Granted Patent
Utility
US 4,306,991 · App. 06/173,935
Scale inhibition
Inventors:
Chih M. Hwa, Dionisio G. Cuisia
Patented Case
View Patent ↗
Granted: Dec 22, 1981
Filed: Jul 31, 1980
Inventors
Chih M. Hwa
Dionisio G. Cuisia
Assignee (at issue)
Chemed 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.