Granted Patent
Utility
US 4,331,484 · App. 06/207,725
Energy saving dishwashing method with heater control
Inventor:
William F. Helwig, Jr.
Patented Case
View Patent ↗
Granted: May 25, 1982
Filed: Nov 17, 1980
Inventor
William F. Helwig, Jr.
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.