Granted Patent
Utility
US 5,710,373 · App. 08/800,597
Visual comparator with test chart and method for evaluating contamination of washing fluids
Inventor:
Frank A. Osmanski
Patented Case
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Granted: Jan 20, 1998
Filed: Feb 18, 1997
Inventor
Frank A. Osmanski
Assignee (at issue)
SAFETY KLEEN 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.