US3716744A - Hermetic end seals for envelope of a metal vapor lamp - Google Patents

Hermetic end seals for envelope of a metal vapor lamp Download PDF

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Publication number
US3716744A
US3716744A US00171578A US3716744DA US3716744A US 3716744 A US3716744 A US 3716744A US 00171578 A US00171578 A US 00171578A US 3716744D A US3716744D A US 3716744DA US 3716744 A US3716744 A US 3716744A
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US
United States
Prior art keywords
seal
envelope
metal
cap
stem
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
US00171578A
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English (en)
Inventor
A Delembre
G Jarrige
J Jarrige
D Nguyen
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.)
TDK Micronas GmbH
ITT Inc
Original Assignee
Deutsche ITT Industries GmbH
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
Application filed by Deutsche ITT Industries GmbH filed Critical Deutsche ITT Industries GmbH
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Publication of US3716744A publication Critical patent/US3716744A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/36—Seals between parts of vessels; Seals for leading-in conductors; Leading-in conductors
    • 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
    • H01J5/20—Seals between parts of vessels
    • H01J5/22—Vacuum-tight joints between parts of vessel
    • H01J5/26—Vacuum-tight joints between parts of vessel between insulating and conductive parts of vessel
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0033—Vacuum connection techniques applicable to discharge tubes and lamps
    • H01J2893/0037—Solid sealing members other than lamp bases
    • H01J2893/0041—Direct connection between insulating and metal elements, in particular via glass material

Definitions

  • ABSTRACT An alkali-metal-vapor discharge lamp has an inner vitreous material hermetic seal between an electrode stem and translucent tubular envelope and an outer metal seal between a metal end cap and the envelope. The cap is also sealed to the stem which extends from the tube.
  • the present invention relates to high-pressure alkalimetal vapor discharge lamps and particularly to highpressure sodium vapor lamps. More particularly, it relates to improvements in hermetic gas or vacuum tight seals which are made in manufacturing the lamps.
  • the high-pressure alkali-metal-vapor discharge lamps comprise tubes of translucent polycrystalline alumina resistant to high pressure alkali-metal vapors. Such a tube is closed at its ends by pieces of refractory material also resistant to alkali-metal vapors.
  • Pumping stems of refractory metal which are used as electrode supports and current leads for the electrodes, pass through the refractory material pieces.
  • a refractory metal is selected among the following metals and alloys thereof: niobium, zirconium, titanium, vanadium, tantalum, and preferably niobium and its well-known alloy with zirconium (1 percent).
  • the metal-alumina seal may be made either with eutectic mixtures of alumina and calcium oxide or a vitreous mixture of alumina, calcium oxide and magnesium oxide, or with active metals such as titanium, vanadium, zirconium or preferably combinations thereof.
  • vitreous seal materials may become devitrified, which is another cause of leakage.
  • active metal seals are used, they are made on the alumina tube end, which results in a short tight length compared with leakage line lengths, just a little longer than the tube thickness.
  • a discharge impact spot may be located on a metal seal part, which can cause leaks,
  • a purpose of the present invention is to provide a tight closure of the discharge area which does not present the above mentioned drawbacks.
  • tight sealing of the discharge area is obtained by proper sealing of the tube and electrode stem with two end seals at each end of the tube.
  • An outer end-seal is formed with a refractory metal cap sealed to the tube end by a combination of active metals and to the stem by brazing.
  • An inner endseal is formed by a ring of alumina sealed to the tube and to the stem by a vitreous mixture.
  • FIG. 1 shows a schematic cross-section view of one of the two ends of the discharge area before melting
  • FIG. 2 shows the same elements after melting.
  • FIG. 1 shows a schematic cross-section view of one end of the discharge tube before melting, the cross-section being obtained across a diametral plane.
  • the gas or vacuum tight closure of the translucent polycrystalline alumina tube or envelope 1 is formed by two endseals.
  • One end-seal 2 is made of a ring of highly pure alumina, which may be translucent or not.
  • the other end-seal 7 is a cap made of refractory metal, preferably of niobium or niobium alloy.
  • Those end-seals 2 and 7, through which the stem 4 passes, are sealed to the alumina tube 1 respectively by a ring 3 of vitreous material mainly constituted by alumina and calcium oxide, and by rings 10 of active metals such as titanium, vanadium and zirconium.
  • FIG. 1 also shows the electrode 5 secured to the stem 4 by a weld 9 made by any known process.
  • the hole 6 is provided for evacuating or filling the discharge area 11.
  • the assemblies are heated to a high temperature, under vacuum or inertgas-filled condition, to cause melting of the various rings.
  • the seals are as shown in the FIG. 2 which includes the same elements as in the FIG. 1, the same reference numbers being used in both figures.
  • the end-seal cap 7 may be sealed to the stem 4 by a seal 8 made according to any known process such as brazing, either before the ring melting operation, or at the same time.
  • the area 12 between the two seals is preferably evacuated or filled with an inert gas.
  • FIG. 2 shows that, after melting, the ring 3 is shaped as shown by 3 and forms a tight hermetic seal between the end-seal 2 and the tube 1, on the one hand, and between the end-seal 2 and the stem 4, on the other hand.
  • the rings 10 are then shaped as shown by 10 and form a tight seal between the tube 1 and the end-seal cap 7.
  • the seal temperature is lowered during operation which results in less severe thermal shocks during the life-time of the lamp
  • the seal is not in contact with alkali-metal vapor because the area 12 is evacuated or filled with inert gas, which reduces the risk of corrosion;
  • the invention may also be utilized in any case where alumina-metal seals are in contact with alkali-metal vapors.
  • a seal for a vapor discharge lamp comprising:
  • said first seal includes a ring of alumina and a vitreous mixture hermetically sealing said ring to said stem and envelope.
  • said second seal includes a ring of refractory metals selected from the group consisting of titanium, vanadium and zirconium.
  • said envelope is of poly-crystalline alumina and said vitreous sealing mixture includes a eutectic mixture of alumina and calcium oxide.

Landscapes

  • Vessels And Coating Films For Discharge Lamps (AREA)
US00171578A 1970-08-27 1971-08-13 Hermetic end seals for envelope of a metal vapor lamp Expired - Lifetime US3716744A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7031286A FR2102865A5 (enrdf_load_stackoverflow) 1970-08-27 1970-08-27

Publications (1)

Publication Number Publication Date
US3716744A true US3716744A (en) 1973-02-13

Family

ID=9060614

Family Applications (1)

Application Number Title Priority Date Filing Date
US00171578A Expired - Lifetime US3716744A (en) 1970-08-27 1971-08-13 Hermetic end seals for envelope of a metal vapor lamp

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US (1) US3716744A (enrdf_load_stackoverflow)
FR (1) FR2102865A5 (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2405335A1 (de) * 1973-02-16 1974-08-22 Philips Nv Hochdruckentladungslampe
US3832588A (en) * 1972-09-25 1974-08-27 Gen Electric Ceramic discharge lamp having metal end cap
US3916242A (en) * 1974-07-30 1975-10-28 Us Army Electrode seal and electrode mount for alkali-metal vapor lamps
EP0052843A1 (en) * 1980-11-21 1982-06-02 GTE Laboratories Incorporated Vacuum-tight assembly
EP0052844A1 (en) * 1980-11-21 1982-06-02 GTE Laboratories Incorporated Vacuum-tight assembly
US5620349A (en) * 1991-12-11 1997-04-15 Osram Sylvania Inc. Method for amalgam relocation in an arc discharge tube

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3363133A (en) * 1966-02-28 1968-01-09 Sylvania Electric Prod Electric discharge device having polycrystalline alumina end caps
US3448319A (en) * 1966-10-31 1969-06-03 Gen Electric Niobium end seal
US3473071A (en) * 1965-10-25 1969-10-14 Gen Electric Co Ltd Electric discharge lamps

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3473071A (en) * 1965-10-25 1969-10-14 Gen Electric Co Ltd Electric discharge lamps
US3363133A (en) * 1966-02-28 1968-01-09 Sylvania Electric Prod Electric discharge device having polycrystalline alumina end caps
US3448319A (en) * 1966-10-31 1969-06-03 Gen Electric Niobium end seal

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3832588A (en) * 1972-09-25 1974-08-27 Gen Electric Ceramic discharge lamp having metal end cap
DE2405335A1 (de) * 1973-02-16 1974-08-22 Philips Nv Hochdruckentladungslampe
US3916242A (en) * 1974-07-30 1975-10-28 Us Army Electrode seal and electrode mount for alkali-metal vapor lamps
EP0052843A1 (en) * 1980-11-21 1982-06-02 GTE Laboratories Incorporated Vacuum-tight assembly
EP0052844A1 (en) * 1980-11-21 1982-06-02 GTE Laboratories Incorporated Vacuum-tight assembly
US5620349A (en) * 1991-12-11 1997-04-15 Osram Sylvania Inc. Method for amalgam relocation in an arc discharge tube
US6100634A (en) * 1991-12-11 2000-08-08 Gte Products Corporation Method for amalgam relocation in an arc discharge tube

Also Published As

Publication number Publication date
FR2102865A5 (enrdf_load_stackoverflow) 1972-04-07

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