US2057124A - Indirectly heated cathode for discharge tubes - Google Patents

Indirectly heated cathode for discharge tubes Download PDF

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Publication number
US2057124A
US2057124A US723510A US72351034A US2057124A US 2057124 A US2057124 A US 2057124A US 723510 A US723510 A US 723510A US 72351034 A US72351034 A US 72351034A US 2057124 A US2057124 A US 2057124A
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US
United States
Prior art keywords
cathode
discharge tubes
indirectly heated
heated cathode
tube
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
US723510A
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English (en)
Inventor
Karel Marinus Van Gessel
Jonker Johan Lodewyk Hendrik
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.)
RCA Corp
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RCA Corp
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Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
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Publication of US2057124A publication Critical patent/US2057124A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
    • H01J1/26—Supports for the emissive material

Definitions

  • This invention relates to an indirectly heated cathode for electric discharge tubes and more particularly to cathodes consisting of a heating element surrounded by a cathode sleeve or body, insulating material being provided, if desired, between said members.
  • cathode heating member and/or the side of the cathode body facing said heating member is coated with a substance having a large heat radiating capacity. It is also possible to make one or both of said members entirely or partly of such a material.
  • vanadium trioxide is preferably used.
  • the effect aimed at by the invention can also be achieved by treating said surfaces with nickel oxide or carbon.
  • cathodes the cathode sleeves of which consist entirely or partly of a substance, for instance, copper or silver, whose heat radiating capacity is smaller than that of nickel.
  • the time required for reaching the emission temperature is often very considerable. Indeed, in this case a comparatively small quantity of energy is suiiicient for heating the cathode to a definite temperature. Since, however, the cathode must be heated to the same temperature as a cathode body consisting, for instance, of nickel, the time required for reaching this temperature is usually fairly considerable. Therefore, it is desired especially with these cathodes to provide means by which the time required for heating is reduced.
  • a rod l consisting, for instance, of magnesium oxide is immersed in Aquadag paste so that it is covered with a thin layer 2 of said paste.
  • This rod is introduced into a cathode sleeve 3 which may be of copper, nickel or other suitable material and turned about a few times so as to intimately contact with the inner wall thereof.
  • the inner Wall of the sleeve is coated with a uniform black layer 4.
  • the Aquadag paste may be permitted to flow through the long cathode tube from which the cathode sleeves are out.
  • an insulating rod or tube of, for instance, magnesium oxide or aluminum oxide is inserted in the cathode sleeve or tube and the heater element 5 of filamentary form, which may itself be coated with insulating material, if desired, is then threaded through said insulating rod or tube, whereupon the cathode thus formed together with the other electrodes are mounted within the evacuated envelope, the other operations required for the manufacture of the tube being effected in the usual manner.
  • Another method within the spirit of the present invention is to smear the insulating tube which is to be provided between the heating member and the cathode sleeve and tube with graphite, or to blacken it by coating with a layer of vanadium trioxide.
  • the insulating tube thus coated and having the heater threaded therethrough is then inserted within the cathode tube, further mounting thereof and other electrodes being effected in a normal manner.
  • An indirectly heated cathode for electron discharge tubes comprising a tubular electron emitting member of metal having a lower heat radiating capacity than nickel, and means for increasing the heat radiating capacity of said tubular member comprising a coating of vanadium trioxide on the inner surface of said memher.
  • An indirectly heated cathode for electron discharge tubes comprising a tubular electron emitting member of copper, and means for increasing the heat radiating capacity of said member, comprising a coating of vanadium trioxide on the inner surface of said copper member.
  • An indirectly heated cathode for electron" discharge tubes comprising a tubular electron emitting member of silver, and means for increasing the heat radiating capacity of said member, comprising a coating of vanadium trioxide on the inner surface of said silver member.

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  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Discharge Lamp (AREA)
US723510A 1933-07-13 1934-05-02 Indirectly heated cathode for discharge tubes Expired - Lifetime US2057124A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL430853X 1933-07-13

Publications (1)

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US2057124A true US2057124A (en) 1936-10-13

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ID=19786148

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US723510A Expired - Lifetime US2057124A (en) 1933-07-13 1934-05-02 Indirectly heated cathode for discharge tubes

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US (1) US2057124A (en))
BE (1) BE404192A (en))
FR (1) FR775737A (en))
GB (1) GB430853A (en))
NL (1) NL40799C (en))

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2527984A (en) * 1943-01-15 1950-10-31 Hartford Nat Bank & Trust Co Method of manufacturing electric discharge tubes
US2889445A (en) * 1955-03-28 1959-06-02 Herman B Wolf Electrically heated mat
US3009044A (en) * 1960-07-11 1961-11-14 Doehler Hans Electric resistance element for space heaters
US3062507A (en) * 1957-11-18 1962-11-06 Smith Corp A O Multi-layer vessel having a heat transfer material disposed between layers
US3161756A (en) * 1961-02-09 1964-12-15 Schloemann Ag Electrically heated billet-containers for metal-extrusion presses
US3662211A (en) * 1961-03-15 1972-05-09 Gen Electric Cathode construction
US3958146A (en) * 1974-02-08 1976-05-18 Gte Sylvania Incorporated Fast warm up picture tube cathode cap having high heat emissivity surface on the interior thereof
US4009409A (en) * 1975-09-02 1977-02-22 Gte Sylvania Incorporated Fast warmup cathode and method of making same
US5156728A (en) * 1987-02-12 1992-10-20 Terumo Kabushiki Kaisha Ion sensor

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2527984A (en) * 1943-01-15 1950-10-31 Hartford Nat Bank & Trust Co Method of manufacturing electric discharge tubes
US2889445A (en) * 1955-03-28 1959-06-02 Herman B Wolf Electrically heated mat
US3062507A (en) * 1957-11-18 1962-11-06 Smith Corp A O Multi-layer vessel having a heat transfer material disposed between layers
US3009044A (en) * 1960-07-11 1961-11-14 Doehler Hans Electric resistance element for space heaters
US3161756A (en) * 1961-02-09 1964-12-15 Schloemann Ag Electrically heated billet-containers for metal-extrusion presses
US3662211A (en) * 1961-03-15 1972-05-09 Gen Electric Cathode construction
US3958146A (en) * 1974-02-08 1976-05-18 Gte Sylvania Incorporated Fast warm up picture tube cathode cap having high heat emissivity surface on the interior thereof
US4009409A (en) * 1975-09-02 1977-02-22 Gte Sylvania Incorporated Fast warmup cathode and method of making same
US5156728A (en) * 1987-02-12 1992-10-20 Terumo Kabushiki Kaisha Ion sensor

Also Published As

Publication number Publication date
NL40799C (en))
BE404192A (en))
GB430853A (en) 1935-06-26
FR775737A (fr) 1935-01-08

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