Granted Patent
Utility
US 4,502,626 · App. 06/448,033
Combustion product condensing water heater
Inventors:
Joseph Gerstmann, Andrew D. Vasilakis
Patented Case
View Patent ↗
Granted: Mar 5, 1985
Filed: Dec 8, 1982
Inventors
Joseph Gerstmann
Andrew D. Vasilakis
Assignee (at issue)
Gas Research Institute
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.