Granted Patent
Utility
US 4,643,880 · App. 06/681,969
Apparatus and process for carbon black production
Inventors:
William R. King, C. Jack Hart
Patented Case
View Patent ↗
Granted: Feb 17, 1987
Filed: Dec 14, 1984
Inventors
William R. King
C. Jack Hart
Assignee (at issue)
Phillips Petroleum 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.