| 摘要 |
921,162. Discharge apparatus. PHILIPS ELECTRICAL INDUSTRIES Ltd. Dec. 4, 1959 [Dec. 9, 1958], No. 41269/59. Class 39 (1). [Also in Group XXIII] In a sodium vapour discharge device having also a filling of neon at, e.g., 13 mm. pressure, and a small proportion of argon the tube is pretreated by filling it with argon, passing a discharge and subsequently providing the filling of Na, Ne and A. The argon is 0.1-1%, e.g. 0.5% of the volume of the neon. The pretreating discharge which is carried out at 0.1-0.15 mms. pressure, saturates the tube wall with argon so that the argon pressure is maintained and the ignition voltage remains at a sufficient level below the starting voltage. The tube is U shaped and is of lime glass with an internal layer of Na resistant glass, i.e. 10-30%, e.g. 24%, B 2 O 3 , 0-15%, e.g. 6%, K 2 O, 20-60% CaO and BaO, e.g. 10%, 38% respectively, 10-40%, e.g. 22% Al 2 O 3 , and is housed in an evacuated cylindrical bulb. It has thermionic electrodes. |
