METAL VAPOUR DISCHARGE LAMP

摘要

PURPOSE:To prevent implosion of outside valve and devitrification of the sealed metal in luminous tube by accomodating the starting circuit connected in parallel with a luminous tube in an outside valve and keeping the charged gas pressure of an ignition lamp below a fixed value and arranging a thermo-switch close to the luminous tube. CONSTITUTION:A luminous tube 2 equipped with electrodes 6a and 6b is installed at the center part of an outside valve 1 through supports 10 and 11. Between the support 10 and an inner conductor 14, a starting series circuit is connected in which an ignition lamp 17, current-limit resistor 18 and a bimetal switch 19 as always- closed-type thermoswitch are connected in series. The gas pressure of charged gas in the ignition lamp 17 is regulated at below 15 Torr, permitting the pulse voltage above 1,000V to be generated. The bimetal switch 19 is positioned at the position closer to the luminous tube 2 side than the ignition tube 17 and operates to be turned-ON by receiving the heat from the luminous tube 2 side.