Granted Patent
Utility
US 4,420,641 · App. 06/457,335
Formaldehyde production
Inventors:
H. Robert Gerberich, Eldred T. Smith
Patented Case
View Patent ↗
Granted: Dec 13, 1983
Filed: Jan 12, 1983
Inventors
H. Robert Gerberich
Eldred T. Smith
Assignee (at issue)
Celanese GmbH
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.