Granted Patent
Utility
US 5,198,021 · App. 07/853,197
Recovery of precious metal
Inventor:
Michael J. Virnig
Patented Case
View Patent ↗
Granted: Mar 30, 1993
Filed: Mar 18, 1992
Inventor
Michael J. Virnig
Assignee (at issue)
Henkel Limited
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.