Granted Patent
Utility
US 4,776,391 · App. 07/033,623
Heat exchanger method and apparatus
Inventor:
Donald F. Warner
Patented Case
View Patent ↗
Granted: Oct 11, 1988
Filed: Apr 3, 1987
Inventor
Donald F. Warner
Assignee (at issue)
Heat Exchanger Industries, Inc.
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.