Granted Patent
Utility
US 4,836,243 · App. 07/162,163
Gate valve with hydraulic actuator
Inventor:
Kent Wayne Ferrell
Patented Case
View Patent ↗
Granted: Jun 6, 1989
Filed: Feb 29, 1988
Inventor
Kent Wayne Ferrell
Assignee (at issue)
Otis Engineering 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.