Granted Patent
Utility
US 4,602,685 · App. 06/683,787
Non-retarding fluid loss additives for well cementing compositions
Inventors:
Lee F. McKenzie, Paul McElfresh, Dyke W. Reese
Patented Case
View Patent ↗
Granted: Jul 29, 1986
Filed: Dec 19, 1984
Inventors
Lee F. McKenzie
Paul McElfresh
Dyke W. Reese
Assignee (at issue)
Hughes Tool Company LLC
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.