Granted Patent
Utility
US 6,394,135 · App. 09/314,257
Balanced plug valve with contour wall
Inventors:
Irving C. Erickson, Gary B. Burwell, Bonnie Dickinson, John Du
Patented Case
View Patent ↗
Granted: May 28, 2002
Filed: May 18, 1999
Inventors
Irving C. Erickson
Gary B. Burwell
Bonnie Dickinson
John Du
Assignee (at issue)
Barber-Coleman Company
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.