US2495580A - Indirectly heated cathode - Google Patents

Indirectly heated cathode Download PDF

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Publication number
US2495580A
US2495580A US653691A US65369146A US2495580A US 2495580 A US2495580 A US 2495580A US 653691 A US653691 A US 653691A US 65369146 A US65369146 A US 65369146A US 2495580 A US2495580 A US 2495580A
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US
United States
Prior art keywords
cathode
indirectly heated
nickel
heated cathode
emitting
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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
US653691A
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English (en)
Inventor
Gall Bernardus Octavianu Maria
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.)
Hartford National Bank and Trust Co
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Hartford National Bank and Trust 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
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2495580A publication Critical patent/US2495580A/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

Definitions

  • the invention relates to av method of manufacturing an indirectly heated cathode, to a cathode manufactured by this method and to a circuit arrangement comprising such a cathode.
  • an indirectly heated cathode by arranging a rod-shaped conductor consisting, for example, of molybdenum, tungsten, chromium nickel or nickel within a tubular body of molybdenum, tungsten, nickel or similar material, by filling the intervening space with insulating material such as magnesia, alumina, or thoria and by hammering and drawing the whole of it thus obtained until a body of the desired dimensions is obtained.
  • This composit-e body can only be used as a cathode after the outside has been coated with electron-emitting material, for example with barium oxide or strontium oxide.
  • a directly heated cathode consisting of an internally hollow tubular element, for example, of nickel which is filled with an electron-emitting metal, more particularly with caesium. Upon heating such a cathode the metal would diffuse from the interior to the outside and ensure there a satisfactory emission.
  • the invention relates to an indirectly heated cathode and to a method of manufacturing such a cathode, in which an emitting substance is present in the interior and during operation diffusion to the outside takes place, owing to which the emission is brought about.
  • the starting point is formed by a tubular body within which one or more conductors are arranged, if desired,
  • the material present in the interior which is preferably composed of oxides of the alkalineor alkaline-earth metals, more particularly of barium oxide and/or strontium oxide, acts at the same time as insulation between the heating element and the cathode body; it also acts as filling material in the drawing operation and finally as emitting material during the operation. It has been found that also with the use of these non-metallic substances a satisfactory diffusion takes place through the wall of the cathode body.
  • a cathode according to the invention it is, however, very easy to form further emitting metal by applying during the operation of the cathode, in accordance with a determined mode of realisation, a uni-directional voltage between the heating element and the cathode body so that electrolysis of the insulating oxide takes place and alkalineor alkaline-earth metal is isolated on the inside of the cathode body, which quantities of metal easily diffuse through the wall and may act on the outside as emitting materials.
  • the voltage to be utilized in this case may be of the order of magnitude of a few volts.
  • the starting point is formed by a tube which consists, for example, of nickel or copper and which has a diameter of 8 mms. and a wall thickness of 0.5 mm.
  • a tube which consists, for example, of nickel or copper and which has a diameter of 8 mms. and a wall thickness of 0.5 mm.
  • two wires consisting of nickel and having a thickness of about 1 mm.
  • These wires ar set firmly relatively to the surrounding tube and then the remaining space is filled, which takes place, for example, in vacuo, with a pulverulent mixture of barium oxide and strontium oxide, the tube being shaken during and also a short time after the filling operation.
  • the whole thus obtained is then hammered until an appreciable increase of length is obtained and then it is drawn and/or rolled until the desired dimensions are obtained.
  • the single figure of the drawing shows in section a tubular cathode body which may be constructed for example, of nickel. Positioned within the cathode body are heater wires, which may also be of nickel. An alkaline-earth oxide compactly fills the space between the Wires and the cathode body. A unidirectional source of voltage applies a potential between the wires and the cathode body, the positive side of the battery being connected to the nickel wires and the negative side of the battery being connected to the cathode body. A source of voltage for the heating of the nickel wires is also shown.

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  • Solid Thermionic Cathode (AREA)
US653691A 1941-10-15 1946-03-11 Indirectly heated cathode Expired - Lifetime US2495580A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL103265A NL59317C (en, 2012) 1941-10-15 1941-10-15

Publications (1)

Publication Number Publication Date
US2495580A true US2495580A (en) 1950-01-24

Family

ID=19780546

Family Applications (1)

Application Number Title Priority Date Filing Date
US653691A Expired - Lifetime US2495580A (en) 1941-10-15 1946-03-11 Indirectly heated cathode

Country Status (7)

Country Link
US (1) US2495580A (en, 2012)
BE (1) BE447568A (en, 2012)
CH (1) CH241098A (en, 2012)
DE (1) DE846739C (en, 2012)
FR (1) FR886755A (en, 2012)
GB (1) GB611933A (en, 2012)
NL (1) NL59317C (en, 2012)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563573A (en) * 1951-08-07 Hot cathode electron tube which re
US3031740A (en) * 1958-03-12 1962-05-01 Eitel Mccullough Inc Matrix type cathode
US3921031A (en) * 1973-01-30 1975-11-18 Commissariat A L En Atomique & Electroemissive component
US4987342A (en) * 1989-03-27 1991-01-22 Gte Products Corporation Self-ballasted glow discharge lamp having indirectly-heated cathode

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB721837A (en) * 1951-01-11 1955-01-12 Egyesuelt Izzolampa Improvements in cathodes and method of making them

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1618499A (en) * 1923-11-06 1927-02-22 Charles P White Electrical apparatus
US2075876A (en) * 1927-12-28 1937-04-06 Electrons Inc Cathode organization
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1618499A (en) * 1923-11-06 1927-02-22 Charles P White Electrical apparatus
US2075876A (en) * 1927-12-28 1937-04-06 Electrons Inc Cathode organization
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563573A (en) * 1951-08-07 Hot cathode electron tube which re
US3031740A (en) * 1958-03-12 1962-05-01 Eitel Mccullough Inc Matrix type cathode
US3921031A (en) * 1973-01-30 1975-11-18 Commissariat A L En Atomique & Electroemissive component
US4987342A (en) * 1989-03-27 1991-01-22 Gte Products Corporation Self-ballasted glow discharge lamp having indirectly-heated cathode

Also Published As

Publication number Publication date
NL59317C (en, 2012) 1946-06-15
FR886755A (fr) 1943-10-25
BE447568A (en, 2012) 1942-11-30
CH241098A (de) 1946-02-15
DE846739C (de) 1952-08-18
GB611933A (en) 1948-11-05

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