Improvements in or relating to vacuum-tight or gas-tight seals in electric apparatusand methods of producing such seals

摘要

603,489. Sealing metal to glass by heat. PHILIPS LAMPS, Ltd. May 17, 1946, No. 14974. Convention date, March 27, 1940. [Class 36] In evacuated or gas-filled discharge apparatus or lamps, or other electrical apparatus having one or more conductors sealed into a glass body, at least five per cent of the latter consists of fine bubbles so that the specific weight is correspondingly lower than that of the bubblefree glass. As shown in Fig. 1, glass powder 3 is placed in a mould 6 in which conductors 2 and an electrode device 1 are mounted, the bulb 4 is placed on the powder and the whole is heated in an oven or by a high-frequency coil 7. An exhaust tube 5 either in the bulb or the base ; and a substance which under heat evolves CO2 or other gas may be mixed with the glass powder. In Fig. 2, glass powder 11 is moulded to the desired shape with the aid of a binder, such as paraffin wax, which volatilizes under heat, and is arranged in a metal base 8 having a central guide-pin 9 provided with a thickening 10.