211+, for processes of preparing heating or illuminating gas including heating and mixing oil and air.
62, Refrigeration,
91+, for processes in which moisture is added to air coiled by a refrigeration producer, and subclass 121 for processes of cooling by gas and liquid contact.
95, Gas Separation: Processes, for processes of gas separation involving gas and liquid contact. See Lines With Other Classes in the Class 261 class definition for an amplification of the line. 165, Heat Exchange,
222+, for a heating and cooling process with humidity control.
