Granted Patent
Utility
US 5,575,330 · App. 08/491,685
Furnace heat exchanger seal and method of making same
Inventor:
Russell W. Hoeffken
Patented Case
View Patent ↗
Granted: Nov 19, 1996
Filed: Jun 19, 1995
Inventor
Russell W. Hoeffken
Assignee (at issue)
Alco Industries
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.