Granted Patent
Utility
US 4,680,446 · App. 06/782,460
Supplemental electric water heater unit for compensating cooling of a hot water supply line
Inventor:
Steven W. Post
Patented Case
View Patent ↗
Granted: Jul 14, 1987
Filed: Oct 1, 1985
Inventor
Steven W. Post
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.