Granted Patent
Utility
US 4,955,359 · App. 07/391,101
Furnace with counterflow heat exchange means
Inventors:
Eugene C. Briggs, Myron T. Cooperrider
Patented Case
View Patent ↗
Granted: Sep 11, 1990
Filed: Aug 8, 1989
Inventors
Eugene C. Briggs
Myron T. Cooperrider
Assignee (at issue)
Robert Sun Company
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.