Granted Patent
Utility
US 4,464,227 · App. 06/418,946
Methods and apparatus for distilling a contaminated solvent
Inventor:
Darrel R. Colwell
Patented Case
View Patent ↗
Granted: Aug 7, 1984
Filed: Sep 16, 1982
Inventor
Darrel R. Colwell
Assignee (at issue)
AT&T Technologies Incorporated
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.