(under subclass 861) Meters having means for metering by determining the effect upon a flow in an open channel of a
constriction, such as a weir. More than a mere graduated water gate must be included. The term "open channel" is intended to include any flow channel wherein the surface of the liquid above and below the constriction is subjected to the same pressure.
SEE OR SEARCH CLASS
251, Valves and Valve Actuation, appropriate subclasses for valves and their actuating means for closed conduits.
405, Hydraulic and Earth Engineering,
87+, for weirs and water gates, per se, with or without adjusting means or graduations and including no meter structure, and subclasses 92+ for water gate structures with regulating means to cause a definite volume of water to pass through an open channel while the head varies.
