Granted Patent
Utility
US 4,278,648 · App. 06/130,874
Method of improving siliceous filter aid dispersion in wet process orthophosphoric acid production systems
Inventor:
Harris G. Walton
Patented Case
View Patent ↗
Granted: Jul 14, 1981
Filed: Mar 17, 1980
Inventor
Harris G. Walton
Assignee (at issue)
Johns Manville
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.