Granted Patent
Utility
US 4,834,547 · App. 07/062,964
Apparatus for mixing chemicals in fibre suspensions
Inventor:
Toivo Niskanen
Patented Case
View Patent ↗
Granted: May 30, 1989
Filed: Mar 10, 1987
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.