GB903375A - Thermo-electronic converters - Google Patents

Abstract

903,375. Thermionic converters. CSF-COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. May 11, 1961 [May 17, 1960], No. 17187/61. Class 39 (1). A device for the direct conversion of heat into electricity comprises an electron emitter 2, Fig. 1, which is heated, and a collector including capillary means 5 impregnated with an ionizable metal and having at least at its collecting surface 6, a material capable of reacting with the ionizable metal during operation to form a substance having a work function lower than that of the metal. As shown, the capillary means 5 comprises a porous body of sintered tungsten, molybdenum or nickel supported in a tank 3 containing caesium, rubidium or potassium 4, and having its surface 6 oxidized or coated with silver oxide, an alkaline earth oxide, or mixtures of antimony, potassium and/or sodium. Bismuth and lithium may also be used in the coating. The emitter and collector bases 13 are sealed to a spacer 7 of insulating material or a resistive alloy. The emitter 2, which may be of tungsten, is heated by sunrays, combustion, residual engine gases or in a nuclear reactor. In an alternative arrangement, the emitter comprises a porous body 10, Fig. 3, of sintered molybdenum, tantalum, nickel or tungsten impregnated with caesium, rubidium or potassium vapour from an auxiliary pool 12. Electrons are emitted from the vapour which is also ionized by contact with the porous body 10. The liquid metal 4 is cooled to about 100‹ C., and the emitter is heated to 900 to 1000‹ C. while the auxiliary pool 12 is maintained at an intermediate temperature. A conduit 18 having pumping means 19 may be provided as shown or between the liquid metal pools 12 and 4.