Granted Patent
Utility
US 4,498,220 · App. 06/410,724
Method for pre-expanding heat exchanger tube
Inventors:
Donald S. Fiegen, Chester D. Ware
Patented Case
View Patent ↗
Granted: Feb 12, 1985
Filed: Aug 23, 1982
Inventors
Donald S. Fiegen
Chester D. Ware
Assignee (at issue)
The Trane Company
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.