Granted Patent
Utility
US 4,673,522 · App. 06/675,774
Methods for removing obstructions from conduits with urea-sulfuric acid compositions
Inventor:
Donald C. Young
Patented Case
View Patent ↗
Granted: Jun 16, 1987
Filed: Nov 28, 1984
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.