Granted Patent
Utility
US 5,073,248 · App. 07/655,478
Asphaltene dispersants - inhibitors
Inventors:
William K. Stephenson, Morris Kaplan
Patented Case
View Patent ↗
Granted: Dec 17, 1991
Filed: Feb 14, 1991
Inventors
William K. Stephenson
Morris Kaplan
Assignee (at issue)
Nalco Chemical 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.