Granted Patent
Utility
US 5,013,218 · App. 07/256,691
Submersible pneumatic pump for water table
Inventor:
Larry K. Spencer
Patented Case
View Patent ↗
Granted: May 7, 1991
Filed: Oct 11, 1988
Inventor
Larry K. Spencer
Assignee (at issue)
SIGMA ENTERPRISES, 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.