GB2154054A - Getter devices - Google Patents

Getter devices Download PDF

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Publication number
GB2154054A
GB2154054A GB08501780A GB8501780A GB2154054A GB 2154054 A GB2154054 A GB 2154054A GB 08501780 A GB08501780 A GB 08501780A GB 8501780 A GB8501780 A GB 8501780A GB 2154054 A GB2154054 A GB 2154054A
Authority
GB
United Kingdom
Prior art keywords
pellet
lamp
getter material
lead
wires
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.)
Granted
Application number
GB08501780A
Other versions
GB8501780D0 (en
GB2154054B (en
Inventor
James Roger Young
John Mapes Houston
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
Publication of GB8501780D0 publication Critical patent/GB8501780D0/en
Publication of GB2154054A publication Critical patent/GB2154054A/en
Application granted granted Critical
Publication of GB2154054B publication Critical patent/GB2154054B/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00Gas-discharge or vapour-discharge lamps
    • H01J61/02Details
    • H01J61/24Means for obtaining or maintaining the desired pressure within the vessel
    • H01J61/26Means for absorbing or adsorbing gas, e.g. by gettering; Means for preventing blackening of the envelope
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00Gas-discharge or vapour-discharge lamps
    • H01J61/96Lamps with light-emitting discharge path and separately-heated incandescent body within a common envelope, e.g. for simulating daylight
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01KELECTRIC INCANDESCENT LAMPS
    • H01K1/00Details
    • H01K1/52Means for obtaining or maintaining the desired pressure within the vessel
    • H01K1/54Means for absorbing or absorbing gas, or for preventing or removing efflorescence, e.g. by gettering
    • H01K1/56Means for absorbing or absorbing gas, or for preventing or removing efflorescence, e.g. by gettering characterised by the material of the getter

Abstract

A getter device for use with incandescent and high intensity discharge lamps comprises an alloy of 85% Zr, 10% Ti and 5% Ni or 85% Zr, 7% Fe, and 8% Al in powder form which is pressed into a small pellet 15 with a cylindrical bore therethrough. The pellet surrounds a support element 11, 23 in the lamp, and is situated spaced away from the source of heat (filament or arc discharge tube) to permit the getter material to operate at the optimum temperature for gettering. <IMAGE>

Description

SPECIFICATION Getter devices Background of the Invention This invention relates to a getter device for incandescent and high intensity discharge lamps.
Present incandescent lamps include a getter of powdered zirconium and aluminum which is painted directly on the filament supportleads in slurry form. The slurry comprises the powdered getter and a hydrocarbon binder such as nitrocellulose in a suitable solvent.
The getter cleans up or absorbs hydrogen from the lamp which is generated by the dissociation of water vapor by the heated filament. If the water vapor level is not controlled, tungsten from the filament is deposited on the glass envelope more rapidly than occurs when water vapor is not present and a shortened filament life results.
During the processing of the lamp, much of the nitrocellulose and solvent are decomposed and pumped away, leaving the powdered zirconium and aluminum attached to the filament support leads. Painting getter material directly on the filament support leads is satisfactory for lamps which do not require large amounts of gettering. Increasing the quantity of getter powder attached to the filament support leads is difficult because thicker coatings tend to crack and fall off.
The quantity of getter powder put on the leads is difficult to control and reproducibility from lamp to lamp is not good. Some of the binder remains in the getter and is evolved after lamp seal off, resulting in a high hydrocarbon atmosphere which reduces filament life. The zirconium plus aluminum powder requires a temperature near or above 500"C for significant gettering of hydrogen.
In lamps which require more gettering, such as multi-vapor lamps having filamentary resistance elements, it has been necessary to use a commercially available getter tab which is spot welded to the arc lamp support lead so that it is maintained at the optimum temperature for gettering during normal lamp operation. This getter is satisfactory, except it is high in cost.
In one aspect of the present invention, a high intensity discharge lamp comprising an evacuable envelope encloses an arc discharge tube having lead-in wires extending from either end of the arc discharge tube. The arch discharge tube is supported inside the evacuable envelope by support leads extending from the exterior to the interior of the evacuable envelope. A pellet of pressed powdered getter material, not containing binder material, has a cylindrical bore extending therethrough. One of the support wires extends through the cylindrical bore of the pellet. Positioning means affixed to the support lead having the pellet, spaces the pellet away from the arc discharge tube to maintain the pellet at a predetermined temperature.
In another aspect of the present invention a lamp comprising an evacuable envelope surrounding a filament supported in the envelope by lead-in wires extending from the exterior to the interior of the envelope is provided. A pellet of pressed powdered getter material, not containing binder material, has a cylindrical bore extending therethrough. One of the support wires extends through the cylindrical bore of the pellet. Positioning means affixed to the support lead with the pellet, space the pellet away from the filament to maintain the pellet at a predetermined temperature.
The getter device allows larger quantities of getter material to be used without danger of the getter material cracking and falling off.
However, the quantity of getter powder used is easy to control and good reproducibility from lamp to lamp can be obtained. The getter device is not expensive and is easy to incorporate into existing production procedures.
In the accompanying drawings, by way of example only: Figure 1 is a partially cut away side view of a multi-vapor lamp including filamentary resistance elements and a getter device in accordance with the present invention; and Figure 2 is a side view of an incandescent lamp with getter device in accordance with the present invention.
Referring now to the Figs. in which like numerals indicate like elements throughout and particularly to Fig. 1 thereof, a lamp assembly comprises a glass envelope 3 which contains a high efficiency arc discharge tube 5 and filamentary resistance elements 7 and 9. A suitable lamp for use as the arc discharge tube is a high pressure discharge lamp that operates by vaporizing mercury and selected metal halides. A high pressure discharge lamp of this type is more fully described in United States patent 4,161,672 assigned to the instant assignee and hereby incorporated by reference. The arc discharge tube 5 is suspended between a long support rod 11 and short support rod 1 3 which are both welded to lead-in wires 1 4 of the arc discharge tube.A pellet 1 5 of pressed, powdered getter material, having a cylindrical bore therethrough, surrounds the long support rod 11 and is held in position by tabs 1 7 predetermined distance away from the arc discharge tube 5, which permits the getter to operate at the optimum temperature for gettering. Tabs 17, each comprising a short length of wire, are shown in the figure affixed perpendicularly to the rod above and below the pellet, thus holding the pellet in a predetermined position. A glass shield 1 8 surrounds the arc tube 5.
The pellets can be formed by pressing a getter material in powder form (typically 200 mesh) comprising an alloy of 85% zirconium, 10% titanium and 5% nickel or an alloy of 85% zirconium, 7% iron and 8% aluminum by weight into cylinders having an axially extending aperture. The percent of titanium, nickel, iron and aluminum may be adjusted by increasing or decreasing the amounts of any of the constitutents individually or in combination in the range between 1 and 14%. The cylindrical pellet can have the dimensions of approximately 1 mm. l.D., 2 mm. O.D., 10 mm. in length and weigh approximately 0.1 grams.The cylindrical pellets when formed are strong enough to be handled with tweezers without cracking and if additional strength is needed the cylindrical pellets may be sintered by vacuum firing at 900-1000"C. The cylindrical pellets are pressed without any binder and are quite porous. The lack of a binder avoids a high hydrocarbon atmosphere in the envelope which would reduce filament life. During lamp operation, heat from the arc discharge tube activates the getter material.
The porosity of the pellet permits the gases being gettered in the envelope, mainly hydrogen, to reach all the getter material.
The resistance elements 7 and 9 are an electrical part of the power supply, being used to ballast the arc discharge lamp 5 and serving as supplemental light sources. A power supply unit includes a rigid case 1 9 attached to the glass enclosure 3 and a screw-in base 20. The unit develops the required energization of the arc discharge lamp during starting and operating conditions and produces instant illumination by use of the supplemental incandescent light source 9 and 7. The supplemental illumination is relatively constant during starting, tapering off as the arc lamp warms up. The lighting unit is more fully described in United States patent no. 4,350,930 assigned to the instant assignee and hereby incorporated by reference.
The two getter materials discussed above have superior gettering characteristics for nitrogen filled lamps. The alloy of 85% zirconium, 10% titanium, and 5% nickel has good gettering characteristics for hydrogen in the presence of nitrogen at 300-400"C while most bulk getters require temperatures above 400 C for significant gettering.
While the invention has been shown with high intensity discharge lamps with filamentary resistance elements between the outer envelope and the arc discharge tube, the getter of the present invention can be used in high intensity discharge lamps without filamentary resistance elements.
Referring now to Fig. 2 an incandescent lamp assembly comprising a glass envelope 21, lead-in wires 23 attached to a filament 25 and a glass support stem 27, through which the lead-in wires extend, is shown. The support stem 27 seals the bottom of the glass enclosure 21. A non-conductive cross support member 26 maintains the spacing between lead-in wires 23 and a support member 28 attached to the support stem 27, restricts motion of the filament 25. A screw in base 29 is cemented to the base of the glass enclosure 21 and is electrically connected to the lead-in wires.A pellet 1 5 of pressed powdered getter material having a cylindrical bore extending therethrough, as described in connection with Fig. 1, surrounds one of the lead-in wires 23 and is held in a position a predetermined distance away from filament 25, which permits the getter material to operate at the optimum temperature for gettering.
Tabs 17 are shown in Fig. 2 affixed to the lead-in wire above and below the pellet 1 5 to hold the pellet in a predetermined position.
The foregoing describes a getter device which allows large quantities of getter material to be used without the danger of the getter material cracking and falling off. The getter of the present invention does not introduce a high hydrocarbon atmosphere which would reduce filament life. The getter device described is low in cost and easy to incorporate in existing production procedures.
While the invention has been particularly shown and described with reference to several preferred embodiments thereof, it will be understood by those skilled in the art that various changes in the form and detail may be made without departing from the spirit and scope of the invention.

Claims (7)

1. A high intensity discharge lamp comprising: an evacuable envelope; support leads extending from the exterior to the interior of said evacuable envelope; an arch discharge tube having lead-in wires attached to said support leads, said arc discharge tube situated inside said evacuable envelope and supported therein by said support leads; a pellet of pressed powdered getter material having a cylindrical bore extending therethrough, one of said support leads extending through said bore; and positioning means affixed to said one of said support leads for spacing said pellet away from said arc discharge tube to maintain said pellet at a predetermined temperature.
2. The high intensity discharge lamp of claim 1 wherein said getter material comprises an alloy of approximately 85% zirconium, 10% titanium and 5% nickel by weight.
3. The high intensity discharge lamp of claim 1 wherein said getter material comprises an alloy of approximately 85% zirconium, 7% iron and 8% aluminum by weight.
4. A lamp comprising: an evacuable envelope; lead-in wires extending from the exterior to the interior of the evacuable envelope; a filament connected at either end to the lead-in wires for support and for carrying electrical current; a pellet of pressed powdered getter material having a cylindrical bore extending therethrough and with one of said lead-in wires passing through said bore; and positioning means affixed to said one of said lead-in wires for spacing said pellet away from said filament to maintain said pellet at a predetermined temperature.
5. The lamp of claim 4 wherein said getter material comprises an alloy of approximately 85% zirconium, 10% titanium and 5% nickel by weight.
6. The lamp of claim 4 wherein said getter material comprises an alloy of approximately 85% zirconium, 7% iron and 8% aluminum by weight.
7. A lamp substantially as herein described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.
GB08501780A 1984-02-02 1985-01-24 Getter devices Expired GB2154054B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US57622284A 1984-02-02 1984-02-02

Publications (3)

Publication Number Publication Date
GB8501780D0 GB8501780D0 (en) 1985-02-27
GB2154054A true GB2154054A (en) 1985-08-29
GB2154054B GB2154054B (en) 1988-03-02

Family

ID=24303460

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08501780A Expired GB2154054B (en) 1984-02-02 1985-01-24 Getter devices

Country Status (7)

Country Link
JP (1) JPS60185356A (en)
BR (1) BR8500523A (en)
DE (1) DE3500430A1 (en)
FR (1) FR2561442A1 (en)
GB (1) GB2154054B (en)
IT (1) IT1184118B (en)
NL (1) NL8500286A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002089174A2 (en) * 2001-05-01 2002-11-07 Koninklijke Philips Electronics N.V. Discharge lamp
WO2003015126A1 (en) * 2001-08-03 2003-02-20 Koninklijke Philips Electronics N.V. High-pressure discharge lamp and method of manufacturing it
EP1398822A2 (en) * 2002-09-12 2004-03-17 Colour Star Limited A Mercury Gas Discharge Device
WO2005045879A1 (en) * 2003-11-10 2005-05-19 Shingcheung Chow A gas discharge tube containing a mercury and a getter means thereof
EP1851783B1 (en) * 2005-02-23 2014-03-26 SAES GETTERS S.p.A. High pressure discharge lamp containing a getter device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0291123B1 (en) * 1987-05-13 1991-09-11 Koninklijke Philips Electronics N.V. Electric lamp provided with a getter

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT963874B (en) * 1972-08-10 1974-01-21 Getters Spa IMPROVED GETTER DEVICE CONTAINING NON-EVAPORABLE MATERIAL
NL7315641A (en) * 1973-11-15 1975-05-20 Philips Nv HIGH PRESSURE GAS DISCHARGE LAMP.
NL7707079A (en) * 1977-06-27 1978-12-29 Philips Nv ELECTRIC LAMP.

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002089174A2 (en) * 2001-05-01 2002-11-07 Koninklijke Philips Electronics N.V. Discharge lamp
WO2002089174A3 (en) * 2001-05-01 2003-02-27 Koninkl Philips Electronics Nv Discharge lamp
US6800998B2 (en) 2001-05-01 2004-10-05 Koninklijke Philips Electronics N.V. Discharge lamp provided with a getter
US6943497B2 (en) 2001-05-01 2005-09-13 Koninklijke Philips Electronics N.V. Discharge lamp provided with a getter
WO2003015126A1 (en) * 2001-08-03 2003-02-20 Koninklijke Philips Electronics N.V. High-pressure discharge lamp and method of manufacturing it
EP1398822A2 (en) * 2002-09-12 2004-03-17 Colour Star Limited A Mercury Gas Discharge Device
EP1398822A3 (en) * 2002-09-12 2005-01-26 Colour Star Limited A Mercury Gas Discharge Device
AU2003258391B2 (en) * 2002-09-12 2007-05-10 Colour Star Limited A mercury gas discharge device
WO2005045879A1 (en) * 2003-11-10 2005-05-19 Shingcheung Chow A gas discharge tube containing a mercury and a getter means thereof
EP1851783B1 (en) * 2005-02-23 2014-03-26 SAES GETTERS S.p.A. High pressure discharge lamp containing a getter device

Also Published As

Publication number Publication date
BR8500523A (en) 1985-09-24
IT1184118B (en) 1987-10-22
NL8500286A (en) 1985-09-02
JPS60185356A (en) 1985-09-20
GB8501780D0 (en) 1985-02-27
FR2561442A1 (en) 1985-09-20
GB2154054B (en) 1988-03-02
DE3500430A1 (en) 1985-08-08
IT8519146A0 (en) 1985-01-18

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PCNP Patent ceased through non-payment of renewal fee