Granted Patent
Utility
US 6,089,321 · App. 09/039,984
Pressure balanced choke and kill line connector
Inventor:
Charles D. Morrill
Patented Case
View Patent ↗
Granted: Jul 18, 2000
Filed: Mar 16, 1998
Inventor
Charles D. Morrill
Assignee (at issue)
Hydril Company
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.