Granted Patent
Utility
US 4,990,249 · App. 07/486,371
Apparatus for the desludging of baths
Inventor:
Andreas Leuenberger
Patented Case
View Patent ↗
Granted: Feb 5, 1991
Filed: Feb 27, 1990
Inventor
Andreas Leuenberger
Assignee (at issue)
Ciba-Geigy
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.