Granted Patent
Utility
US 5,012,840 · App. 07/521,058
Fluid flow indicator system
Inventor:
Mark H. Betzler
Patented Case
View Patent ↗
Granted: May 7, 1991
Filed: May 2, 1990
Inventor
Mark H. Betzler
Assignee (at issue)
Dresser Industries, 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.