Granted Patent
Utility
US 4,898,367 · App. 07/222,934
Dispersing gas into molten metal
Inventor:
Paul V. Cooper
Patented Case
View Patent ↗
Granted: Feb 6, 1990
Filed: Jul 22, 1988
Inventor
Paul V. Cooper
Assignee (at issue)
Stemcor 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.