Patent US3721846A successfully refreshed from Google Patents.
US3721846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sodium vapor lamp having improved starting means including a heater
Assignee: GTE Sylvania Inc
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Filing: 1972-06-26
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Granted: 1973-03-20
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Expires: 1992-06-26
Abstract
Abstract The arc tube of a sodium vapor arc discharge lamp has an external heater in heat transfer relationship with the arc tube and extending about the length of the arc tube. The ends of the heater are electrically connected to electrodes at the respective opposite ends of the arc tube in order to reduce the starting voltage of the lamp.
Inventors
- 👤 S Cohen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:53
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/54; H01J61/541; H01J61/544
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
118 words
A high pressure sodium vapor lamp comprising: a glass envelope; an alumina arc tube disposed within said envelope and having electrodes sealed therein at the ends thereof and containing a filling including sodium, mercury and an inert gas; a heater proximate said arc tube and in heat transfer relationship therewith and extending about the length of said arc tube, one end of said heater being electrically connected to the electrode at the opposite end of said arc tube through a thermal switch, said switch being normally closed during non-operation of said lamp, said switch being open during lamp operation, the other end of said heater being connected to the elctrode at the opposite end of said arc tube.
Claim 2
Dependent Claim
118 words
A high pressure sodium vapor lamp comprising: a glass envelope; an alumina arc tube disposed within said envelope and having electrodes sealed therein at the ends thereof and containing a filling including sodium, mercury and an inert gas; a heater proximate said arc tube and in heat transfer relationship therewith and extending about the length of said arc tube, one end of said heater being electrically connected to the electrode at the opposite end of said arc tube through a thermal switch, said switch being normally closed during non-operation of said lamp, said switch being open during lamp operation, the other end of said heater being connected to the elctrode at the opposite end of said arc tube.
Claim 3
Dependent Claim
18 words
The lamp of claim 1 wherein said heater comprises refractory metal wire wound directly on said arc tube.
References Cited (Backward Citations)
US2581959A
Cited
US2765416A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |