Granted Patent
Utility
US 4,770,795 · App. 07/088,734
Calcium tolerant deflocculant for drilling fluids
Inventors:
David M. Giddings, Dodd W. Fong
Patented Case
View Patent ↗
Granted: Sep 13, 1988
Filed: Aug 24, 1987
Inventors
David M. Giddings
Dodd W. Fong
Assignee (at issue)
Nalco Chemical 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.