Granted Patent
Utility
US 4,473,091 · App. 06/441,932
Fluid flow control valves
Inventor:
Derek Stoves
Patented Case
View Patent ↗
Granted: Sep 25, 1984
Filed: Nov 15, 1982
Inventor
Derek Stoves
Assignee (at issue)
British Gas
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.