Granted Patent
Utility
US 4,700,739 · App. 06/798,634
Pneumatic well casing pressure regulating system
Inventor:
Mark C. Flohr
Patented Case
View Patent ↗
Granted: Oct 20, 1987
Filed: Nov 14, 1985
Inventor
Mark C. Flohr
Assignee (at issue)
SMITH INTERNATIONAL, 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.