Granted Patent
Utility
US 5,312,657 · App. 07/395,618
Phosphate cement pipe cladding
Inventors:
Jeffery L. Barrall, Debra L. Morris, Carrielee Fidler
Patented Case
View Patent ↗
Granted: May 17, 1994
Filed: Aug 18, 1989
Inventors
Jeffery L. Barrall
Debra L. Morris
Carrielee Fidler
Assignee (at issue)
ARMSTRONG WORLD INDUSTRIES, 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.