Granted Patent
Utility
US 4,254,629 · App. 06/145,882
Cryogenic system for producing low-purity oxygen
Inventor:
Walter Joseph Olszewski
Patented Case
View Patent ↗
Granted: Mar 10, 1981
Filed: May 1, 1980
Inventor
Walter Joseph Olszewski
Assignee (at issue)
Union Carbide 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.