Granted Patent
Utility
US 5,297,389 · App. 07/926,349
Method and apparatus for maintaining a required temperature differential in vacuum deaerators
Inventors:
Roderick E. Athey, Elliot Spencer, Lance L. Frens
Patented Case
View Patent ↗
Granted: Mar 29, 1994
Filed: Aug 6, 1992
Inventors
Roderick E. Athey
Elliot Spencer
Lance L. Frens
Assignee (at issue)
Graham Holdings 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.