Granted Patent
Utility
US 4,255,258 · App. 06/036,856
Filtration of a coal liquid slurry using an alkylmethacrylate copolymer and an alcohol
Inventors:
Norman L. Carr, Edgar L. McGinnis
Patented Case
View Patent ↗
Granted: Mar 10, 1981
Filed: May 7, 1979
Inventors
Norman L. Carr
Edgar L. McGinnis
Assignee (at issue)
Gulf Research & Development 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.