US2018470A - Incandescent lamp, filament therefor and process and apparatus for making the same - Google Patents

Incandescent lamp, filament therefor and process and apparatus for making the same Download PDF

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Publication number
US2018470A
US2018470A US394649A US39464929A US2018470A US 2018470 A US2018470 A US 2018470A US 394649 A US394649 A US 394649A US 39464929 A US39464929 A US 39464929A US 2018470 A US2018470 A US 2018470A
Authority
US
United States
Prior art keywords
filament
coating
lamp
core
mixture
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
US394649A
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English (en)
Inventor
Ruben Samuel
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.)
SIRIAN LAMP Co
Original Assignee
SIRIAN LAMP CO
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
Priority to BE373635D priority Critical patent/BE373635A/xx
Application filed by SIRIAN LAMP CO filed Critical SIRIAN LAMP CO
Priority to US394649A priority patent/US2018470A/en
Priority to FR702427D priority patent/FR702427A/fr
Application granted granted Critical
Publication of US2018470A publication Critical patent/US2018470A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K3/00—Apparatus or processes adapted to the manufacture, installing, removal, or maintenance of incandescent lamps or parts thereof
    • H01K3/02—Manufacture of incandescent bodies
    • 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
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2922—Nonlinear [e.g., crimped, coiled, etc.]
    • Y10T428/2925—Helical or coiled
    • 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
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2933—Coated or with bond, impregnation or core
    • Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
    • Y10T428/2958—Metal or metal compound in coating

Definitions

  • This invention relates to incandescent lamps, filaments therefor and process and apparatus for making the same. More specifically, the invention relates to a new type of electric lamp suitable for use in house lighting, automobile lighting, projector illumination and various other types of illuminating devices. The invention also pertains to a. coated filament adapted to be heated by the passage of electricity therethrough which is an improvement over the ordinary simple form of tungsten filament.
  • a filament adapted for use in lamps and other means of light projection and illumination having a. core or base of refractory material such as tungsten on which is placed a coating having a material rich in light emitting characteristics, whereby a relatively high luminous efiiciency is obtained.
  • Another object is to provide a filament in an electric lamp which consists of a core and a coating, the coating having bonding means to effectively unite the material of the coating to the core so that there is minimum loss of heat efiiciency intermediate the core and the coating when the filament is utilized as an illuminant for electric lamps.
  • Still another object of the invention is to provide a bonding agent between a highly luminous coating and a refractory filamentary core which has high melting'point characteristics similar to that of the material of the coating and core.
  • Another object involves the formation of an incandescent lamp of the gas-filled type, wherein pressure requisite to diminish the vaporization of the filamentary material is'low relative to that of the ordinary gas-filled lamp.
  • Additional objects of the invention are the provision of a lamp which will operate with eificiency greater than that of the tungsten lamp and to provide a process and apparatus for manufacturing the improved filament and lamp.
  • FIG. 1 is a view of an ordinary type of automobile lamp provided with a filament of the improved type herein set forth;
  • Fig. 2 is an enlarged fragmentary view of a section of the lamp filament.
  • tungsten is preferably used, although molybdenum or other refractory metals or substances may be employed.
  • This filamentary core is coated by a mixture of thorium oxide or thoria and cerium oxide or ceria, bound together into the core by means of boron oxide.
  • the thoria-ceria. mixture is made by heating a water solution of commercial thorium nitrate and cerium nitrate, the proportion being by weight 99% of thorium nitrate and 1% of cerium nitrate.
  • This material is heated so as to be completely evaporated and then to the decomposition temperature, thus leaving a mixture of thoria and ceria, the proportion by weight being approximately 99% thoria and 1% ceria.
  • To this mixture is added 25% by weight of crystallized commercial boric acid of various compositions (such for example, as 3H2O, B203 or 11330: or B(OH) 3 or H2B4O7) and enough water to form a thin paste.
  • the entire mixture is then ground in a ball mill of an ordinary type, preferably for a period of about twenty (20) hours, so as to give an intimate and finely grained mixture, which is then in condition appropriate for coating on the filament.
  • the coating mixture may now he applied directly to the formed filaments.
  • the filaments Prior to the coating operation, however, the filaments should be thoroughly cleaned with a solution made of caustic soda and the coating may then be applied by appropriate means as a thin layer on the filament.
  • the coating as applied has sufiicient consistency so that it adheres to the filament until it is properly secured to its base inthe lamp and then placed on the pump racks and subjected to exhaustion by vacuum pumps.
  • the lamp filaments are slowly heated by electric current until the gas and vapor of the filament and base have been removed and the material 01' the filament coating sinters.
  • the lamps are available for illuminating purposes and the filament may be brought to an incandescent temperature; but in the form of lamp herein described, in order to prolong the life or the lamp by decreasing the vaporization rate oi the filament, gas is introduced into the lamp bulb-after the sintering operation at low pressures in a range not exceeding 75 millimeters, and preferably in the neighborhood of 25 millimeters.
  • Argon gas is desirableior this purpose, although nitrogen is also available and may be used with good results.
  • gases having a low heat conductivity and inert chemical characteristics may also be used.
  • Fig. i an ordinary type of automobile lamp for headlamps having an envelope in, base H, stem l2, filament supports 03, and a coiled filament I.
  • Fig. 2 the enlarged detall'shows a wire core l5 of tungsten or similar material, on which is affixed the coating I 6 consisting of a mixture of boron oxide, thoria and ceria.
  • Both thoria and ceria have high melting points and when combined as a mixture in the proportions stated, have high selective luminosity when heated to the luminous range of temperatures. When used alone, however, and with other types of binders, this mixture becomes a fairly good conductor at high temperatures, thus bringing about undesirable current and electrolytic cf i'ects.
  • Boric acid used as a binder in the present invention is converted to boric oxide in the neighborhood of 1000 C. which also at that temperature is plastic and thoroughly binds the radiant layer to the tungsten base, giving an integralstructure with a negligible temperature gradient between the base and radiator.
  • boric oxide is an excellent resistant material at high temperatures and, therefore, will not conduct any appreciable quantities of current so that the deficiencies above noted with reference to thoria and ceria alone are nullified by the intimate lntermixture of the poorly conducting boric oxide.
  • a filament for an electric lamp comprising.
  • a filament for an electric lamp comprising a refractory metal wire and a coating thereon formed of a mixture of approximately 99% or thorium oxide and 1% of cerium oxide through which boron oxide is uniformly distributed to an extent less than 25% by weight 01 the mixture of thorium and cerium oxide.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Discharge Lamp (AREA)
US394649A 1929-09-23 1929-09-23 Incandescent lamp, filament therefor and process and apparatus for making the same Expired - Lifetime US2018470A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE373635D BE373635A (xx) 1929-09-23
US394649A US2018470A (en) 1929-09-23 1929-09-23 Incandescent lamp, filament therefor and process and apparatus for making the same
FR702427D FR702427A (fr) 1929-09-23 1930-09-20 Perfectionnements relatifs aux filaments résistants isolés et procédés de fabrication d'une couche isolante sur lesdits filaments

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US394649A US2018470A (en) 1929-09-23 1929-09-23 Incandescent lamp, filament therefor and process and apparatus for making the same

Publications (1)

Publication Number Publication Date
US2018470A true US2018470A (en) 1935-10-22

Family

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Application Number Title Priority Date Filing Date
US394649A Expired - Lifetime US2018470A (en) 1929-09-23 1929-09-23 Incandescent lamp, filament therefor and process and apparatus for making the same

Country Status (3)

Country Link
US (1) US2018470A (xx)
BE (1) BE373635A (xx)
FR (1) FR702427A (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721838A (en) * 1950-10-28 1955-10-25 Hartford Nat Bank & Trust Co Method of electrolytically pointing wires
DE1061901B (de) * 1954-07-24 1959-07-23 Philips Nv Elektrische Zweifaden-Gluehlampe fuer Kraftfahrzeugscheinwerfer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721838A (en) * 1950-10-28 1955-10-25 Hartford Nat Bank & Trust Co Method of electrolytically pointing wires
DE1061901B (de) * 1954-07-24 1959-07-23 Philips Nv Elektrische Zweifaden-Gluehlampe fuer Kraftfahrzeugscheinwerfer

Also Published As

Publication number Publication date
FR702427A (fr) 1931-04-08
BE373635A (xx)

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