Granted Patent
Utility
US 4,285,140 · App. 06/102,073
Dewatering and upgrading low rank coal by a two-step hydrothermal treatment
Inventors:
Leopold van Raam, Herman P. Ruyter, Josefus W. van Breugel
Patented Case
View Patent ↗
Granted: Aug 25, 1981
Filed: Dec 10, 1979
Inventors
Leopold van Raam
Herman P. Ruyter
Josefus W. van Breugel
Assignee (at issue)
SHELL OIL 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.