GB191502020A - Improvements in the Manufacture of Neon Vacuum Tubes. - Google Patents

Abstract

2020. Claude, G. Feb. 12, 1914, [Convention date]. Neon.-In the manufacture of vacuum tubes containing neon, mechanical or physical means are employed for causing movement of the gas from the tubes to purifying-bulbs and back again, during passage of electric current. The bulbs may contain strongly cooled charcoal, or cold or hot magnesium or lithium. One method consists in interrupting the electric currents at intervals. The movements thus caused are, however, inadequate in the case of narrow tubes containing gas at considerable pressure, say 10mm. of mercury. Larger movements can be obtained by immersing a purifying bulb alternately in liquid air and liquid hydrogen. If two bulbs R, R', Fig. 2, are connected to the ends of the tube, one may be immersed in liquid oxygen and the other in liquid nitrogen, the vessels of liquefied gases being rapidly interchanged at intervals, optionally with the help of an additional vessel, so that a considerable quantity of gas passes from one bulb to the other through the tube. In another method, a purifying-bulb D, Fig. 4, is connected to one of a pair of mercury receptacles B, C intercommunicating by way of a flexible tube, which may be furnished with a cock. Two bulbs and two such pairs of mercury receptacles may be provided, the apparatus being then analogous to that shown in Fig. 2. The lamp is subjected to electric current to remove occluded gases before admission of the neon, which may take place through one of the purifying bulbs.