The 200 lb/in/sup 2/ centrifugal feeder developed in Phase II was modified and used to develop design data for a second generation centrifugal feeder prototype. This prototype was designed to operate at backpressures to 500 psig and feed rates of 3 to 5 tons/h. Testing of the feeder was terminated after 6 weeks to conserve funds for the LPF development work. The 500 lb/in/sup .