(under subclass 97) Apparatus having means responsive to a change in a flow line condition acting of the face of a valve disc or plug itself to permit flow in one direction only.
SEE OR SEARCH THIS CLASS, SUBCLASS:
103, for diverse sensing means.
117+, for a check valve controlling discharge of treated material.
120, for a check valve controlled vent.
130+, for a fluid pressure responsive bypass.
416, for valves which form a part of a pump organization.
