US2267821A - High-pressure metal vapor discharge tube - Google Patents

High-pressure metal vapor discharge tube Download PDF

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Publication number
US2267821A
US2267821A US333653A US33365340A US2267821A US 2267821 A US2267821 A US 2267821A US 333653 A US333653 A US 333653A US 33365340 A US33365340 A US 33365340A US 2267821 A US2267821 A US 2267821A
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US
United States
Prior art keywords
discharge
tube
discharge tube
receptacle
pressure
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
US333653A
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English (en)
Inventor
Elenbaas Willem
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
Application granted granted Critical
Publication of US2267821A publication Critical patent/US2267821A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/52—Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space
    • H01J61/523—Heating or cooling particular parts 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
    • H01J61/24—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

Definitions

  • a high-pressure metal vapor discharge tube therefore exhibits the property that when the tube is in normal use the operating voltage is substantially higher than (at least twice as high as) the operating voltage which occurs directly upon initiation of the arc discharge.
  • the increase in the vapor pressure is also attended by the phenomenon that the discharge contracts, that is to say no longer fills the whole section of the discharge tube.
  • the invention relates to high-pressure metal vapor discharge tubes having such a limited is in normal use all the metal is vaporized and it has for its object to improve the said tubes.
  • the unpleasant phenomenon occurs that when the tube is in normal use and the discharge is interrupted (either deliberately by interruption of the circuit or unintentionally due to the fact that, for example, the voltage of the source of current momentarily falls below the voltage necessary for the maintenance of the discharge) the voltage necessary for reinitiation of the discharge is substantially higher than the starting-up voltage when the discharge tube is in the cold condition. In normal cases the voltage available is therefore too low to bring about immediate reignition. This is due to the high-vapor pressure which prevails in the tube on the discharge being interrupted.
  • the discharge tube is provided with an auxiliary receptacle which is heated by a heating element connected in series with the discharge path, the thermal capacity of the said receptacle being made so low and its heat dissipating capacity being made so high that when the discharge is interrupted while the tube is in normal use the temperature in the auxiliary receptacle decreases more rapidly than the lowest temperature in the discharge space proper, the heating element being in addition so proportioned that onthe discharge tube being put into service the auxiliary receptacle is caused to assume a higher temperature so rapidly that ,the heating-up period of the discharge tube is not longer than in the absence of the auxiliary quantity of vaporizable metal that when the tube receptacle.
  • the heating element By making the capacity of the heating element suificiently high it may be ensured that the heating-up period of the discharge tube, that is to say the time required for bringing the tube from the cold condition into the normal operating condition, is not increased by the provision of the auxiliary receptacle. Obviously, the heating element must also be proportioned in such manner that when the discharge tube is in normal use the temperature in the auxiliary receptacle is not lower than the temperature at which the desired vapor pressure is obtained.
  • the thermal capacity of the auxiliary receptacle can be reduced by decreasing the wall thickness and the width thereof. Simultaneous decrease of the wall thickness and of the width permits of high pressures being nevertheless admitted in the discharge tube.
  • the external diameter of the auxiliary receptacle is preferably less than half the external diameter of the discharge tube.
  • auxiliary receptacle When the auxiliary receptacle is enclosed in a gaseous atmosphere a small diameter is also favorable as regards dissipation of heat since the smaller the diameter the higher is the dissipation of heat per unit of wall surface.
  • the dissipation of heat is also influenced by the pressure and the nature of the surrounding gaseous atmosphere and increases as the pressure and the heat conduction of the gas increase. In order to intensify the dissipation of heat by radiation it may be advisable to blacken the outside of the wall of the auxiliary receptacle.
  • the wall of the auxiliary receptacle has preferably one or more metal bodies, for example metal wires, led through it. Due to the heat conduction by these bodies the heat dissipating capacity of the auxiliary receptacle is increased, it being preferable for the said bodies to have a large surface area outside the auxiliary receptacle and in some circumstances, to be black- .ened. For this purpose, for example, a small metal plate may be fixed to a wire led through the wall.
  • a heat-radiating body of low thermal capacity for example a thin metal plate, may be housed in the auxiliary receptacle. In the cooling period this body dissipates its heat rapidly by radiation so that it very rapidly assumes a lower temperature than the wall of the auxiliary receptacle and the metal vapor is thus condensed on the said body.
  • the heating element is preferably so constructed as to leave free a large part, for example more than 75%, of the wall of the auxiliary recept'acle so that this part can dissipate its heat directly to the surroundings.
  • l designates a cylindrical discharge tube made of quartz and having an internal and an external diameter of 7.5 and 10 mms. respectively.
  • This discharge tube comprises two incandescent electrodes 2 and 3 which are provided with a material capable of copiously emitting electrons and are heated to the required 'high temperature solely by the discharge.
  • the spacing between the electrodes is 22 mms.
  • the gas-filling of the tube is constituted by argon at a pressure of about 2 cms. to which a small quantity of mercury is added.
  • the bottom end of the discharge tube I has sealed to it an auxiliary receptacle 4 constituted by a small cylindrical tube of quartz having an internal and an external diameter of 2 and 2.5 mms. respectively.
  • the length of this auxiliary receptacle is about 10 mms.
  • the closed end of this auxiliary receptacle has a tungsten wire 5 of 400 microns thickness sealed in it.
  • the auxiliary receptacle contains a small molybdenum plate 6 which is fixed to the said tungsten wire and is about 4 mms. in length and almost 2 mms.
  • the plate 6 is blackened.
  • the wire 5 has fixed to it a blackened nickel plate 1 which has a thickness of microns and is 20 mms. in length and width.
  • the auxiliary receptacle 4 is surrounded by a heating element 8 constituted by 10 turns of a nickel-chromium wire (diameter microns). One end of this heating element is connected through a wire 9 to the electrode 3, whereas the other end is connected through wire H] to the leading-in wire II which is lead through the pinch i2 of the bulb l3 and is connected to the contact member [4 of the cap I 5.
  • This pinch has also two supporting wires l6 and" I1 secured in it to carry the discharge tube 1, the wire I! also serving as a current-supply member for the electrode 2 and being connected to the contact member IS.
  • the space between the discharge tube and the bulb I3 is filled with nitrogen at a pressure of 50 cms.
  • the lamp is used for the emission of rays, for example for illumination or radiation by ultraviolet rays, 'and is supplied from an alternating current supply circuit of 220 volts with the interposition of a choke coil.
  • the tube When the tube is in use it exhibits a high-pressure mercury vapor discharge at which the absorption of energy in the discharge tube is 75 watts and the strength of the discharge current is 0.75 ampere.
  • the quantity of mercury introduced into the discharge tube is so low that the operating voltage of the discharge when the tube is in normal use is .120 volts. In this case the mercury vapor is superheated.
  • a high-pressure metal vapor discharge tube comprising a sealed envelope containing a pair of electrodes and a gaseous atmosphere comprising a vaporizable metal in an amount so small that it is completely vaporized during operation or the tube, an auxiliary receptacle extending from said envelope and communicating with the interior thereof, a heating element connected in series with the discharge path between said electrodes and located adjacent to said receptacle so as to supply appreciably more heat thereto than to the envelope proper, the thermal capacity of said receptacle being so lowand its heat dissipation being so high that upon interruption of the discharge the receptacle cools more rapidly than any portion of said envelope, the said heating element serving to heat the said receptacle, upon restarting of the discharge in the tube, so that the restarting time is not longer that it would be in the absence of the said receptacle.
  • the auxiliary receptacle is provided with a metallic conductor member extending through the end thereof and serving

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  • Discharge Lamps And Accessories Thereof (AREA)
US333653A 1939-04-01 1940-05-06 High-pressure metal vapor discharge tube Expired - Lifetime US2267821A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL538855X 1939-04-01

Publications (1)

Publication Number Publication Date
US2267821A true US2267821A (en) 1941-12-30

Family

ID=19787240

Family Applications (1)

Application Number Title Priority Date Filing Date
US333653A Expired - Lifetime US2267821A (en) 1939-04-01 1940-05-06 High-pressure metal vapor discharge tube

Country Status (6)

Country Link
US (1) US2267821A (en))
BE (1) BE438506A (en))
DE (1) DE730066C (en))
FR (1) FR865414A (en))
GB (1) GB538855A (en))
NL (1) NL52397C (en))

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3942062A (en) * 1974-10-15 1976-03-02 Rca Corporation Metal vapor laser discharge device
FR2565733A1 (fr) * 1984-06-12 1985-12-13 Tungsram Reszvenytarsasag Lampe a vapeur de sodium a haute pression
WO1986002445A1 (en) * 1984-10-10 1986-04-24 Andros Analyzers Incorporated Oxygen analysis employing absorption spectroscopy
US4797598A (en) * 1986-06-19 1989-01-10 Canon Kabushiki Kaisha Illumination apparatus
US4798997A (en) * 1985-12-26 1989-01-17 Canon Kabushiki Kaisha Lighting device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3942062A (en) * 1974-10-15 1976-03-02 Rca Corporation Metal vapor laser discharge device
FR2565733A1 (fr) * 1984-06-12 1985-12-13 Tungsram Reszvenytarsasag Lampe a vapeur de sodium a haute pression
US4678958A (en) * 1984-06-12 1987-07-07 Tungsram Rt. High pressure sodium vapor lamp with improved color reproduction index
WO1986002445A1 (en) * 1984-10-10 1986-04-24 Andros Analyzers Incorporated Oxygen analysis employing absorption spectroscopy
US4798997A (en) * 1985-12-26 1989-01-17 Canon Kabushiki Kaisha Lighting device
US4797598A (en) * 1986-06-19 1989-01-10 Canon Kabushiki Kaisha Illumination apparatus

Also Published As

Publication number Publication date
GB538855A (en) 1941-08-19
DE730066C (de) 1943-01-06
FR865414A (fr) 1941-05-23
BE438506A (en))
NL52397C (en))

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