Granted Patent
Utility
US 4,456,693 · App. 06/486,089
Hydrocracking catalyst
Inventor:
William A. Welsh
Patented Case
View Patent ↗
Granted: Jun 26, 1984
Filed: Apr 18, 1983
Inventor
William A. Welsh
Assignee (at issue)
W. R. Grace & Co.
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.