Granted Patent
Utility
US 4,708,092 · App. 06/915,065
Circulating fluidized bed boiler
Inventor:
Folke Engstrom
Patented Case
View Patent ↗
Granted: Nov 24, 1987
Filed: Sep 22, 1986
Inventor
Folke Engstrom
Assignee (at issue)
A. Ahlstrom Corporation
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.