US1939997A - Indirectly heated cathode - Google Patents

Indirectly heated cathode Download PDF

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Publication number
US1939997A
US1939997A US287812A US28781228A US1939997A US 1939997 A US1939997 A US 1939997A US 287812 A US287812 A US 287812A US 28781228 A US28781228 A US 28781228A US 1939997 A US1939997 A US 1939997A
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Prior art keywords
cathode
heating
heat
heated
current
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Expired - Lifetime
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US287812A
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English (en)
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Loewe Siegmund
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Individual
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Individual
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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

  • My invention now consists in the main cathode not being itself heated by the source of heat, but in heating it by the source of heat of a third element which is in good heat-conducting connec-- tion with the main cathode to be heated.
  • the main cathode may be, for instance, a solid wire which offers maniifold advantages inthe construction of tubes.
  • Fig. 1 shows by means of example an arrangement by which the principle of my invention may be understood
  • Fig. 2 illustrates an arrangement in which small auxiliary metallic bodies, connected to the cathode, may be heated by electron bombardment
  • Fig. 3 shows a somewhat modified form of such an arrangement, in which such metallic bodies are formed by a screw-shaped wire
  • Fig. 4 shows an arrangement in which the heating of the cathode is made by means of connections in which electrical currents are running.
  • FIG. 5 shows a complete three-electrode-valve in which a cathode containing such three-electrode-systems with a cathode according to my invention is arranged.
  • Fig. 1 l is the main cathode, e. g. a solid tungsten wire.
  • a control grid is indicated, by 3 the anode.
  • 1, 2 and 3 represent together an amplifying system of the customary kind with a grid 2.
  • this cathode may be heated by heat conduction in such manner that it is in good vmay likewise be made to glow by electronnantly be heated from one side so that one of its ends would be considerably warmer than the 'manner effected in part by heat radiation on the heat-conducting connection with a body 4 which in its turn is made to glow by any method whatsoever. Body 4 may therefore be heated in any chosen manner.
  • the heating may be effected by J oule-heat in which case the body 4 is made as a current carrying heating spiral. All other methods of heat generation may be used too.
  • Body 4 may, for instance, be a metal cylinder which is made to glow by means of a coil slipped over and carrying low or high frequency currents. Body 4 bombardment. In the latter case it would appropriately be given the form of a hollow cylinder with which the main cathode 1 is heat-conductingly connected. Inside the hollow. cylinder the glowing cathode is to be arranged and a direct voltage or alternating voltage is to be connected between the latter and the tinplate cylinder 4. 7
  • Fig. 2 illustrates such arrangement with the use of the electron bombardment for the indirect heating of bodies 4.
  • Main cathode 1 is at both ends heat-conductively connected with cylinders 4 and, as in Fig. 1 surrounded by grid 2 and the cylindricalanode 3.
  • two incandescent wires indicated by dots and consisting, for instance, of tungsten wire, are placed which are made to glow by direct or alternating current.
  • a direct or alternating voltage is connected between the cylinders 4 connected with one another by the lead 5 and the incandescent wires inside of them a direct or alternating voltage is connected. (Actually a special connection 5 is not required since the cylinders are already conductively connected by cathode 1).
  • the cylinders 4 should consist of tantalum, molybdenum or tungsten sheet in order that they may take very high temperatures.
  • the main cathode 1 is then from both ends made to glow by heat coduction so that the amplifying system 1, 2, and 3 operates like a normal incandescent filament amplifying system.
  • the main cathode 1 more particularly may also consist of a thor'iated tungsten wire.
  • Fig. 2 affords the possibility of providing screens 6 which are, for instance, circular and centrally perforated mica discs which prevent the penetration of stray 119 electrons from the inside of cylinder 4 into the inside of amplifying system 1, 2, 3.
  • screens 6 which are, for instance, circular and centrally perforated mica discs which prevent the penetration of stray 119 electrons from the inside of cylinder 4 into the inside of amplifying system 1, 2, 3.
  • the employment of such screens is, however, recommended also for all other embodiments of the invention and is always possible.
  • FIG. 3 A practical embodiment of the arrangement according to Fig. 2 is illustrated in Fig. 3.
  • cylinders 4 are produced by cathode 1 being at both ends wound up to a cylindrical spiral 7.
  • These spirals are made to glow very brightly, e. g. to 2300 by the electron bombardment.
  • heat conduction part 1 extending through amplifying system 2, Bis heated from both ends and, as tests have proved, may easily be heated sufilciently to the temperature of about 1700 necessary for the formation of the thorium oxide (oxide cathode), considerably lower temper-- atures will, of course, suflice.
  • spirals 7 are'woun'd very closely and with closely approaching turns. The employment of the electron bombardment according to Figs.
  • Figs. 2 and 3 with the use of the electron bombardment have certain advantages, this, however, is also true with the further embodiment of the invention illustrated by Fig. 4.
  • the main cathode 1 is simply extended on both sides, the current supply being, however, arranged in such manner that only its two, outer ends 8 and 9 are traversed by heating current and are therefore made to glow brightly.
  • the heating current flows in at 10 and out at ll and 12.
  • the current is alternating current. Parts 8 and 9 are thus made to glow brightly.
  • the inner part 1 of the cathode is heated by heat conduction from both ends. This part, of course, is at a considerably lower temperature which, however, is still high enough to provoke the thorium or oxide emission.
  • An electron discharge device containing a thermionic cathode, one tinplate cylinder arranged at each end of said thermionic cathode, a heating wire arranged inside of each tinplate cylinder, said heating wires being connected with one another, said heating wires being adapted to heat said cylinders by electron bombardment.

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  • Discharge Lamp (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Measuring Fluid Pressure (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Solid Thermionic Cathode (AREA)
US287812A 1927-06-25 1928-06-23 Indirectly heated cathode Expired - Lifetime US1939997A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEL69010D DE584068C (de) 1927-06-25 1927-06-25 Indirekt geheizte Kathode
DE292913X 1927-06-25

Publications (1)

Publication Number Publication Date
US1939997A true US1939997A (en) 1933-12-19

Family

ID=25780058

Family Applications (1)

Application Number Title Priority Date Filing Date
US287812A Expired - Lifetime US1939997A (en) 1927-06-25 1928-06-23 Indirectly heated cathode

Country Status (6)

Country Link
US (1) US1939997A (xx)
AT (1) AT124871B (xx)
DE (1) DE584068C (xx)
FR (1) FR656047A (xx)
GB (2) GB292913A (xx)
NL (1) NL25429C (xx)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL110237C (xx) * 1951-06-10

Also Published As

Publication number Publication date
GB292913A (en) 1929-06-20
GB308823A (en) 1929-09-12
AT124871B (de) 1931-10-10
FR656047A (fr) 1929-04-26
NL25429C (xx)
DE584068C (de) 1933-09-14

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