Methods for removing contaminants from arc discharge lamps
AssigneeOsram Sylvania Inc.
InventorPhilip B. Newell
Life of this patent
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Abstract
A method for removing contaminants from an arc tube includes introducing an inert gas into the arc tube through a conduit extending through the lamp tubulation and exhausting the gas through the space between the conduit and the wall of the lamp tubulation. Contaminated gas thereby always flows away from the arc tube. The arc tube can be heated during the gas flushing process to release adsorbed water and vaporize volatile oxides. Gas is preferably flushed through the lamps tubulation during and after press sealing of electrodes into the arc tube to remove contaminants introduced during press sealing.
Claims13
A method for removing contaminants from an elongated arc tube having a lamp tubulation and having electrodes mounted therein on opposite sides of said tubulation, said method comprising the steeps of:
- inserting a removable metallic conduit in the form of a needle extending longitudinally through said lamp tubulation for forming a first gas flow passage;
- introducing a gas into said arc tube through said removable metalic conduit extending through said lamp tubulation;
- simultaneously with introducing said gas, heating said arc tube for vaporizing contaminants including water present in said arc tube,
- simultaneously with introducing said gas, exhausting the gas from said arc tube through a second gas flow passage extending through said lamp tubulation, said second gas flow passage being separated from said first gas flow passage and comprising an annular space between said removable metallic conduit and a wall of said lamp tubulation whereby gas flows in a stream through said first gas flow passage into said arc tube and then flows from said arc tube only through said second gas flow passage, said steps of introducing the gas and exhausting the gas are performed at about atmospheric pressure;
- cooling said arc tube while continuing said gas flow;
- removing said metallic conduit, dosing said arc tube with chemicals through said tubulation, and backfilling said arc tube prior to sealing said arc tube.
Dependencies are inferred from the claim text.