GB543072A - Improvements in or relating to metal vapour electric discharge devices - Google Patents

Abstract

543,072. Metal. vapour apparatus. WHITE, J. E. Sept. 6, 1940, No. 13955. Convention date, Sept. 7, 1939. [Class 39 (i)] In discharge devices of the pool cathode type, the ignition rod 39, of boron or silicon carbide, dips into the mercury &c. pool 49, and is surrounded by a ring 47 also dipping into the pool and disposed so as to form a capillary space between it and the rod. The ring is supported by a U-shaped wire 45 welded to the ends of a bent wire 43 sealed to a bead 41 of glass &c. at the lower end of the rod. The ring may be of a material such as molybdenum which is wetted by mercury or one which is not wetted thereby. The envelope of the device consists of double-walled steel cylinders 3 forming an annular space closed at the ends to provide a water-cooled chamber. The anode 23 is carried by a rod 21 extending through a cup 19 of cobalt-nickel-iron alloy sealed to a ring of glass 17 which is sealed to a ring 15 of the same alloy and is welded to a metal ring 9. The other end of the envelope is sealed by a disc 25 with passages lined with an alloy which seals with glass for the exhausting tube 29 and the insulating sleeve 33 of the ignition lead 35.