US2275674A - Electric incandescent lamp - Google Patents

Electric incandescent lamp Download PDF

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Publication number
US2275674A
US2275674A US167354A US16735437A US2275674A US 2275674 A US2275674 A US 2275674A US 167354 A US167354 A US 167354A US 16735437 A US16735437 A US 16735437A US 2275674 A US2275674 A US 2275674A
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US
United States
Prior art keywords
lamp
mercury
pressure
filament
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
US167354A
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English (en)
Inventor
Davies Leonard John
Warren Henry William Hugh
Hamilton Gavin
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
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Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Application granted granted Critical
Publication of US2275674A publication Critical patent/US2275674A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K1/00—Details
    • H01K1/50—Selection of substances for gas fillings; Specified pressure thereof

Definitions

  • This invention relates to electric incandescent lamps and more particularly to such lamps of the type in which an incandescent filament operates in the presence of an inert gas filling, and it is an object of th invention to secure operation at an efliciency and with a life greater than has hitherto been possible.
  • any normal incandescent filament lamp can be increased by simply over-running it, orincreasing its temperature, but in known lamps, any such increase of efficiency is accompanied by a corresponding decrease of life or lumen maintenance due to evaporation of the filament material and the development of hot spots etc.
  • inert gas such as nitrogen or argon or a mixture of these is known to be beneficial in preventing evaporation of the filament and it is known that as the pressure of .the filling gas is increased the beneficial effect of the filling also increases.
  • Lamps however, have not hitherto been operated at pressures appreciably above 1 atmosphere and the present invention consists in providing a lamp which will operate at pressures of from 1 to 20 atmospheres or even higher.
  • At least two diificulties have existed up to now in connection with lamps operating at above one atmosphere.
  • a lamp intended for operation at a pressureof 1 to 20 atmospheres or more is made much smaller than normally.
  • the size may vary from a diameter of 5 to 12 mms. and a length of 20 to 25 mms. for a quartz-envelope to a larger size of say, 7 mm. diameterand 35 mms. long for a hard glass envelope.
  • the energy released, should the lamp burst, is small, and owing to the small size any unsupported span of bulb wall is relatively short and consequently the wall thickness need not be unduly great.
  • quartz tubing 1 to 2 mms. wall thickness and 5 mms. bore will withstand at a temperature of approximately 1000" C. an in-.
  • ternal pressure of more than 20 atmospheres.
  • the lamp is made with a filling of mercury as the inert gas.
  • mercury vapour pressure is low, and much below 1 atmosphere
  • the amount of mercury placed within the lamp is controlled, and the lamp shape is controlled so that at some value, for example of the operating wattage, the mercury is completely vaporised.
  • Two difilculties are associated with the use of mercury, both connected with the-low pressure when the filament is cold.
  • the pressure of mercury vapour- is below 1 atmosphere and a certain time must elapse after switching on before the mercury reaches the desired operating pressure.
  • the filament is operating at a high temperature in a low pressure, and consequently may suffer serious evaporation.
  • an arc may occur between the ends or other portions of the filament, with destructive or undesirable effects.
  • the lamp may contain a pressure of permanent gas such as argon or nitrogen or krypton or a mixture of such gases at about. 300-600 mms. in addition to the controlled quantity of mercury.
  • a pressure of permanent gas such as argon or nitrogen or krypton or a mixture of such gases at about. 300-600 mms. in addition to the controlled quantity of mercury.
  • the lamp may contain argon, ni-
  • trogen or other inert gas or a mixture of these at a pressure of one toten atmospheres or more and be fitted with a metal exhaust tube.
  • the sealoi'l is then performed by pressing the side of the metal together and then electrically welding these, preferably using a heavy current short duration spot weld.
  • the metal seal-011 tubernay be attached to the lamp by means of a metal to glass seal.
  • a metal to glass seal For example a metal of the type known by the trade name of Femico which has a coeflicient of expansion substantially the same as glass may be used with a borosilicate glass. If'desired the lamp body may be made of-a glass sealing to this or may be made of quartz with a graded. glass seal.
  • the metal exhaust tube may be of steel electrically welded to a. Fernico or other alloy part velope; and Fig. 2 is a similar view of a modification in the form of a double-ended lamp with a longitudinally extending coiled filament, the metal seal-off tube at one end being shown as it appears prior to sealing or closure thereof.
  • the translucent envelope ll, filament l2, and metal sealoif tube I3 are shown in assembled relation.
  • the said envelope contains a predetermined quantity of mercury H which, as fully described above, is completely vaporized during operation of the lamp.
  • Fig. I the sides of the metal seal-off tube l3 are shown pressed together and welded while, in Fig. 2, the seal-ofi tube I3 is illustrated as it might appear before the sides are pressed together.
  • An incandescent electric lamp comprising a light-transmitting envelope of high melting point vitreous material having a filament mounted therein and containing a quantity of mercury and a filling of an inert gas, the amount of mercury taken with the pressure of the inert gas being such that at the operating temperature of the lamp the mercury is completely vaporised and the pressure of the combined gas and mercury vapour exceeds one atmosphere.
  • An incandescent electric lamp comprising a light-transmitting envelope of high melting point vitreous material having a filament mountwhich in turn is sealed to the glass envelope.
  • the filament-leads may becarried by the metal part or the glass envelope.
  • Fig. 1 is a schematic elevation, partly in section, of a single-ended lamp comprising our invention and having a compact coil filament in the envelope with a closed metal seal-off tube at one end of the said en-' ed therein and containing a filling of an inert gas at a pressure of about 300 mms. and also such a quantity of mercury that at the operating temperature of the lamp the mercury is completely vaporised and the combined pressure of the gas and vapour exceeds one atmo phere.
  • An incandescent electric amp comprising a light-transmitting envelope of high melting point vitreous material having: a filament mounted therein and containing a filling of an inert gas at a pressure of less than one atmosphere and also such a quantity 0? mercury that at the operating temperature 0 the lamp the mercury is completely vaporized and the combined pressure of the gas and vapour exceeds one atmosphere.

Landscapes

  • Discharge Lamp (AREA)
  • Resistance Heating (AREA)
US167354A 1936-10-05 1937-10-05 Electric incandescent lamp Expired - Lifetime US2275674A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB26976/36A GB484566A (en) 1936-10-05 1936-10-05 Improvements in and relating to electric incandescent lamps

Publications (1)

Publication Number Publication Date
US2275674A true US2275674A (en) 1942-03-10

Family

ID=10252160

Family Applications (1)

Application Number Title Priority Date Filing Date
US167354A Expired - Lifetime US2275674A (en) 1936-10-05 1937-10-05 Electric incandescent lamp

Country Status (4)

Country Link
US (1) US2275674A (en:Method)
BE (1) BE423936A (en:Method)
FR (1) FR827499A (en:Method)
GB (1) GB484566A (en:Method)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2732513A (en) * 1952-01-31 1956-01-24 anderson
US2894166A (en) * 1949-04-02 1959-07-07 Heraeus Gmbh W C Heat radiation devices
US4810932A (en) * 1985-11-15 1989-03-07 General Electric Company Tungsten-halogen incandescent and metal vapor discharge lamps and processes of making such
US5045748A (en) * 1985-11-15 1991-09-03 General Electric Company Tungsten-halogen incandescent and metal vapor discharge lamps and processes of making such

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2894166A (en) * 1949-04-02 1959-07-07 Heraeus Gmbh W C Heat radiation devices
US2732513A (en) * 1952-01-31 1956-01-24 anderson
US4810932A (en) * 1985-11-15 1989-03-07 General Electric Company Tungsten-halogen incandescent and metal vapor discharge lamps and processes of making such
US5045748A (en) * 1985-11-15 1991-09-03 General Electric Company Tungsten-halogen incandescent and metal vapor discharge lamps and processes of making such

Also Published As

Publication number Publication date
BE423936A (en:Method)
GB484566A (en) 1938-05-05
FR827499A (fr) 1938-04-27

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