Granted Patent
Utility
US 4,428,223 · App. 06/366,270
Apparatus for periodically testing the operation of safety valves
Inventor:
Ottavio Trevisan
Patented Case
View Patent ↗
Granted: Jan 31, 1984
Filed: Apr 7, 1982
Inventor
Ottavio Trevisan
Assignee (at issue)
FURMANITE INTERNATIONAL LIMITED
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.