Granted Patent
Utility
US 4,284,212 · App. 06/099,433
Pilot actuated diaphragm valve
Inventor:
Richard L. Caswell
Patented Case
View Patent ↗
Granted: Aug 18, 1981
Filed: Dec 3, 1979
Inventor
Richard L. Caswell
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.