Granted Patent
Utility
US 4,614,148 · App. 06/707,427
Control valve system for blowout preventers
Inventor:
H. John Bates
Patented Case
View Patent ↗
Granted: Sep 30, 1986
Filed: Mar 1, 1985
Inventor
H. John Bates
Assignee (at issue)
NL 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.