US3721845A - Sodium vapor lamp having improved starting means - Google Patents

Sodium vapor lamp having improved starting means Download PDF

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Publication number
US3721845A
US3721845A US00267097A US3721845DA US3721845A US 3721845 A US3721845 A US 3721845A US 00267097 A US00267097 A US 00267097A US 3721845D A US3721845D A US 3721845DA US 3721845 A US3721845 A US 3721845A
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United States
Prior art keywords
heater
lamp
arc tube
wire
electrode
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Expired - Lifetime
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US00267097A
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English (en)
Inventor
D Richardson
S Cohen
J Gutta
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GTE Sylvania Inc
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GTE Sylvania Inc
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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
    • H01J61/54—Igniting arrangements, e.g. promoting ionisation for starting
    • H01J61/541—Igniting arrangements, e.g. promoting ionisation for starting using a bimetal switch
    • H01J61/544—Igniting arrangements, e.g. promoting ionisation for starting using a bimetal switch and an auxiliary electrode outside the vessel

Definitions

  • ABSTRACT 5 Claims 1 Drawing Figure SODIUM VAPOR LAMP HAVING IMPROVED STARTING MEANS BACKGROUND OF THE INVENTION Field of the Invention
  • This invention relates to are discharge lamps and, in particular, to high pressure sodium vapor lamps.
  • Such lamps are called high pressure in order to distinguish them from low pressure sodium vapor lamps in which the sodium operating vapor pressure is in the order of a few microns.
  • Low pressure sodium lamps have been in use for about thirty to forty years, but, although efficient, they produce an unattractive monochromatic yellow light. The color of light from high pressure sodium lamps is considerably improved over that from low pressure sodium lamps.
  • High pressure sodium lamps generally comprise an alumina ceramic arc tube and an arc tube fill of sodium, mercury and an inert gas. Examples of such lamps are shown in the following U.S. Pat. Nos. 3,248,590; 3,384,798; 3,448,319; 3,453,477; 3,485,343; 3,519,406; 3,521,108; 3,558,963.
  • One of the problems of high pressure sodium arc discharge lamps relates to the starting thereof. Such lamps require a considerably higher starting voltage to initiate an arc discharge than do other types of arc discharge lamps, such as fluorescent, mercury or metal halide. This higher starting voltage requirement necessitates the use of a special ballast for high pressure sodium lamps.
  • a simpler more economical ballasting arrangement becomes quite practicable and, in fact, conventional mercury lamp ballasts can often be used.
  • copending application Ser. No. 214,000, filed l2307l, entitled Arc Discharge Tube With Surrounding Starting Coil and assigned to the same assignee as the instant application the invention disclosed in the instant application differs from that in said copending application.
  • a high pressure sodium vapor lamp in accordance with this invention comprises an arc tube having electrodes at its ends and containing a fill including sodium, mercury and an inert gas. Adjacent the arc tube is a coiled heater made of refractory metal wire, such as tungsten, mounted on an insulating support rod which is substantially parallel to the arc tube.
  • the wattage and spacing of the heater are such that the heater will heat up the arc tube sufficiently in less than about three or four minutes to permit ignition thereof by a relatively low voltage between the electrodes.
  • the relatively low voltage about 220 volts for an existing 400 watt design, is in relation to the approximate 2 kilovolt pulse that is normally needed to initiate the arc discharge in a high pressure sodium lamp and which high voltage pulse requires a special ballast.
  • the starting voltage can be reduced even more, as low as about volts for said 400 watt design, by connecting one end of the heater to a wire wrapped around the arc tube proximate the electrode at the opposite end. Said wire reduces the length of the arc discharge starting gap to the distance between the electrode and the outer surface of the arc tube, in contrast to the usual gap which is the distance between electrodes.
  • the insulating rod is made of high temperature material, such as ceramic, because of its close proximity to the arc tube. Also, the diameter of the insulating rod should be less than about 40 percent the diameter of the arc tube in order that the amount of light intercepted and blocked by the insulating rod be small in relation to the total light output from the arc tube.
  • the tungsten heater is electrically connected to a thermal switch that opens and removes the heater from the circuit after the arc has been struck between the electrodes.
  • FIGURE in the drawing is an elevational view, partly broken away, of a high pressure sodium vapor lamp in accordance with this invention.
  • a high pressure sodium vapor lamp in accordance with this invention comprises an outer glass envelope 1 which can be of elongated ovoid shape, such as is commonly used in high pressure sodium lamps, or of bulbous shape, such as is commonly used in mercury vapor and metal halide lamps.
  • the neck of the envelope is closed by a reentrant stem 2 having a press 3 through which extend stiff lead-in wires 4,5 connected at their outer ends to a threaded shell 6 and center contact 7 of a conventional screw base.
  • alumina arc tube 8 Disposed within envelope 1 is an alumina arc tube 8 sealed at its lower end by niobium end cap 9 and at its upper end by niobium end cap 10.
  • Niobium tubes 11,12 are brazed or welded to end caps 9,10 and are used to support are tube 8 as well as to conduct current to electrodes 13,14 within the arc tube.
  • one of the niobium tubes serves as an exhaust tube during manufacture and is used to introduce a fill including an inert gas (e.g. argon or xenon), sodium and mercury into the arc tube, after which the niobium tube is sealed, such as by a cold weld.
  • an inert gas e.g. argon or xenon
  • Arc tube 8 is supported within envelope 1 by a structure consisting of side support wire 15, vertical support wire 16, metal strap 17 and horizontal metal strap 18. Support wire 15 is welded to lead-in wire 5, support wire 16 is welded to wire 15, strap 17 is welded to wire 16, strap 18 is welded to strap 17 and strap 18 is connected to upper niobium tube 12. Electrical connection between lead-in wire 5 and upper electrode 14 is established by said structure.
  • arc tube 8 The lower end of arc tube 8 is supported by metal strap 19 which is connected between niobium tube 11 and support wire 27, with support wire 27 being welded to lead-in wire 4. Electrical connection is also established thereby between lead-in wire 4 and lower electrode 13.
  • a coiled coil heater Disposed parallel to are tube 8, and spaced about one-sixteenth inch therefrom is a coiled coil heater which is made of a length of 4 mil tungsten wire primary coiled on an 8 mil mandrel and then secondary coiled on an alumina rod 21 having a diameter of three thirty-seconds inch.
  • the ends of rod 21 are supported by straps 18,19.
  • the lower end of heater 20 is electrically connected directly to strap 19.
  • electrical connection to the upper end of heater 20 is established through a bimetallic switch 22.
  • the upper end of heater 20 is connected to a metal strap 23 which tightly encircles rod 21 and which is connected to a vertical metal post 24.
  • Post 24 is insulatively supported on side wire 15 by means of glass rod 25.
  • One end of switch 22 makes electrical contact with post 24 and the other end of switch 22 is welded to vertical wire 16.
  • spring fingers 26 Attached to the upper and lower ends of side wire 15 are spring fingers 26 which press against the interior wall of envelope 1 and provide increased support for the arc tube.
  • Loops 28 are joined by a wire 29 which is connected to the lower end of heater 20 at strap 19.
  • This structure establishes the outer surface of the arc tube around upper electrode 14 at the same potential as the lower end of heater 20.
  • a high pressure sodium vapor lamp comprising: a glass envelope; an alumina arc tube disposed within said envelope and having electrodes sealed therein at the ends thereof and containing a filling including sodium, mercury and an inert gas; a heater disposed parallel to said are tube and closely spaced therefrom said heater comprising refractory metal wire coiled around an insulating rod; a wire loop encircling said are tube near one electrode, said loop being connected to said heater at the end opposite said one electrode; and a thermal switch disposed within said envelope and electrically connected to one end of said heater.
  • the lamp of claim 1 comprising two additional wire loops, one encircling the arc tube at about its center and the other encircling the arc tube proximate the otherelectrode.

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  • Discharge Lamps And Accessories Thereof (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
US00267097A 1972-06-28 1972-06-28 Sodium vapor lamp having improved starting means Expired - Lifetime US3721845A (en)

Applications Claiming Priority (1)

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US26709772A 1972-06-28 1972-06-28

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US3721845A true US3721845A (en) 1973-03-20

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US (1) US3721845A (en, 2012)
JP (1) JPS4964276A (en, 2012)
CA (1) CA983987A (en, 2012)
GB (1) GB1424447A (en, 2012)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3872340A (en) * 1974-05-28 1975-03-18 Gen Electric High temperature lamp starting aid
US3900753A (en) * 1974-05-23 1975-08-19 Gte Sylvania Inc High pressure sodium vapor lamp having low starting voltage
US4037129A (en) * 1976-03-10 1977-07-19 Gte Sylvania Incorporated High pressure sodium vapor lamp having low starting voltage
US4039880A (en) * 1975-01-17 1977-08-02 U.S. Philips Corporation Method of operating a self-stabilizing discharge lamp
US4179640A (en) * 1977-12-05 1979-12-18 Westinghouse Electric Corp. Hid sodium lamp which incorporates a high pressure of xenon and a trigger starting electrode
US4316122A (en) * 1979-10-03 1982-02-16 Matsushita Electronics Corporation High pressure sodium vapor discharge lamp

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62198046A (ja) * 1986-02-25 1987-09-01 Nissan Motor Co Ltd 車両用前照灯

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2765416A (en) * 1953-09-24 1956-10-02 Westinghouse Electric Corp Vapor lamps utilizing chemical compounds

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2765416A (en) * 1953-09-24 1956-10-02 Westinghouse Electric Corp Vapor lamps utilizing chemical compounds

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3900753A (en) * 1974-05-23 1975-08-19 Gte Sylvania Inc High pressure sodium vapor lamp having low starting voltage
US3872340A (en) * 1974-05-28 1975-03-18 Gen Electric High temperature lamp starting aid
US4039880A (en) * 1975-01-17 1977-08-02 U.S. Philips Corporation Method of operating a self-stabilizing discharge lamp
US4037129A (en) * 1976-03-10 1977-07-19 Gte Sylvania Incorporated High pressure sodium vapor lamp having low starting voltage
DE2710179A1 (de) * 1976-03-10 1977-09-29 Gte Sylvania Inc Hochdrucknatriumdampflampe mit niedriger zuendspannung
US4179640A (en) * 1977-12-05 1979-12-18 Westinghouse Electric Corp. Hid sodium lamp which incorporates a high pressure of xenon and a trigger starting electrode
US4316122A (en) * 1979-10-03 1982-02-16 Matsushita Electronics Corporation High pressure sodium vapor discharge lamp

Also Published As

Publication number Publication date
GB1424447A (en) 1976-02-11
CA983987A (en) 1976-02-17
JPS4964276A (en, 2012) 1974-06-21

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