Granted Patent
Utility
US 4,369,655 · App. 06/215,677
Method of determining the concentration of solid lubricants in drilling fluids
Inventor:
Forest A. Scearce
Patented Case
View Patent ↗
Granted: Jan 25, 1983
Filed: Dec 12, 1980
Inventor
Forest A. Scearce
Assignee (at issue)
NL Industries, Inc.
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.