Granted Patent
Utility
US 4,925,631 · App. 07/249,414
Method of casting a hopcalite filter and cast ceramic fiber-hopcalite
Inventors:
Van Ness Harwood, Jr., Joseph F. Wojtasik
Patented Case
View Patent ↗
Granted: May 15, 1990
Filed: Sep 26, 1988
Inventors
Van Ness Harwood, Jr.
Joseph F. Wojtasik
Assignee (at issue)
Figgie Inernational Inc.
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.