US3840768A - High intensity lamp with cermet igniter - Google Patents

High intensity lamp with cermet igniter Download PDF

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Publication number
US3840768A
US3840768A US00279548A US27954872A US3840768A US 3840768 A US3840768 A US 3840768A US 00279548 A US00279548 A US 00279548A US 27954872 A US27954872 A US 27954872A US 3840768 A US3840768 A US 3840768A
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US
United States
Prior art keywords
igniter
main electrode
electrode
tungsten
lamp
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
US00279548A
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English (en)
Inventor
J White
R Smialek
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
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 General Electric Co filed Critical General Electric Co
Priority to US00279548A priority Critical patent/US3840768A/en
Priority to JP48080404A priority patent/JPS4945580A/ja
Priority to GB3587073A priority patent/GB1427598A/en
Priority to FR7328290A priority patent/FR2195843B1/fr
Priority to BE134196A priority patent/BE803175A/xx
Priority to DE19732340126 priority patent/DE2340126C3/de
Priority to NL7310965A priority patent/NL7310965A/xx
Application granted granted Critical
Publication of US3840768A publication Critical patent/US3840768A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J61/545—Igniting arrangements, e.g. promoting ionisation for starting using an auxiliary electrode inside the vessel

Definitions

  • ABSTRACT A high intensity metal vapor electric discharge lamp having self-heating main electrodes at opposite ends and a starter electrode at one end.
  • a cermet igniter comprising a sintered mixture of metal and refractory or emissive metal oxide is attached to and spaced close to the main electrode at the end having the starter electrode.
  • the igniter operates as much as 1,000C. cooler than the main electrode and retains its emission material throughout life.
  • a glow or are initiated-on it readily transfers to the main electrode. It serves to reduce the starting voltage or prevent rise in starting voltage in seasoned lamps.
  • the invention relates to metal vapor arc lamps using an arc discharge in metal or metal halide vapors to produce light, and is particularly concerned with the starting of such lamps.
  • High pressure metal vapor lamps such as mercury or metal halide lamps generally have self-heating main electrodes at opposite ends andare usually provided with an auxiliary starting electrode. It'may take the form of a starter wire spaced close to one of the main electrodes. The latter is usually negative, or cathode, at the a.c. phase moment when ignition occurs, so that it is convenient to speak of this main electrode adjacent to the auxiliary electrode as cathode, and of the other more distant main electrode as anode.
  • the starter voltage becomes sufficiently positive a glow discharge appears between starter and cathode. This glow discharge quickly transfers to the anode from the starter, and subsequently is converted into an are, such completing the ignition process.
  • the main electrodes comprise a base metal body bearing emission material, the form commonly used being a close wound tungsten coil bearing low work function emission mix in the interstices between turns. Presence of the emission material tends to facilitate ignition of the glow discharge or Paschen breakdown and also transition of the glow into an arc. However, operation of the lamp with repeated starts tends to remove the emission material by processes such-as ion bombardment and simple flaking due to thermal expansion or distortion. Concomitantly, it is observed that some lamps become hard starters as life progresses.
  • the development of hard starting with life is prevented by assuring that there is emission mix available to provide normal starting throughout life. This is achieved by providing an igniter having a well-bonded supply of emission mix in a region out of range of the normal wandering of the arc terminus and maintained at a temperature several hundred degrees Centigrade lower than the front end of the main electrode.
  • a ceramic-metal or cermet igniter comprising a sintered mixture of metal and metal oxide on a conductor is attached to the main electrode at the end of the lamp having the auxiliary electrode.
  • the metal oxide may be refractory, or emissive, or preferably refractory and emissive.
  • a desirable arrangement is to locate the igniter in the space between the main electrode and the auxiliary electrode.
  • a glow or arc initiated at the cermet igniter can readily transfer to the cathode.
  • the end of the cermet igniter is placed back from the tip or face of the cathode so thatthe arc, which prefers a short length, will quickly transfer to the cathode.
  • the cermet igniter operates at least l,000C. cooler than the main electrode and retains its emission material throughout life. Thus it serves to reduce the starting voltage or prevent rise in starting voltage in seasoned lamps.
  • FIG. -1 shows in side view a metal halide lamp embodying the invention.
  • FIG. 2 is an enlarged sectioned view of the cathode" electrode provided with cermet igniter.
  • a mercury metal halide vapor arc lamp 1 in which the invention is embodied comprises an outer vitreous envelope or jacket 2 of ellipsoidal form having a neck portion 3.
  • the neck is closed by 'a re-entrant stem 4 having a press 5 through which extend stiff inlead wires 6,7.
  • These inleads are connected at their outer ends to the contacts of the usual screw-type base 8, namely the threaded shell 9 and the insulated center contact 10.
  • the inner arc tube 12 made of quartz or fused silica has therein at opposite ends a pair of main arcing electrodes, 13 at the base end and 14 at the dome end, plus an auxiliary starting electrode 15 at the base end.
  • the electrodes are supported on inleads which include intermediate thin molybdenum foil sections 16 hermetically sealed to the flattened ends 17, 18 of the arc tube, commonly referred to as full diameter pinch seals.
  • the main electrodes 13, 14 each comprise a double layer tungsten wire helix 19 (best seen in FIG. 2) wrapped around a tungsten core wire 20.
  • the mainelectrodes are activated by thorium oxide which coats the turns and fills the interstices within the helix.
  • the are tube is supported within the outer jacket by a divided or two-part mount.
  • the lower mount sectionv comprises U-shaped support rod 21 welded to inlead 6 and having metal straps 22 extending across its ends to clamp pinch seal 11.
  • the upper mount section comprises inverted U-shaped support rod 23 to which is attached a springy collar 24 engaging a re-entrant dimple 25 in the dome end of the outer envelope, and which has straps 26 extending across its ends and clamping pinch seal 18.
  • the right angle braces 27 connected to support rods 21 and 23 engage blind notches 28 in the ends of pinch seals 17, 18 to stiffen the assembly.
  • Main electrode 13 is connected to inlead 6 through strap 29 and the lower support rod, while main electrode 14 is connected to inlead 7 through curving wire 31.
  • Starting electrode 15 is connected to inlead 7 through a current limiting resistor 32 which may have a value for instance of 40,000 ohms.
  • a thermal switch consisting of a U-shaped bimetal 33 is welded at one end to the inlead of main electrode 13 with its free end disposed to engage the inlead of starting electrode 15 as the lamp warms up.
  • the auxiliary electrode is thereby connected to the adjacent main electrode during operation of the lamp whereby to prevent harmful electrolytic effects in accordance with the teachings of U.S. Pat. No. 3,226,597 to Green.
  • the arc tube contains an inert rare gas such as argon at a low pressure, for instance 25 torr, to facilitate starting and warm-up, and a fill of metal or metal halide.
  • the arc tube may contain a quantity of mercury which is substantially totally vaporized and exerts a partial pressure in the range of l to 15 atmospheres during operation.
  • a metal halide such as sodium iodide in excess of the quantity vaporized at the operating temperature, plus smaller amounts of other metal halides such as thallium and indium iodides, or scandium iodide.
  • the availability of emission mix for normal starting is assured by providing a well-bonded supply of it in a region out of range of the normal wandering of the arc terminus.
  • such supply takes the form of a ceramic or cermet igniter 35.
  • the igniter comprises a sintered mixture of refractory metal and emissive or refractory metal oxide powders as a coating 36 on a refractory metal wire 37 which is welded to core wire 20 of main electrode 13 below or to the rear of helix 19.
  • the preferred mixture for a metal halide containing lamp is tungsten powder'and thoria, each 50 percent by weight.
  • the mixture in a flexible sleeve of polyvinyl chloride, is pressed at 40,000 pounds per square inch around an 18 mil diameter tungsten wire.
  • the sleeve is dissolved away and the green compact is then fired in vacuo for an hour at temperatures of 1,750 to 2,000C. After firing, the thickness of the cermet coating 36 around wire 37 averaged approximately 6 mils.
  • Other mixtures which have been used include tungsten and alkaline earth oxides; tungsten, thoria, and rare earth oxides; and tungsten, tungsten carbide, and thoria.
  • the tip or upper end of the igniter 35 is preferably placed back from the tip or front face of electrode 13 in order that the are, which prefers a short path, will quickly transfer to the cathode, that is, to electrode 13.
  • the cap shape of the cermet coating 36 is not critical and wire support 37 may project through the coating without harm.
  • auxiliary starter electrode 15 is shown in dash lines in FIG. 2 to indicate its location relative to the igniter. Ignition starts as a glow discharge between starter wire 15 and igniter 35. The discharge transfers without delay from starter to anode" l4 and from igniter to contiguous cathode" l3 and developes into an arc. Operating temperature of the cermet igniter, about 900C, is at least 1,000 Centigrade below that of the upper coil region of the main electrode, so the igniter does not dispense emission mix as does the electrode. Also sputtering due to spot motion, routine on the main electrode, is absent from the igniter.
  • a high intensity metal vapor lamp comprising:
  • vitreous envelope containing metal vapor and having a pair of thermionic self-heating arc-supporting main electrodes sealed therein at opposite ends and a starter electrode at one end;
  • said igniter comprising a sintered mixture of metal and metal oxide on a conductor, said igniter being spaced close to the main electrode to which it is connected whereby it operates at a lower temperature without appreciable loss of metal oxide and a discharge initiated on it readily transfers to said main electrode.
  • a lamp as in claim 1 wherein said igniter comprises a sintered mixture of tungsten powder and refractory emissive metal oxide on a tungsten conductor.
  • a lamp as in claim 1 wherein said igniter comprises a sintered mixture of tungsten powder and thorium oxide on a tungsten conductor.
  • a high intensity metal vapor lamp comprising:
  • each of said main electrodes comprising a winding of tungsten wire on a tungsten core activated by emissive metal oxide thereon,
  • said igniter comprising a sintered mixture of tungsten powder and emissive metal oxide powder on a tungsten conductor attached for the tungsten core of said main electrode to the rear of the winding of tungsten wire,
  • said igniter being spaced close to said main electrode to which it is connected, whereby it operates at a lower temperature without appreciable loss of emissive metal oxide and a discharge initiated on it readily transfers to said main electrode.

Landscapes

  • Discharge Lamp (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
US00279548A 1972-08-10 1972-08-10 High intensity lamp with cermet igniter Expired - Lifetime US3840768A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US00279548A US3840768A (en) 1972-08-10 1972-08-10 High intensity lamp with cermet igniter
JP48080404A JPS4945580A (enrdf_load_stackoverflow) 1972-08-10 1973-07-18
GB3587073A GB1427598A (en) 1972-08-10 1973-07-27 High intensity metal vapour lamp
FR7328290A FR2195843B1 (enrdf_load_stackoverflow) 1972-08-10 1973-08-02
BE134196A BE803175A (fr) 1972-08-10 1973-08-03 Lampe a intensite elevee presentant un dispositif d'allumage a base de cermet
DE19732340126 DE2340126C3 (de) 1972-08-10 1973-08-08 Hochleistungsmetalldampflampe
NL7310965A NL7310965A (enrdf_load_stackoverflow) 1972-08-10 1973-08-08

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00279548A US3840768A (en) 1972-08-10 1972-08-10 High intensity lamp with cermet igniter

Publications (1)

Publication Number Publication Date
US3840768A true US3840768A (en) 1974-10-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00279548A Expired - Lifetime US3840768A (en) 1972-08-10 1972-08-10 High intensity lamp with cermet igniter

Country Status (6)

Country Link
US (1) US3840768A (enrdf_load_stackoverflow)
JP (1) JPS4945580A (enrdf_load_stackoverflow)
BE (1) BE803175A (enrdf_load_stackoverflow)
FR (1) FR2195843B1 (enrdf_load_stackoverflow)
GB (1) GB1427598A (enrdf_load_stackoverflow)
NL (1) NL7310965A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0430560A3 (en) * 1989-11-20 1991-08-28 Hamamatsu Photonics K.K. Gaseous-discharge lamp
US20040075390A1 (en) * 2002-07-23 2004-04-22 Ushiodenki Kabushiki Kaisha Short arc discharge lamp and light source device
US11125439B2 (en) 2018-03-27 2021-09-21 Scp Holdings, An Assumed Business Name Of Nitride Igniters, Llc Hot surface igniters for cooktops

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4437039A (en) * 1978-10-03 1984-03-13 North American Philips Electric Corp. Starting arrangement for high-intensity-discharge sodium lamp

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1193820A (enrdf_load_stackoverflow) * 1959-11-05

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0430560A3 (en) * 1989-11-20 1991-08-28 Hamamatsu Photonics K.K. Gaseous-discharge lamp
US20040075390A1 (en) * 2002-07-23 2004-04-22 Ushiodenki Kabushiki Kaisha Short arc discharge lamp and light source device
US7057345B2 (en) * 2002-07-23 2006-06-06 Ushiodenki Kabushiki Kaisha Short arc discharge lamp and light source device
DE10331510B4 (de) * 2002-07-23 2013-07-18 Ushiodenki Kabushiki Kaisha Kurzbogen-Entladungslampe sowie Lichtquellenvorrichtung
US11125439B2 (en) 2018-03-27 2021-09-21 Scp Holdings, An Assumed Business Name Of Nitride Igniters, Llc Hot surface igniters for cooktops
US11493208B2 (en) 2018-03-27 2022-11-08 Scp Holdings, An Assumed Business Name Of Nitride Igniters, Llc Hot surface igniters for cooktops
US11788728B2 (en) 2018-03-27 2023-10-17 Scp R&D, Llc Hot surface igniters for cooktops

Also Published As

Publication number Publication date
DE2340126B2 (de) 1976-01-29
BE803175A (fr) 1973-12-03
FR2195843B1 (enrdf_load_stackoverflow) 1976-11-12
DE2340126A1 (de) 1974-03-07
JPS4945580A (enrdf_load_stackoverflow) 1974-05-01
GB1427598A (en) 1976-03-10
FR2195843A1 (enrdf_load_stackoverflow) 1974-03-08
NL7310965A (enrdf_load_stackoverflow) 1974-02-12

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