Granted Patent
Utility
US 5,944,981 · App. 08/958,825
Pyrolysis furnace tubes
Inventor:
James Sievert
Patented Case
View Patent ↗
Granted: Aug 31, 1999
Filed: Oct 28, 1997
Inventor
James Sievert
Assignee (at issue)
The M.W. Kellogg Company
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.