| 摘要 |
<p>338,713. General Electric Co., Ltd., (Assignees of Patent-Treuhand-Ges. f³r Elektrische Gl³hlampen). Jan. 21, 1929, [Convention date]. Low - pressure metallic - vapour apparatus: vacuum tubes. - A luminous electric discharge tube having a gas filling, more particularly of a rare gas, is provided with a sealed reservoir having a reserve supply of gas at a higher pressure, the reservoir being provided at the end nearer the luminous tube with a closure member which can be fused readily on being heated and thus admits the gas into the tube. In one form a tube 1 with electrodes 2, 3 has a lateral extension 8 connected to a small glass reservoir 9 which has a capillary tube 10 leading into the extension 8 and is closed hermetically by a plug 11 of a readily fusible metal alloy such as Wood's metal. A foot tube 12 with a pinch 13 and a small exhaust tube 14 facilitates the exhaustion of the reservoir 9 and the introduction of the reserve gas, the tube 14 being subsequently sealed off in known manner. Towards the end of the normal life of the tube the reserve gas is admitted by fusing the plug 11, for example, by a gas jet or electric heating ring. In another form the reserve gas is contained in a glass reservoir which has a thin, blown-out, domed portion extending into a lateral extension of the luminous tube, and a heating-filament disposed immediatelv beneath the dome is connected to two leading-in wires extending through a. pinch at the bottom of the reservoir. By passing current through the filament the thin dome is softened and is blown out by the, pressure of the gas beneath it. A tube may be provided with several extensions connected to sealed gas reservoirs. The current through the heating- filament may be switched on either manually or automatically. In the latter instance the switching is effected by the change in the current loading arising from the consumption of the gas contained in the tube.</p> |
