US2225726A - Method of producing incandescent lamp cores or bases - Google Patents

Method of producing incandescent lamp cores or bases Download PDF

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Publication number
US2225726A
US2225726A US215030A US21503038A US2225726A US 2225726 A US2225726 A US 2225726A US 215030 A US215030 A US 215030A US 21503038 A US21503038 A US 21503038A US 2225726 A US2225726 A US 2225726A
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United States
Prior art keywords
bases
tube
glass
lamp
quartz glass
Prior art date
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Expired - Lifetime
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US215030A
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English (en)
Inventor
Vessi Gabor
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General Electric Co
Original Assignee
General Electric Co
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Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
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Publication of US2225726A publication Critical patent/US2225726A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K3/00—Apparatus or processes adapted to the manufacture, installing, removal, or maintenance of incandescent lamps or parts thereof
    • H01K3/20—Sealing-in wires directly into the envelope

Definitions

  • This invention relates to electric lamps, or improvements therein, and aims to provide a desirable improvement in the construction of such core or base parts of the same.
  • Hard glass or' quartz glass bulbs are always used when, for any reason, it is preferable or essential to reduce the size of the bulb below a certain limit, as, for example, in the case of high pressure incandescent lamps, with filling pressures in excess of five atmospheres, incandescent lamps with a filling of mercury vapour etc.
  • a certain limit as, for example, in the case of high pressure incandescent lamps, with filling pressures in excess of five atmospheres, incandescent lamps with a filling of mercury vapour etc.
  • the size of the bulb which compels the use of hard, glass or quartz glass as a material for thebulbs and bases, the importance of being able to make lamp bases of small size in these materials will very readily be apparent.
  • Significant examples of the application of such bases are high pressure incandescent lamps with filling pressures of thirty, fifty or more atmospheres, and tubular hard glass or quartz glass bulbs 6 mm. or less in diameter.
  • One object of the present invention is to provide a novel and simple method of making lamp bases of hard glass or quartz glass.
  • Another object is to provide an improved method of making lengths of two-duct capillary tubing in hard glass or quartz glass, to serve as starting material or stock for the manufacture of bases or stems for lamps as hereinbefore referred to.
  • Another object is to provide a method of making small, compact electric incandescent lamps of a kind adapted for operation with a high internal gas pressure and/or vapor pressure.
  • Yet another object is to provide lamp bases or For exam- 1 ple, tungsten wires, up to a millimetre or more in I stems of novel construction, for incorporation in electric incandescent lamps and a final object is .to provide a lamp of very simple and compact construction, such lamp being particularly well adapted for operation under a high internal pres- 5 sure of filling gas and/or vapor.
  • the lamp bases according to'the invention areproduced by sealing the current leads "simultaneously into one hard glass or quartz glass capillary tube having or formed with two ducts. 'Ijhe 10 sealing in of such leads may be effected under reduced (1. e. less than the usual) pressure and this expedient is indeed usually desirable when sealing foils of refractory metal directly into quartz glass. Particularly in the case of very small lamp bases, it is preferable, 'when using current leads in the form of metal foils, so to arrange the foils for sealing in that their broader faces (as distinguished fromtheir edges) confront one another and are parallel. 5
  • the wires can be sealed directly into the glass and the sealing-in operation can be conducted inatmospheric air.
  • the mode of pro-' cedure adopted when using a quartz glass double capillary tube may, for example, be as follows:' Two thin molybdenum foils, about ZO thick and 1 mm. wide, to the ends of which tungsten or .30 molybdenum wires of suitable shape and dimensions are welded, are introduced into the two ducts of a double capillary tube of quartz glass.
  • the capillary is sealed off at one end and evacuated and then, by heating the appropriate points 85 with an oxy-hydrogen flame, the quartz glass is allowed to collapse onto the the ,moiybdenum foils, after which the projecting ends of the tube can be cut oil.
  • the process according to the present invention 40 permits of working to fine limits of tolerance. even in the case of very small bases; it eliminates the risk of short circuits and it can be carried out rapidly.
  • a quartzglass capillary tube is used in conjunction with leads made of i5 molybdenum foil, it has also the'g-reat advantage that the lamp base can be sealed intothe lamp bulb in atmospheric air. This is of great im portance, particularly in high, pressure lamps; wherein it is necessary to exercise meticulous 5 care in making the fused joint between the bulb of the lamp and the base thereof.
  • Fig. 11- isan enlarged cross sectional view'illustratingla tube and'ariinserted rod,. both of quartz 0 glass, in concentric arrangement between press plates which unite and shape the twoglass elements so'as together to forma double capillary I figure the references 2, 3, 4 again designate the tube;
  • v V s Fig. 2 is a cross section through a capillary tube 1 pressed together;
  • Y i a Fig. 3 is a longitudinal section of such a double capillary tube, having current leads inserted in its capillary ducts; this view beingJdrawn to a.
  • Figil 4 is a'cross, section taken on the line 3-3 of Fig..3'and is drawn to the same scaleas Figs. 1
  • Fig. 6 illustrates a finished incandescent lamp incorporating a base such as thatshownin Fig. 5.
  • l indicates a quartz glass tube from which theaforemention'ed double capillary or lamp base part is formed.
  • Y represents the method or manner, of formation "as last above described. That is, a. rod 1 of the 5 same, or also quartz glass, material is inserted into said tube, in this instance in a concentric relation. Upon heating said glass tube l sufliciently, the same can be pressed from opposite sides as by means of jawsprpress plates l0 and H until its diametrically opposed portions or walls meet and are flattened upon saidrod I into substantial fusion therewith. -In thisvery simple way a quartz glass bar with two longitudinalcapillary ducts, i. e. with channels on, opposite sides of the rod, is produced as shown in Fig. 2.
  • FIG. 2 shows the thus flattened tube l unitarily fused to. the rod 1, the said ductswhich are resultantly crescent shaped in cross section being designated'B and 8' respectively
  • the two (composite) current leads, in this instance uncoated but which may be coated as with a glass that becomes intermediate (fused) between them and the capillary body in the hermetic seal later effected,
  • Each of said current leads consists of a molybdenum wire 2 and a tungsten inner lead or electrode 4, cono .nected by a molybdenum strip 3, whichmay for instance be 251/. thick and 0.8 mm. wide.
  • the double capillary tube thus composed is I next evacuated. This can be done in vacuum or any other suitable way, but if the capillary ducts -5 are closed at one nd, by closure of the tube -I as shown in Fig. 3, the other (open) end A-of the j tube can be connected directly to an air pump.
  • the double capillary tube is then heated at the region of the line .B-B, in Fig. 3, until it collapses or flattens in fusibly upon itself and the ends are cut off at C and D, without severing the wires 2 and 4.
  • the form of the lamp base thus obtained is shown in Fig. 5.
  • the completed base or body 9 with said connected leads or electrodes is then fused into the quartzglass bulb 6, in air in the usual way.
  • the isaid bulb is next evacuated at I 2 (through a pump tube not shown) and filled with a gas mixture, to a pressure higher than 10 at-' lmospheres, after which it is sealed off or closed.
  • the method of making a seal for electric lamps'and similar devices which comprises arranging a rod of vitreous material within a tube of vitreous material, heating said tube to render it plastic and then compressing it upon said rod in such a manner as to leave a plurality of longitudinally extending capillary ducts formed by unfused portions of the exterior surface of said rod and the interior surface of said tube, subsequently introducing metal conductors severally into said ducts, and then fusing the vitreous material and causing it to collapse around said conductors to form a'hermetic seal.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
US215030A 1937-06-25 1938-06-21 Method of producing incandescent lamp cores or bases Expired - Lifetime US2225726A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE204635X 1937-06-25

Publications (1)

Publication Number Publication Date
US2225726A true US2225726A (en) 1940-12-24

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ID=5782893

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US215030A Expired - Lifetime US2225726A (en) 1937-06-25 1938-06-21 Method of producing incandescent lamp cores or bases

Country Status (5)

Country Link
US (1) US2225726A (en)van)
CH (1) CH204635A (en)van)
FR (1) FR839180A (en)van)
GB (1) GB504874A (en)van)
NL (1) NL48889C (en)van)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481906A (en) * 1942-04-18 1949-09-13 Chilcot Arthur Leslie Mounting of electrodes in electric discharge tubes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481906A (en) * 1942-04-18 1949-09-13 Chilcot Arthur Leslie Mounting of electrodes in electric discharge tubes

Also Published As

Publication number Publication date
NL48889C (en)van)
FR839180A (fr) 1939-03-28
CH204635A (de) 1939-05-15
GB504874A (en) 1939-05-02

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