Granted Patent
Utility
US 6,371,525 · App. 09/402,012
Gas riser with free rotating plastic riser casing
Inventors:
Steven Passerell, Dave Robison
Patented Case
View Patent ↗
Granted: Apr 16, 2002
Filed: Sep 28, 1999
Inventors
Steven Passerell
Dave Robison
Assignee (at issue)
Perfection Holdings LLC
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.