Granted Patent
Utility
US 4,267,701 · App. 06/092,232
Helium liquefaction plant
Inventor:
William M. Toscano
Patented Case
View Patent ↗
Granted: May 19, 1981
Filed: Nov 9, 1979
Inventor
William M. Toscano
Assignee (at issue)
Helix 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.