Method and apparatus to make a discharge vessel for a sodium high-pressure discharge lamp
US5192239A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 1, 1991 |
| Grant date | Mar 9, 1993 |
| Priority date | — |
| Expiry date | Nov 1, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/825
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The method is suitable to make sodium high-pressure discharge lamps operag operating under saturated condition. After placing and melt-sealing a first electrode system into the discharge vessel, sodium is introduced in the form of NaN.sub.3 through the second end of the vessel. Upon heating of the second end, and due to heat conduction, the NaN.sub.3, collected at the first end, dissociates, resulting in a sudden pressure rise due to liberation of nitrogen within a vacuum. As soon as the nitrogen has dissipated, noble gas to cool the first end is introduced, and the second melt seal is then made. The noble gas may, at the same time, form an ignition gas, or a gas mixture for the discharge lamp. One or more half-finished lamps are preferably held in a holder structure which has vertical bores leaving a gap of between 0.2 to 3 mm between the wall surface of the bore and the vessel and, as such, are introduced into a vacuum furnace, where the pressure can be monitored.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.