Granted Patent
Utility
US 4,280,925 · App. 06/164,473
Filter for sorption of heavy metals
Inventor:
John E. Kiefer
Patented Case
View Patent ↗
Granted: Jul 28, 1981
Filed: Jun 30, 1980
Inventor
John E. Kiefer
Assignee (at issue)
EASTMAN KODAK 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.