Granted Patent
Utility
US 6,422,273 · App. 09/986,730
Evacuation system filter
Inventor:
Michael Clark Campbell
Patented Case
View Patent ↗
Granted: Jul 23, 2002
Filed: Nov 9, 2001
Inventor
Michael Clark Campbell
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.