Granted Patent
Utility
US 4,294,700 · App. 06/047,191
Submerged large diameter seal
Inventor:
Thomas J. Casper
Patented Case
View Patent ↗
Granted: Oct 13, 1981
Filed: Jun 8, 1979
Inventor
Thomas J. Casper
Assignee (at issue)
Envirex, 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.