Granted Patent
Utility
US 4,252,182 · App. 06/022,256
Tube sheet shield
Inventor:
David A. Fender
Patented Case
View Patent ↗
Granted: Feb 24, 1981
Filed: Mar 20, 1979
Inventor
David A. Fender
Assignee (at issue)
Ecolaire Incorporated
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.