(under subclass 120) Apparatus including a device utilizing mechanical or kinetic energy to move the atmosphere in the work chamber in a flow pattern providing for the return of some of the atmosphere to repeat its transversal of the work.
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21, for a process of heater operation including recycling of the work atmosphere.
144+, for apparatus having structure recirculating combustion products along a work path extending through a work chamber.
152, for a work chamber having a means by which work is moved and a means providing for distinct atmosphere supply, removal or recirculation structure.
176, for a work chamber heating work by combustion products having an exhaust return passage or recirculating fan or jet.