Granted Patent
Utility
US 4,993,442 · App. 07/416,824
Methods for removing obstructions from conduits using sulfuric acid adducts
Inventor:
Donald C. Young
Patented Case
View Patent ↗
Granted: Feb 19, 1991
Filed: Oct 3, 1989
Inventor
Donald C. Young
Assignee (at issue)
Union Oil Company of California
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.