Thermolytic processes as provided for in this class in which the charge is heated by means of a hot, extraneous, inert gas cyclicly circulated.
SEE OR SEARCH CLASS
162, Paper Making and Fiber Liberation,
41+, for a process of fiber liberation including circulating a hot digesting fluid through the digester and subclasses 248+ for a fiber liberation digester having means to circulate the digesting fluid.
202, Distillation: Apparatus,
109, for apparatus for moving the volatile matter distilled off in a closed circuit through the retort.
