Granted Patent
Utility
US 4,891,169 · App. 07/271,693
Transition duct for centrifugal fan
Inventors:
Vladimir Kaplan, Richard H. Harrison, Jr.
Patented Case
View Patent ↗
Granted: Jan 2, 1990
Filed: Nov 16, 1988
Inventors
Vladimir Kaplan
Richard H. Harrison, Jr.
Assignee (at issue)
AMSTED INDUSTRIES INCORPORATED
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.