Granted Patent
Utility
US 6,481,221 · App. 09/802,178
Apparatus and methods for placing an additive fluid into a refrigerant circuit
Inventors:
James E. Ferris, William J. Quest
Patented Case
View Patent ↗
Granted: Nov 19, 2002
Filed: Mar 8, 2001
Inventors
James E. Ferris
William J. Quest
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.