Granted Patent
Utility
US 4,984,594 · App. 07/427,418
Vacuum method for removing soil contamination utilizing surface electrical heating
Inventors:
Harold J. Vinegar, George Leo Stegemeier
Patented Case
View Patent ↗
Granted: Jan 15, 1991
Filed: Oct 27, 1989
Inventors
Harold J. Vinegar
George Leo Stegemeier
Assignee (at issue)
SHELL OIL COMPANY
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.