Granted Patent
Utility
US 4,509,989 · App. 06/478,951
Cleaning method for removing sulfur containing deposits from coke oven gas lines
Inventor:
L. Walter Sumansky
Patented Case
View Patent ↗
Granted: Apr 9, 1985
Filed: Mar 25, 1983
Inventor
L. Walter Sumansky
Assignee (at issue)
United States Steel Corporation
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.