Granted Patent
Utility
US 4,921,400 · App. 07/216,009
Pump and a method of separating gas by such from a fluid to be pumped
Inventor:
Toivo Niskanen
Patented Case
View Patent ↗
Granted: May 1, 1990
Filed: Jul 6, 1988
Inventor
Toivo Niskanen
Assignee (at issue)
A. Ahlstrom Corporation
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.