High-pressure sodium discharge lamp - incorporates glow starter and heat shielding ceramic resistor within clear outer envelope, displaced by half diameter from discharge vessel

摘要

A high-pressure sodium discharge vessel (1), closed at each end by a lead-through (6,6') and provided with electrodes (8,9), is contained within a clear outer envelope (2) and connected via conductors (10,7) to an electrical connection cap (3). A starting circuit within the envelope comprises a glow starter (4) and ceramic resistor (5), secured by supports (11,11') to the conductor (7). The resistor also serves as a heat radiation shield for the glow starter. The centre of the discharge vessel is located at a distance m, the light centre length, from the bottom (20) of the lamp cap. The glow starter is laterally displaced a distance D/2 from the discharge vessel where D is the diameter of the vessel. Nominal powers in the range 150-400W are obtainable using discharge vessels of diameter 5,3-8,2mm and lengths 79-116mm.