Granted Patent
Utility
US 6,569,328 · App. 09/705,458
Underdrain filtration system with stamped perforations
Inventor:
Gary D. Haggard
Patented Case
View Patent ↗
Granted: May 27, 2003
Filed: Nov 2, 2000
Inventor
Gary D. Haggard
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.