Granted Patent
Utility
US 5,240,609 · App. 07/786,110
Sludge filtering device and grid system
Inventor:
Tony L. Langley
Patented Case
View Patent ↗
Granted: Aug 31, 1993
Filed: Nov 4, 1991
Inventor
Tony L. Langley
Assignee (at issue)
Enviroquip 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.