GB611687A - Improvements in or relating to electric incandescent lamps - Google Patents

Abstract

611,687. Incandescent lamps. PHILIPS LAMPS, Ltd. May 6, 1946. No. 13674. Convention date, Feb. 3, 1942. [Class 39 (ii)] [Also in Group XXVIII] All dust particles are excluded, or removed, from its interior in the manufacture of an incandescent lamp which is filled with one or more rare gases, such as krypton and/or xenon, and not more than 20 per cent nitrogen. The nitrogen may be less than 5 per cent. The making of the lamp parts and the assembling thereof may take place in a dustf r e e atmosphere, or the lamp may be vibrated whilst being heated and washed with a dust-free gas prior to the filling operation. Getters other t h a n phosphorous are preferably employed in this case. Other alternative methods are suggested. An annular, blower-nozzle 5, slidable between the bulb 1, and stem 2, may supply dust-free air to remove dust and glass particles whilst the parts 1, 2 are being heated to 400 deg. C and vibrated, the blower meanwhile moving up and down. After this the blower is lowered, the lamp parts are sealed together and the lamp filled through the tube 7. The bulb may have a volume, in cubic centimetres, of the wattage plus 25 or less.