Granted Patent
Utility
US 6,805,480 · App. 10/069,218
Cylinder for a twin-screw extruder with a helical channel of varying depth
Inventor:
Michael Behling
Patented Case
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Granted: Oct 19, 2004
Filed: Jun 6, 2002
Inventor
Michael Behling
Assignee (at issue)
Berstorff GmbH
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.