Granted Patent
Utility
US 4,478,424 · App. 06/574,359
Ferrofluid seal apparatus and method
Inventor:
Kuldip Raj
Patented Case
View Patent ↗
Granted: Oct 23, 1984
Filed: Jan 27, 1984
Inventor
Kuldip Raj
Assignee (at issue)
Ferrofluidics 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.