Granted Patent
Utility
US 4,909,484 · App. 07/292,924
Prevention of slag buildup in steel ladles
Inventors:
Peter T. Sutor, Edward L. Erny
Patented Case
View Patent ↗
Granted: Mar 20, 1990
Filed: Jan 3, 1989
Inventors
Peter T. Sutor
Edward L. Erny
Assignee (at issue)
Dresser Industries, Inc.
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.