Granted Patent
Utility
US 4,392,377 · App. 06/305,947
Early gas detection system for a drill stem test
Inventor:
E. Edward Rankin
Patented Case
View Patent ↗
Granted: Jul 12, 1983
Filed: Sep 28, 1981
Inventor
E. Edward Rankin
Assignee (at issue)
Gearhart 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.