(under the class definition) Processes directed to returning a product of the distillation operation to the distillation zone.
(1) Note. To be considered a product of distillation for purposes of this subclass an overhead vapor or side stream must be condensed to a liquid before being returned to the distillation zone. In other words to be considered a "product" the substance must be isolated outside the distillation zone.
SEE OR SEARCH THIS CLASS, SUBCLASS:
165, Heat Exchange, subclasses 104.21+ apparatus in which liquid is vaporized in one zone, condensed in another and the condensate is returned to the first zone.
196, Mineral Oils: Apparatus, subclass 99 for mineral oil distilling apparatus including the combination of vaporizing and condensing means and means for returning a part or all of the condensate to the vaporizer.
208, Mineral Oils: Processes and Products, subclass 358 for a mineral oil distillation process in which condensate or residue is returned to the rectification zone after having been removed therefrom to assist in the vaporization process.
