A Solar Furnace of 120 Inches Diameter for Studying Highly Refractory Substances

Abstract

Previous work with large solar furnaces is reviewed. New developments in the design of the 120 in. (3.05 m) solar furnace are discussed, in particular the mounting of the reflector, the parabolizing of the aluminum shell, and the production of a surface of high reflectivity. Close control of the temperature to which a sample is heated is attained by means of an aluminum cylinder which travels along the axis of the mirror and which controls the amount of radiation incident on the sample. Rotating sectors are used for separating the temperature radiation emitted by the sample and the incident radiation from the sun. Heating tests for obtaining molten materials, glasses, and products of crystallization are discussed. Methods are presented for work approximating blackbody conditions at very high temperatures. A method for the accurate determination of melting points of highly refractory samples under pure conditions is presented.