Granted Patent
Utility
US 4,607,697 · App. 06/762,779
Propping agent based on zirconia and silica for deep geological fractures
Inventor:
Daniel Urffer
Patented Case
View Patent ↗
Granted: Aug 26, 1986
Filed: Aug 6, 1985
Inventor
Daniel Urffer
Assignee (at issue)
SOCIETE EUROPEENNE DES PRODUITS REFRACTAIRES
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.