Granted Patent
Utility
US 5,131,817 · App. 07/497,326
Two-stage pumping system
Inventor:
Michael Joseph Pastore
Patented Case
View Patent ↗
Granted: Jul 21, 1992
Filed: Mar 22, 1990
Inventor
Michael Joseph Pastore
Assignee (at issue)
The Nash Engineering 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.