Granted Patent
Utility
US 4,597,842 · App. 06/711,644
Metal recovery process
Inventor:
Joseph Evans
Patented Case
View Patent ↗
Granted: Jul 1, 1986
Filed: Feb 19, 1985
Inventor
Joseph Evans
Assignee (at issue)
Porters Grove Metal Recovery Co., Inc.
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.