GB356984A - Improvements relating to incandescent electric lamps, electron discharge devices, and the like - Google Patents

Abstract

356,984. Electric incandescent lamps- NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, 13A, Emmasingel, Eindhoven, Holland. Oct. 24, 1930, No. 32047. Convention date, Dec. 9, 1929. [Class 39 (ii).] Residual gases; making lamps.-In a method of exhausting high power electric incandescent lamps &c., where high temperatures are set up, as in high power incandescent lamps having a mercury vapour filling, the vitreous portions of the envelope into which the lead-in wires are sealed project outwards from the gas-filled or vacuum space and carry a metal exhausting tube having a coefficient of expansion substantially equal to that of the glass into which it is sealed. An incandescent lamp 7, Fig. 1, has a filament 9 fed from lead-in wires 8, embedded in a pinch 10. A metal tube 11 surrounded by a vitreous sleeve 12 passes through and is sealed into the pinch. After exhaustion of the lamp the end of the tube 12 is sealed off. Tungsten tubes are used with high temperature softening glass such as that known under the registered Trade Mark " Pvrex." A tube of ferrochromium is used with glass such as is used in the manufacture of X-Ray tubes and a nickel-iron alloy tube is used with lime glass or soda potassium glass. Fig. 2 shows the envelope 13 of a high power incandescent lamp having a cylindrical extension 14 of relatively large diameter connected to the pinch 15 by a flange 18. The Specification as open to inspection under Sect. 91 (3) (a) describes a form in which the pinch is re-entrant into the envelope and is carried on the ordinary stem or foot. This construction permits of gettering materials being arranged in the vicinity of the filament. This subject-matter does not appear in the Specification as accepted.