Granted Patent
Utility
US 4,443,421 · App. 06/358,744
Process for removing particulate impurities from aqueous phosphoric acid
Inventors:
Charles M. Hollifield, Teddy D. Smith
Patented Case
View Patent ↗
Granted: Apr 17, 1984
Filed: Mar 16, 1982
Inventors
Charles M. Hollifield
Teddy D. Smith
Assignee (at issue)
Occidental Chemical 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.