Granted Patent
Utility
US 4,798,850 · App. 07/043,205
Blended-fibre filter material
Inventor:
Richard C. Brown
Patented Case
View Patent ↗
Granted: Jan 17, 1989
Filed: Apr 27, 1987
Inventor
Richard C. Brown
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT CORPORATION
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.