(under subclass 263) Apparatus in which the means for dividing the gaseous fluid mixture or the separated gaseous constituent is a device which regulates the flow of the gaseous fluid mixture by opening, closing, or obstructing ports or passageways through which the gaseous fluid mixture flows.
SEE OR SEARCH CLASS
251, Valves and Valve Actuation, appropriate subclasses for the specific structure of valves, per se.
