Granted Patent
Utility
US 4,370,201 · App. 06/276,604
Process for maintaining coal proportions in a coal blend
Inventor:
Douglas E. Lowenhaupt
Patented Case
View Patent ↗
Granted: Jan 25, 1983
Filed: Jun 23, 1981
Inventor
Douglas E. Lowenhaupt
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.