Granted Patent
Utility
US 4,942,351 · App. 07/329,437
System for monitoring a level of material, device therefor and methods of making the same
Inventor:
Paul D. Kronau
Patented Case
View Patent ↗
Granted: Jul 17, 1990
Filed: Mar 28, 1989
Inventor
Paul D. Kronau
Assignee (at issue)
ROBERTSHAW CONTROLS PRIVATE LIMITED
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.