Granted Patent
Utility
US 4,862,993 · App. 07/252,983
Fireplace flue ambient noise reducing device
Inventor:
Heinz H. Rieger
Patented Case
View Patent ↗
Granted: Sep 5, 1989
Filed: Oct 4, 1988
Inventor
Heinz H. Rieger
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.