Granted Patent
Utility
US 4,342,330 · App. 06/178,871
Ball type valve having improved redundant sealing system
Inventors:
Raymond E. Wieveg, Julian D. Keithahn
Patented Case
View Patent ↗
Granted: Aug 3, 1982
Filed: Aug 18, 1980
Inventors
Raymond E. Wieveg
Julian D. Keithahn
Assignee (at issue)
Hydril Company
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.