Granted Patent
Utility
US 4,263,128 · App. 06/090,247
Upgrading petroleum and residual fractions thereof
Inventor:
David B. Bartholic
Patented Case
View Patent ↗
Granted: Apr 21, 1981
Filed: Nov 1, 1979
Inventor
David B. Bartholic
Assignee (at issue)
Engelhard Minerals & Chemicals Corporation
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.