Granted Patent
Utility
US 4,401,549 · App. 06/322,335
Liquefaction of calcium-containing coals
Inventor:
Peter Urban
Patented Case
View Patent ↗
Granted: Aug 30, 1983
Filed: Nov 17, 1981
Inventor
Peter Urban
Assignee (at issue)
UOP LLC
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.