Granted Patent
Utility
US 5,230,721 · App. 07/760,801
Apparatus for supplying ultrahigh purity gas
Inventor:
Tadahiyo Ohmi
Patented Case
View Patent ↗
Granted: Jul 27, 1993
Filed: Sep 9, 1991
Inventor
Tadahiyo Ohmi
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.