Granted Patent
Utility
US 5,267,897 · App. 07/835,667
Method and apparatus for ventilation measurement via carbon dioxide concentration balance
Inventor:
Kirk A. Drees
Patented Case
View Patent ↗
Granted: Dec 7, 1993
Filed: Feb 14, 1992
Inventor
Kirk A. Drees
Assignee (at issue)
Johnson Service Company
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.