Granted Patent
Utility
US 5,755,554 · App. 08/769,453
Multistage pumps and compressors
Inventor:
Michael Leslie Ryall
Patented Case
View Patent ↗
Granted: May 26, 1998
Filed: Dec 18, 1996
Inventor
Michael Leslie Ryall
Assignee (at issue)
Weir Pumps Limited
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.