Granted Patent
Utility
US 4,303,434 · App. 06/215,478
Method and apparatus for preheating pulverous materials prior to their introduction into a melting furnace
Inventors:
Robert R. Rough, Sr., Duane C. Nugent
Patented Case
View Patent ↗
Granted: Dec 1, 1981
Filed: Dec 11, 1980
Inventors
Robert R. Rough, Sr.
Duane C. Nugent
Assignee (at issue)
Owens-Illinois 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.