US3851207A - Stabilized high intensity sodium vapor lamp - Google Patents

Stabilized high intensity sodium vapor lamp Download PDF

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Publication number
US3851207A
US3851207A US00277095A US27709572A US3851207A US 3851207 A US3851207 A US 3851207A US 00277095 A US00277095 A US 00277095A US 27709572 A US27709572 A US 27709572A US 3851207 A US3851207 A US 3851207A
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Prior art keywords
lamp
emissive
turns
envelope
resistive heater
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Expired - Lifetime
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US00277095A
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English (en)
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C Mcvey
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General Electric Co
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General Electric Co
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Priority to US00277095A priority Critical patent/US3851207A/en
Priority to JP48080528A priority patent/JPS5241983B2/ja
Priority to FR7327981A priority patent/FR2195065B1/fr
Application granted granted Critical
Publication of US3851207A publication Critical patent/US3851207A/en
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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
    • H01J61/24—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J61/28—Means for producing, introducing, or replenishing gas or vapour during operation of the lamp
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H01J61/06—Main electrodes
    • H01J61/073—Main electrodes for high-pressure discharge lamps
    • H01J61/0732—Main electrodes for high-pressure discharge lamps characterised by the construction of the electrode

Definitions

  • the invention relates to high intensity metal vapor arc lamps utilizing a slender tubular ceramic envelope, and more particularly to high intensity sodium vapor lamps of the kind described in U.S. Pat. No. 3,248,590 to Schmidt, entitled High Pressure Sodium Vapor Lamp.
  • Such lamps utilize an elongated inner envelope of ceramic material resistant to the attack of sodium at high temperatures, such as a high density polycrystalline alumina tube, for containing the arc discharge.
  • the filling comprises an amalgam of sodium and mercury and a rare gas, preferably xenon, to facilitate starting.
  • the ends of the alumina tube are sealed by suitable closure members such as caps or plugs which carry the electrodes between which the discharge passes in operation.
  • suitable closure members such as caps or plugs which carry the electrodes between which the discharge passes in operation.
  • One construction utilizes a refractory metal closure member comprising an end cap of niobium whose coefficient of expansion is close to that of alumina and which serves as an electrical inlead and supports an electrode internally.
  • the ceramic arc tube is supported within an outer vitreous envelope or jacket having at one end a screw base providing terminals to which the end caps of the arc tube are connected.
  • the jacket is evacuated in order to conserve heat and maintain the arc tube at a sufi'iciently high temperature.
  • the high pressure sodium vapor lamp has a relatively I high starting voltage due in part to the small diameter of the arc tube and in part to the use of xenon as a starting gas. Also the metal end caps used for the arc tube closures do not lend themselves conveniently to the incorporation of an auxiliary starting electrode.
  • a ballast circuit is generally used which supplies high voltage pulses near the peak of the open circuit waveform until the lamp ignites. When the lamp starts, the reduction in voltage at the lamp terminals from the open circuit value to the lamp running value disables the pulsing circuit until the next time the lamp is started.
  • High intensity sodium vapor lamps of the present kind containing an excess of sodium-mercury amalgam typically have an arc voltage drop which increases as the lamp ages.
  • the voltage rise with life which is characteristic of this lamp is due to the conjunction of several factors.
  • deposits of emission material and tungsten from the electrodes on the arc tube walls of relatively small diameter entail rapid darkening in the vicinity of the electrodes.
  • the darkened walls absorb more energy causing the ends of the lamp to run even hotter.
  • the lamp contains an excess of sodium mercury amalgam and the vapor pressure in the arc tube is determined primarily by the temperature at the lower end where the excess amalgam collects as a liquid pool.
  • the rise in vapor pressure is extremely rapid in relation to the rise in temperature of the liquid pool.
  • the black deposits on the walls also'tend to hold amalgam by surface tension effect and this further accentuates the rise in vapor pressure with life.
  • a reduced voltage rise characteristic makes the lamp less sensitive to transients such as lightning strokes, less likely to drop out on a line voltage dip. It also reduces variations in light output and color with line voltage.
  • the high intensity sodium vapor lamp by reason of the slendemess of its arc tube, is particularly suitable for use in compact fixtures or luminaires designed to provide a precise lighting pattern.
  • the sensitivity of the lamp, in respect of the arc voltage drop, to the temperature of the liquid amalgam pool has been a decided drawback in such applications. For instance it has been necessary to avoid passing reflected radiation back through the arc tube and to avoid directing radiation at the lower closure in which the liquid amalgam pool collects.
  • the object of the invention is a high intensity sodium vapor lamp which is improved with respect to the voltage rise characteristic.
  • the voltage rise characteristic of the high intensity sodium vapor lamp is greatly reduced and the tolerance of the lamp to external conditions is improved by incorporating in the electrode at the lower end of the arc tube a resistive heater portion through which lamp current is caused to flow.
  • Lamp current flowing through the heater portion provides supplementary heat to the amalgam pool which, at constant heater resistance, is proportional to the square of the lamp current.
  • the rise in resistance of the heater with temperature due to the positive temperature coefficient of resistance of tungsten is also in a direction to increase the heating. This stabilizes the cold spot temperature and amalgam vapor pressure and counters the tendency to are voltage rise with life. It also reduces the sensitivity of the lamp to radiant energy reflected back from the fixture.
  • FIG. 1 illustrates a jacketed high pressure sodium vapor lamp embodying the invention.
  • FIG. 2 is a sectioned view of the lower end of the arc tube to a larger scale showing the construction of the electrode with integral heater portion.
  • FIG. 3 is a graph showing the lamp wattage versus lamp voltage characteristic for a typical ballast-lamp combination.
  • FIG. 1 A high intensity sodium vapor discharge lamp 11 in which the invention is embodied is illustrated in FIG. 1 and comprises an outer vitreous envelope or jacket 2 of elongated ovoid shape.
  • the neck 3 of the jacket is closed by re-entrant stem 4 terminated in a press 5 through which extend stiff inleads or current conductors 6, 7 which are connected to the threaded shell 8 and insulated center contact 9 of a conventional mogul screw base.
  • the inner envelope or are tube 11 is made of sintered high density polycrystalline alumina ceramic per U.S. Pat. No. 3,026,210 to Coble, Transparent Alumina and Method of Preparation, or of other lighttransmitting ceramic capable of withstanding the attack of sodium vapor at high temperatures.
  • the ends of the tube are closed by thimbIe-like niobium metal end caps 12, 13 hermetically sealed to the alumina by means of a sealing composition comprising a major proportion of aluminum oxide and calcium oxide and a minor proportion of magnesium oxide and barium oxide.
  • Thermionic electrodes are mounted in the ends of the arc tubes and supported from the end caps.
  • Upper electrode 15 is conventional and comprises for instance a double layer tungsten wire coil or helix i6 wound around a tungsten shank or core 17 extending from a niobium tube 18 welded through the end cap.
  • the electrode is activated by metal oxides retained in the interstices between turns of the coil, the preferred material being dibarium calcium tungstate Ba CaWO described and claimed in the previously referred to copending application of William E. Smyser et al.
  • Upper niobium tube 18 has an opening into the arc tube and may contain a small quantity of yttrium metal which serves as a brazing material to assure a hermetic seal where the tungsten shank l7 penetrates the niobium tube. By so doing, the pinch 19 at the upper end of the niobium tube need not be hermetic.
  • Electrode 20 at the lower end of the arc tube is best seen in FIG. 2. It comprises the electrode portion proper wherein tungsten wire is wound around a tungsten stud 21 in two layers of close wound turns 22 and continued in spread or spaced turns 23. The bottom turn 24 of the spaced turns is seized in the outspread end of the niobium exhaust tube 25 which is folded over the turn to provide a mechanical lock. Since niobium had a greater expansion coefficient than tungsten, the joint tightens when the lamp heats up and also some diffusion bonding takes place.
  • the electrode portion proper consists of the tungsten stud 21 and the two close wound layers of tungsten wire turns which form a compact body.
  • the electrode is activated by metal oxides retained in the interstices between turns in the same fashion as for the upper electrode, preferably utilizing dibarium calcium tungstate Ba CaWO Lower niobium tube 25 is pierced through at 26 to allow its use as an exhaust tube during manufacture.
  • exhaust tube 25 is hermetically pinched off by a cold weld indicated at 27 and serves thereafter as a reservoir for the excess of condensed sodium-mercury amalgam which forms a liquid pool during operation.
  • the illustrated lamp is intended for baseup operation wherein the longer niobium tube 25 which must be the coolest portion of the arc tube for the excess amalgam to condense therein, is located lowermost.
  • the arc tube is reversed relative to the outer jacket.
  • the are tube is supported within the outer envelope by means of a mount comprising a single side rod 29 which extends the length of the envelope from inlead 6 at the stem end to a dimple 30 at the dome end to which it is anchored by a resilient clamp 31.
  • End cap 13 of the arc tube is connected to the frame by band 32 welded to expansion strap 33 while end cap 12 is connected to inlead 6 through band 34 and connecting rod 35.
  • the interenvelope space Prior to sealing off the outer jacket, the interenvelope space is desirably evacuated in order to reduce the heat loss from the arc tube during operation.
  • a getter, for instance barium aluminum alloy powder pressed into channeled rings 36 is flashed after sealing in order to assure a high vacuum.
  • the heater portion of the lower electrode consisting of the spaced turns 23 serves as a supplementary heat source to the liquid amalgam pool regulating its temperature, and thereby its vapor pressure and the lamp operating voltage.
  • the common sizes of high intensity sodium vapor lamps presently available are 250 watts, 400 watts and 1000 watts.
  • the heater portion of the electrode is designed to have an ohmic dissipation in the range from 0.5 to 10.0 watts depending upon the size of lamp for which it is'intended.
  • the lamp should preferably be designed to operate somewhat near the peak in the lamp wattage versus lamp voltage curve of the ballast and lamp combinations.
  • a typical curve is shown in FIG. 3 wherein maximum power transfer occurs when the voltage drop across the lamp load is about percent of line voltage, as is conventional with a generator having internal reactance and supplying energy to a substantially resistive load.
  • the arc tube is 7.24 millimeters in internal diameter and 112 millimeters long.
  • the dose consists of about 54 milligrams of sodium mercury amalgam made up of 14 mg. of sodium and 40 mg. of mercury, and results in about torr P and 290 torr P for an appendix control temperature of about 675C.
  • the lamp operates at about 400 watts with an efiicacy of about lumens per watt.
  • tungsten stud 21 is 0.057 inch in diameter and 0.240 inch long.
  • the coiling consists of 0.020 inch tungsten 218 wire whereof two layers of turns each are close wound 0.200 inch high for portion 22, and 10 turns are space wound 0.300 inch high at 0.135 inch internal diameter for spread turns 23.
  • heater portion 23 of the electrode produced about 4 watts of ohmic dissipation.
  • the regulatory effect of this supplemental heat was demonstrated by a comparison test with a conventional high pressure sodium production lamp of 400 watt size.
  • the production lamp was operated with a simple inductive reactor ballast in an open socket without reflector at 102 volts arc drop.
  • An aluminum foil reflector was then placed about the production lamp to simulate a compact fixture which would reflect radiation on the arc tube and on the lower closure, and the arc drop voltage rose to 180 volts.
  • the test was then repeated with the lamp of this invention which operated in the open socket at an arc drop voltage of 95 volts at 400 watts input.
  • the addition of the same aluminum foil reflector caused an increase in arc drop voltage to only 130 volts at the same wattage.
  • a 400 watt production lamp and the present lamp embodying the invention were operated in turn on an unmodified commerically available ballast for 400 watt high pressure sodium lamps (LU-400) having a maximum sustaining voltage of only 140 volts.
  • the test was conducted with and without the aluminum foil reflector on both lamps operated successively. With the foil reflector, the reflected energy raised the voltage of the production lamp beyond the maximum sustaining voltage of the ballast and the lamp extinguished.
  • the stabilized lamp of the invention having ohmic regulation could not be extinguished through the use of the foil reflector on the same ballast. Both lamps were photometered at 400 watts and each produced about 120 lumens per watt.
  • a high intensity sodium vapor stabilized discharge lamp comprising a slender tubular ceramic envelope, closures sealing the ends of said envelope, electrodes in opposite ends of said envelope, a filling of sodium, mercury, and inert gas within said envelope, said lamp containing in operation an excess pool of sodium-mercury amalgam at the lower end, the lower electrode comprising an electron-emissive portion and a resistive heater portion interposed between the emissive portion and the lower closure and through which lamp current flows to reach the emissive portion, said resistive heater portion being supported by the lower closure and supporting the emissive portion.
  • a high intensity sodium vapor stabilized discharge lamp comprising a slender tubular ceramic envelope, closures sealing the ends of said envelope, at least one of said closures including a metal exhaust tube sealed at the outer end and projecting inwardly into said envelope, electrodes supported from said closures at opposite ends of said envelope, a filling of sodium, mercury, and inert gas within said envelope, the closure at the lower end of said envelope containing in operation an excess pool of sodium mercury amalgam, the lower electrode comprising an electron-emissive portion and a resistive heater portion interposed between the emissive portion and the lower closure, said resistive heater portion supporting the emissive portion and being attached to and supported by the inwardly projecting metal tube of the lower closure so that lamp current must flow through the resistive portion to reach the emissive portion.
  • a lamp as in claim 5 wherein the emissive portion of the lower electrode comprises axially wound close turns of tungsten wire activated with electron-emissive metal oxides coated thereon and lodged in the interstices between turns, and the resistive heater portion comprises axially wound spaced turns of tungsten wire.

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  • Vessels And Coating Films For Discharge Lamps (AREA)
US00277095A 1972-08-01 1972-08-01 Stabilized high intensity sodium vapor lamp Expired - Lifetime US3851207A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US00277095A US3851207A (en) 1972-08-01 1972-08-01 Stabilized high intensity sodium vapor lamp
JP48080528A JPS5241983B2 (ro) 1972-08-01 1973-07-19
FR7327981A FR2195065B1 (ro) 1972-08-01 1973-07-31

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US00277095A US3851207A (en) 1972-08-01 1972-08-01 Stabilized high intensity sodium vapor lamp

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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4182976A (en) * 1978-07-07 1980-01-08 Westinghouse Electric Corp. High pressure sodium vapor lamp with voltage rise compensator
EP0017281A1 (en) * 1979-04-03 1980-10-15 Koninklijke Philips Electronics N.V. High-pressure discharge lamp
US4367432A (en) * 1979-04-03 1983-01-04 U.S. Philips Corporation Blended lamp
US4442378A (en) * 1982-07-30 1984-04-10 General Electric Company High pressure sodium vapor lamp having resistance heater means
US4442379A (en) * 1982-07-30 1984-04-10 General Electric Company High pressure sodium vapor lamp having resistance heater means
DE3240359A1 (de) * 1982-11-02 1984-05-03 W.C. Heraeus Gmbh, 6450 Hanau "elektrode fuer laseranregungslampen"
US4459513A (en) * 1982-07-30 1984-07-10 General Electric Company High pressure sodium vapor lamp having resistance heater means
US4621216A (en) * 1983-04-22 1986-11-04 U.S. Philips Corporation High-pressure discharge lamp with shielded electrode
EP0204382A1 (en) * 1985-06-05 1986-12-10 Koninklijke Philips Electronics N.V. High-pressure sodium discharge lamp
EP0269957A2 (de) * 1986-12-01 1988-06-08 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Einseitig gequetschte Hochdruckentladungslampe
US6100634A (en) * 1991-12-11 2000-08-08 Gte Products Corporation Method for amalgam relocation in an arc discharge tube
US20060267495A1 (en) * 2003-04-03 2006-11-30 Light Sources, Inc. Germicidal low pressure mercury vapor discharge lamp with amalgam location and temperature control permitting high output
WO2007091187A1 (en) * 2006-02-10 2007-08-16 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp with amalgam
WO2008009571A2 (de) * 2006-07-20 2008-01-24 Osram Gesellschaft mit beschränkter Haftung Beleuchtungssystem mit einer entladungslampe und einem elektronischen vorschaltgerät und verfahren zum betreiben eines beleuchtungssystems
WO2011124310A1 (de) * 2010-04-06 2011-10-13 Heraeus Noblelight Gmbh Verfahren zum betreiben einer amalgamlampe
US20150008821A1 (en) * 2013-07-03 2015-01-08 General Electric Company Hermetically sealed ceramic discharge lamps

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2208998A (en) * 1936-11-13 1940-07-23 Gen Electric Electric lamp
US2217438A (en) * 1937-10-18 1940-10-08 Gen Electric Electrode for high-pressure mercury-vapor discharge device
US3113234A (en) * 1960-12-27 1963-12-03 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Discharge lamp with magnetic stabilization
US3349276A (en) * 1964-09-30 1967-10-24 Philips Corp High-pressure mercury vapor halogen lamp having an electrode thermally insulated from lead-in conductor
US3384798A (en) * 1966-04-26 1968-05-21 Gen Electric High pressure saturation vapor sodium lamp containing mercury

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB513321A (en) * 1938-04-01 1939-10-10 Siemens Electric Lamps & Suppl Improvements in or relating to electric discharge lamps
GB1071102A (en) * 1963-08-16 1967-06-07 Sylvania Electric Prod Electric discharge lamp
FR1467482A (fr) * 1966-02-05 1967-01-27 Duro Test Corp Lampe à arc à stabilisateur incorporé

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2208998A (en) * 1936-11-13 1940-07-23 Gen Electric Electric lamp
US2217438A (en) * 1937-10-18 1940-10-08 Gen Electric Electrode for high-pressure mercury-vapor discharge device
US3113234A (en) * 1960-12-27 1963-12-03 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Discharge lamp with magnetic stabilization
US3349276A (en) * 1964-09-30 1967-10-24 Philips Corp High-pressure mercury vapor halogen lamp having an electrode thermally insulated from lead-in conductor
US3384798A (en) * 1966-04-26 1968-05-21 Gen Electric High pressure saturation vapor sodium lamp containing mercury

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4182976A (en) * 1978-07-07 1980-01-08 Westinghouse Electric Corp. High pressure sodium vapor lamp with voltage rise compensator
EP0017281A1 (en) * 1979-04-03 1980-10-15 Koninklijke Philips Electronics N.V. High-pressure discharge lamp
US4367432A (en) * 1979-04-03 1983-01-04 U.S. Philips Corporation Blended lamp
US4442378A (en) * 1982-07-30 1984-04-10 General Electric Company High pressure sodium vapor lamp having resistance heater means
US4442379A (en) * 1982-07-30 1984-04-10 General Electric Company High pressure sodium vapor lamp having resistance heater means
US4459513A (en) * 1982-07-30 1984-07-10 General Electric Company High pressure sodium vapor lamp having resistance heater means
DE3240359A1 (de) * 1982-11-02 1984-05-03 W.C. Heraeus Gmbh, 6450 Hanau "elektrode fuer laseranregungslampen"
US4621216A (en) * 1983-04-22 1986-11-04 U.S. Philips Corporation High-pressure discharge lamp with shielded electrode
EP0204382A1 (en) * 1985-06-05 1986-12-10 Koninklijke Philips Electronics N.V. High-pressure sodium discharge lamp
EP0269957A2 (de) * 1986-12-01 1988-06-08 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Einseitig gequetschte Hochdruckentladungslampe
EP0269957A3 (en) * 1986-12-01 1989-10-18 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh High-pressure discharge lamp having a single pinch
US6100634A (en) * 1991-12-11 2000-08-08 Gte Products Corporation Method for amalgam relocation in an arc discharge tube
US20060267495A1 (en) * 2003-04-03 2006-11-30 Light Sources, Inc. Germicidal low pressure mercury vapor discharge lamp with amalgam location and temperature control permitting high output
US7816849B2 (en) * 2003-04-03 2010-10-19 Light Sources, Inc. Germicidal low pressure mercury vapor discharge lamp with amalgam location and temperature control permitting high output
US20090026965A1 (en) * 2006-02-10 2009-01-29 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp with amalgam
US8018130B2 (en) 2006-02-10 2011-09-13 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp with amalgam
WO2007091187A1 (en) * 2006-02-10 2007-08-16 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp with amalgam
EP2447981A1 (en) * 2006-02-10 2012-05-02 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp with amalgam, lamp system, water treatment system, use of a lamp system
CN101490796B (zh) * 2006-07-20 2012-07-04 欧司朗股份有限公司 带有放电灯和电子镇流器的照明系统以及用于驱动照明系统的方法
WO2008009571A2 (de) * 2006-07-20 2008-01-24 Osram Gesellschaft mit beschränkter Haftung Beleuchtungssystem mit einer entladungslampe und einem elektronischen vorschaltgerät und verfahren zum betreiben eines beleuchtungssystems
WO2008009571A3 (de) * 2006-07-20 2008-03-20 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Beleuchtungssystem mit einer entladungslampe und einem elektronischen vorschaltgerät und verfahren zum betreiben eines beleuchtungssystems
WO2011124310A1 (de) * 2010-04-06 2011-10-13 Heraeus Noblelight Gmbh Verfahren zum betreiben einer amalgamlampe
CN102812535A (zh) * 2010-04-06 2012-12-05 赫罗伊斯诺布尔莱特股份有限公司 用于运行汞齐灯的方法
US9048083B2 (en) 2010-04-06 2015-06-02 Heraeus Noblelight Gmbh Method for operating an amalgam lamp
CN102812535B (zh) * 2010-04-06 2015-11-25 赫罗伊斯诺布尔莱特股份有限公司 用于运行汞齐灯的方法
US20150008821A1 (en) * 2013-07-03 2015-01-08 General Electric Company Hermetically sealed ceramic discharge lamps

Also Published As

Publication number Publication date
JPS5241983B2 (ro) 1977-10-21
JPS4945578A (ro) 1974-05-01
FR2195065B1 (ro) 1976-11-12
FR2195065A1 (ro) 1974-03-01

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