CA1280149C - Mercury pressurized incandescent lamp - Google Patents
Mercury pressurized incandescent lampInfo
- Publication number
- CA1280149C CA1280149C CA000522989A CA522989A CA1280149C CA 1280149 C CA1280149 C CA 1280149C CA 000522989 A CA000522989 A CA 000522989A CA 522989 A CA522989 A CA 522989A CA 1280149 C CA1280149 C CA 1280149C
- Authority
- CA
- Canada
- Prior art keywords
- mercury
- envelope
- incandescent lamp
- 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
Links
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 229910052753 mercury Inorganic materials 0.000 title claims abstract description 39
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 31
- 239000010937 tungsten Substances 0.000 claims abstract description 31
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000001301 oxygen Substances 0.000 claims abstract description 17
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 17
- 239000011261 inert gas Substances 0.000 claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims abstract description 7
- 239000002184 metal Substances 0.000 claims abstract description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 5
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 5
- 229910052796 boron Inorganic materials 0.000 claims description 5
- 230000008020 evaporation Effects 0.000 claims description 5
- 238000001704 evaporation Methods 0.000 claims description 5
- 239000011521 glass Substances 0.000 claims description 5
- 229910052715 tantalum Inorganic materials 0.000 claims description 5
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 5
- 239000010936 titanium Substances 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 229910052726 zirconium Inorganic materials 0.000 claims description 5
- 229910052743 krypton Inorganic materials 0.000 claims description 4
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 229910052724 xenon Inorganic materials 0.000 claims description 4
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 claims description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims description 3
- 239000011574 phosphorus Substances 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims 1
- 229910052736 halogen Inorganic materials 0.000 abstract description 16
- 150000002367 halogens Chemical class 0.000 abstract description 14
- 239000000654 additive Substances 0.000 abstract description 3
- 230000000996 additive effect Effects 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000001172 regenerating effect Effects 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- VNQLBSAIKVNHFM-UHFFFAOYSA-N [W].[Hg] Chemical compound [W].[Hg] VNQLBSAIKVNHFM-UHFFFAOYSA-N 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000002939 deleterious effect Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000011850 initial investigation Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/50—Selection of substances for gas fillings; Specified pressure thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/52—Means for obtaining or maintaining the desired pressure within the vessel
- H01K1/54—Means for absorbing or absorbing gas, or for preventing or removing efflorescence, e.g. by gettering
- H01K1/56—Means for absorbing or absorbing gas, or for preventing or removing efflorescence, e.g. by gettering characterised by the material of the getter
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
Landscapes
- Discharge Lamp (AREA)
- Vessels And Coating Films For Discharge Lamps (AREA)
Abstract
MERCURY PRESSURIZED INCANDESCENT LAMP
ABSTRACT OF THE DISCLOSURE
An incandescent lamp housing a tungsten filament and containing an inert gas, a vaporizable metal mercury at a high operating pressure and an oxygen getter is disclosed. The high pressure mercury in cooperation with the oxygen getter and without the need of a halogen additive reduces or even eliminates the typically experienced wall blackening of the incandescent lamp.
ABSTRACT OF THE DISCLOSURE
An incandescent lamp housing a tungsten filament and containing an inert gas, a vaporizable metal mercury at a high operating pressure and an oxygen getter is disclosed. The high pressure mercury in cooperation with the oxygen getter and without the need of a halogen additive reduces or even eliminates the typically experienced wall blackening of the incandescent lamp.
Description
1~30149 MERCURY PRESSUPIZED INCANDESCENT L~P
BACKGROUND OF THE TNVENTION
This invention is related to an incandescent lamp, and more particularly, to an incandescent lamp housing a tungsten filament and containing an inert gas along with the vaporizable metal mercury.
In typical operation of incandescent lamps over an extended period of time, some of the tungsten of a tungsten type filament evaporates and becomes deposited on the-wall of the lamp. This deposition typically causes darkening of the bulb wall which, in turn, decreases the lumen output of the lamp thereby decreasing the lumens per watt or efficacy of the lamp.
It is known that the darkening of the bulb wall caused by the tungsten type filament may be substantially reduced by providing a halogen gas type atmosphere surrounding the tungsten-type filament so as to provide a regenerative (transport) cycle which returns the evaporated tungsten to the filament and keeps the bulb walls clean and results in improved efficacy of the incandescent lamp. '"~
, `3 - 2 - LD 77~3 Incandescent la~ps utilizing a halogen atmosphere are well-known and are described as such in lU.S. Patent 2,883,571 of Fridrich et al, U.S. Patent 3,497,754 of P. D. Johnson and U. K. Patent Specification 952,93~3 of J. N Bowtell and J. A. Moore.
Although the halogen atmosphere operates very effectively as a transport agent it also has a deleterious effect with regard to its reaction with the inner leads supporting the tungsten filament within the lamp. To avoid such a deleterious effect these inleads are commonly formed of a relatively expensive material such as molybdenum and tungsten. The halogen atmosphere also has a drawback in that during the manufacturing process of the halogen lamp safeguards need to be accomplished to prevent gaseous impurities from entering the confines of the lamp that would otherwise degrade the tungsten-halogen regenerative cycle.
It is desired that the tungsten deposition rate onto the walls of the incandescent type lamps be reduced in order to eliminate the use of a halogen transport agent so as to allow the use of less expensive inner leads e.g., nickel, and nickel-plated iron and, also to ease the manufacturing process of the incandescent type lamp.
Accordingly, it is an object of the present invention to provide a means whereby the bulb walls of the incandescent type lamp remain clean without the use of a halogen transport agent.
These and other objects of the present invention will become apparent upon consideration of the following description taken in conjunction with the accompanying drawing.
SUMMARY OF THE INVENTION
In accordance with the present invention an efficacy improved mercury pressurized incandescent lamp is provided having an envelope containing a tungsten filament, an inert gas, a predetermined amount of )149 _ ~ - LD 7763 vaporizable mercury, and an oxygen getter.
The mercury pressurized incandescent lamp comprises a light transmitting envelope having spatially disposed therein the tungsten filament, the oxygen getter, and contains an inert gas along with the vapor-izable metal mercury. The inert gas has a fill pressure of about slightly less than 1 atmosphere for ease of manufacturing but can be greater than 1 atmosphere and is selected from the group consisting of argon, nitrogen, krypton and xenon. The mercury pressure is desired to be as high as possible to suppress tungsten evaporation from the filament and is determined by cold spot temperatures of the lamp. A
cold spot temperature of about 450 C or more is necessary so as to advantageously obtain an operating mercury pressure of five (5) atmospheres or more. The oxygen getter is selected from the group consisting of titanium, zirconium, tantalum, phosphorous and boron.
The features of this invention believed to be novel as set forth with particularity in the appended - claims. The invention, itself, however, both as to its method and operation, together with further objects and ldvantages thereof, may be best understood by referring to the following description taXen in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is the only drawing of the present invention and illustrates an improved efficacy, mercury pressurized light sources findinq application in various incandescent type lamps.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1, illustrates a mercury pressurized incandescent lamp 10 in accordance with one of the embodiments of the present invention.
The lamp 10 has an envelope 12 which may be comprised of a relatively thick, about 1.0 mm., translucent glass material. The envelope 12 may be 'i~8~)14~
BACKGROUND OF THE TNVENTION
This invention is related to an incandescent lamp, and more particularly, to an incandescent lamp housing a tungsten filament and containing an inert gas along with the vaporizable metal mercury.
In typical operation of incandescent lamps over an extended period of time, some of the tungsten of a tungsten type filament evaporates and becomes deposited on the-wall of the lamp. This deposition typically causes darkening of the bulb wall which, in turn, decreases the lumen output of the lamp thereby decreasing the lumens per watt or efficacy of the lamp.
It is known that the darkening of the bulb wall caused by the tungsten type filament may be substantially reduced by providing a halogen gas type atmosphere surrounding the tungsten-type filament so as to provide a regenerative (transport) cycle which returns the evaporated tungsten to the filament and keeps the bulb walls clean and results in improved efficacy of the incandescent lamp. '"~
, `3 - 2 - LD 77~3 Incandescent la~ps utilizing a halogen atmosphere are well-known and are described as such in lU.S. Patent 2,883,571 of Fridrich et al, U.S. Patent 3,497,754 of P. D. Johnson and U. K. Patent Specification 952,93~3 of J. N Bowtell and J. A. Moore.
Although the halogen atmosphere operates very effectively as a transport agent it also has a deleterious effect with regard to its reaction with the inner leads supporting the tungsten filament within the lamp. To avoid such a deleterious effect these inleads are commonly formed of a relatively expensive material such as molybdenum and tungsten. The halogen atmosphere also has a drawback in that during the manufacturing process of the halogen lamp safeguards need to be accomplished to prevent gaseous impurities from entering the confines of the lamp that would otherwise degrade the tungsten-halogen regenerative cycle.
It is desired that the tungsten deposition rate onto the walls of the incandescent type lamps be reduced in order to eliminate the use of a halogen transport agent so as to allow the use of less expensive inner leads e.g., nickel, and nickel-plated iron and, also to ease the manufacturing process of the incandescent type lamp.
Accordingly, it is an object of the present invention to provide a means whereby the bulb walls of the incandescent type lamp remain clean without the use of a halogen transport agent.
These and other objects of the present invention will become apparent upon consideration of the following description taken in conjunction with the accompanying drawing.
SUMMARY OF THE INVENTION
In accordance with the present invention an efficacy improved mercury pressurized incandescent lamp is provided having an envelope containing a tungsten filament, an inert gas, a predetermined amount of )149 _ ~ - LD 7763 vaporizable mercury, and an oxygen getter.
The mercury pressurized incandescent lamp comprises a light transmitting envelope having spatially disposed therein the tungsten filament, the oxygen getter, and contains an inert gas along with the vapor-izable metal mercury. The inert gas has a fill pressure of about slightly less than 1 atmosphere for ease of manufacturing but can be greater than 1 atmosphere and is selected from the group consisting of argon, nitrogen, krypton and xenon. The mercury pressure is desired to be as high as possible to suppress tungsten evaporation from the filament and is determined by cold spot temperatures of the lamp. A
cold spot temperature of about 450 C or more is necessary so as to advantageously obtain an operating mercury pressure of five (5) atmospheres or more. The oxygen getter is selected from the group consisting of titanium, zirconium, tantalum, phosphorous and boron.
The features of this invention believed to be novel as set forth with particularity in the appended - claims. The invention, itself, however, both as to its method and operation, together with further objects and ldvantages thereof, may be best understood by referring to the following description taXen in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is the only drawing of the present invention and illustrates an improved efficacy, mercury pressurized light sources findinq application in various incandescent type lamps.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1, illustrates a mercury pressurized incandescent lamp 10 in accordance with one of the embodiments of the present invention.
The lamp 10 has an envelope 12 which may be comprised of a relatively thick, about 1.0 mm., translucent glass material. The envelope 12 may be 'i~8~)14~
formed of glass tubing with an outer diameter in the range of about 5 mm to about 10 mm. The envelope 12 may be of a ~180 type low sodium, high temperature glass r available from the General Electric Glass Department of Cleveland, Ohio, and permits high wall temperatures necessary to vaporize the mercury and also advantageously provide high operating pressures.
The light transmissive envelope 12, shown in FIG. 1, has spatially disposed therein, in a transverse manner, a tungsten filament 14. The filament 14 may also be arranged to be disposed in a coaxial manner within the envelope 12. Further, the lamp 10 shown in FIG. 1 as being of a single-ended arrangement with both inner leads 16 and 18 extending out of the same end of envelope 12, may also be arranged as a double-ended lamp wherein inner leads 16 and 18 extend out of opposite ends of envelope 12.
The parameter of the filament 14, such as the number of turns of tungsten wire, the pitch ratio of the turns, the length and wire size, are all preselected in according with the excitation voltage desired to operate the lamp 10. The filament 14, shown in FIG 1, is connected across the pair of inner leads 16 and 18 which enter, extend through and exit out of a pinch seal region 20 of the envelope 12.
The inner leads 16 and 18 are formed of a relatively inexpensive material such as nickel, and nickel-plated iron. As discussed in the "Background"
section of the present invention, the use of these 30 relatively inexpensive inner leads in the lamp 10 is advantageous over prior art tungsten lamps having a halogen gas which require relatively expensive materials inner leads such as molybdenum and tungsten. These relatively expensive inner leads are necessitated by the use of a halogen gas within the envelope as a transport agent to return evaporated tungsten back to the filament. Further~ the halogen gas necessitates _ 5 _ LD 7763 safeguards during the related manufacturing process so as to prevent gaseous impurites from entering the c:onfines of the related lamp which would otherwise r clegrade the performance of the tungsten-halogen regenerative cycle.
The present invention negates the need of these expensive inner leads and eases the manufacturing process of related lamp by eliminatin~ the use of a halogen additive and instead provides a vaporizable metal mercury operated at a relatively high pressure as the transport agent of lamp 10.
The light transmissive envelope contains an inert gas, a vaporizable metal mercury and an oxygen getter. The inert gas has a fill pressure of slightly less than one atmosphere, more particularly, it is the range of about 600 torr to about 700 torr, for ease of manufacturing and is selected from the group consisting of argon, krypton, xenon, and nitrogen. The lamp may contain a pressure of inert gas in excess of 1 atmosphere for higher total pressure during operation.
The mercury pressure within the lamp is desired to be as high as possible and is determined by the cold spot temperatures of the lamp. A cold spot temperature in excess of 450 C is desired so as to obtain an operating mercury pressure of five (5) atmospheres or 25 more. The cold spot temperatures are occurring within the envelope 12 at locations remote from the operating filament such as those locations in the upper and lower regions of the envelope 12. For an envelope with a volume of lcc and a cold spot temperature of 450C, 16.7 mg of mercury produces an operating pressure of five (5) atmospheres, and for the same envelope having a cold spot temperature of 510~C, 31 mg of mercury produces an operating pressure of ten (10) atmospheres. The amount of mercury within the lamp should also be such that it is completely vaporized during operation so that there is no condensed liquid mercury present that would otherwise result in a potential arcing problem between the inner leads of the lamp.
Further, the envelope 12 contains an oxygen getter 22 selected from the group consisting of titanium, zirconium, tantalum, phosphorus and boron. If an oxygen getter 22 is selected from the group consisting of titanium, zirconium, tantalum, and boron it may be in the form of a pad affixed to either or both of the inner leads, so long as it is connected within the confines of the envelope 12, and is shown in FIG. 1 as being affixed to inner lead 18. If phosphorus is selected as the oxygen getter 22, it may be placed into the envelope in the form of a slurry added onto the filament 14.
For the operation of lamp 10, it is necessary to eliminate or minimize the transport of tungsten from the filament to the bulb wall by the well-known water cycle, and this can be accomplished by the addition of the known getters such as titanium, zirconium, tantalum, phosphorous and boron. In general, these getters are added in milligram quantities which is a function of the volu~e of the lamp 10. For the lamps contemplated by the present invention, the amount of getter is desired to be in the range of 0.1 milligrams to 1.0 milligram.
The incandescent lamp 10 of the present invention containing the high pressure of mercury in the envelope 12 reduces the occurrences of arcing between the inner leads which may renders the lamp 10 inoperable.
These arcing conditions, without the benefits of the present invention, are most prominent when the lamp is operated with voltage excitation in excess of 120 volts and reduces as the operating voltage is lowered to a value of about 10 volts. The arcing problem particularly noticed at the higher voltages, may be reduced by the selection of the relatively heavy inert gases of krypton and xenon along with the addition of nitrogen. The present invention of lamp 10 also containing the high pressure of mercury suppresses the evaporation of 1~30149 - 7 - LD 77~3 tungsten from the filament and thus reduces the rate of wall blackening of the envelope 12.
In our initial investigation, an attempt to r calculate the evaporation rate of tungsten, or more particularly, the arrival rate of the evaporated tungsten from the filament at the walls of the mercury pressured lamp, revealed that an unusual situation exists in such a lamp in that the mercury ingredient which acts as buffer gas was heavier than the dilute species of tungsten which evaporates from the filament.
As a result of our lamp test findings, we were unable to determine, by a light transmission technique, the approximate rate of tungsten evaporation in this environment. The contribution of concentration or thermal diffusion to the tungsten transport from the filament to the walls of the envelope is related to the temperature difference between the energized filament and the walls of the envelope. The contribution and the sign~ positive or negative contribution, of the transport due to thermal diffusion was unknown initially.
After further investigation, we determined that because mercury, which is heavier than the tungsten material being evaporated, was acting as a buffer gas and up-gradient transport was apparently taking place.
The up-gradient transport was unexpected in that a down-gradient transport of tungsten from the hot filament to the cold wall, was expected which would otherwise increase the deposition rate of the evaporated tungsten to the walls of the envelope. ~owever, the 3~ unique mercury-tungsten interaction decreased the rate of arrival of the evaporated tungsten at the walls of the envelope 12.
We further recognized that in the mercury pressurized lamps of our invention not having a halogen additive, an effective oxygen getter, such as those previously described, further reduces the transport of tungsten from the filament to the wall of the envelope 014g otherwise occurring by a water cycle transfer created by oxygen bearing impurities, specifically water (H2O) or carbon dioxide (CO2) that may have entered the confines of envelope 12.
The combination of mercury-tungsten interaction and the oxygen getter both of the present invention reduces the deposition rate of the evaporated tungsten at the wall of the envelope 12 and thereby prolongs the life of lamp 10 with regard to its efficient operation.
In the practice of our invention two (2) lamps havin~ ar~on and mercury, in amounts previously described and an oxygen getter were tested. In contemplation of the testing, it was our expectation that the lamps to be tested which were processed to minimize oxygen contamination, and accordingly, the water cycle transfer, would experience blackening of the walls of the envelope a~ter a period of approximately 50 hours. To our surprise the lamps were successfuly operated for a period of over 700 hours without experiencing any visible blackening of the walls of the inner envelope.
It should now be appreciated that the present invention provides a mercury pressurized incandescent lamp that provides for means to reduce or even eliminate the wall blackening of the incandescent lamp without the need of a halogen gas.
The light transmissive envelope 12, shown in FIG. 1, has spatially disposed therein, in a transverse manner, a tungsten filament 14. The filament 14 may also be arranged to be disposed in a coaxial manner within the envelope 12. Further, the lamp 10 shown in FIG. 1 as being of a single-ended arrangement with both inner leads 16 and 18 extending out of the same end of envelope 12, may also be arranged as a double-ended lamp wherein inner leads 16 and 18 extend out of opposite ends of envelope 12.
The parameter of the filament 14, such as the number of turns of tungsten wire, the pitch ratio of the turns, the length and wire size, are all preselected in according with the excitation voltage desired to operate the lamp 10. The filament 14, shown in FIG 1, is connected across the pair of inner leads 16 and 18 which enter, extend through and exit out of a pinch seal region 20 of the envelope 12.
The inner leads 16 and 18 are formed of a relatively inexpensive material such as nickel, and nickel-plated iron. As discussed in the "Background"
section of the present invention, the use of these 30 relatively inexpensive inner leads in the lamp 10 is advantageous over prior art tungsten lamps having a halogen gas which require relatively expensive materials inner leads such as molybdenum and tungsten. These relatively expensive inner leads are necessitated by the use of a halogen gas within the envelope as a transport agent to return evaporated tungsten back to the filament. Further~ the halogen gas necessitates _ 5 _ LD 7763 safeguards during the related manufacturing process so as to prevent gaseous impurites from entering the c:onfines of the related lamp which would otherwise r clegrade the performance of the tungsten-halogen regenerative cycle.
The present invention negates the need of these expensive inner leads and eases the manufacturing process of related lamp by eliminatin~ the use of a halogen additive and instead provides a vaporizable metal mercury operated at a relatively high pressure as the transport agent of lamp 10.
The light transmissive envelope contains an inert gas, a vaporizable metal mercury and an oxygen getter. The inert gas has a fill pressure of slightly less than one atmosphere, more particularly, it is the range of about 600 torr to about 700 torr, for ease of manufacturing and is selected from the group consisting of argon, krypton, xenon, and nitrogen. The lamp may contain a pressure of inert gas in excess of 1 atmosphere for higher total pressure during operation.
The mercury pressure within the lamp is desired to be as high as possible and is determined by the cold spot temperatures of the lamp. A cold spot temperature in excess of 450 C is desired so as to obtain an operating mercury pressure of five (5) atmospheres or 25 more. The cold spot temperatures are occurring within the envelope 12 at locations remote from the operating filament such as those locations in the upper and lower regions of the envelope 12. For an envelope with a volume of lcc and a cold spot temperature of 450C, 16.7 mg of mercury produces an operating pressure of five (5) atmospheres, and for the same envelope having a cold spot temperature of 510~C, 31 mg of mercury produces an operating pressure of ten (10) atmospheres. The amount of mercury within the lamp should also be such that it is completely vaporized during operation so that there is no condensed liquid mercury present that would otherwise result in a potential arcing problem between the inner leads of the lamp.
Further, the envelope 12 contains an oxygen getter 22 selected from the group consisting of titanium, zirconium, tantalum, phosphorus and boron. If an oxygen getter 22 is selected from the group consisting of titanium, zirconium, tantalum, and boron it may be in the form of a pad affixed to either or both of the inner leads, so long as it is connected within the confines of the envelope 12, and is shown in FIG. 1 as being affixed to inner lead 18. If phosphorus is selected as the oxygen getter 22, it may be placed into the envelope in the form of a slurry added onto the filament 14.
For the operation of lamp 10, it is necessary to eliminate or minimize the transport of tungsten from the filament to the bulb wall by the well-known water cycle, and this can be accomplished by the addition of the known getters such as titanium, zirconium, tantalum, phosphorous and boron. In general, these getters are added in milligram quantities which is a function of the volu~e of the lamp 10. For the lamps contemplated by the present invention, the amount of getter is desired to be in the range of 0.1 milligrams to 1.0 milligram.
The incandescent lamp 10 of the present invention containing the high pressure of mercury in the envelope 12 reduces the occurrences of arcing between the inner leads which may renders the lamp 10 inoperable.
These arcing conditions, without the benefits of the present invention, are most prominent when the lamp is operated with voltage excitation in excess of 120 volts and reduces as the operating voltage is lowered to a value of about 10 volts. The arcing problem particularly noticed at the higher voltages, may be reduced by the selection of the relatively heavy inert gases of krypton and xenon along with the addition of nitrogen. The present invention of lamp 10 also containing the high pressure of mercury suppresses the evaporation of 1~30149 - 7 - LD 77~3 tungsten from the filament and thus reduces the rate of wall blackening of the envelope 12.
In our initial investigation, an attempt to r calculate the evaporation rate of tungsten, or more particularly, the arrival rate of the evaporated tungsten from the filament at the walls of the mercury pressured lamp, revealed that an unusual situation exists in such a lamp in that the mercury ingredient which acts as buffer gas was heavier than the dilute species of tungsten which evaporates from the filament.
As a result of our lamp test findings, we were unable to determine, by a light transmission technique, the approximate rate of tungsten evaporation in this environment. The contribution of concentration or thermal diffusion to the tungsten transport from the filament to the walls of the envelope is related to the temperature difference between the energized filament and the walls of the envelope. The contribution and the sign~ positive or negative contribution, of the transport due to thermal diffusion was unknown initially.
After further investigation, we determined that because mercury, which is heavier than the tungsten material being evaporated, was acting as a buffer gas and up-gradient transport was apparently taking place.
The up-gradient transport was unexpected in that a down-gradient transport of tungsten from the hot filament to the cold wall, was expected which would otherwise increase the deposition rate of the evaporated tungsten to the walls of the envelope. ~owever, the 3~ unique mercury-tungsten interaction decreased the rate of arrival of the evaporated tungsten at the walls of the envelope 12.
We further recognized that in the mercury pressurized lamps of our invention not having a halogen additive, an effective oxygen getter, such as those previously described, further reduces the transport of tungsten from the filament to the wall of the envelope 014g otherwise occurring by a water cycle transfer created by oxygen bearing impurities, specifically water (H2O) or carbon dioxide (CO2) that may have entered the confines of envelope 12.
The combination of mercury-tungsten interaction and the oxygen getter both of the present invention reduces the deposition rate of the evaporated tungsten at the wall of the envelope 12 and thereby prolongs the life of lamp 10 with regard to its efficient operation.
In the practice of our invention two (2) lamps havin~ ar~on and mercury, in amounts previously described and an oxygen getter were tested. In contemplation of the testing, it was our expectation that the lamps to be tested which were processed to minimize oxygen contamination, and accordingly, the water cycle transfer, would experience blackening of the walls of the envelope a~ter a period of approximately 50 hours. To our surprise the lamps were successfuly operated for a period of over 700 hours without experiencing any visible blackening of the walls of the inner envelope.
It should now be appreciated that the present invention provides a mercury pressurized incandescent lamp that provides for means to reduce or even eliminate the wall blackening of the incandescent lamp without the need of a halogen gas.
Claims (4)
1. A mercury pressurized incandescent lamp comprising:
a light transmissive envelope;
a tungsten filament having parameters selected in accordance with the desired operating voltage of said lamp and spatially disposed within said envelope by a pair of inner leads composed of the group of metals of nickel and nickel-plated iron;
an inert gas contained within said envelope and having a fill pressure of about 600 torr to about 700 torr or more, said inert gas being selected from the group consisting of argon, nitrogen, krypton and xenon;
a vaporizable metal of mercury contained within said envelope having an amount determined by the cold spot temperature of said envelope, said cold spot temperature being in excessive of 450°C so as to obtain an operating mercury pressure of five (5) atmospheres or more; and an oxygen getter within said envelope and selected from the group consisting of titanium, zirconium, tantalum, phosphorus and boron;
said operating pressure of mercury in cooperation with said oxygen getter being effective in suppressing evaporation of tungsten from said filament and reducing the rate of wall blackening of said light transmissive envelope.
a light transmissive envelope;
a tungsten filament having parameters selected in accordance with the desired operating voltage of said lamp and spatially disposed within said envelope by a pair of inner leads composed of the group of metals of nickel and nickel-plated iron;
an inert gas contained within said envelope and having a fill pressure of about 600 torr to about 700 torr or more, said inert gas being selected from the group consisting of argon, nitrogen, krypton and xenon;
a vaporizable metal of mercury contained within said envelope having an amount determined by the cold spot temperature of said envelope, said cold spot temperature being in excessive of 450°C so as to obtain an operating mercury pressure of five (5) atmospheres or more; and an oxygen getter within said envelope and selected from the group consisting of titanium, zirconium, tantalum, phosphorus and boron;
said operating pressure of mercury in cooperation with said oxygen getter being effective in suppressing evaporation of tungsten from said filament and reducing the rate of wall blackening of said light transmissive envelope.
2. A mercury pressurized incandescent lamp according to claim 1 wherein said envelope is formed of glass having a high operating characteristic and having an outer diameter in the range of about 5 mm to about 10 mm.
3. A mercury pressurized incandescent lamp according to claim 1 wherein said oxygen getter is in the range of about 0.1 mg to about 1 mg, depending on the lamp volume.
4. A mercury pressurized incandescent lamp according to claim 1 wherein said envelope has a volume of about 1 cc and said mercury is of a quantity in the range of about 16.7 mg to about 31 mg.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US79855085A | 1985-11-15 | 1985-11-15 | |
| US798,550 | 1985-11-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1280149C true CA1280149C (en) | 1991-02-12 |
Family
ID=25173685
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000522989A Expired - Lifetime CA1280149C (en) | 1985-11-15 | 1986-11-14 | Mercury pressurized incandescent lamp |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS62157670A (en) |
| CA (1) | CA1280149C (en) |
| DE (1) | DE3637693A1 (en) |
| FR (1) | FR2606933A1 (en) |
| GB (1) | GB2183088A (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2156057A (en) * | 1937-04-30 | 1939-04-25 | Gen Electric | Electric lamp |
-
1986
- 1986-11-05 GB GB08626418A patent/GB2183088A/en not_active Withdrawn
- 1986-11-05 DE DE19863637693 patent/DE3637693A1/en not_active Withdrawn
- 1986-11-07 FR FR8615543A patent/FR2606933A1/en not_active Withdrawn
- 1986-11-14 CA CA000522989A patent/CA1280149C/en not_active Expired - Lifetime
- 1986-11-14 JP JP61270033A patent/JPS62157670A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB2183088A (en) | 1987-05-28 |
| FR2606933A1 (en) | 1988-05-20 |
| GB8626418D0 (en) | 1986-12-03 |
| JPS62157670A (en) | 1987-07-13 |
| DE3637693A1 (en) | 1987-05-21 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed |