Granted Patent
Utility
US 4,238,315 · App. 05/956,394
Recovery of oil from oil shale
Inventor:
John F. Patzer, II
Patented Case
View Patent ↗
Granted: Dec 9, 1980
Filed: Oct 31, 1978
Inventor
John F. Patzer, II
Assignee (at issue)
Gulf Research & Development 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.