Granted Patent
Utility
US 4,276,182 · App. 06/042,898
High temperature cement mud spacer
Inventor:
Robert M. Beirute
Patented Case
View Patent ↗
Granted: Jun 30, 1981
Filed: May 29, 1979
Inventor
Robert M. Beirute
Assignee (at issue)
Western Company of North America
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.