Granted Patent
Utility
US 4,292,991 · App. 06/104,301
Erosion resistant valve
Inventor:
Paul G. Wing
Patented Case
View Patent ↗
Granted: Oct 6, 1981
Filed: Dec 17, 1979
Inventor
Paul G. Wing
Assignee (at issue)
Masoneilan International, 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.