Granted Patent
Utility
US 5,884,708 · App. 08/076,603
Normally closed retainer valve with fail-safe pump through capability
Inventors:
Virgilio Garcia-Soule, Darrin N. Towers, Kenneth L. Schwendemann
Patented Case
View Patent ↗
Granted: Mar 23, 1999
Filed: May 11, 1998
Inventors
Virgilio Garcia-Soule
Darrin N. Towers
Kenneth L. Schwendemann
Assignee (at issue)
Halliburton Energy Services, 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.