Granted Patent
Utility
US 5,931,190 · App. 09/106,271
Relief valve
Inventor:
Carl A. Engstrom
Patented Case
View Patent ↗
Granted: Aug 3, 1999
Filed: Jun 29, 1998
Inventor
Carl A. Engstrom
Assignee (at issue)
Watts Investment 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.