Granted Patent
Utility
US 4,318,692 · App. 06/222,034
Helical duct gas/meal separator
Inventor:
Paul Hess
Patented Case
View Patent ↗
Granted: Mar 9, 1982
Filed: Jan 2, 1981
Inventor
Paul Hess
Assignee (at issue)
Allis-Chalmers 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.