Granted Patent
Utility
US 5,012,865 · App. 07/413,187
Annular and concentric flow wellhead isolation tool
Inventor:
Roderick D. McLeod
Patented Case
View Patent ↗
Granted: May 7, 1991
Filed: Sep 27, 1989
Inventor
Roderick D. McLeod
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.