Granted Patent
Utility
US 4,407,327 · App. 06/256,876
Flow control valve
Inventors:
Lloyd D. Hanson, Robert M. Purton
Patented Case
View Patent ↗
Granted: Oct 4, 1983
Filed: Apr 24, 1981
Inventors
Lloyd D. Hanson
Robert M. Purton
Assignee (at issue)
Dresser Industries, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.