Granted Patent
Utility
US 4,363,218 · App. 06/252,799
Heat pump using solar and outdoor air heat sources
Inventor:
Otto J. Nussbaum
Patented Case
View Patent ↗
Granted: Dec 14, 1982
Filed: Apr 10, 1981
Inventor
Otto J. Nussbaum
Assignee (at issue)
Halstead Industries, Inc.
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.