Granted Patent
Utility
US 4,427,374 · App. 06/294,202
Recirculation device
Inventor:
John W. Miller
Patented Case
View Patent ↗
Granted: Jan 24, 1984
Filed: Aug 19, 1981
Inventor
John W. Miller
Assignee (at issue)
Phelps Dodge 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.