Granted Patent
Utility
US 4,947,548 · App. 07/375,637
Method of making a heat exchanger for condensing furnace
Inventor:
Richard M. Bentley
Patented Case
View Patent ↗
Granted: Aug 14, 1990
Filed: Jul 3, 1989
Inventor
Richard M. Bentley
Assignee (at issue)
CARRIER CORPORATION
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.