Granted Patent
Utility
US 5,118,419 · App. 07/698,900
Slotted scallop-shaped underdrain screened lateral elements
Inventors:
Thomas W. Evans, Robert G. Norell, Stephen A. Uban, Richard C. Maxson
Patented Case
View Patent ↗
Granted: Jun 2, 1992
Filed: May 13, 1991
Inventors
Thomas W. Evans
Robert G. Norell
Stephen A. Uban
Richard C. Maxson
Assignee (at issue)
Johnson Filtration Systems
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.