Granted Patent
Utility
US 4,854,819 · App. 07/131,128
Method and apparatus for pumping fibre suspensions
Inventor:
Johan Gullichsen
Patented Case
View Patent ↗
Granted: Aug 8, 1989
Filed: Dec 10, 1987
Inventor
Johan Gullichsen
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.