(under subclass 386) Apparatus wherein the level responding or maintaining flow is increased or diminished by an external means or in response to a change in condition other than liquid level, either by a means acting upon the liquid level responsive control means or by a second means in series or parallel therewith.
(1) Note. See the class definition, section 3 for collected search notes on automatic and combined automatic and nonautomatic controls in this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
410, for valves which are opened by external means and closed by float means.
