| 摘要 |
PURPOSE:To prevent a rise of starting voltage due to impurities, by connecting an exhaust means having pumping effect without exhausting rare gas to a portion of an exhaust system. CONSTITUTION:A pump 14 not exhausting rare gas is arranged in a portion of the exhaust system B of a luminous tube 9. In the case of exhausting the inside of the luminous tube 9, after opening a leak valve 11 and leading dry rare gas into the exhaust system B until its pressure balances with the atmospheric pressure, the luminous tube 9 is set on a connecting mouth 12, and the leak valve 11 is closed. Next, after opening a vacuum valve 8, the exhaust system B is liminarily exacutated with an oil rotary pump 10, and after the effect of decompression approaches to predetermined pressure, the vacuum value 4 is opened. Then, after exhausting gas by heating the luminous tube 9, an enclosure is enclosed, and the vacuum valve 4 is closed. After that, a valve 15 opened and the pump 14 is put in operation, while rare gas is enclosed by opening a rare gas lead in valve 7, and the exhaust port of the luminous tube 9 is cut by melting. |
