Granted Patent
Utility
US 5,590,715 · App. 08/527,114
Underground heat exchange system
Inventor:
Thomas R. Amerman
Patented Case
View Patent ↗
Granted: Jan 7, 1997
Filed: Sep 12, 1995
Inventor
Thomas R. Amerman
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.