Granted Patent
Utility
US 4,593,716 · App. 06/182,125
Control valve assembly for abrasive slurry
Inventor:
Joseph V. Cesna
Patented Case
View Patent ↗
Granted: Jun 10, 1986
Filed: Aug 28, 1980
Inventor
Joseph V. Cesna
Assignee (at issue)
SPEEDFAM CO., LTD.
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.