Granted Patent
Utility
US 4,957,890 · App. 07/265,241
Surface treated permeable inorganic membranes and method of making same
Inventors:
Larry F. Wieserman, Karl Wefers, Kathryn Cross, Edward S. Martin, H. Philip Hsieh, William H. Quayle
Patented Case
View Patent ↗
Granted: Sep 18, 1990
Filed: Oct 31, 1988
Inventors
Larry F. Wieserman
Karl Wefers
Kathryn Cross
Edward S. Martin
H. Philip Hsieh
William H. Quayle
Assignee (at issue)
Aluminum Company of America
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.