Patent US3721845A successfully refreshed from Google Patents.
US3721845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sodium vapor lamp having improved starting means
Assignee: GTE Sylvania Inc
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Filing: 1972-06-28
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Granted: 1973-03-20
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Expires: 1992-06-28
Abstract
Abstract The arc tube of a sodium vapor arc discharge lamp has an external electrical heater spaced from but in heat transfer relationship therewith. The heater is made of refractory metal wire and is coiled around an insulating supporting rod. One end of the heater is connected to a wire that is wrapped around the arc tube near the end thereof that is opposite said heater end.
Inventors
- 👤 D Richardson
- 👤 S Cohen
- 👤 J Gutta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:13
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/54; H01J61/541; H01J61/544
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
102 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 disposed parallel to said arc tube and closely spaced therefrom said heater comprising refractory metal wire coiled around an insulating rod; a wire loop encircling said arc tube near one electrode, said loop being connected to said heater at the end opposite said one electrode; and a thermal switch disposed within said envelope and electrically connected to one end of said heater.
Claim 2
Dependent Claim
102 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 disposed parallel to said arc tube and closely spaced therefrom said heater comprising refractory metal wire coiled around an insulating rod; a wire loop encircling said arc tube near one electrode, said loop being connected to said heater at the end opposite said one electrode; and a thermal switch disposed within said envelope and electrically connected to one end of said heater.
Claim 3
Dependent Claim
12 words
The lamp of claim 1 wherein said heater comprises a coiled coil.
Claim 4
Dependent Claim
13 words
The lamp of claim 1 wherein said insulating rod is made of alumina.
Claim 5
Dependent Claim
30 words
The lamp of claim 1 comprising two additional wire loops, one encircling the arc tube at about its center and the other encircling the arc tube proximate the other electrode.
Claim 6
Dependent Claim
22 words
The lamp of claim 1 wherein said switch is normally closed during non-operation of the lamp and is open during lamp operation.
References Cited (Backward Citations)
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 |