Granted Patent
Utility
US 4,900,441 · App. 07/306,619
Small filter and method of its manufacture
Inventors:
Andreas Graus, Michael Schutzler
Patented Case
View Patent ↗
Granted: Feb 13, 1990
Filed: Feb 6, 1989
Inventors
Andreas Graus
Michael Schutzler
Assignee (at issue)
Sartorius AG
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.