Granted Patent
Utility
US 4,430,239 · App. 06/464,480
Ferrofluid composition and method of making and using same
Inventor:
John E. Wyman
Patented Case
View Patent ↗
Granted: Feb 7, 1984
Filed: Feb 7, 1983
Inventor
John E. Wyman
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.