Granted Patent
Utility
US 6,209,637 · App. 09/312,737
Plunger lift with multipart piston and method of using the same
Inventor:
Edward Alexander Wells
Patented Case
View Patent ↗
Granted: Apr 3, 2001
Filed: May 14, 1999
Inventor
Edward Alexander Wells
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.