Granted Patent
Utility
US 4,638,491 · App. 06/263,440
Method for protecting the heating electrodes of glass melting furnaces
Inventor:
Richard Perkins
Patented Case
View Patent ↗
Granted: Jan 20, 1987
Filed: May 14, 1981
Inventor
Richard Perkins
Assignee (at issue)
Owens-Corning Fiberglas Corp.
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.