Granted Patent
Utility
US 5,630,691 · App. 08/514,950
Rotary airlock valve
Inventor:
Richard E. Newbolt
Patented Case
View Patent ↗
Granted: May 20, 1997
Filed: Aug 14, 1995
Inventor
Richard E. Newbolt
Assignee (at issue)
MAC Equipment, Inc.
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.