Granted Patent
Utility
US 4,982,578 · App. 07/455,965
Refrigerant purge valve
Inventors:
Joseph H. Heffner, G. Thomas Seener
Patented Case
View Patent ↗
Granted: Jan 8, 1991
Filed: Dec 22, 1989
Inventors
Joseph H. Heffner
G. Thomas Seener
Assignee (at issue)
Sporlan Valve 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.