Granted Patent
Utility
US 4,755,202 · App. 07/078,757
Process and apparatus to produce ultra high purity oxygen from a gaseous feed
Inventor:
Harry Cheung
Patented Case
View Patent ↗
Granted: Jul 5, 1988
Filed: Jul 28, 1987
Inventor
Harry Cheung
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.