Granted Patent
Utility
US 4,287,072 · App. 06/086,049
Water treatment by ion exchange resin
Inventor:
Jesse S. Beecher
Patented Case
View Patent ↗
Granted: Sep 1, 1981
Filed: Oct 18, 1979
Inventor
Jesse S. Beecher
Assignee (at issue)
Drew Chemical 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.