 12 and 13 are end and side views respectively of the separator block employed between the refractory hooks of Figs. 6 to 11; Fig. 14 is a sectional view illustrating the method of insertion of one of the resistor supporting members in the groove 'formed in the furnace Wall; Fig. 15 shows a form of refractory hook embodying my invention in which reenforcing means are provided for strengthening the hook against breakage; Fig. 16 is an end view on a small scale of ay refractory hook insert embodying my invention; Figs. 17 and 18 showend views of inserts having a pair of refractory hooks integrally mounted thereon in different spacial relationship for supporting a` metallic resistor; and Figs. 19, 20, and 21 are end views of separator element-s having from one to three separators integrally mounted thereon for the proper spacing of the metallic resistor element along the furnace Wall.

In electric furnace construction, it has heretofore been proposed to build in, as part of the furnace wall, blocks which carry projecting supports for the mounting of resistance elements with respect to the wall of the furnace. The coefficient of expansion of these blocks has been substantially the same as the material of the furnace wall, but the blocks have a relative high thermal conductivity compared to that of the furnace wall, which is usually fire brick. When the builtin block is used, it has been found necessary to chisel away the block from the furnace wall which results in a shut-down of the furnace over a substantial time period. In the case of metallic refractory supports embedded in the wall, an excess quantity of heat is carried by conductivity into the furnace wall, with a resulting excess conduction through the wall, and consequent radiation from the furnace shell. Where metallic hooks are employed, and must be replaced, the furnace wall must practically be re-constructed to replace the hooks.

By the construction of the refractory support of my invention, I avoid disadvantages heretofore experienced in the art and provide supporting means combined with thermal-resistivity to the conduction of heat from the furnace chamber through the furnace wall.

The refractory supports of my invention are readily detachable from, and insertable into, the furnace wall and may bespaced, and easily changed, with respect to such spacing in any desired location for securing the required release of heat from any given wall area, as may be required to secure temperature uniformity throughout the furnace chamber.

I prevent conduction of heat through the furnace wall from the resistor support, by providing a confined air space between the refractory member, which projects into the Wall, and the longitudinally extending groove in the furnace Wall in which the refractory member is mounted. A furnace wall of fire brick at 100o C. has a thermal conductivity of approximately .00109. The porcelain-like supports, or spacers, or separators, usually used for such purposes, when at 1000, have a thermal conductivity of approximately .0039. Air at the same temperature has a thermal conductivity of approximately .0000719 Thus, the refractory supports have a thermal conductivity approximately four times that of the fire brick, while air has a thermal conductivity only about 1/50 of that of porcelain. Therefore, by providing a substantial space in the rear of the insertable refractory members, and thus substantially confining such air by means of the near Contact relationship of successive adj acent refractory members, a. confined air space of large heat-resistivity may be established. Such air gap offers a large resistance to heat fiow. I so construct the insertable refractories, with respect to the contour of a. groove in a furnace wall, that I build up such a confined air space and thereby obtain the desired high thermal resistance to heat conduct-ion. Furthermore, by the contour relationship between the. insertable refractories, and the contour of the groove in the furnace wall, I establish substantially line contacts between such refractories and the groove in the furnace wall. To insure such substantially confined or dead air space between the rear of the insertable refractories and the groove in the furnace ivall, I construct the insertable refractory in such manner that the radius of curvature of the insert is substantially greater than the radius of curvature of the groove; or conversely the radius of curvature of the groove is substantially less than the radius of curvature of the insertable refractory. In this way the refractory may be mounted in the nature of a cantilever projecting from the furnace wall and yet thermally insulated from the furnace wall by an air gap of large heat-resistivity. The cantilever construction of the refractory support, spacers and separators, is such as to permit ready removal and replacement. By reason of the method of insertion of the refractory supports, any of the insertable members therefore may be removed and replaced without any substantial displacement of the turns of the resistor. rPhat is, a separator, or refractory support, may be manually inserted by lifting a single turn of the resistor through a short distance and replacing the resistor on the refractory thus inserted.

To prevent failure of the heating elements, by short circuit, in case of breakage of the support portion of the insertable refractories, T.'

l may provide metallic inserts for augmenting the strength of the supporting or separating refractories.

By providing Ja selected number of insertable spacer members between the insertable support refractories the turns of the resistor element may be selectively spaced along the furnace wall. This construction provides means for establishing a predetermined temperature gradient along th-e furnace. Tha-t is, adjacent the door of the furnace the turns may be .closely spaced by mounting the insertable refractories immediately adjacent each other, while along the furnace wall insertable spacer members between the insertable refractory supports may be introduced for more widely spacing the turns of the resistor, While at a greater dist-ance along the furnace wall a larger number of inse-rtable spacer members are employed between the insertable refractory supports for more widely spacing-` the turns of the resistor. These ceramic spacer members may also serve as electro-insulators between adjacent refractory supports when a metallic support is used.

That portion of the refractory supports on which the upper loop or ribbon elements is lodged, is usually cylindrical in form. The under surface of the ribbon therefore does not have yfree heat release by radiation as `from the balance of the ribbon resistor. This causes a local over-heating of such portion of the ribbon. To overcome this local over-heating, T preferably use a iiuted seat on the support for the ribbon elements. This ygivesl `substantially several line contacts between the refractory support and the ribbon, and between such line contacts, formed grooves through which any excessive .heat may readily be released as by convection.

Referring to the drawings in more detail, reference character 1 designates the face of the tiles 2 on the inside of the furnace wall designated at 15 which is directed toward the furnace chamber, which is in turn surrounded by a metal shell 6 which encloses the furnace. The tiles 2 have longitudinally extending grooves 3 formed therein, the groove having a vertical depending portion 8 adjacent the upper extremity thereof. The ceramic refractory 5 of high dielectric strength but a relatively low heat resistivity compared to that of the furnace wall, is insertable into the longitudinally extending grooves in the furnace wall. An upwardly extending hook-like member 7 is formed on the refractory 5 and serves to engage the v depending flange 8 of tile 2. Substantially a line contact is established between the refractory 5 and the overhanging portion 8 of the vtile 2, the hook-like member 7 being rounded at 7 a so that the line of contact between the overhanging edge 8 and the pertion 7 a ofthe upwardly extending .hook-like member 7 is substantially tangential. The

refractory 5 engages the lower portion of the groove 3 in a substantially line contact formed by the juncture of the substantially vertically extending face 9 of the refractory 5 and the substantially curved face 9a of the refractory 5 with the lower edge 2a of the groove 3 formed in the furnace wall 1. The outwardly projecting portion of the refractory `5 is shaped as indicated at 6 to provide a support for the turns of the resistor elements 10 which are arranged in a series of loops forming a sinuous or convoluted form of heating coil.

While I have illustrated the heating element in the form of a ribbon, it is obvious that various shapes of heating elements, such as a round rod element, may be employed and the projecting portion of the refractory shaped accordingly. The resistor elements 10 are shown suspended at the top thereof. A flange 5a on the extremity of the refractory prevents the resistance element 10 from slipping away from the refractory support. To provide for the quick release of heat from the resistor element, the `portion 6 is provided with a plurality of longitudinally extending flutes 6a, '65, 60, and 6d formed in such manner that the refractory may be readily withdrawn from a forming mold and positioned with respect to the upper bends of the resistor to provide circulation channels for convection currents beneath the ribbon resistor. In order to maintain the turns of the resistor element in predetermined spacial relation, I provide a multiplicity o-f separator elements located in similar grooves 3 which extend longitudinally through a tile 2 below the grooves 3 in which the refractory supports 5 are inserted. In the lower grooves 8 the refractory separator members 12 are inserted, the refractories 12 having a head extension preferably diamond shaped as illustrated at 11, inserted adjacent each other in such manner as to keep the vertical strands of the depending resistor in alignment. The ceramic refractories 12 are insertable in the grooves?)V in the furnace wall in the same manner as previously described for the refractory members 5 which serve to support the resistor 10. That is, each of the refractories 12 have curved and substantially vertical faces 9a, and 9 which at their junction form a substantially line contact with the corner 2a in the lower Iextremity of Jthe groove 3. In order to` establish a desired temperature gradient along the furnace wall, I may provide insertable refractory spacer members indicated at 17 disposed intermittently with respect tothe refractory supports 5, or I may use spacers 17 in combination with separators 12, as in Fig. 1b.

ln 1, I have shown the resistor element 1l) arranged in convolutions uniformly spaced in a vertical plane where single spacer members 17 are inserted between the refractories 5 with single separator members 12 inserted in lower groove 3. A condition as represented by the close relationship of the turns of resistor 10 exists for example adj acent the front of a furnace, where a larger amount of heat is desired adjacent the door of the furnace. At 17 and 17a, I have shown in Fig. 1a two spacer members adjacent each other and disposed between the refractories 5 and separators 12a and 12b disposed between separator members 12 for more widely spacing the turns of the resistor element 10. At 17, 17a and 17 Z) in Fig. 1b, I have illustrated three spacer members disposed between the refractory supports 5 and spacer members 12a, .spacer 17 and separator 120 disposed between separator members 12 still more widely spacing the turns of the resistor element. By this arrangement a temperature gradient is obtained, the heat release being a maximum with the strands of resistor 10 closest together, and reducing proportionately according to the increase in distance between strands of the resistor 10.

I have represented the difference in the thermal conductivity of the material of the furnace wall structure 2, and the material of the refractory inserts, by different cross-sectional lines, the cross-sectional lines of each refractory insert being shown relatively heavier, corresponding to its relatively high thermal conductivity, while the cross-section of the tiles 2 is shown in marked contrast by the lighter cross-sectional lines as being of less thermal conductivity. The material of the insertable ceramic refractory has high dielectric .strength and therefore is a good electro-insulator, but has low thermal resistivity and is therefore at least a fair conductor of heat. On the other hand, when the insertable support is of a metallic refractory, the thermal conductivity is substantially greater than the thermal conductivity of the wall. In order to substantially prevent flow of heat from the resistor elements by conduction through the insertable refra ctories to the furnace wall. the insertable refractories each terminate short of the depth of `grooves 3. The radius of curvature of the body portion of the insertable refractory which extends into the groove 3 indicated at 5?) in Fig. 2 is substantially larger than the radius of curvature of the groove 3 indicated at 50 in 2; or the relationship may be defined by observing that the radius of curvature of groove 3 is substantially less than the radius of curvature of the insertable refractory. This relationship provides substantially a confined air space 4; immediately behind the refractory insert and between the points of substantially7 line contact, between the hook-like member 7 and overhanging flange 8 and the substantially line contact between corner portion 2a and the vertically and curved portions 9 and 9a of the insertable refractory. The major area of theinsertable refractory is maintained' out of contact with the furnace wall and thermally insulated therefrom by the confined air space of appreciable depth thereby substantially eliminating thermal conduction through the furnace wall.

In Figs. 1, la and 1b, I have indicated the support of resistor elements 10 upon insertable refractories 5 in the upper groove 3 of the furnace wall, while in the lower groove 3 the separator members 12 or with spacers 17 are inserted for maintaining the resistor element 10 in proper spacial relation. While only one groove 3 is illustrated for the insertion of .separator members 12 and the spacer members therefor, I desire that it be understood that any number of such grooves may be provided for receiving the separators for resistors of different lengths.

In Fig. 2, I have illustrated rows of insertable refractory separators 12 beneath the laterally extending row of insertable supporting refractories 5.

Figs. L and 5 illustrate cross-sectional views taken through the refractory supporting members 5 and spacer members therefor and through the separators 12 on lines 4 4 and 5 5 of Fig. 2 respectively.

In Fig. 14, I have shown the method of assembly wherein one of the supporting refractories 5 is being inserted in position in the furnace wall. The general construction of insertable supporting refractory 5 will be more clearly understood from the several .views shown in Figs. 6 to 11.

I have represented in Fig. 16 an end view of a single refractory support 5 which may be separated from the next refractory support by an insertable spacer block 17 as shown in Figs. 1a, 1?), 1c, 3, 5, 12 and 13. In order to avoid the insertion of spacers 17 between hook members having predetermined spacing, I may provide a construction as shown in Fig. 17 consisting of insertable refractory 20 having a pair of projecting portions 21 and 22 shaped in a manner similar to the projecting portion 5 for supporting the resistor element 10 in predetermined spacial relation. While I have illustrated two projections 21 and 22, I may provide a multiplicity of projections in such manner that a row of supporting members may be inserted into or removed from the groove in the furnace wall. As shown in Fig. 18, the spacial relation of the hook members may be modified to meet all construction requirements.

In Fig. 19, I have shown a single refractory separator 12 for spacing the turns of the resistor by diamond head 11. However, as shown in Figs. 20 and 21, the insertable refractory may be constructed as indicated at 23 similar to the refractory 12 but having a plurality of separator projections 24, 25 and 26 for spacially relating the looped turns of j the resistor element 10.

From Fig. 2, the method of reducing the transfer of heat between the insertable refractory 5 and the groove 3 by establishing substantially tangent contact between the depending flange 8 and the hook portion 7a of the refractory 5 will be clear.

In Fig. l5, I have shown the refractory 5 provided with an angularly disposed bore 27 into which there is inserted a pin 28, less in diameter than the bore 27 which prevents sagging of the resistor 10 should the refractory be `accidentally broken away. The bore 27 in refractory 5 is disposed in a substantially downward angular direction in an acute angle to the lateral axis of the insertable Vrefractory 5, so that pin 28 is gravitationally retained.

In order to provide for the rapid release of heat from the resistor which is supported by the refractory hook, the flutes 6a, 6b, 6c and 6d are merged at each end in valleys which I have designated at 5a', 5b', 50, and 5cl at one end and 5a, 5b, 5o and 5cl at the other end. The valleys form ports for flutings beneath the resistor 10, through which the heat may be dissipated. The ribs formed by the flutes provide substantially line contact forl supporting the resistor l0 so that the heat may be freely released in theY intern mediate valleys or flutings between the points of support. The arrangement of the valleys 5a', 5b', 50 and 5d at one end of the portion of the hoolrover which the resistor l0 is supported and the valleys 5a, 5b, 5c and 5c at the other end of the refractory is such that the refractory may be readily withdrawn from the mold. It will be observed that the peaks intermediate the valleys extend normal to the vertical axis of the refractory hook whilel the intermediate peak is directly in line with the central axis of the hook which facilitates the molding of the refractory insert.

The construction of the several inserts and separators according to my invention is such that the resistor element is operatively mounted in position along the furnace wall but subject to repair of any of the refractories without delay. By merely raising one turn of the resistor an injured refractory hook may be removed and a renewal hook inserted without chiseling or working upon the furnace wall. `The heat insulation aorded by the construction of my invention conserves lheat and raises the efficiency of the furnace.

l While Ihave described the system of supporting heat elements within an electric furnace and preventing the conduction of heat through the walls thereof in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than those imposed by the scope of the appended claims.

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

l. In a support for electrical heating elements within an electric furnace, the combination with a furnace wall having a longitudinally extending groove therein, a vertically depending ange forming the top edge thereof, and refractory membersleach having resistor supporting portion and a portion projectible into the groove in the furnace wall, the projectible portion operating to engage the groove in said furnace wall at the upper and lower extremities thereof while being substantially spaced from said groove intermediate the upper and lower extremities thereof and substantially closing the opening to said groove opposite said refractory members.

2. In a support for resistor elements in an electric furnace, a furnace wall having a longitudinally extending groove therein, a vertically depending flange forming the top edge thereof, and members, of relative high thermal conductivity, projectible into the groove, said members having means for supporting said resistance element, and means on said members for engaging the remote edge portions of said groove while being substantially spaced from said groove intermediate the remote edge portions thereof and substantially closing the opening to said groove occupied by said members.

3. In a support for electrica-l heating elements in an electric furnace, a furnace wall having a longitudinally extending groove therein, a vertically depending flange yforining the top edge thereof, with the upper portion of the furnace wall adjacent said groove overhanging the groove, refractory parts having a portion thereof shaped to support a resistor element and having a portion thereof projectible into said groove to a position behind the overhanging portion of said groove, the major area of the projecting portion of said member being substantially spaced from said longitudinally extending groove in the furnace wall and substantially closing the opening to said groove opposite said portions.

4. In a support for heating elements in an electric furnace, a furnace wall having a longitudinally extending groove therein, a refractory member having a. portion thereof arranged to support a resistor element and having a portion thereof projectible into the grooved furnace wall, the proj ectible portion of said refractory member establishing opposing forces upon said grooved furnace wall at different elevations thereof and terminating short of the depth of said groove for providing substantially a confined air space of substantial depth between the end of said member and the interior portion of said groove.

EEO

5. In a support for an electrical resistor, a furnace Wall structure for a furnace chamber, a longitudinally extending groove formed therein, a multiplicity of removable refractory hook members inserted in said groove and closing said groove With respect to the furnace chamber, said hook members terminating short of the depth of said groove for providing a dead air space of substantial depth of high heat resistivity immediately behind said members for limiting the transfer of heat between said members and the furnace Wall. Y

6. In a support for electrical resistor elements in combination with a furnace Wall having longitudinally extending grooves therein and refractory members removably supported as cantilevers in said grooves and each establishing an interlock with the upper and lower portions of said grooves, said members having the major area thereof substantially separated from said grooves by a heat insulating air gap of substantial depth, and means formed on the projecting ends of said members for carrying an electrical resistor element.-

7. A support for resistor elements in an electric furnace comprising in combination With a furnace Wall having a longitudinally extending groove therein, an insertable refractory, and a resistor supporting portion on said refractory, the radius of curvature of said insertable refractory being substantially greater than the radius of curvature of the groove in Which said refractory is inserted.

8. A support for an electric resistor in an electric furnace comprising in combination With a furnace Wall having a longitudinally extending groove therein, a refractory member projecting into the groove in said furnace Wall, said refractory member having a portion thereof shaped to support a resistor element and having the projecting portion thereof engaging the groove Within said furnace Wall in substantially line contact adj acent the top and bottom edge portions thereof While being spaced away from said groove intermediate the upper and lower edge portions thereof for establishing aV confined air gap in the rear of said refractory member fol` decreasing the conductivity of heat from said resistor through said furnace Wall.

9. In a support for electrical resistors in i combination with a furnace Wall having longitudinally extending grooves therein, insertable refractories projectible into said grooves, said refractories constituting intermittently positioned resistor supports, and spacer members for the lateral spacing of said supports, each of said spacer members and supports terminating short of the depth of said grooves for providing a confined air space in the rear of said supports and said spacer members,

for substantially preventing the conduction of heatfrom said resistor through said furnace Wall.

10. In a support for electrical resistors in an electric furnace in combination with a furnace Wall having a longitudinally extending groove, and a portion thereof extendin outside of said groove, said last mentione portion formed to support a resistor, and the portion of said refractory projecting into said groove being curved for establishing contact With the depending flange forming the top portion of said groove in a line whlch is substantially tangent to the portion of said member which projects Within said groove.

11. In a support for electrical resistors in an electric furnace in combination with a furnace wall having a longitudinally extending groove therein, a multiplicity of refractory members insertable into the groove Within the furnace Wall, said refractory members carrying projections thereon for engaging the looped turns of an electrical resistor in alterable spacial relation, and insertable ceramic refractory spacers for said groove to effect said alterable spacing.

12. In a support for an electrical resistor in combination With a furnace Wall having a longitudinally extending groove therein, refractory members insertable into the groove in the furnace Wall, some of said refractory members having projections thereon for engaging the looped turns of an electrical re sistor, and others of said refractory members being insertable into said groove, and for altering the spacial relation of said turns, said insertable refractory members terminating short of the depth of the groove for providing a confined air space or for preventing the conduction of heat from said resistor element through said furnace wall.

13. A support for electrical heating elements comprising a refractory hook having means for engaging a turn of the resistor element, said hook having a plurality of curved fiutings extending longitudinally thereof beneath the resistor element supported thereby, and channels interconnecting said curved flutings for facilitating the release of heat generated by said resistor element adjacent said hook. j

14. A support for an electrical resistor comprising a refractory hook for engaging a turn of an electrical resistor, and a plurahty of heat releasing longitudinally extending channels formed in the surface of said refractory hook beneath the resistor for dissipating heat generated by said resistor on the under side of such turn. V

15. A refractory support having an electrical resistor, comprising a hook member having retaining flange like portions at the lio iis

izo

end thereof and a plurality of longitudinally extending ribs on the surface thereof adapted to establish substantially line contact with a resistor element looped thereover, valleys intermediate said ribs interconnecting other radially extending valleys formed on the inner faces of said retaining flange like portions of said hook member for effecting the dissipation of heat generated by said electrigal resistor extending around said hook mem- 16. A support for an electrical resistor comprising a hook adapted to engage a resistor looped thereover, a plurality of longitudinally extending curved flutes on said hook, said curved flutes forming ribs with valleys therebetween, and the ends of said valleys at each end extending in a direction normally vertical to the center horizontal axis of said support for releasing heat from the area immediately beneath said resistor.

17. A support for an electrical resistor comprising in combination with a furnace wall having a longitudinally extending groove therein, an insertable refractory establishing substantially line contact with said groove, a plurality of longitudinally extending flutes on said insertable refractory, said flutes forming ribs with valleys therebetween, a resistor looped over said refractory and the ends of said valleys at each end extending in a direction normally vertical to the center horizontal axis of said support for releasing heat from the area immediately beneath said resistor.

18. A support for an electrical resistor comprising in combination with a furnace wall having a longitudinally extending groove therein, an insertable refractory establishing substantially line contact with the top and bottom edges of said groove and providng a qconfined air pocket with respect to said groove, a plurality of longitudinally extending flutes on said refractory forming ribs with valleys therebetween, a resistor looped over said ribs and establishing substantially line contact therewith and ports at each end of said valleys for the release of heat from the area immediately beneath said resistor.

In testimony whereof I aiiix my signature.

EDWIN L. SMALLEY.

Images