(under subclass 36) Method or apparatus wherein means are provided to cause or control fluid flow within a flow confining passage.
(1) Note. For placement herein, a patent must recite a flow controller used as part of an irrigation or drainage system. Merely reciting a valve culvert associated with a levee or a water gate in a channel even though the disclosed utility is for irrigation or drainage is not sufficient for placement in this or indented subclasses.
SEE OR SEARCH THIS CLASS, SUBCLASS:
87+, for water gates and adjustable weirs associated with open channels.
108, for valved spillways or culverts associated with dams, dikes, levees, etc.
