GB2037478A - Metal vapour lasers - Google Patents
Metal vapour lasers Download PDFInfo
- Publication number
- GB2037478A GB2037478A GB7934171A GB7934171A GB2037478A GB 2037478 A GB2037478 A GB 2037478A GB 7934171 A GB7934171 A GB 7934171A GB 7934171 A GB7934171 A GB 7934171A GB 2037478 A GB2037478 A GB 2037478A
- Authority
- GB
- United Kingdom
- Prior art keywords
- wick
- metal
- metal vapor
- vapor laser
- wicks
- 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
Links
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 27
- 239000002184 metal Substances 0.000 title claims abstract description 27
- 239000000758 substrate Substances 0.000 claims abstract description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 16
- 239000010410 layer Substances 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 11
- 229910001220 stainless steel Inorganic materials 0.000 claims description 9
- 239000010935 stainless steel Substances 0.000 claims description 9
- 229910052759 nickel Inorganic materials 0.000 claims description 8
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 8
- 229910052721 tungsten Inorganic materials 0.000 claims description 8
- 239000010937 tungsten Substances 0.000 claims description 8
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims description 5
- 239000011733 molybdenum 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
- 239000002344 surface layer Substances 0.000 claims description 2
- NFFIWVVINABMKP-UHFFFAOYSA-N methylidynetantalum Chemical compound [Ta]#C NFFIWVVINABMKP-UHFFFAOYSA-N 0.000 claims 1
- 229910003468 tantalcarbide Inorganic materials 0.000 claims 1
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims 1
- 239000000203 mixture Substances 0.000 abstract 1
- 230000003134 recirculating effect Effects 0.000 abstract 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- LTPBRCUWZOMYOC-UHFFFAOYSA-N Beryllium oxide Chemical compound O=[Be] LTPBRCUWZOMYOC-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910001120 nichrome Inorganic materials 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 238000007750 plasma spraying Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/36—Accumulators not provided for in groups H01M10/05-H01M10/34
- H01M10/39—Accumulators not provided for in groups H01M10/05-H01M10/34 working at high temperature
- H01M10/3909—Sodium-sulfur cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings; Jackets or wrappings
- H01M50/138—Primary casings; Jackets or wrappings adapted for specific cells, e.g. electrochemical cells operating at high temperature
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/02—Constructional details
- H01S3/03—Constructional details of gas laser discharge tubes
- H01S3/031—Metal vapour lasers, e.g. metal vapour generation
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Manufacturing & Machinery (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
Wicks for recirculating condensed vapor back to the discharge zone of a metal vapor laser are disclosed. The wicks 22, 24 are generally tubular in configuration and may be formed of sintered metal or of a metal substrate with a porous plasma sprayed layer thereon. Separate gas discharge electrodes 13, 14, may be used, so the wicks additionally function as electrodes. The gas mixture may include a buffer gas. <IMAGE>
Description
SPECIFICATION
Plasma sprayed wicks for pulsed metal vapor lasers
This invention relates generally to metal vapor lasers and more particularly to wicks used in such lasers for recirculation of condensed metal vapor.
In operation of a metal vapor laser some of the metal vapor tends to nigrate from the hot discharge zone of the centre to the cooler areas at the ends where it condenses. It has previously been disclosed to use a wick structure such as is used in a heat pipe to recirculate the liquid metal back to the central zone where it will re-vaporize (see U.S. Patent 3,654,567).
According to the present invention, there is provided a metal vapor laser having a central discharge zone with both an electrode and a wick element at each end of said discharge zone; wherein each of the wick elements has at least a porous surface layer.
The wicks are used to convey condensed vapor back to the discharge zone of a metal vapor laser where it will revaporize. The wicks may have a porous plasma sprayed layer of a suitable metal on a substrate of a compatible metal. The wick may alternatively be formed from sintered metal.
The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 illustrates in section the overall structure of a laser including an embodiment of the invention; and
Figure 2 A-D illustrates wick cross-sections and fabrications.
Referring to Fig. 1, discharge tube 10 is impervious, non-electrically conducting, and of a high-density refractory material, preferably alumina, although zirconia, beryllia, or quartz may be used. Electrodes 12 and 14, at each end of discharge tube 10, are provided for initiating discharges therebetween responsive to laser discharge circuit 16. A laser discharge circuit 16, known per se, is not essential to the understanding of this invention and is only included to illustrate a complete laser system.
Housing 18, which may be stainless steel or copper, encloses discharge tube 10. Insulating member 20, which may be alumina, provides insulation between electrodes 12 and 14.
In accordance with the invention, positioned within and near the ends of discharge tube 10 and wicks 22 and 24. Each wick is normally displaced inwardly a short distance from the end of tube 10 to avoid an electrical connection to electrodes 12 and 14, although under some conditions they may be in contact and the wicks may act as electrodes. Electrode holders 26 and 28 make a mechanical and electrical connection to electrodes 12 and 14 respectively.
End sections 30 and 32 have windows 34 and 36, respectively, sealed to them. Mirrors 38 and 40 are provided outside windows 34 and 36 respectively.
In operation, a discharge between electrodes 12 and 14 through an inert gas, such as helium or neon, produces a vapor by heating a vapor source. Thermal shield 42 is employed to maintain the discharge zone of the discharge tube 10 at the desired temperature and the inside end of each wick at a temperature sufficiently high so that they might act as the source of vapor. The outside ends of the wicks are so placed with respect to the thermal shield so that they are sufficiently cool to prevent significant vaporization but not so cold that any condensed vapor will solidify.
Vapor which escapes from the discharge tube 10 and moves in the direction of windows 34 and 36 tends to condense on the ends of wicks 22 and 24 which are most distant from the discharge zone, i.e. the cooler ends. The condensate moves along wicks to the ends nearest the discharge zone where the higher temperature causes it to evaporate.
This recirculation minimizes depletion of vapor in the discharge zone-thereby extending the period over which the laser will operate in the desired fashion.
The mode of operation must not be similar to a heat pipe, however. In that mode large heat flux would be needed to maintain the temperature gradient in the wicks. There should consequently be a buffer gas having a pressure greatly exceeding that of the vapor pressure of the material being transported to restrict the transported material which can diffuse through the buffer. (The gas pressure should be at least three times higher than the vapor pressure.) The length of the wick needed will thus be partially controlled by this buffer since it must be sufficient to insure that almost all of the diffusing atoms will hit the wick walls before leaving the inside of the wick structure.
Wicks 22 and 24 may be thin porous shells as in Fig. 2B typically 1 mm (0.04 in) thick and 18 cm long (7 in) machined out of sintered metal. The grain size used has generally been about 5 microns giving 20%-30% porosity. Because of the requirement that the laser material wet the wick and the high temperatures involved, only specific materials are suitable for the wick. Tungsten, molybdenum, and tantalum are suitable for the copper and gold vapor lasers; nickel and stainless steel for the lead and bismuth vapor lasers, and stainless steel for the barium vapor laser.
A wick shell thickness of about 1 mm has been used. Too thick a shell will not be able to sustain the temperature differences needed between the two ends of each wick without unacceptable heat flow, particularly when a high conductivity material like copper fills the wick. Thinner shell walls will not have sufficient structural integrity.
Shapes similar to those shown in Fig. 2B or 2D can be easily produced by machining.
Wicks 22 and 24 may alternatively have a thin porous plasma sprayed inner layer on a suitable substrate. The plasma sprayed layer acts as the wick. Because of the typically high temperatures involved in laser operation, as well as the need for "wetting", only certain materials are suitable for use in the wick.
Substrate materials which may be employed include: tungsten, molybdenum, tantalum, nickel, nichrome and stainless steel. The plasma sprayed materials which may be used are: Tungsten, for the copper and gold vapor lasers, nickel and stainless steel for the lead and bismuth lasers, and stainless steel (probably also tungsten and nickel) for the barium laser.
The plasma sprayed material which is se- lected must also be compatible with the substrate material. Thus a plasma sprayed tungsten layer may be used with a substrate of tungsten, molybdenum, or tantalum. A stainless steel or nickel sprayed layer may be applied to nichrome or nickel substrate.
Referring to Fig. 2 A-D, the wick configuration may be cylindrical as in Fig. 2 A-C or have a rectangular or other cross-section. Because of the current sizes of lasers and plasma spraying equipment, it is not presently practical to apply a plasma spray to the inner surface of a configuration such a Fig. 2 B or
D. Wicks have been made successfully using the Fig. 2A configuration which is bent to the desired cross-section after the plasma sprayed layer has been applied. Substrate thicknesses of between 0.125 mm (.005 inches) and 0.25 mm (.010 inches) with plasma sprayed layers applied thereon of from 0. 125 mm (.005 inches) to 0.25 mm (010 inches have been fabricated. The limitation on thickness results from the need to have satisfactory wicks after bending. Too thick a layer will crack. As the sprayed layer is made thinner, it can become discontinuous, so there is also a practical limit to how thin the layer should be.
The Fig. 2C configuration is also readily fabricated. A substrate cylinder is cut in half, sprayed and then rejoined.
Claims (9)
1. A metal vapor laser having a central discharge zone with both an electrode and a wick element at each end of said discharge zone; wherein each of the wick elements has at least a porous surface layer.
2. A metal vapor laser as claimed in claim 1 wherein the wick is a sintered material.
3. A metal vapor laser as claimed in claim 1 or claim 2 wherein each of the wick elments has a porous plasma sprayed layer on a substrate.
4. A metal vapor laser as claimed in any one of claims 1 to 3 wherein the wick is a metal tube.
5. A metal vapor laser as claimed in any one of claims 1 to 4 wherein the wick is a porous plasma of nickel or stainless steel sprayed on a substrate of nickel or stainless steel.
6. A metal vapor laser as claimed in any one of claims 1 to 4 wherein the wick is a porous plasma layer of tungsten, molybdenum, tantalum, tungsten carbide or tantalum carbide sprayed on a substrate of tungsten, molybdenum and tantalum.
7. A metal vapor laser as claimed in any one of the preceding claims wherein the discharge zone also contains a buffer gas at a pressure greatly exceeding the vapor pressure of the active metal in use.
8. A metal vapor laser as claimed in claim 7 wherein the pressure is at least three times greater than that of the vapor pressure of the active metal in use.
9. A metal vapor laser as claimed in claim 1 substantially as hereinbefore described.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/959,035 US4247830A (en) | 1978-11-08 | 1978-11-08 | Plasma sprayed wicks for pulsed metal vapor lasers |
| ZA786815A ZA786815B (en) | 1978-12-05 | 1978-12-05 | Electrochemical cell and the protection of an electrochemical cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2037478A true GB2037478A (en) | 1980-07-09 |
| GB2037478B GB2037478B (en) | 1983-07-27 |
Family
ID=27130403
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7934171A Expired GB2037478B (en) | 1978-11-08 | 1979-10-02 | Metal vapour lasers |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2037478B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0204541A2 (en) * | 1985-06-04 | 1986-12-10 | English Electric Valve Company Limited | Discharge tube apparatus |
| EP0212776A2 (en) * | 1985-06-04 | 1987-03-04 | English Electric Valve Company Limited | Metal vapour discharge tubes |
-
1979
- 1979-10-02 GB GB7934171A patent/GB2037478B/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0204541A2 (en) * | 1985-06-04 | 1986-12-10 | English Electric Valve Company Limited | Discharge tube apparatus |
| EP0212776A2 (en) * | 1985-06-04 | 1987-03-04 | English Electric Valve Company Limited | Metal vapour discharge tubes |
| EP0212776A3 (en) * | 1985-06-04 | 1987-08-12 | English Electric Valve Company Limited | Metal vapour discharge tubes |
| EP0204541A3 (en) * | 1985-06-04 | 1987-08-12 | English Electric Valve Company Limited | Discharge tube apparatus |
| US4794614A (en) * | 1985-06-04 | 1988-12-27 | English Electric Valve Company Limited | Discharge tubes |
| US4805180A (en) * | 1985-06-04 | 1989-02-14 | English Electric Valve Company Limited | Discharge tube apparatus |
| AU582244B2 (en) * | 1985-06-04 | 1989-03-16 | English Electric Valve Company Limited | Discharge tubes |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2037478B (en) | 1983-07-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |