Restarting arrangement for high-pressure mercury-vapor lamp which includes metallic halide additives

Claim 1

In combination with a high-pressure mercury-vapor discharge lamp which is adapted to be operated in a generally horizontal orientation and which comprises an elongated light-transmitting arc bulb adapted to be disposed generally horizontally during operation and having electrodes operatively disposed therein proximate the ends thereof, the spacing between said electrodes being greater than the diameter of said arc-enclosing bulb, said electrodes adapted to be electrically connected to an external source of starting and energizing potential, a dischargesustaining filling within said arc-enclosing bulb and comprising mercury and metallic halide, said metallic halide condensed proximate the lowest longitudinal portion of said arc-enclosing bulb, and an outer bulb surrounding said arc-enclosing bulb, the improved structure for starting said lamp when it is still hot from operation, which structure comprises: an elongated electrically conductive refractory member having an electrical conductivity substantially greater than that of said condensed metallic halide and positioned exteriorly of and proximate the outer surface of said arc-enclosing bulb and extending longitudinally thereof, said member also positioned generally diametrically opposite the lowest longitudinally disposed portion of said arc-enclosing bulb, and said member insulated from direct electrical connection with said electrodes.