US1372330A - Resistance element - Google Patents

Description

"T. F. BAILY AND F. T. COPE.

RESISTANCE ELEMENT.

' APPLICATION FILED APR.3, 1919.

1,372,830. E E Patnted Mar. 22,

J, INVEN 70/?6} Thaddeus 1'15 aiZy 549 Frank 7. Copa,

ayawws wgrw UNITED STATES PATENT OFFICE.

THADDEUS r. BAILY ANn FRANK 1*. corn, or ALLIANCE, onro, ASSIGNORS TO THE ELECTRIC FURNACE comrANz-or ALLIANCE, 01110, A ConronA'rIoN or 01110.

RESISTANCE ELEMENT.

Specification of Letters Patent. I Patented 1131', 22,1921,

Application filed April 3, 1919. Serial N6. 287,280.

To all whom it may concern Be it known that we, THADDEUs BA ILY and FRANK T. Corn, citizens of the United States, both residing at Alliance," in the county of Stark and State of Ohio, have invented a new and useful Resistance Element, of which the following is a specificathe appended claims, it

tion. 7

This invention relates to resistance elements for electric furnaces, the object being to construct a resistance element of a material of high conductivity, inclosed within material of low conductivity, the said material of high conductivity being sealed .within the material of low conductivityand being designed to function nrim'arilv as a heating element to raise the temperature of the material of low conductivity to thereby increase the conductive efiioiency of the material of low conductivity.

With this and other objects 111 view the invention consists in the novel construction and arrangement of parts, hereinafter de-.

scribed, illustrated in the accompanying drawings, and particularl eing understood that various changes in the form, .proportions, size and minor details of construc- 3 tion may be made within the scope 'ofthe appended claims, without departmg -from the spirit or sacrificing any of the advantages ofthe invention. In the drawings: Figure l is a transverse section through an electric furnace of the resistance type showin our improved resistance element in position within the heating chamber. I

Fig. 2 is a cross section through, a resistance element constructed in accordance with our invention, said element being made in tubular form.

tion of one of our improved resistance elements.

1 Similar numerals of; reference indicate corresponding parts throughout the several figures of the drawing.

In electrlcal furnaces of the kind known as the granular 'ca'rbon resistance type, the

material of an extremely high fusing point,

fill the said trough with particles of cracked carbon or similar materialand place elecpointed out in oxidation ,as ,well as other objections are found to this type of element, but because of the fact that a material of high conductivity must be used to create theheat, this type of element continues to be used.

In our device we aim to obviate the obj ections which exist in the now known types of elements. The outer portion 1 of our resistance element is preferably formed of carborundum which is a material of very I high fusing temperature, but of low electricalconductivity at atmospheric temperature. l he element is placed within the heating chamber 2 in the ordinary way and may be formed,as shown in Fig. 2, of a single solid piece of carborundum with an aperture 3 extending longitudinally-through its center portion. This aperture or bore is relatively small in comparison with the diameter of the carborundum portion of the element' Cracked carbon, shown at 4 or other suitable material ispacked within the bore and the usual electrodes 5 are then inserted to form a sealed joint at each end, no air being permitted tocontact with the particles of carbon. When the current is turned on it will readily flow from one of the electrodes 5 through the cracked carbon to the other. electrode, since the carbon is a material'of low conductivity, but little cur-3 rent will flow through the carborundum portion of the element until the temperature of i I the said carborundum has been raised to a Fig. 3 is a fragmentary yiew showing a longitudinal section through an endjpor-- high point due to'fthe' heating of'the carbon. When, however, the temperature of the carborundum has begunto rise, its conductivitywillalso rise and upon reaching a high temperature, the carborundum itsel becomes a conductor and the current .will flow freely through the carborundum portion of the element. I The cracked carbon being sealed within'the carborundum portion of the element cannot be lost through oxidating and since the carborundum itself I does not'begin to oxidate until it reaches a temperature considerably higher than any working temperature needed within the fur- I we claim as new and in sections and fitted together to" give any 'outside contour without changing the pr1n-' 10 ciple of the invention.

Having fully described our invention what Letters Patent, is' I 1. A resistance element comprising an outer portion formed of material of low electrical conductivity and having a bore therethrough, and a material of high electrical conductivity within said bore.

2. A resistance element having a hollow' portion formed of a material of low electrical conductivity, said hollow portion be ing filled with a material of high electrical conductivity;

3. A resistance element composed of a portion formed of material of relatively low electrical conductivity and a portion formed of material of relatively high electrical conductivity, the material of high conductivity being sealed within the material of low conductiv-ity and electrodes in contact with the material of high conductivity.

4. A resistance element'formed of material of low electrical conductivity with an aperture extending lengthwise of said eledesire to secure by ment, a'material oi highelectrical conductivity filling said aperture and electrodes in contact with said material of high conductivity said material of high conductivity being sealed within the material of low conductivity;

5. A resistance elementformed of carborundum or like material and having an aperture extending lengthwise therethrough,

cracked carbon or like material filling said aperture and sealed therein. "t '6. A heating element which carries our rent at a high temperature and a resistance element within said heating element to bring the temperature of the heating element to the point where it will-carry; current.

7'; A heatingelement which normally at low temperature is afp'oor' electrical con-- du'ctor and a resistance element embedded within the heating element to bring the tem-' perature of .the heating element to a point where it will carry current.

8. A primary conductor comprising a jacket of material having a high electrical resistance at low or normal temperatures and a secondary resistance contained within.

said jacket for heating the jacket to a point where the major portion of the electricity will flow through thejacket;

/ In testimony that we claim the above, we

have hereunto subscribed our names.

' .THADDEUS EBA/1L1 --FRANK 1. COPE.

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