Granted Patent
Utility
US 6,171,449 · App. 09/100,433
Cascade reboiling of ethylbenzene/styrene columns
Inventor:
Vincent A. Welch
Patented Case
View Patent ↗
Granted: Jan 9, 2001
Filed: Jun 19, 1998
Inventor
Vincent A. Welch
Assignee (at issue)
Washington Group International, 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.