Granted Patent
Utility
US 5,263,683 · App. 07/878,734
Sliding sleeve valve
Inventor:
Fred Wong
Patented Case
View Patent ↗
Granted: Nov 23, 1993
Filed: May 5, 1992
Inventor
Fred Wong
Assignee (at issue)
Grace Energy Corporation
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.