Granted Patent
Utility
US 5,873,135 · App. 08/028,286
Air pressure driven vacuum sewer system
Inventor:
Hans TÖRNQVIST
Patented Case
View Patent ↗
Granted: Feb 23, 1999
Filed: Feb 24, 1998
Inventor
Hans TÖRNQVIST
Assignee (at issue)
Evac AB
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.