US3902093A - Cathode heater element with a dark heat radiating coating and method of producing such - Google Patents

Cathode heater element with a dark heat radiating coating and method of producing such Download PDF

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Publication number
US3902093A
US3902093A US415256A US41525673A US3902093A US 3902093 A US3902093 A US 3902093A US 415256 A US415256 A US 415256A US 41525673 A US41525673 A US 41525673A US 3902093 A US3902093 A US 3902093A
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US
United States
Prior art keywords
heater element
heat radiating
aluminum oxide
coating
producing
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Expired - Lifetime
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US415256A
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English (en)
Inventor
Eberhard Weiss
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Nokia Deutschland GmbH
Original Assignee
International Standard Electric Corp
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Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
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Assigned to ALCATEL N.V., DE LAIRESSESTRAAT 153, 1075 HK AMSTERDAM, THE NETHERLANDS, A CORP OF THE NETHERLANDS reassignment ALCATEL N.V., DE LAIRESSESTRAAT 153, 1075 HK AMSTERDAM, THE NETHERLANDS, A CORP OF THE NETHERLANDS ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: INTERNATIONAL STANDARD ELECTRIC CORPORATION, A CORP OF DE
Assigned to NOKIA GRAETZ GESELLSCHAFT MIT BESCHRANKTER HAFTUNG reassignment NOKIA GRAETZ GESELLSCHAFT MIT BESCHRANKTER HAFTUNG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ALCATEL N.V.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/08—Manufacture of heaters for indirectly-heated cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/04—Cathodes

Definitions

  • This object is attained by the use of a coating of insulating material applied to the filament which is completely porous and consists of a homogeneous dark colored sintered crystalline mixture of the insulating material, preferably aluminum oxide, A1 and of a refractory highmelting point metal such as tungsten.
  • the present heater element has proven to be completely satisfactory and has durable insulating properties.
  • An important advantage of this heater element is in the fact that it is particularly suitable for use in instant heat type cathodes.
  • the heater element As regards the manufacture of the heater element, one method has proved to be particularly favorable. This is characterized by coating the filament with a layer of aluminum oxide and by simultaneously effecting electrolysis. The resulting porous insulating layer is then dried, the heater element is thereafter impregnated with an aqueous ammoniumtungstate solution, rinsed in a suitable liquid (such as methanol) and then dried again. Finally, the heater element is heated in a nitrogen and hydrogen atmosphere with the insulating layer being sintered.
  • aqueous ammoniumtungstate solution such as methanol
  • FIGURE schematically shows the construction of an indirectly heated cathode.
  • a cathode tubing 3 has a cap 4 welded at one end which carries the emitting layer 5.
  • the structure is secured by the holder 6 which is mounted to a supporting disc 7.
  • the heater element consisting of the filament 2 coated with the insulating layer 1 is inserted into the tubing 3.
  • the filament 2 is coated with a layer of insulating material 1 which is porous throughout, with no intermediate layers, and consists of a dark colored sintered crystalline mixture of the insulating material aluminum oxide, Al O and of a refractory highmelting point metal such as tungsten.
  • the dark insulating layer 1 apart from the desired thermal properties, also provides very satisfactory results as regards insulating properties and long life, as well as only a very slight tendency toward melting during electrolysis.
  • the layer is applied or deposited as follows.
  • the heater element is dipped or immersed into a suitable coating bath containing a mixture of aluminum oxide, water, alcohol and salt, and the mixture is dissociated upon application of an electric voltage.
  • the aluminum oxide which floats in the bath, is precipitated onto the cathode, i.e. on the filament. Simultaneously, during this electrophoretic process, hydrogen appears on the cathode due to the electrolysis.
  • the mixture ratio it is possible to achieve a particular porosity for the precipitating oxide of aluminum which also has a particular elasticity.
  • the coated filaments are removed from the coating bath, and dried.
  • the dried heater elements are thereafter dipped into an aqueous ammonium-tungstate solution until the dried porous coat of insulating material is impregnated or saturated. In the course of a subsequent rising process, the heater element is again freed from a portion of the aqueous ammonium-tungstate solution.
  • a suitable rinsing liquid may be methanol. This is followed by a further drying process.
  • the heater element is heated in an oven having a nitrogen/hydrogen atmosphere up to a temperature of about 1500 to 2000C at which the insulating layer is sintered.
  • a cathode heater element comprising a conductive filament having a coating of a dark colored heat radiating insulating material, said coating being porous throughout and including a non-emissive homogeneous dark colored sintered crystalline mixture of aluminum oxide and tungsten.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Solid Thermionic Cathode (AREA)
US415256A 1973-04-06 1973-11-12 Cathode heater element with a dark heat radiating coating and method of producing such Expired - Lifetime US3902093A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2317446A DE2317446C3 (de) 1973-04-06 1973-04-06 Verfahren zum Herstellen eines Heizelementes für eine indirekt geheizte Kathode

Publications (1)

Publication Number Publication Date
US3902093A true US3902093A (en) 1975-08-26

Family

ID=5877284

Family Applications (1)

Application Number Title Priority Date Filing Date
US415256A Expired - Lifetime US3902093A (en) 1973-04-06 1973-11-12 Cathode heater element with a dark heat radiating coating and method of producing such

Country Status (10)

Country Link
US (1) US3902093A (enrdf_load_stackoverflow)
JP (1) JPS5513102B2 (enrdf_load_stackoverflow)
BE (1) BE813271R (enrdf_load_stackoverflow)
CA (1) CA1032592A (enrdf_load_stackoverflow)
DE (1) DE2317446C3 (enrdf_load_stackoverflow)
ES (1) ES425053A1 (enrdf_load_stackoverflow)
FR (1) FR2224866B1 (enrdf_load_stackoverflow)
GB (1) GB1461495A (enrdf_load_stackoverflow)
IT (1) IT1007777B (enrdf_load_stackoverflow)
NL (1) NL7404521A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4079164A (en) * 1975-11-07 1978-03-14 Hitachi, Ltd. Base metal plate for directly heated oxide cathode
US4208208A (en) * 1977-11-18 1980-06-17 Hitachi, Ltd. Nickel alloy base metal plate for directly heated oxide cathodes

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4000435A (en) * 1975-06-20 1976-12-28 Westinghouse Electric Corporation Electron gun cathode with a fast warm-up characteristic
DE2835490C2 (de) * 1978-08-12 1986-09-18 Standard Elektrik Lorenz Ag, 7000 Stuttgart Verfahren zur Herstellung einer indirekt geheizten Kathode
DE2938248A1 (de) * 1979-09-21 1981-03-26 Standard Elektrik Lorenz AG, 70435 Stuttgart Heizelement fuer eine indirekt geheizte kathode
JPS573039U (enrdf_load_stackoverflow) * 1980-06-06 1982-01-08
DE3029853C2 (de) * 1980-08-07 1982-08-26 Standard Elektrik Lorenz Ag, 7000 Stuttgart Indirekt durch Elektronenstoß geheizte Wehneltkathode
DE19828158C1 (de) * 1998-06-24 1999-11-25 Siemens Ag Indirekt geheizte Kathode, insbesondere für Röntgenröhren

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3029360A (en) * 1958-04-29 1962-04-10 Rca Corp Heater wire coating process
US3195004A (en) * 1960-08-19 1965-07-13 Rca Corp Cathode heater for electron discharge devices
US3372297A (en) * 1964-09-28 1968-03-05 Varian Associates High frequency electron discharge devices and thermionic cathodes having improved (cvd) refractory insulation coated heater wires
US3401297A (en) * 1965-08-23 1968-09-10 Varian Associates Thermionic cathodes for electron discharge devices with improved refractory metal heater wires
US3531678A (en) * 1968-06-24 1970-09-29 Raytheon Co Heater with boron nitride coating
US3558966A (en) * 1967-03-01 1971-01-26 Semicon Associates Inc Directly heated dispenser cathode
US3737714A (en) * 1964-12-18 1973-06-05 Sylvania Electric Prod Dark coated heater for vacuum tube cathode
US3765939A (en) * 1972-05-10 1973-10-16 Gte Sylvania Inc Method of coating cathode heaters

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1017292B (de) * 1956-07-18 1957-10-10 Telefunken Gmbh Aluminiumoxydueberzug fuer den Heizdraht mittelbar geheizter Kathoden elektrischer Entladungsroehren und Verfahren zur Herstellung eines Isolierueberzuges auf einem Heizdraht
DE1146594B (de) * 1961-10-31 1963-04-04 Standard Elektrik Lorenz Ag Aus zwei Schichten bestehender Isolationsueberzug fuer das Heizelement mittelbar geheizter Kathoden elektrischer Entladungsroehren und Verfahren zu seiner Herstellung
DE1133835B (de) * 1961-12-16 1962-07-26 Telefunken Patent Verfahren zur Herstellung einer mittelbar geheizten Kathode fuer eine elektrische Entladungsroehre
NL113095C (enrdf_load_stackoverflow) * 1961-12-22
NL281567A (enrdf_load_stackoverflow) * 1962-07-30
DE1281038B (de) * 1962-08-01 1968-10-24 Telefunken Patent Verfahren zur Herstellung einer mittelbar geheizten Kathode fuer eine elektrische Entladungsroehre
US3246197A (en) * 1962-10-02 1966-04-12 Westinghouse Electric Corp Cathode heater having an aluminum oxide and tungesten coating
US3500454A (en) * 1967-11-16 1970-03-10 Sylvania Electric Prod Insulator heater coating for heater-cathode assembly

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3029360A (en) * 1958-04-29 1962-04-10 Rca Corp Heater wire coating process
US3195004A (en) * 1960-08-19 1965-07-13 Rca Corp Cathode heater for electron discharge devices
US3372297A (en) * 1964-09-28 1968-03-05 Varian Associates High frequency electron discharge devices and thermionic cathodes having improved (cvd) refractory insulation coated heater wires
US3737714A (en) * 1964-12-18 1973-06-05 Sylvania Electric Prod Dark coated heater for vacuum tube cathode
US3401297A (en) * 1965-08-23 1968-09-10 Varian Associates Thermionic cathodes for electron discharge devices with improved refractory metal heater wires
US3558966A (en) * 1967-03-01 1971-01-26 Semicon Associates Inc Directly heated dispenser cathode
US3531678A (en) * 1968-06-24 1970-09-29 Raytheon Co Heater with boron nitride coating
US3765939A (en) * 1972-05-10 1973-10-16 Gte Sylvania Inc Method of coating cathode heaters

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4079164A (en) * 1975-11-07 1978-03-14 Hitachi, Ltd. Base metal plate for directly heated oxide cathode
US4208208A (en) * 1977-11-18 1980-06-17 Hitachi, Ltd. Nickel alloy base metal plate for directly heated oxide cathodes

Also Published As

Publication number Publication date
FR2224866B1 (enrdf_load_stackoverflow) 1978-11-03
GB1461495A (en) 1977-01-13
CA1032592A (en) 1978-06-06
NL7404521A (enrdf_load_stackoverflow) 1974-10-08
JPS5052962A (enrdf_load_stackoverflow) 1975-05-10
DE2317446B2 (de) 1977-08-18
DE2317446C3 (de) 1983-11-10
DE2317446A1 (de) 1974-10-24
ES425053A1 (es) 1976-11-16
FR2224866A1 (enrdf_load_stackoverflow) 1974-10-31
IT1007777B (it) 1976-10-30
JPS5513102B2 (enrdf_load_stackoverflow) 1980-04-07
BE813271R (nl) 1974-10-04

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AS Assignment

Owner name: ALCATEL N.V., DE LAIRESSESTRAAT 153, 1075 HK AMSTE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:INTERNATIONAL STANDARD ELECTRIC CORPORATION, A CORP OF DE;REEL/FRAME:004718/0023

Effective date: 19870311

AS Assignment

Owner name: NOKIA GRAETZ GESELLSCHAFT MIT BESCHRANKTER HAFTUNG

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ALCATEL N.V.;REEL/FRAME:007074/0030

Effective date: 19890130