Granted Patent
Utility
US 6,591,915 · App. 09/863,993
Method for selective draining of liquid from an oil well pipe string
Inventors:
Mark Burris, Donald R. Hibler, Jr.
Patented Case
View Patent ↗
Granted: Jul 15, 2003
Filed: May 23, 2001
Inventors
Mark Burris
Donald R. Hibler, Jr.
Assignee (at issue)
Fike 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.