US1925129A - Process of equalizing resistance of enlarged ends of electric heating elements - Google Patents

Process of equalizing resistance of enlarged ends of electric heating elements Download PDF

Info

Publication number
US1925129A
US1925129A US619502A US61950232A US1925129A US 1925129 A US1925129 A US 1925129A US 619502 A US619502 A US 619502A US 61950232 A US61950232 A US 61950232A US 1925129 A US1925129 A US 1925129A
Authority
US
United States
Prior art keywords
enlarged ends
unit resistance
circuit
intermediate portion
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US619502A
Inventor
Carroll H Boyles
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US619502A priority Critical patent/US1925129A/en
Application granted granted Critical
Publication of US1925129A publication Critical patent/US1925129A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49082—Resistor making
    • Y10T29/49101—Applying terminal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49758—During simulated operation or operating conditions

Definitions

  • PROCESS OF EQUALIZING RESISTANCE OF ENLARGED ENDS OF ELECTRIC HEATING ELEMENTS Filed June 27, 1932 INVENTOR ATTORNEYS Patented Sept. 5, 1933 PROCESS OF EQUALIZING RESISTANCE F ENLARGED ENDS OF ELECTRIC HEATING ELEMENTS Carroll H. Boyles, Milwaukee, Wis.
  • the unit resistance of the enlarged ends be equal to, or at least not greater than, the unit resistance of the intermediate bodyportion.
  • the object of the present invention is to provide means for equalizing the unit resistance of the enlarged ends to that of the intermediate body portion.
  • the heating element is completed and rendered conductive by the passage of current through its entire length.
  • these ends are given a subsequent current treatment which however must not be applied to the intermediate body portion.
  • the invention provides a simple and emcient means for the additional electrical treatment of the enlarged ends to the exclusion of the intermediate body portion.
  • the method consists essentially in connecting both ends into an electrical circuit and short-circuiting the intermediate body portion by coating the same with a material which is a much better conductor than the material constituting the heating element.
  • the conducting material is applied in the form of a liquid or fluid and is of such a character that it solidifies on heating and may be removed from the heating element when cooled.
  • several such elements are connected end to end or in series by a conductor such as graphite paste, and the current is passed through the whole series.
  • Fig. 2 is a longitudinal section of the trough furnace, showing a series of elements embedded therein;
  • Fig. 3 is a corresponding transverse section.
  • the heating element is an elongated member having an intermediate body portion 1 and enlarged end portions 2, as shown in Figure l,
  • the element may be or" any desired cross sectional shape, both at the intermediate and end portions, and consists mainly of silicon carbide as disclosed in the aforementioned pending application.
  • the element is made operatively conductive of electrical current by the passage of current therethrough from end to end, but it does not always follow that the enlarged end portions have a unit resistance equal to 01' less than that of the intermediate portion, which is necessary in order to bring about the desired conductivity relations above mentioned.
  • the unit resistance of the enlarged ends is equalized to that of the intermediate portion by passing a current through the ends, exclusive of the intermediate portion, and this passage of current is in addition to the electrification described in the above mentioned application for fusing the particles of carbide together.
  • the intermediate portion 1 is excluded from the action of a current passed through the ends 2, by coating the portion 1 with the material 3 having a much'higher conductivity than the carbide material constituting the element proper.
  • This material is applied in liquid or plastic form, generally designated in the claims as fluid, and preferably contains carbon or a substance which forms carbon on being heated, mixed with graphite or similar material having a comparatively high electrical conductivity.
  • the coating material must further solidify on being heated and be capable of being removed from the element when cold.
  • Suitable materials for this purpose are coal tar, molasses, dextrine compounds, sulphate compounds and colloidal graphite mixed with graphite or a similar conductor, if necessary, to produce a high conductivity when solidified by heat treatment.
  • a number of elements thu's coated at their respective intermediate portions 1 are connected in series by means of carbon paste 4 or similar means which holds the elements together under heat.
  • Carbon electrodes 5 are connected to the ends of the series in like manner and are placed in a furnace 6. It is preferable to pack the elements with a non-gassing material 7 which holds the heat and has no chemical action on the elements.
  • This material may be the packing material described in the aforementioned application, consisting of 60% silica, 30% carbon, 10% colloidal clay or Bentonite the whole being calcined to 4500" F., pulverized and screened.
  • the lead-in wires 8 are clamped at 9 to the carbon electrodes 5, and the circuit further contains well known mechanism for controlling the voltage and current according to the resistance of the ends 2. A controlled and regulated current is passed through the ends 2 until their unit resistance is reduced to that of the intermediate portion 1; On completion of the electrical treatment, the elements are removed from the furnace and separated from one another, and the solidified coating material is scraped oil or otherwise removed
  • the amount of current passed through the enlarged ends in the subsequent treatment is so calculated that the total amount of current passed therethrough shall equal the amount of current passed through the intermediate portion of the rod, per unit of cross sectional area.
  • the total amount or" current applied to the end sections is forty-five amperes for -fifteen minutes. In practice, the current applied to the end sections may slightly exceed the calculated amount.

Landscapes

  • Resistance Heating (AREA)

Description

Sept. 5, 1933. c. H. BOYLES 1,925,129
PROCESS OF EQUALIZING RESISTANCE OF ENLARGED ENDS OF ELECTRIC HEATING ELEMENTS Filed June 27, 1932 INVENTOR ATTORNEYS Patented Sept. 5, 1933 PROCESS OF EQUALIZING RESISTANCE F ENLARGED ENDS OF ELECTRIC HEATING ELEMENTS Carroll H. Boyles, Milwaukee, Wis.
Application June 27, 1932. Serial No. 619,502
, 12 Claims.
In my application Serial No. 616,961, filed June 13, 1932, I have disclosed a method of making an elongated electrical heating element consisting principally of silicon carbide. In certain instances it is desirable to enlarge the ends of such elements, in order to provide a greater conductivity at the ends, so that the lead-in wires may be connected directly to the ends in service, and at the same time furnish ample current carrying capacity-to the body of the heating element.
In order to attain this desired result, it is also necessary that the unit resistance of the enlarged ends be equal to, or at least not greater than, the unit resistance of the intermediate bodyportion. In the manufacture of the element, .how-
ever, these conditions do not always occur; and the object of the present invention, therefore, is to provide means for equalizing the unit resistance of the enlarged ends to that of the intermediate body portion.
As described in the aforementioned application, the heating element is completed and rendered conductive by the passage of current through its entire length. In order to equalize the resistance of the enlarged ends, according to the present invention, these ends are given a subsequent current treatment which however must not be applied to the intermediate body portion. The
invention provides a simple and emcient means for the additional electrical treatment of the enlarged ends to the exclusion of the intermediate body portion. The method consists essentially in connecting both ends into an electrical circuit and short-circuiting the intermediate body portion by coating the same with a material which is a much better conductor than the material constituting the heating element. The conducting material is applied in the form of a liquid or fluid and is of such a character that it solidifies on heating and may be removed from the heating element when cooled. In the preferred embodiment of the method, several such elements are connected end to end or in series by a conductor such as graphite paste, and the current is passed through the whole series.
The invention is more fully disclosed with reference to the accompanying drawing, in which-- Figure 1 is an elevation of an element with enlarged ends to be treated according to this invention;
Fig. 2 is a longitudinal section of the trough furnace, showing a series of elements embedded therein; and
Fig. 3 is a corresponding transverse section.
Reference to these'views will now be made by use of like characters which are employed to designate corresponding parts throughout.
The heating element is an elongated member having an intermediate body portion 1 and enlarged end portions 2, as shown in Figure l,
whereby these end portions may ultimately have greater conductivity than the intermediate portion, so that sufficient current will be carried to the intermediate portion if the lead-in wires are attached directly to the ends. The element may be or" any desired cross sectional shape, both at the intermediate and end portions, and consists mainly of silicon carbide as disclosed in the aforementioned pending application.
The element is made operatively conductive of electrical current by the passage of current therethrough from end to end, but it does not always follow that the enlarged end portions have a unit resistance equal to 01' less than that of the intermediate portion, which is necessary in order to bring about the desired conductivity relations above mentioned.
The unit resistance of the enlarged ends is equalized to that of the intermediate portion by passing a current through the ends, exclusive of the intermediate portion, and this passage of current is in addition to the electrification described in the above mentioned application for fusing the particles of carbide together. The intermediate portion 1 is excluded from the action of a current passed through the ends 2, by coating the portion 1 with the material 3 having a much'higher conductivity than the carbide material constituting the element proper. This material is applied in liquid or plastic form, generally designated in the claims as fluid, and preferably contains carbon or a substance which forms carbon on being heated, mixed with graphite or similar material having a comparatively high electrical conductivity. The coating material must further solidify on being heated and be capable of being removed from the element when cold. Examples of suitable materials for this purpose are coal tar, molasses, dextrine compounds, sulphate compounds and colloidal graphite mixed with graphite or a similar conductor, if necessary, to produce a high conductivity when solidified by heat treatment.
A number of elements thu's coated at their respective intermediate portions 1 are connected in series by means of carbon paste 4 or similar means which holds the elements together under heat. Carbon electrodes 5 are connected to the ends of the series in like manner and are placed in a furnace 6. It is preferable to pack the elements with a non-gassing material 7 which holds the heat and has no chemical action on the elements. This material may be the packing material described in the aforementioned application, consisting of 60% silica, 30% carbon, 10% colloidal clay or Bentonite the whole being calcined to 4500" F., pulverized and screened. The lead-in wires 8 are clamped at 9 to the carbon electrodes 5, and the circuit further contains well known mechanism for controlling the voltage and current according to the resistance of the ends 2. A controlled and regulated current is passed through the ends 2 until their unit resistance is reduced to that of the intermediate portion 1; On completion of the electrical treatment, the elements are removed from the furnace and separated from one another, and the solidified coating material is scraped oil or otherwise removed.
The amount of current passed through the enlarged ends in the subsequent treatment is so calculated that the total amount of current passed therethrough shall equal the amount of current passed through the intermediate portion of the rod, per unit of cross sectional area. For exam ple, if an element having a cross sectional area of one-half square inch in the body is treated at thirty amperes for fifteen minutes and the end sections have a cross sectional area of threequarters square inch, the total amount or" current applied to the end sections is forty-five amperes for -fifteen minutes. In practice, the current applied to the end sections may slightly exceed the calculated amount.
The scope of the invention is indicated by the appended claims rather than by the particular details illustrated and described herein, as various alterations and modifications in procedure will readily suggest themselves to persons skilled in the art.
What I claim is:--
1. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of different unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, short-circuiting said intermediate portion, and passing electrical current through the circuit.
2. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of different unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, coating said intermediate portion With a material having a higher conductivity than the element material, whereby to short-circuit said portion, passing electrical current through the circuit, and removing said coating material.
3. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of different unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, coating said intermediate portion with a material having a higher conductivity than the element material and adapted to be removed when cold, whereby to short-circuit said portion, passing electrical current through the circuit, and removing said coating material.
4. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of different unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, coating said intermediate portion with a fluid material having a higher. conductivity than the element material, whereby to short-circuit said portion, passing electrical current through the circuit, and removing said coating material.
5. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of different unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, coating said intermediate portion with a fluid material having a higher conductivity than the element material and adapted to be removed when cold, whereby to short-circuit said portion, passing electrical current through the circuit, and removing said coating material.
6. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of different unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, coating said intermediate portion with a material which, on heating, is solid and contains asubstantial amount of carbon and has a higher conductivity than the element material, whereby to short-circuit said portion, passing electrical current through the circuit, and removing said coating material.
7. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of difierent unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, coating said inter mediate portion with a fluid material, which on heating, solidifies and contains a substantial, amount of carbon and has a higher conductivity than the element material, whereby to shortcircuit said portion, passing electrical current through the circuit, and removing said coating material.
8. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of different unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, short-circuiting the intermediate portion, packing the element in a heat insulating material, and passing electrical current through the circuit.
9. The method of equalizing the unit resistance of an elongated heating element having enlarged ends of difierent unit resistance than the intermediate portion, consisting in inserting the element in an electrical circuit, short-circuiting said intermediate portion, packing the element in a calcined mixture of 60% silica, 30% carbon and 10% colloidal clay, and passing electrical current through the circuit.
10. The method of equalizing the unit resistance of elongated heating elements having enlarged ends of different unit resistance than the intermediate portions, consisting in connecting a plurality of such elements in series in an electrical circuit, short-circuiting said intermediate portions, and passing electrical current through the circuit. i
11. The method of equalizing the unit resistance of elongated heatingelements having enlarged ends of difierent unit resistance than the intermediate portions, consisting in connecting a plurality of such elements in series in an electrical circuit, short-circuiting said intermediate portions, packing the elements in a heat insulating material, and passing electrical current through the circuit.
12. The method of equalizing the unit resistance
US619502A 1932-06-27 1932-06-27 Process of equalizing resistance of enlarged ends of electric heating elements Expired - Lifetime US1925129A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US619502A US1925129A (en) 1932-06-27 1932-06-27 Process of equalizing resistance of enlarged ends of electric heating elements

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US619502A US1925129A (en) 1932-06-27 1932-06-27 Process of equalizing resistance of enlarged ends of electric heating elements

Publications (1)

Publication Number Publication Date
US1925129A true US1925129A (en) 1933-09-05

Family

ID=24482174

Family Applications (1)

Application Number Title Priority Date Filing Date
US619502A Expired - Lifetime US1925129A (en) 1932-06-27 1932-06-27 Process of equalizing resistance of enlarged ends of electric heating elements

Country Status (1)

Country Link
US (1) US1925129A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2529144A (en) * 1945-03-29 1950-11-07 Gen Electric Resistance material
US2861160A (en) * 1955-08-26 1958-11-18 Sidney H Hersh Making photodetectors
US2913695A (en) * 1955-07-11 1959-11-17 Kanthal Ab Electric resistance heating elements
US2993980A (en) * 1959-07-30 1961-07-25 Westinghouse Electric Corp Method for making tubular structure
US3351882A (en) * 1964-10-09 1967-11-07 Polyelectric Corp Plastic resistance elements and methods for making same

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2529144A (en) * 1945-03-29 1950-11-07 Gen Electric Resistance material
US2913695A (en) * 1955-07-11 1959-11-17 Kanthal Ab Electric resistance heating elements
US2861160A (en) * 1955-08-26 1958-11-18 Sidney H Hersh Making photodetectors
US2993980A (en) * 1959-07-30 1961-07-25 Westinghouse Electric Corp Method for making tubular structure
US3351882A (en) * 1964-10-09 1967-11-07 Polyelectric Corp Plastic resistance elements and methods for making same

Similar Documents

Publication Publication Date Title
US2484063A (en) Electric heater for subsurface materials
DE60116077T2 (en) ELECTRIC BORING HEATING DEVICE AND METHOD
DE68919513T2 (en) Flexible, elongated heating structure with positive temperature coefficient and process.
DE1565888A1 (en) Self-regulating radiator and process for its manufacture
DE2919763C2 (en) Atomizing burners for oil firing systems
DE2427992A1 (en) METHOD OF MEASURING HIGH TEMPERATURES WITH THERMOCOUPLES
US1925129A (en) Process of equalizing resistance of enlarged ends of electric heating elements
DE1640471A1 (en) Method of connecting a thin wire to a terminal
DE2719572A1 (en) FEED CHANNEL FOR MELT LIQUID GLASS TO COMPARE THE TEMPERATURE OF THE MELT
DE2157530B2 (en) LONG EXTENDED HEAT GENERATING DEVICE IN TUBE SHAPE
DE3853091T2 (en) Flexible knitted thermistor heating cable.
DE2320269C3 (en) Electrical resistance heating for float glass systems
DE3853056T2 (en) Thermistor heating unit with positive temperature coefficient.
DE541333C (en) Process and electric furnace for melting metals and metal alloys
DE626822C (en) Ironless induction furnace for heating, melting or metallurgical treatment of metals, metal oxides, aggregates or slag, in which the bath content consists of layers of different electrical conductivity
US1836880A (en) Electrode
GB253165A (en) Improvements in electrical resistances
AT222204B (en) High voltage fuse
DE826325C (en) Electric resistance heater
DE490963C (en) Process for melting quartz in a high-frequency induction furnace
EP0057385B1 (en) Method for the direct electrical resistance heating of metal workpieces
US762628A (en) Apparatus for promoting flow of oil and gas in wells.
DE467347C (en) Induction heated electric heating plate
DE1106732B (en) Process for zone cleaning of polycrystalline fusible semiconductors
AT33003B (en) Method for producing an electrical heating resistor mass.