US2320204A - Method of stem construction for vacuum tubes - Google Patents

Method of stem construction for vacuum tubes Download PDF

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Publication number
US2320204A
US2320204A US427606A US42760642A US2320204A US 2320204 A US2320204 A US 2320204A US 427606 A US427606 A US 427606A US 42760642 A US42760642 A US 42760642A US 2320204 A US2320204 A US 2320204A
Authority
US
United States
Prior art keywords
sleeve
lead
conductors
stem
glass
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
US427606A
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English (en)
Inventor
Harry L Thorson
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.)
General Electric Co
Original Assignee
General Electric 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
Priority to BE472242D priority Critical patent/BE472242A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US427606A priority patent/US2320204A/en
Application granted granted Critical
Publication of US2320204A publication Critical patent/US2320204A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/32—Seals for leading-in conductors

Definitions

  • the present invention relates-to lead-in seals for enclosed electrical apparatus such as evacuated electronic discharge devices, and more particularly to methods of making such seals.
  • the invention is principally concerned with the provision of an improved stem press of the type in which the lead-in wires are sealed in a circular arrangement through a unitary structure which includes a glass flare centrally joined to an exhaust tubulation.
  • An important aspect of the invention consists in a' procedure by which a stem structure of this type may be built up from its elementary parts in a form which assures maximum protection of the stem seals from stresses apt to be encountered in the practical use of the device with which the stem is associated.
  • Fig. 1 is a longitudinal sectional view of an electronic tube suitably embodying the invention
  • Fig. 2 is a sectional view which illustrates the prior art practice with respect to forming a stem press of the general character of that employed in the structure of Fig. 1
  • Figs. 3, 4 and 5 illustrate successive steps in the improved procedure of the present invention. 7
  • an evacuated discharge tube of the type to which the present invention is applicable This comprises an elongated cylindrical metal anode H! which constitutes a portion of the enclosing envelope for the tube.
  • a heatable cathode comprising a plurality of filaments H which are in a hollow configuration. These filaments are in turn surrounded by a grid structure consisting of wires I2 wound helically on a plurality of stay rods l3 which parallel the filaments ll. 1
  • the open end of the anode I is hermetically sealed. to a glass enclosure l5, the sealed joint being indicated at I6.
  • a re-entrant circular press l8 which serves as a mount for a plurality of cathode leadin conductors l9.
  • These conductors which may consist, for example, of tungsten, are arranged in circular array and are connected outside the enclosure with a plurality of current supply conductors 2
  • the wires 19 are maintained in parallelism with one another by means of a pair of insulating disks 24 and 25 through which they pass.
  • the individual wires are relatively stiff and provide fixed anchorages for the cathode filaments II to which they are joined at their extremities.
  • the ends of the filaments I l more remote from the supporting wires l9 are joined to a common terminal structure (not shown).
  • This struc- I ture is fixedly secured to a rod 21 which is arranged at the center of the filament array and which serves as a means for applying tension to the filament.
  • the rod is associated with a compression spring (not shown) which is located within a two-parthousing'29 and which acts on the rod 21 to cause it to move in a longitudinal direction.
  • which extends toward the interior of the discharge space.
  • this sleeve is joined to a cylindrical metal member 32 which in turn is secured to a similarly formed member 33 placed in abutting relation with it.
  • This latter member is connected directly to the grid stay rods l3.
  • a terminal for the grid structure - is provided by means of a ring-like conductor 35 which is clamped between the members 32 and which connects with a lead-in wire 36.
  • the wire 36 terminates in a cup-shaped contact member 38 which is sealed intothe Wall of the glass enclosure I5.
  • the present invention is primarily concerned with the procedure employed for fabricating the circular press l8 and in particular with a novel method of uniting it to the fiare 40 and the exhaust tubulation M of Fig. 1 in a manner which results in the production of a lead-in press having maximum protection from cracking.
  • the circular stem press is, in itself, well known to the art and has been conventionally produced in the manner indicated in Fig. 2.
  • a plurality of lead-in conductors are initially interposed between the outer surface of a cylindrical tribulation-bearing part 5
  • the throat portion of the flare 53 is heated and subjected to pressure in such manner as to cause it to shrinl;
  • suflicient mechanical pressure is exerted on the outer surface of the sleeve (as by means of a contractible clamping ring) to cause it to be compressed against the part 51 in such manner as hermetically to seal to the conductors 62.
  • the seal may be joined to a suitable flare (e. g. the flare 61 of Fig. 5) by fusing the inner edge of the fiare to the outer surface of the sleeve 68.
  • a suitable flare e. g. the flare 61 of Fig. 5
  • the fiare is secured to the central portion of the sleeve since this results in a symmetrical arrangement which tends to minimize the creation of strains as a result of the sealing on of the flare.
  • this arrangement assures that in the event the externally extending parts of the lead-in conductors shall accidentally be subjected to forces of such magnitude as to injure the seals, any cracks initiated in the sleeve 60 (i.
  • a lead-in stem which comprises encircling a central part with a loosely fitting glass sleeve, positioning one or more lead-in conductors in the space between said central part and the sleeve, fusing the sleeve into engagement with the lead-in conductors and the said central part, and thereafter joining the inner edge of a separately formed flare to an externally accessible surface of the sleeve.
  • the method of forming a lead-in stem '01" a type which in finished form includes an evacuating tubulation joined to a flare, which method comprises encircling a tubulation-bearing part with a loosely fitting glass sleeve, positioning one or more lead-in conductors in the space between said tubulation-bearing part and said sleeve, fusing the sleeve into engagement with the tubulation-bearing part and the lead-in conductors, and thereafter joining the inner edge of a separately formed fiare to an externally accessible surface of the said sleeve.
  • the method of fabricating a lead-in stem of a type which in finished form includes an evacuating tubulation joined to a flare, which method comprises initially forming on one end of the tubulation an enlarged annular glass part, encircling said part with a loosely fitting glass sleeve, positioning a lead-in conductor in the space between said annular part and said sleeve, fusing the sleeve into engagement with the annular part, and thereafter joining the inner edge of a separately formed flare to said sleeve.
  • the method of fabricating a lead-in stem which comprises forming an evacuating tubulation having an enlarged annular part on one end thereof, encircling the said part with a loosely fitting glass sleeve, positioning one or more lead-in conductors in the space between said annular part and said sleeve, fusing the sleeve into sealing engagement with the lead-in conductors and the annular part, heating both extremities of the circular press thus formed to improve the seals produced between the glass and the lead-in conductors, and thereafter joining the inner edge of a separately formed 'fiare to the exposed surface of the said sleeve.

Landscapes

  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
US427606A 1942-01-21 1942-01-21 Method of stem construction for vacuum tubes Expired - Lifetime US2320204A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE472242D BE472242A (fi) 1942-01-21
US427606A US2320204A (en) 1942-01-21 1942-01-21 Method of stem construction for vacuum tubes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US427606A US2320204A (en) 1942-01-21 1942-01-21 Method of stem construction for vacuum tubes

Publications (1)

Publication Number Publication Date
US2320204A true US2320204A (en) 1943-05-25

Family

ID=23695557

Family Applications (1)

Application Number Title Priority Date Filing Date
US427606A Expired - Lifetime US2320204A (en) 1942-01-21 1942-01-21 Method of stem construction for vacuum tubes

Country Status (2)

Country Link
US (1) US2320204A (fi)
BE (1) BE472242A (fi)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2518924A (en) * 1944-09-15 1950-08-15 Gen Electric Stem making method and apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2518924A (en) * 1944-09-15 1950-08-15 Gen Electric Stem making method and apparatus

Also Published As

Publication number Publication date
BE472242A (fi)

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