Abstract: The present invention provides an ionic and electronic insulator interposed between a BASE tube and a tube mounting member in an AMTEC cell for preventing shunt currents from forming between BASE tube electrodes. In a first embodiment of the invention, an insulator is formed integral with the BASE tube by leaching out an alkali metal ion component of the BASE tube at a desired location. In a second embodiment of the present invention, an alpha alumina ring is brazed to the end of the BASE tube. In a third embodiment of the present invention, a glass material seal is formed between the BASE tube and the mounting member.

Abstract: The present invention provides an alkali metal thermal to electric conversion (AMTEC) cell of the type employing an alkali metal flowing between a high-pressure zone and low-pressure zone in the cell through a solid electrolyte structure. The cell preferably includes a condenser communicating with the low-pressure zone for condensing alkali metal vapor migrating through the low-pressure zone from the solid electrolyte structure. An artery is coupled to the condenser for directing condensed alkali metal from the condenser toward a hot end of the cell. An evaporator for evaporating the condensed alkali metal is coupled to the artery channel and communicates with the high-pressure zone. The artery and evaporator combine to form a return channel which preferably includes a graded pore size capillary structure for creating a region having a large pore size transitioning in any predetermined manner to a region having a relatively smaller pore size.

Abstract: The present invention provides an alkali metal thermal to electric conversion cell having radially projecting beta-alumina type solid electrolyte elements and a central heat input region.

Abstract: The present invention provides an AMTEC cell having a more robust power conductance path (conduction, radiation, convection, and latent heat transfer) from the heat input surface of the cell to the working fluid, evaporation surface, and SES. More particularly, one embodiment of the present invention includes collars, post and/or bridges extending between the SES support plate and the heat input surface. In another embodiment, a plurality of channels or conduits extend between the heat input surface and SES support plate. These embodiments simultaneously increase the thermal conductance path between the heat input surface of the cell and the evaporation surface as well as between the heat input surface of the cell and the SES, and enables superheating of the working fluid.

Abstract: The present invention provides an alkali metal thermal to electric conversion (AMTEC) cell of the type employing an alkali metal flowing between a high-pressure zone and low-pressure zone in the cell through a solid electrolyte structure. The cell preferably includes a condenser communicating with the low-pressure zone for condensing alkali metal vapor migrating through the low-pressure zone from the solid electrolyte structure. An artery is coupled to the condenser for directing condensed alkali metal from the condenser toward a hot end of the cell. An evaporator for evaporating the condensed alkali metal is coupled to the artery and communicates with the high-pressure zone. A heat shield is disposed in the low pressure zone of the cell for reducing the radiative heat transfer between the hot end of the cell and the cold end of the cell. The heat shield preferably includes a first end having a known area transitioning to a second end encompassing a smaller area than the first end.