Granted Patent
Utility
US 5,203,693 · App. 07/769,963
Rotary drum dryer having internal flights
Inventor:
Malcolm L. Swanson
Patented Case
View Patent ↗
Granted: Apr 20, 1993
Filed: Oct 1, 1991
Inventor
Malcolm L. Swanson
Assignee (at issue)
Astec Industries, Inc.
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.