Granted Patent
Utility
US 4,976,004 · App. 07/255,592
Apparatus and method for cleaning hot water heater tanks
Inventor:
Barbara A. Bufford-Thacker
Patented Case
View Patent ↗
Granted: Dec 11, 1990
Filed: Oct 11, 1988
Inventor
Barbara A. Bufford-Thacker
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.