GB945020A - Method of introducing iodine into incandescent lamps - Google Patents

Abstract

945,020. Incandescent electric lamps. SYLVANIA ELECTRIC PRODUCTS Inc. April 12, 1962 [April 12, 1961], No. 14257/62. Heading H1F. A controlled quantity of iodine is introduced into the envelope of an electric lamp by inserting a quantity of iodine into the exhaust tube, melting the iodine to cause it to adhere to the walls of the tube which is then cooled, exhausting the envelope and introducing a filling gas or gases, sealing off the end of the exhaust tube remote from the envelope, heating the envelope and exhaust tube to vaporize the required quantity of iodine into the envelope, chilling the envelope and sealing of the envelope from the exhaust tube near the envelope. The lamp envelope may be of fuzed quartz with a coiled coil 6 of tungsten, the ends of which are connected e.g. by spot welding to thin foil sections 4 of molybdenum similarly connected to molybdenum leads 3, the foils and leads being secured in press seals 2 at the ends of the lamp. The iodine crystals may be inserted in the exhaust tube by a spatula. After sealing off the exhaust tube remote from the envelope the lamp is heated in a bath of liquid maintained at constant temperature by a thermostat for a specified period, washed and chilled in a bath of liquid nitrogen and finally the exhaust tube is sealed off close to the envelope. Specification 935,397 is referred to.