Granted Patent
Utility
US 4,824,643 · App. 07/050,363
Apparatus for producing carbon black
Inventors:
Mark L. Gravley, E. Webb Henderson
Patented Case
View Patent ↗
Granted: Apr 25, 1989
Filed: May 18, 1987
Inventors
Mark L. Gravley
E. Webb Henderson
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.