Granted Patent
Utility
US 5,228,296 · App. 07/842,494
Cryogenic rectification system with argon heat pump
Inventor:
Henry Edward Howard
Patented Case
View Patent ↗
Granted: Jul 20, 1993
Filed: Feb 27, 1992
Inventor
Henry Edward Howard
Assignee (at issue)
Praxair Technology, Inc.
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.