Granted Patent
Utility
US 4,535,838 · App. 06/549,093
Heat exchange coil and method of making
Inventors:
David A. Gray, Donald O. Webb
Patented Case
View Patent ↗
Granted: Aug 20, 1985
Filed: Nov 7, 1983
Inventors
David A. Gray
Donald O. Webb
Assignee (at issue)
American Standard 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.