| 摘要 |
PURPOSE:To adjust the generated surge voltage to a given value, and secure the start of a metal vapor electric-discharge lamp by charging the outer tube with a charging gas at below a given pressure, and installing zirconium bulk getters in the outer tube, and thereby making a starting heat responsive element to operate in an atmosphere of the charging gas. CONSTITUTION:A rare gas such as xenon is charged into an outer tube 7 of a high-pressure sodium lamp at a pressure of below 100 Torr. Zirconium bulk getters 27 and 28 are placed near an emission tube 1. When a bimetal 4 is heated and operateds with radiation heat produced by heating a bimetal heating filament 5 by use of current for cutting off the contact between contacts 22 and 23, surge voltage generated in a ballast is reduced. The getters 27 and 28 absorb impure gas developed within the outer tube 7 during the life of the lamp. |
