Granted Patent
Utility
US 4,054,515 · App. 05/636,263
Water purification methods
Inventor:
Edgar W. Sawyer, Jr.
Patented Case
View Patent ↗
Granted: Oct 18, 1977
Filed: Nov 28, 1975
Inventor
Edgar W. Sawyer, Jr.
Assignee (at issue)
International Telephone and Telegraph 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.