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US 4,376,259 AGranted
High intensity discharge lamp including arc extinguishing means
AssigneeGTE Products Corporation
InventorsHarold L. Rothwell, Jr., Robert S. White, Jr.
Life of this patent
Estimating the term…
Abstract
A high intensity discharge lamp includes, within the outer envelope, a strip of niobium foil serially connected between a power source and one of the electrodes of the arc tube of the lamp. The foil is not a power consuming element but will oxidize and open the circuit, thus extinguishing the lamp, in the event the outer envelope is ruptured.
Claims3
A high intensity discharge lamp comprising:
- an arc discharge tube operating within a given environment;
- an oxidizable, end-of-life device connected in series with the electrodes of said arc discharge tube;
- and means for providing said given environment with a residual oxygen pressure of about 0.1 torr whereby long operation of said lamp will cause slow, but continuous oxidation of said end-of-life device to eventually achieve rupture of said end-of-life device at a predetermined time, thereby opening the circuit and disabling said lamp, said predetermined time being approximately equal to the life expectancy of said lamp.
Dependencies are inferred from the claim text.