Granted Patent
Utility
US 4,340,233 · App. 06/208,438
Ferrofluid seal apparatus
Inventors:
Akira Yamamura, Kuldip Raj
Patented Case
View Patent ↗
Granted: Jul 20, 1982
Filed: Nov 19, 1980
Inventors
Akira Yamamura
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.