US3757158A - Sodium vapor lamp having a grooved alumina arc tube - Google Patents

Sodium vapor lamp having a grooved alumina arc tube Download PDF

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Publication number
US3757158A
US3757158A US00265523A US3757158DA US3757158A US 3757158 A US3757158 A US 3757158A US 00265523 A US00265523 A US 00265523A US 3757158D A US3757158D A US 3757158DA US 3757158 A US3757158 A US 3757158A
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United States
Prior art keywords
arc tube
lamp
tube
heater
wire
Prior art date
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Expired - Lifetime
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US00265523A
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English (en)
Inventor
B Kopelman
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.)
GTE Sylvania Inc
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GTE Sylvania Inc
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Publication date
Application filed by GTE Sylvania Inc filed Critical GTE Sylvania Inc
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Publication of US3757158A publication Critical patent/US3757158A/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
    • H01J61/54—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

  • the are tube of a sodium vapor arc discharge lamp has a spiral groove on the outer surface thereof.
  • a refractory metal wire heater is wound around the arc tube and seated in the groove in order to maintain uniform spacing between the turns of the heater throughout the life of the lamp.
  • 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 or 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.
  • the invention disclosed in the instant application is an improvement thereover in that means are provided for maintaining uniform spacing of the heater turns throughout lamp life.
  • a high pressure sodium vapor lamp in accordance with this invention comprises an alumina arc tube having electrodes at its ends and containing a fill including sodium, mercury and an inert gas.
  • the manufacture of such an arc tube is disclosed in U.S. Pat.'No. 3,026,210 to Coble, issued on Mar. 20, 1962, entitled Transparent Alumina And Method of Preparation.”
  • the arc tube has a spiral groove onits outer surface extending from about one end of the tube to the other or, at least, for a distance about equal to the electrode spacing.
  • the depth of the groove should be less than about one-third of the wall thickness of the arc tube in order to avoid weakening the arc tube.
  • a heater made of refractory metal wire. It is not necessary that the wire be completely seated in the groove; however, at least about half of the wire should be seated in order to obtain substantial improvement in turn spacing throughout lamp life. That is to say, the depth of the groove should be greater than about 50 percent of the diameter of the heater wire.
  • FIGURE of the drawing is an elevational view, partly in section, of a high pressure sodium vapor lamp in accordance with this invention.
  • a high pressure sodium vapor lamp in accordance with this invention comprises a conventional outer glass jacket 1 extending from a base 2.
  • a reentrant stem having a press 3 supports lead-in wires 4 and 6, the first of which is connected by strap 7 welded to lower niobium tube 8 of alumina arc tube 10.
  • the other lead-in wire 6 is connected by a weld to C-shaped frame 11 extending to about the top of the outer jacket 1.
  • Straps 14 are connected by welds between the top of the frame and upper niobium tube 9 of arc tube 10.
  • the lower and upper niobium tubes 8, 9 are connected to electrodes 16 within arc tube 10.
  • Spring fingers 12 engage jacket 1 positioning frame 11 and are tube 10.
  • a typical arc tube 10 for a 400 watt lamp is manufac tured of polycrystalline, high density, high purity alumina tubing resistant to sodium attack such as is described in previously mentioned U.S. Pat. No. 3,026,210.
  • the tube has a length of 4% inches with an outer diameter of 0.350 inches and a wall thickness of 0.030 inches.
  • the are tube has a gas fill argon at 23 torr, or xenon at 13 torr, and a chemical fill of 20 milligrams of mercury and 50 milligrams of mercurysodium amalgam, approximately 1 part sodium to 3 parts mercury by weight.
  • a refractory wire conductor 17 of ohmic heating material is in coiled form around and supported in contact with arc tube 10 throughout a major portion, or preferably as shown, throughout substantially the entire length of the arc discharge space between the electrodes 16.
  • the conductor is a tungsten filament, made of 3 mil wire, drawing watts at volt operation.
  • the turns of the coil may be spaced approximately one-eighth to one-half inch apart, the end turns being about one-fourth inch from end caps 5 of the arc tube.
  • the upper turn of filament 17 is welded to wire rod 18 which is insulatively supported on frame 11 by wires 19 separately imbedded in glass cylinders 21.
  • the electrical gap between rod 18 and frame 11 is completed at cold lamp temperature by bimetallic, thermostatic switch leaf 22 welded to rod 18 and contacting frame 11.
  • the lower turn of filament 17 is welded to rod 23 insulatively supported on lead-in wire 4.
  • One or both of the thermostatic switches may be replaced by a permanent connection, although with a loss of efficiency if both switches are omitted.
  • the thermostatic switches open the filament circuit after are igni tion and during normal lamp warm up and operation.
  • thermally responsive mechanical switch While a thermally responsive mechanical switch is shown, other switches such as switches responsive to arc starting temperature or arc operating voltage or current including solid state and gaseous discharge switches may be used.
  • Arc tube 10 has a spiral groove about 5 to mils deep extending along its outer surface in which heater 17 is seated.
  • the groove is readily formed in the arc tube, such as by machining on a lathe, when the arc tube is in its green, pre-sintered state. After grooving, the arc tube is sintered at the usual firing temperature of 1,700 to 1,950 C.
  • tube 10 it may be desirable to tie heater 17 in place on are tube 10 to ensure that the turns of the heater remain in place in the grooves.
  • Short lengths 25 of refractory metal wire are used for this purpose. The wire is tightly wrapped around the arc tube for one revolution and the ends thereof are twisted together to secure the wire against the arc tube.
  • tie wires are used at the center and ends of heater 17 as shown in the draw- 4 ing.
  • 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, said are tub having a spiral groove on its outer surface extending from about one electrode to the other; a heater or refractory metal wire wrapped around said are tube and seated in said groove; and a thermal switch disposed within aid envelope and electrically connected to one end of said heater.

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  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
US00265523A 1972-06-23 1972-06-23 Sodium vapor lamp having a grooved alumina arc tube Expired - Lifetime US3757158A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US26552372A 1972-06-23 1972-06-23

Publications (1)

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US3757158A true US3757158A (en) 1973-09-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00265523A Expired - Lifetime US3757158A (en) 1972-06-23 1972-06-23 Sodium vapor lamp having a grooved alumina arc tube

Country Status (4)

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US (1) US3757158A (de)
CA (1) CA983988A (de)
DE (1) DE2331905A1 (de)
GB (1) GB1429044A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3806748A (en) * 1973-03-08 1974-04-23 Gte Sylvania Inc Sodium vapor lamp having a grooved alumina arc tube with side rod heater retainer
US3806747A (en) * 1973-03-08 1974-04-23 Gte Sylvania Inc Sodium vapor lamp having an improved grooved alumina arc tube
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

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5267174A (en) * 1975-12-02 1977-06-03 Iwasaki Electric Co Ltd High voltage discharge lamp containing starter circuit
US4325004A (en) * 1980-10-02 1982-04-13 Gte Laboratories Incorporated Method and apparatus for starting high intensity discharge lamps

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3806748A (en) * 1973-03-08 1974-04-23 Gte Sylvania Inc Sodium vapor lamp having a grooved alumina arc tube with side rod heater retainer
US3806747A (en) * 1973-03-08 1974-04-23 Gte Sylvania Inc Sodium vapor lamp having an improved grooved alumina arc tube
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

Also Published As

Publication number Publication date
DE2331905A1 (de) 1974-01-10
CA983988A (en) 1976-02-17
GB1429044A (en) 1976-03-24

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