Granted Patent
Utility
US 4,938,155 · App. 07/345,189
Fluidized bed combustion apparatus for generating environmentally-innocent ash
Inventor:
Robert M. Williams
Patented Case
View Patent ↗
Granted: Jul 3, 1990
Filed: May 1, 1989
Inventor
Robert M. Williams
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.