The most notable special feature of the liquefier was the large cold chamber, which could be maintained at any temperature down to the helium level.

An investigation at the Massachusetts Institute of Technology, sponsored by the Bureau of Ordnance and later by the Office of Naval Research, of the feasibility of the liquefaction of hydrogen by condensation at one atmosphere on surfaces cooled by helium from an expansion engine, led to the development of the machine to be described. It was completed in 1949 and its performance described in routine reports which were made to the sponsors but not otherwise published. In order to render it a more useful tool in the laboratory, features other than the ability to liquefy hydrogen were incorporated in the design. Helium could also be liquefied, although at a smaller rate than hydrogen. The most notable special feature of the liquefier was the large cold chamber, which could be maintained at any temperature down to the helium level.

The most notable special feature of the liquefier was the large cold chamber, which could be maintained at any temperature down to the helium level.

HELIUM REFRIGERATOR AND LIQUEFIER