US2069713A - Electric lamp for producing short wave length radiation - Google Patents
Electric lamp for producing short wave length radiation Download PDFInfo
- Publication number
- US2069713A US2069713A US634481A US63448132A US2069713A US 2069713 A US2069713 A US 2069713A US 634481 A US634481 A US 634481A US 63448132 A US63448132 A US 63448132A US 2069713 A US2069713 A US 2069713A
- Authority
- US
- United States
- Prior art keywords
- filament
- tantalum
- electric lamp
- melting point
- coating
- 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
Links
- 230000005855 radiation Effects 0.000 title description 16
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 19
- 239000011248 coating agent Substances 0.000 description 17
- 238000000576 coating method Methods 0.000 description 17
- 238000002844 melting Methods 0.000 description 17
- 230000008018 melting Effects 0.000 description 17
- 229910052715 tantalum Inorganic materials 0.000 description 16
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 15
- 229910052751 metal Inorganic materials 0.000 description 13
- 239000002184 metal Substances 0.000 description 13
- 229910052721 tungsten Inorganic materials 0.000 description 8
- 239000010937 tungsten Substances 0.000 description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 230000001464 adherent effect Effects 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- OEIMLTQPLAGXMX-UHFFFAOYSA-I tantalum(v) chloride Chemical compound Cl[Ta](Cl)(Cl)(Cl)Cl OEIMLTQPLAGXMX-UHFFFAOYSA-I 0.000 description 2
- 241000127225 Enceliopsis nudicaulis Species 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007787 electrohydrodynamic spraying Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 1
- 239000006069 physical mixture Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910001936 tantalum oxide Inorganic materials 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- ZNOKGRXACCSDPY-UHFFFAOYSA-N tungsten trioxide Chemical compound O=[W](=O)=O ZNOKGRXACCSDPY-UHFFFAOYSA-N 0.000 description 1
- 238000001429 visible spectrum Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/02—Incandescent bodies
- H01K1/04—Incandescent bodies characterised by the material thereof
- H01K1/08—Metallic bodies
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S65/00—Glass manufacturing
- Y10S65/08—Quartz
Definitions
- This invention relates to radiation devices for producing short wave length radiation and is dlrected particularly to an electric lamp having a filament for producing radiation at the violet end of the spectrum including ultra-violet invisible rays.
- the principal object of the invention is to provide an electric lamp with a high output of ultraviolet radiation.
- Another object of the invention is to provide a filament for an electric lamp which when raised to its operating temperature will be rich in ultra-violet radiation.
- Another object of the invention is to maintain in a lamp a radiating surface at a temperature near the melting point of the material forming such surface so as to increase its radiation of' short waves both visible and invisible.
- Another object of the invention is to provide a lamp filament of metal having a radiating surface of another metal which has a lower melting point.
- Still anotherobject of the invention is to pro vide a method of applying a radiating surface to a filament.
- This invention contemplates, therefore, providing means to maintain in an electric lamp a radiating surface at a. temperature closely approaching its melting point by mounting the surface on a base of a metal having a. higher melting point which can stand the temperature under which the device is operated.
- Tungsten has a melting point of about 3200C. While the melting point of tantalum is in the neighborhood of 2850 C., and hence the temperature of the filament may be maintained to a point almost reaching the melting point of tantalum without affecting the strength of the tungsten core. Thus with the tantalum maintained near its melting point the short wave radiation therefrom is greatly increased.
- Fig. -1 is a sectional elevational view of a lamp which may be the preferred form of the invention.
- Fig. 2 is an enlarged longitudinal sectional view of the coiled filament of the lamp of Fig. 1;
- Fig. 3 is an enlarged fragmentary view partly in section of a slug out of which the lamp filament'may be formed.
- the lamp shown in Fig. 1 may comprise an en'- velope I of a material which is'transparent to the ultra-violet rays, such as quartz, uviol", vita glass, corex, sanalux", sun-ray, and the like.
- This envelope may be shaped similarly to an ordinary electric light bulb and may be provided with a neck II to the end of. which is fused the inturned press I2.
- Two filament support rods I3 and-I4 are sealed'in the press and extend upwardly to a point near the center of the rounded portion of the envelope and to the ends thereof are attached the ends of the closely coiled filament I5, as indicated.
- a central glass stem I6 may be fused to the press I2 and may extend upwardly along the axis of the envelope to a point adjacent the upper end of the rods I3 and I4 where it may terminate in a bead H which carries a plurality of fine support wires I 8 for supporting the middle part of. the filament which is preferably bent to form a portion of a circle.
- the envelope may be filled with a suitable inert gasfor increasing the heat radiation from the filament.
- This gas may be a mixture of about 84% argon and 16% nitrogen at a pressure such that at the operating temperature the pressure will be about one atmosphere.
- a standard type of screw base I9 may be mounted on the end of the neck II with the usual cement 20, and the side of the base 2i may be attached by a leadin wire 22 to the support rod I3; while a second lead-in wire 23 may connect the rod I4 with the center contact terminal 24 as indicated.
- the filament I shown enlarged in Figure 2 of the drawing is preferably formed of a. tungsten core 25 provided with a. thin surface coating 26 of tantalum.
- One way of applying the tantalum coating to the coiled tungsten filament is to mix finely divided tantalum pentachloride with alcohol until a paste is formed which can then be applied to the surface of the wire. This paste may be brushed onto the filament, or the mixture of alcohol and tantalum pentachloride may be made thinner and applied to the filament by tains a shiny white surface which appears to be tantalum metal but may and probably does contain tantalum hydride.
- the constituentsof the coating it has a melting point lower than that of tungsten, and if this filament is-mounted in a lamp, preferably with an inert gas, as mentioned above, the operating temperature can be maintained at a point close to the melting point of tantalum. In the presence of an inert gas the temperature may be maintained higher without danger of damaging the filament as the gas tends to rapidly dissipate the heat evolved.
- the filament may, however, be operated in a vacuum although the results obtained are not as good.
- a slug 21 (Fig. 3) may be coated with tantalum in a. manner described above for the filament. After the tantalum coating has been sintered onto the slug by heating, the slug may be swaged to decrease its diameter and compact the metal particles more strongly together, after which the slug may be drawn into a wire similar to the manner of drawing tungsten wire. .After the wire is formed it has a. surface of a thin film of the tantalum and may be coiled or otherwise formed into the proper shape of the filament.
- the metal to the filament core or to theslug before drawing may be'used, such as by electro-plating or spraying molten metal thereon, it being only necessary that the coating metal be firmly adherent to the core or otherwise arranged so as not to be thrown off therefrom.
- a tungsten core is coated with a coating of tantalum the tantalumwhas another beneficial effect as the coating prevents the evaporation-of the tungsten core caused by the presence of a slight amount of water vapor in the bulb.
- Water vapor attacking the tantalum coating appears to form a stable tantalum oxide which is not affected by tungsten forms tungstic oxide and free hydrogen.
- the oxide is deposited on the wall of the lamp where hydrogen combines with it again to form free tungsten and water vapor, and the cycle is repeated until the filament is destroyed.
- the invention also contemplates the incorporation of such lower melting point metal with the other metal to form a physical mixture or an alloy.
- the invention also contemplates the association of the lower melting point metal with that of higher melting point without any physical attachment therebetween, as by merely positioning the two in close juxtaposition or by wrapping a wire or ribbon of the lower melting point metal around a wire of thehigher melting point metal.
- Such a construction will not be as effective as the coating because the latter provides a larger radiating surface and may be maintained at a higher temperature due to the rapid heat flow between the core and the coating.
- An electric lamp comprising an envelope having a high degreeof transparency for ultraviolet radiation, a tungsten filament within said envelope, a coating of tantalum on the surface thereof and closely adherent thereto, and an inert gas including argon and nitrogen within said envelope, the pressure of said gas being approximately atmospheric.
- An electric lamp comprising an envelope having a high degree of transparency for ultraviolet radiation, a tungsten filament within said envelope, a coating of tantalum on the surface thereof and closely adherent thereto, and an inert gas by volume over of argon and over 10% of nitrogen within said envelope having a pressure substantially atmospheric.
- An electric lamp comprising an envelope having'a high degree of transparency for ultraviolet radiation, a tungsten filament within said envelope, and a coating of tantalum and tantalum hydride on the surface thereof and closely adherent thereto.
Landscapes
- Vessels And Coating Films For Discharge Lamps (AREA)
Description
Feb. 2, 1937. c. H. BRASELTON 2,069,713
ELECTRIC LAMP FOR PRODUCING SHORT WAVE LENGTH RADIATION Filed Sept. 25, 1932 Jagj INVENTOR Patented Feb. 2, 1937 ELECTRIC LAMP FOR PRODUCING SHORT WAVE LENGTH RADIATION Chester H. Braselton, New York, N. Y., assignor to Sirian Lamp Company, Newark, NHL, a corporation of Delaware Application September 23, 1932, Serial No. 634,481
3 Claims.
This invention relates to radiation devices for producing short wave length radiation and is dlrected particularly to an electric lamp having a filament for producing radiation at the violet end of the spectrum including ultra-violet invisible rays.
The principal object of the invention is to provide an electric lamp with a high output of ultraviolet radiation.
Another object of the invention is to provide a filament for an electric lamp which when raised to its operating temperature will be rich in ultra-violet radiation.
Another object of the invention is to maintain in a lamp a radiating surface at a temperature near the melting point of the material forming such surface so as to increase its radiation of' short waves both visible and invisible.
Another object of the invention is to provide a lamp filament of metal having a radiating surface of another metal which has a lower melting point.
Still anotherobject of the invention is to pro vide a method of applying a radiating surface to a filament.
Other objects of the invention will be apparent as the description proceeds.
The amount of short wave radiation in the neighborhood of the violet end of the spectrum and including radiation outside of the visible spectrum itself appears to increase from a radiating surface as the temperature of the surface approaches its melting point. This invention contemplates, therefore, providing means to maintain in an electric lamp a radiating surface at a. temperature closely approaching its melting point by mounting the surface on a base of a metal having a. higher melting point which can stand the temperature under which the device is operated. Y 7
While a large number of metals may be selected for developing this principle to come within the province of. this invention, I may prefer to use a. tungsten filament upon which has been applied a surface coating -of tantalum. Tungsten has a melting point of about 3200C. While the melting point of tantalum is in the neighborhood of 2850 C., and hence the temperature of the filament may be maintained to a point almost reaching the melting point of tantalum without affecting the strength of the tungsten core. Thus with the tantalum maintained near its melting point the short wave radiation therefrom is greatly increased.
The invention is illustrated in the accompanying drawing, in which:
Fig. -1 is a sectional elevational view of a lamp which may be the preferred form of the invention;
Fig. 2 is an enlarged longitudinal sectional view of the coiled filament of the lamp of Fig. 1; and
Fig. 3 is an enlarged fragmentary view partly in section of a slug out of which the lamp filament'may be formed.
The lamp shown in Fig. 1 may comprise an en'- velope I of a material which is'transparent to the ultra-violet rays, such as quartz, uviol", vita glass, corex, sanalux", sun-ray, and the like. This envelope may be shaped similarly to an ordinary electric light bulb and may be provided with a neck II to the end of. which is fused the inturned press I2. Two filament support rods I3 and-I4, are sealed'in the press and extend upwardly to a point near the center of the rounded portion of the envelope and to the ends thereof are attached the ends of the closely coiled filament I5, as indicated. A central glass stem I6 may be fused to the press I2 and may extend upwardly along the axis of the envelope to a point adjacent the upper end of the rods I3 and I4 where it may terminate in a bead H which carries a plurality of fine support wires I 8 for supporting the middle part of. the filament which is preferably bent to form a portion of a circle. v
The envelope may be filled with a suitable inert gasfor increasing the heat radiation from the filament. This gas may be a mixture of about 84% argon and 16% nitrogen at a pressure such that at the operating temperature the pressure will be about one atmosphere. A standard type of screw base I9 may be mounted on the end of the neck II with the usual cement 20, and the side of the base 2i may be attached by a leadin wire 22 to the support rod I3; while a second lead-in wire 23 may connect the rod I4 with the center contact terminal 24 as indicated.
The filament I shown enlarged in Figure 2 of the drawing, is preferably formed of a. tungsten core 25 provided with a. thin surface coating 26 of tantalum. One way of applying the tantalum coating to the coiled tungsten filament is to mix finely divided tantalum pentachloride with alcohol until a paste is formed which can then be applied to the surface of the wire. This paste may be brushed onto the filament, or the mixture of alcohol and tantalum pentachloride may be made thinner and applied to the filament by tains a shiny white surface which appears to be tantalum metal but may and probably does contain tantalum hydride. But whatever the constituentsof the coating, it has a melting point lower than that of tungsten, and if this filament is-mounted in a lamp, preferably with an inert gas, as mentioned above, the operating temperature can be maintained at a point close to the melting point of tantalum. In the presence of an inert gas the temperature may be maintained higher without danger of damaging the filament as the gas tends to rapidly dissipate the heat evolved. The filament may, however, be operated in a vacuum although the results obtained are not as good.
In some cases it may be preferable to apply the tantalum coating before the filament is drawn into a wire. In this case a slug 21 (Fig. 3) may be coated with tantalum in a. manner described above for the filament. After the tantalum coating has been sintered onto the slug by heating, the slug may be swaged to decrease its diameter and compact the metal particles more strongly together, after which the slug may be drawn into a wire similar to the manner of drawing tungsten wire. .After the wire is formed it has a. surface of a thin film of the tantalum and may be coiled or otherwise formed into the proper shape of the filament.
Other methods of applying. the metal to the filament core or to theslug before drawing may be'used, such as by electro-plating or spraying molten metal thereon, it being only necessary that the coating metal be firmly adherent to the core or otherwise arranged so as not to be thrown off therefrom.
When inthe preferred form of the invention a tungsten core is coated with a coating of tantalum the tantalumwhas another beneficial effect as the coating prevents the evaporation-of the tungsten core caused by the presence of a slight amount of water vapor in the bulb. Water vapor attacking the tantalum coating appears to form a stable tantalum oxide which is not affected by tungsten forms tungstic oxide and free hydrogen. The oxide is deposited on the wall of the lamp where hydrogen combines with it again to form free tungsten and water vapor, and the cycle is repeated until the filament is destroyed. The
coating, therefore, acts as a protecting shield for the tungsten core and also as a clean-up agent to eliminate any water vapor which may be present.
While the complete coating of the lower melting point metal upon the core may be preferred the invention also contemplates the incorporation of such lower melting point metal with the other metal to form a physical mixture or an alloy. The invention also contemplates the association of the lower melting point metal with that of higher melting point without any physical attachment therebetween, as by merely positioning the two in close juxtaposition or by wrapping a wire or ribbon of the lower melting point metal around a wire of thehigher melting point metal. Such a construction, however, will not be as effective as the coating because the latter provides a larger radiating surface and may be maintained at a higher temperature due to the rapid heat flow between the core and the coating.
Many other variations and changes in the construction shown and described may be resorted to without departing from the spirit of the invention, and I do not, therefore, desire to limit myself to what has been shown and described except as such limitations occur in the appended claims.
What I claim is:
1. An electric lamp comprising an envelope having a high degreeof transparency for ultraviolet radiation, a tungsten filament within said envelope, a coating of tantalum on the surface thereof and closely adherent thereto, and an inert gas including argon and nitrogen within said envelope, the pressure of said gas being approximately atmospheric.
2. An electric lamp comprising an envelope having a high degree of transparency for ultraviolet radiation, a tungsten filament within said envelope, a coating of tantalum on the surface thereof and closely adherent thereto, and an inert gas by volume over of argon and over 10% of nitrogen within said envelope having a pressure substantially atmospheric.
3. An electric lamp comprising an envelope having'a high degree of transparency for ultraviolet radiation, a tungsten filament within said envelope, and a coating of tantalum and tantalum hydride on the surface thereof and closely adherent thereto.
CHESTER H. BRIASELTON.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US634481A US2069713A (en) | 1932-09-23 | 1932-09-23 | Electric lamp for producing short wave length radiation |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US634481A US2069713A (en) | 1932-09-23 | 1932-09-23 | Electric lamp for producing short wave length radiation |
Publications (1)
Publication Number | Publication Date |
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US2069713A true US2069713A (en) | 1937-02-02 |
Family
ID=24543973
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US634481A Expired - Lifetime US2069713A (en) | 1932-09-23 | 1932-09-23 | Electric lamp for producing short wave length radiation |
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US (1) | US2069713A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3960533A (en) * | 1974-09-20 | 1976-06-01 | Gte Sylvania Incorporated | Lamp having crystallizable light diffusing envelope |
US3982046A (en) * | 1973-01-19 | 1976-09-21 | Thorn Lighting Limited | Incandescent lamps |
US6510264B2 (en) | 2000-07-31 | 2003-01-21 | Corning Incorporated | Bulk internal bragg gratings and optical devices |
US6632759B2 (en) | 2000-07-31 | 2003-10-14 | Corning Incorporated | UV photosensitive melted germano-silicate glasses |
US6731839B2 (en) | 2000-07-31 | 2004-05-04 | Corning Incorporated | Bulk internal Bragg gratings and optical devices |
US6828262B2 (en) | 2000-07-31 | 2004-12-07 | Corning Incorporated | UV photosensitive melted glasses |
-
1932
- 1932-09-23 US US634481A patent/US2069713A/en not_active Expired - Lifetime
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3982046A (en) * | 1973-01-19 | 1976-09-21 | Thorn Lighting Limited | Incandescent lamps |
US3960533A (en) * | 1974-09-20 | 1976-06-01 | Gte Sylvania Incorporated | Lamp having crystallizable light diffusing envelope |
US6510264B2 (en) | 2000-07-31 | 2003-01-21 | Corning Incorporated | Bulk internal bragg gratings and optical devices |
US6632759B2 (en) | 2000-07-31 | 2003-10-14 | Corning Incorporated | UV photosensitive melted germano-silicate glasses |
US6731839B2 (en) | 2000-07-31 | 2004-05-04 | Corning Incorporated | Bulk internal Bragg gratings and optical devices |
US6828262B2 (en) | 2000-07-31 | 2004-12-07 | Corning Incorporated | UV photosensitive melted glasses |
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