Granted Patent
Utility
US 5,033,504 · App. 07/469,359
Automatic relief valve
Inventor:
Dieter H. F. Kallenbach
Patented Case
View Patent ↗
Granted: Jul 23, 1991
Filed: Jan 24, 1990
Inventor
Dieter H. F. Kallenbach
Assignee (at issue)
BPH Patent Holding AG
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.