US3619699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Discharge lamp having cavity electrodes
Assignee: General Electric Co
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Filing: 1970-05-25
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Granted: 1971-11-09
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Expires: 1990-05-25
Abstract
Abstract A high-intensity electric discharge lamp having cavity electrodes operating in the hollow cathode mode. Penetration of the arc terminus into the electrode cavity is assisted by vapor breathing which injects plasma into the cavity during AC reignition after current zero. Breathing is favored by a cavity which is gastight and which has a depth not substantially greater than the terminus penetration. Relatively low temperatures deep within the cavity are avoided by providing enhanced thermal coupling between the forward end of the cavity member and the radiation shield surrounding it, and also by thermal insulation between the sides of the cavity member and the shield. Emission material located within the lower portion of the cavity favors deep terminus penetration. Projection of the radiation shield beyond the cavity member toward the other electrode is avoided.
Inventors
- 👤 John E White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:18
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/04; H01J61/06; H01J61/073; H01J61/0732
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
117 words
A high intensity metal vapor lamp comprising a vitreous envelope containing metal vapors and having a pair of electrodes sealed therein at least one of which is a thermionic self-heating cavity electrode operating in the hollow cathode mode, said one electrode comprising an inner hollow coil of tungsten mounted on a metal shank and open at the front end facing the arc, an outer coil of tungsten wire concentric with said inner coil, a heat radiation shield between inner and outer coils, the inner coil projecting forward beyond the outer coil, the depth of the cavity in said inner coil being greater than its diameter, and a reservoir of emission material in the bottom of the cavity.
Claim 2
Dependent Claim
117 words
A high intensity metal vapor lamp comprising a vitreous envelope containing metal vapors and having a pair of electrodes sealed therein at least one of which is a thermionic self-heating cavity electrode operating in the hollow cathode mode, said one electrode comprising an inner hollow coil of tungsten mounted on a metal shank and open at the front end facing the arc, an outer coil of tungsten wire concentric with said inner coil, a heat radiation shield between inner and outer coils, the inner coil projecting forward beyond the outer coil, the depth of the cavity in said inner coil being greater than its diameter, and a reservoir of emission material in the bottom of the cavity.
Claim 3
Dependent Claim
21 words
A lamp as in claim 1 wherein the diameter of the cavity is in the range of 20 to 100 mils.
Claim 4
Dependent Claim
16 words
A lamp as claim 1 wherein the heat radiation shield is a sheet of tungsten foil.
Claim 5
Dependent Claim
24 words
A lamp as in claim 1 wherein the heat radiation shield is an intermediate winding of tungsten wire between inner and outer tungsten coils.
Claim 6
Dependent Claim
118 words
A high-intensity metal vapor lamp comprising a vitreous envelope containing mercury and metal halide and having a pair of electrodes sealed therein at least one of which is a thermionic self-heating cavity electrode operating in tee hollow cathode mode, said one electrode comprising an inner hollow coil of tungsten wire mounted on a metal shank and open at the front end facing the arc, an outer coil of tungsten wire concentric with said inner coil, a heat radiation shield between inner and outer coils, the inner coil projecting forward beyond the outer coil, the depth of the cavity in said inner coil being greater than its diameter, and a reservoir of thoria in the bottom of the cavity.
Claim 7
Dependent Claim
118 words
A high-intensity metal vapor lamp comprising a vitreous envelope containing mercury and metal halide and having a pair of electrodes sealed therein at least one of which is a thermionic self-heating cavity electrode operating in tee hollow cathode mode, said one electrode comprising an inner hollow coil of tungsten wire mounted on a metal shank and open at the front end facing the arc, an outer coil of tungsten wire concentric with said inner coil, a heat radiation shield between inner and outer coils, the inner coil projecting forward beyond the outer coil, the depth of the cavity in said inner coil being greater than its diameter, and a reservoir of thoria in the bottom of the cavity.
Claim 8
Dependent Claim
21 words
A lamp as in claim 5 wherein the diameter of the cavity is in the range of 20 to 100 mils.
Claim 9
Dependent Claim
17 words
A lamp as in claim 5 wherein the heat radiation shield is a sheet of tungsten foil.
Claim 10
Dependent Claim
24 words
A lamp as in claim 5 wherein the heat radiation shield is an intermediate winding of tungsten wire between inner and outer tungsten coils.
Claim 11
Dependent Claim
13 words
A lamp as in claim 5 wherein the metal halide includes sodium iodide.
Claim 12
Dependent Claim
36 words
A lamp as in claim 5 for operation at a current of 3 to 4 amperes wherein the metal halide includes sodium iodide and the cavity diameter is in the range of 20 to 40 mils.
Claim 13
Dependent Claim
118 words
A high-intensity high-pressure lamp comprising a vitreous envelope containing an ionizable medium and having a pair of electrodes sealed therein at least one of which is a thermionic self-heating cavity electrode operating in the hollow cathode mode, said one electrode comprising an inner cavity member of refractory metal and an outer shielding member surrounding it, said inner member having a cavity therein which is substantially gastight but open at the front end facing the arc, said cavity having a depth not substantially greater than the penetration of the arc terminus therein, said inner member having enhanced thermal coupling to said outer member at the front end, and electron-emitting material located within the lower portion of said inner member.
Claim 14
Dependent Claim
118 words
A high-intensity high-pressure lamp comprising a vitreous envelope containing an ionizable medium and having a pair of electrodes sealed therein at least one of which is a thermionic self-heating cavity electrode operating in the hollow cathode mode, said one electrode comprising an inner cavity member of refractory metal and an outer shielding member surrounding it, said inner member having a cavity therein which is substantially gastight but open at the front end facing the arc, said cavity having a depth not substantially greater than the penetration of the arc terminus therein, said inner member having enhanced thermal coupling to said outer member at the front end, and electron-emitting material located within the lower portion of said inner member.
Claim 15
Dependent Claim
27 words
A lamp as in claim 11 wherein no pArt of said outer shielding member projects beyond said inner cavity member in the direction of the other electrode.
Claim 16
Dependent Claim
18 words
A lamp as in claim 11 wherein said inner and outer members are made of molded tungsten powder.
Claim 17
Dependent Claim
49 words
A lamp as in claim 11 wherein both inner and outer members are made of molded tungsten powder, said inner member consisting of substantially pure tungsten powder at the front end and of tungsten powder admixed with electron-emitting material in the lower portion contained within said outer shielding member.
Claim 18
Dependent Claim
36 words
A lamp as in claim 14 wherein said inner member is in the form of a hollow cylinder and said outer member is in the form of a cup into which the inner member is fitted.
Claim 19
Dependent Claim
45 words
A lamp as in claim 15 wherein the outer diameter of said hollow cylinder tapers inwardly from front to rear relative to the diameter of the opening in said cup whereby pressure contact and enhanced thermal coupling occurs with the front only of said cup.
References Cited (Backward Citations)
US3029359A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |