US2098807A - Electrical discharge apparatus - Google Patents

Electrical discharge apparatus Download PDF

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Publication number
US2098807A
US2098807A US600456A US60045632A US2098807A US 2098807 A US2098807 A US 2098807A US 600456 A US600456 A US 600456A US 60045632 A US60045632 A US 60045632A US 2098807 A US2098807 A US 2098807A
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US
United States
Prior art keywords
cathode
heater
electrical discharge
discharge apparatus
heaters
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
US600456A
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English (en)
Inventor
Jonker Johan Lodewyk Hendrik
Karel Marinus Van Gessel
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 US2098807A publication Critical patent/US2098807A/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
    • H01J1/22—Heaters

Definitions

  • the present invention relates to electrical discharge apparatus, more especially to tubes employing indirectly heated cathodes.
  • the heater In cathodes of the indirectly heated type, the heater usually consists of a U- or V-shaped filament.
  • the dimensions of the filament i. e. the gage and length are predetermined in order to provide the proper resistance so that the heat generated by the current will be sufficient for electron emission purposes.
  • the cathode In the fabrication of tubes provided with cathodes of this sort, the cathode is heated to a high temperature and the tube pumped so as to deprive the metal of the cathode of gas held by occlusion; this temperature ordinarily is higher than the operating temperature for which the cathode is designed. Under these conditions, the current passing through the heater is greater than normal and tends to render the filament brittle, which may be due to re-crystallization of the metal.
  • An object of the present invention is to provide an indirectly heated cathode which is adapted not only to ordinary operating or working conditions but also to manufacturing conditions. In both cases, the cathode must operate efficiently.
  • the object is attained in brief, by providing a pair of heater filaments, one of which is designed to operate at the evacuation or manufacturing temperature and the other at the ordinary working temperature.
  • Fig. 1 is an elevational view of a tube containing a cathode improved in accordance with the present invention, with several of the electrodes shown in cross-section
  • Fig. 2 is a cross-sectional view of a modified form of cathode.
  • numeral I designates an evacuated envelope which may contain gas or vapor, if desired.
  • the envelope terminates in an inverted stem or press 2 which supports the electrodes.
  • the latter comprises a cylindrical anode 3, a helical grid 4 and an indirectly heated cathode 5 held in position at the bottom by a rigid rod 6 fused in the press, and at the top, by a rod 1 secured to a glass arbor 8.
  • This construction and arrangement are well known in the art and need no elaboration.
  • Leading-in conductors 9 are provided for the various electrodes, including the cathode.
  • the improved cathode consists of a cylindrical member 5 of a suitable metal, such as nickel, closed at the top and open at the bottom.
  • the cathode may be coated with electronically active material, such as alkaline earth oxide.
  • electronically active material such as alkaline earth oxide.
  • Within the cathode cylinder there are-two or more filamentary heaters I 0, ll of tungsten or other refractory metal joined at one end to a common leading-in conductor and at the other end to individual leading-in conductors.
  • the filaments are of substantially the same shape but as will be noted, one is longer. They are arranged, one withinthe other as shown, so as to be mutually independent, physically and electrically.
  • One of the filaments is designed in accordance with well-known calculations, to carry the current necessary for heating the cathode during the gas denudation process and the other is adapted to heat the cathode during the regular operating period. Consequently, when the evacuation of the tube, including the electrodes, has been completed by the usual heating methods, the heater, designed to carry the ordinary operating current, is employed during the life of the tube.
  • both heaters may be employed together, during either the manufacturing or the operating period or both, although ordinarily, the heaters are used separatelyand in a discriminate manner.
  • the heater most suited for the particular work at hand is employed, which feature lends enhanced efficiency of operation to the tube, as well as longer life.
  • the extra filament necessitates only a small addition by way of structure and in quantity production increases the cost of manufacture by a very few per cent which is offset by the resulting reduced tube shrinkage.
  • a modified form of heater H2 in which the filament takes the form of an M or .a double inverted V.
  • the two parts of the heater may be arranged side by side and the apexes brought out to separate leading-in conductors, as shown.
  • One-half of the heater may be used for gas denudation purposes during manufacture of the tube and the other half for operating purposes, each being designed eflicient- 1y to perform its individual function.
  • An electric discharge device comprising an'envelope containing a cylindrical anode, a helical grid and an indirectly heated cathode of cylindrical configuration, a plurality of heaters withw in the cathode cylinder and the space between said heaters and the cylinder being substantially free of insulating material, one of said heaters of said heaters being arranged within another 10 heater.

Landscapes

  • Solid Thermionic Cathode (AREA)
  • Discharge Lamp (AREA)
US600456A 1931-03-24 1932-03-22 Electrical discharge apparatus Expired - Lifetime US2098807A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL391938X 1931-03-24

Publications (1)

Publication Number Publication Date
US2098807A true US2098807A (en) 1937-11-09

Family

ID=19785802

Family Applications (1)

Application Number Title Priority Date Filing Date
US600456A Expired - Lifetime US2098807A (en) 1931-03-24 1932-03-22 Electrical discharge apparatus

Country Status (4)

Country Link
US (1) US2098807A (fr)
BE (1) BE386698A (fr)
FR (1) FR732375A (fr)
GB (1) GB391938A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263114A (en) * 1960-10-26 1966-07-26 Firm Egyesult Izzolampa Es Vil Shock and vibration resistant heater for indirectly heated cathodes of radio receiving tubes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263114A (en) * 1960-10-26 1966-07-26 Firm Egyesult Izzolampa Es Vil Shock and vibration resistant heater for indirectly heated cathodes of radio receiving tubes

Also Published As

Publication number Publication date
BE386698A (fr)
GB391938A (en) 1933-05-11
FR732375A (fr) 1932-09-19

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