Granted Patent
Utility
US 4,909,227 · App. 07/331,839
Direct top venting high efficiency fireplace
Inventor:
Heinz H. Rieger
Patented Case
View Patent ↗
Granted: Mar 20, 1990
Filed: Apr 3, 1989
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.