Granted Patent
Utility
US 6,616,832 · App. 10/019,857
Multi-layer recirculating filter wastewater treatment apparatus
Inventor:
Kevin R. Chaffee
Patented Case
View Patent ↗
Granted: Sep 9, 2003
Filed: Nov 9, 2001
Inventor
Kevin R. Chaffee
Assignee (at issue)
Earthtek Environmental Systems, 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.