Granted Patent
Utility
US 4,870,989 · App. 07/268,191
High temperature safety relief system
Inventors:
Cleo M. Bickford, Walter W. Powell, Larry A. Sample
Patented Case
View Patent ↗
Granted: Oct 3, 1989
Filed: Nov 7, 1988
Inventors
Cleo M. Bickford
Walter W. Powell
Larry A. Sample
Assignee (at issue)
Keystone International
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.